ASPHALT COMPOSITIONS COMPRISING DIGESTATE

FIELD OF THE INVENTION

The present disclosure provides an asphalt composition comprising digestate. The digestate may be obtained from waste treatment processes wherein waste is subjected to enzymatic and/or microbial treatment followed by anaerobic digestion of the bioliquid fraction obtained from the treatment process. The digestate may also be obtained from anaerobic digestion of other biomasses than bioliquid, e.g., sewage sludge and food waste.

BACKGROUND OF THE INVENTION

Anaerobic digestion (AD) is a series of biological processes in which microorganisms break down biodegradable material in the absence of oxygen. One of the end products is biogas, which can be combusted to generate electricity and heat, or can be processed into renewable natural gas and transportation fuels. A range of AD technologies exists in the state of the art for converting waste or fractions hereof, such as municipal solid waste, municipal wastewater solids, food waste, high strength industrial wastewater and residuals, fats, oils and grease, and various other organic waste streams into biogas. Apart from the production of primary outputs, such as gas and fuel, AD processes also produce digestate. Digestate is thus a by-product of an anaerobic digestion process and can be used for different purposes such as fertilizer or feed for pyrolysis, but otherwise needs to be deposed of in a safely manner. The composition of the digestate depend to some extend of the substrate subjected to anaerobic digestion but composes mainly of ash, carbohydrates, and protein. When measuring organic material content of compositions such as digestate it is typically done by measuring loss of ignition (LOI). The LOI value is a measure of the amount of organic material lost at a given high temperature. Thus, the LOI value is considered to correlate to the amount of organic material lost at a given high temperature, Santisteban et al., Journal of Paleolimnology, 32(3), 2014. The organic material as measured by LOI in digestate obtained from AD e.g., of waste compositions comprising organic matter, typically comprises biodegradable and non-biodegradable compounds such as plastics and lignin, that is because LOI measure volatile solids and not all the measured volatile solids are biodegradable and origins from living material. However, most of the volatile solids measured by LOI are organic and biodegradable and therefore LOI correlates well with the amount of organic material in a composition. The typical LOI value of digestate is between 20-80% but may be lower or higher depending on the biomass subjected to AD process.

As mentioned, digestate may be obtained from anaerobic digestion of different substrates and the digestate by-product will to some extend reflect the substrate digested and thus digestate from waste will comprise components of waste. Digestate are sometimes landfilled and used as fertilizer. However, digestate from waste may preferably be sent for land restoration. Nevertheless, digestate is currently not recycled and the potential resources of the by-product rarely exploited in full. It has been shown that the digestate may be incorporated in construction materials WO19158477A1 (Renescience A/S) as well as in asphalt compositions W020002153A1 (Renescience A/S). However, none of these applications disclose an asphalt composition comprising digestate wherein the digestate has a high to moderate amount of organic material content, such as at least 15%, at least 20%, at least 30 % or at least 40% organic material defined as LO c.

Reusing asphalt is both economically and environment friendly way of making new asphalt roads. Thus, incorporating digestate in asphalt compositions comprising Reused Asphalt Pavement (RAP) would be beneficial. Another environmentally friendly way of making asphalt is the so-called foam technique or cold mix, where the asphalt is made by mixing the components at low temperature and therefore saving the energy for heating the materials. It would also be beneficial to incorporate digestate in asphalt compositions, which are made by cold or foam mixing techniques.

Incorporating digestate in asphalt can be done to replace aggregates such as igneous rocks, basalt, dolerite, granite or andesite, sedimentary rock, for example limestone, dolomite, or sandstone. Dolomite is limestone transformed by exchange of calcium ions with magnesium ions due to its presence in waters. Or metamorphic rock as for example meta-quartzite (page 222, in Bitumen Handbook). The materials can be either mined from quarries, sea bottoms or retrieved from bag house fines from the dust collection devises at asphalt mixing. Reclaimed building materials such as crushed cement, bricks or reused asphalt pavement (RAP) are also used as aggregates. Industrial by-products such as steel slag and blast furnace slag is also used as well as other recycled materials such as crushed glass, railway slags, foundry sand, rail ballast, construction and demolition waste, bottom ash from municipal incinerators. Further, incorporation of digestate in asphalt can be done to replace filler materials such as cement, limestone, mixed filler with high calcium hydroxide content or hydrated lime can also be used for improved binding properties of the mastic. In general, aggregates with high carbonate content such as limestone are easier to coat with binder than aggregates with a high silica content. Further, some components of digestate might interact with the binder (bitumen) in asphalt compositions and might give benefits enabling lowering the binder concentration, thus replacing both aggregates and indirectly binder.

Thus, incorporation digestate in asphalt compositions is generally beneficial for recycling of a (waste) by-product, reducing the carbon dioxide footprint in the asphalt pavement production but may also serve the purposes such as, improving the quality of the asphalt composition as a beneficial filler or binder replacement.

It is commonly accepted within the asphalt industry that materials with a high organic content cannot be used as an aggregate, as for example described in the industry standard EN 13043:2003, page 25. However, we show in the present application that digestate may be incorporated in asphalt composition, without compromising the asphalt composition despite the high amount of organic material in digestate, compared to e.g., filler material. Moreover, we show that such asphalt compositions may even have some beneficial effects compared to asphalt compositions not comprising the digestate. It is very surprising that moderate amounts of digestate can replace fine aggregates and filler material in asphalt compositions due to the relatively high organic content in the digestate without significantly influencing the strength and water stability of the final asphalt pavement. It was also surprising that the digestate may be added to asphalt compositions in higher amount than previously assumed, e.g., in W020002153A1 despite the high organic content measured as LOI and still maintaining a suitable quality of the asphalt.

SUMMARY OF THE INVENTION

The present invention relates to asphalt compositions comprising digestate with moderate to high organic material, which in the present context corresponds to at least 15%, such as at least 20%, such as at least 30%, such as at least 40% LOIgso-c on dry matter basis according to EN 1744- 1 :2009. The amount of organic material is high compared to the asphalt components which it replaces i.e. , the fine aggregates, filler and/or aggregates.

Thus, one aspect of the invention relates to an asphalt composition comprising, a) 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, b) 5-10 wt% bitumen with respect to total weight of composition, and c) 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

One aspect relates to an asphalt according to the invention composition, comprising 1.5-20 wt%, 2- 20 wt% digestate, such as 5-20 wt%, 10-20 wt%, 15-20 wt%, 5-15 wt%, 5-10 wt%, preferably 1- 8 wt%, 1.5-8 wt%, 2-8 wt%, preferably 1.5 wt% -8 wt%, 3-8 wt%, or 4-8 wt% by weight of the total composition. One aspect relates to an asphalt according to the invention comprising 1.5 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 % or such as at least 60 %.

One aspect relates to an asphalt according to the invention, comprising 10-90 wt % aggregates, such as 10-80 wt %, such as 10-70 wt %, such as 10-60 wt %, such as 10-50 wt %, such as 10-40 wt %, such as 10-30 wt %, such as 10-20 wt %, such as 20-70 wt %, such as 30-70 wt %, such as 40-70 wt %, such as 50-70 wt %, such as 60-70 wt %, with respect to total weight of composition.

One aspect relates to an asphalt according to the invention, comprising 5-20 wt %, such as 5-15 wt %, such as 5-10 wt %, such as 1-15 wt %, such as 1-10 wt %, such as 1-5 wt % filler or fine aggregates defined by size below 2 mm, with respect to total weight of aggregates.

One aspect relates to an asphalt according to the invention, comprising 1-10 wt% bitumen, such as at least 2-10 wt%, such as at least 3-10 wt%, such as at least 4-10 wt%, such as at least 5-10 wt%, such as at least 6-10 wt%, such as at least 7-10 wt%, such as at least 8-10 wt%, such as at least 2- 8 wt%, such as at least 3 - 7wt% such as at least 4-6 wt% bitumen, preferably 5-10 wt% bitumen with respect to total weight of composition.

One aspect relates to an asphalt according to the invention, wherein the filler particles comprise digestate with a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15% in a ratio of 2:1 to 1 :2 of filler.

One aspect relates to an asphalt according to the invention, wherein the filler particles comprise digestate with a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15% in a ratio of 1 :1 of limestone filler or of reclaimed filler.

One aspect relates to an asphalt according to the invention, wherein the fine aggregate particles comprise digestate with a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15% in a ratio of from 0.5:1 to 1 :1 of fine aggregate particles.

One aspect relates to an asphalt according to the invention, wherein the asphalt is applied as a base course, a binder course or as a surface course.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 : diagram showing the shear stress modules (G*) [Pa] against the angular frequency [rad/sec] of master curves for fresh and aged samples of 70/100 bitumen asphalt composition. Figure 2: diagram showing the shear stress modules (G*) [Pa] against the angular frequency [rad/sec] of master curves for fresh and aged samples of 40/60 bitumen asphalt composition.

Figure 3: diagram showing the phase shift angle (p) [°] against the angular frequency [rad/sec] of master curves for fresh and aged samples of 70/100 bitumen asphalt composition.

Figure 4: diagram showing the phase shift angle (p) [°] against the angular frequency [rad/sec] of master curves for fresh and aged samples of 40/60 bitumen asphalt composition.

Figure 5: Optimisation plot for combination of reclaimed filler and dried digestate as filler in asphalt from Minitab regression of ITSR [%] and rutting [%] results from Example 3

DEFINITIONS

LOI means loss on ignition, and measure the amount of volatile solids, at a defined temperature, e.g. 550°C for waste (PAS 110:2014), sludge and sediments (EN 15935:2021) or at 950°C for aggregates (EN 1744-1 :2009). Volatile solids are primarily organic materials, which are prone to oxidation and therefore less stable. In digestate the volatile solids comprises both biodegradable and non-biodegradable volatile solids. Non-biodegradable volatile solids include plastic and derivates here from, as well as lignin, both of which are not prone to e.g., oxidation. Thus, when “organics” or amount or organic material is measured by LOI, this measurement includes synthetic matter made by chemical reactions that do not involve life, e.g., carbonates depending on temperature used, plastic etc. that are usually not biodegradable. Even so LOI correlates well with the amount of organic matter in a composition as most of the volatile solids measured by LOI are organic.

Construction aggregate is granular material used in construction and is simply referred to as “aggregates” in the context of the present invention. Aggregates may be natural, manufactured or recycled. Natural aggregate is from mineral sources which has been subjected to nothing more than mechanical processing. Manufactured aggregate is of mineral origin and results from an industrial process involving thermal or other modification. Recycled aggregate results from processing of inorganic material previously used in construction. Aggregate size is designated in terms of lower (d) and upper (D) sieve sizes expressed as d/D. This designation accepts the presence of some particles which are retained on the upper sieve (oversize) and some which pass the lower sieve (undersize). The lower sieve side (d) can be zero. Larger aggregate sizes with D less than or equal to 45 mm and d greater than or equal to 2 mm is designated coarse aggregate (EN 13043:2002). Aggregate sizes with D less than or equal to 2 mm and containing particles which mostly are retained on a 0.063 mm sieve are designated fine aggregate. Filler aggregate is the aggregate, most of which passes a 0.063 mm sieve, which can be added to construction materials to provide certain properties.

Ash content is the inorganic residue after dry oxidation for LOI determination at a defined temperature, typically 550°C, 575°C or 950°C. In the context of the present invention the ash content is the inorganic residue after dry oxidation at 550°C.

For the purpose of the present invention, asphalt composition, asphalt concrete, asphalt mixture composition, asphalt mixture, asphalt mix, asphalt pavement or simply asphalt means a composition comprising at least one aggregate, at least one filler, optionally at least one additive and at least one binder, such as bitumen and/or other, in varying amounts and relative percentages. The term ‘asphalt’ is herein also used to describe the wide range of mixtures of, at least, bituminous binder and aggregate individually known as Warm mix asphalt (WMA), Hot Rolled Asphalt (HRA), Stone Mastic Asphalt (SMA), Porous asphalt (PA) or Reused asphalt pavement (RAP), Foamed asphalt or cold mixed asphalt, thin Surfacing, Mastic Asphalt, Asphalt Concrete etc., which are available for use in constructing and maintaining paved areas. Asphalt pavements are frequently described as flexible pavements, implying their ability to absorb the stresses imposed by traffic and weather, without cracking. An asphalt mixture composition according to the present invention is suitable for building roads, pavements and paved areas, roofing, vehicle parking areas, housedrives, footways, recreation areas such as tennis courts or playgrounds, agricultural uses such as farm roads or animal cubicles, airfields, runways and access roads, hard standings, storage areas, hydraulic applications such as dam construction, coastal protection or other.

Anaerobic Digestion (AD) refers to the biological processes in which microorganisms such as archaea break down biodegradable material in the absence of oxygen. One of the end products may be biogas, which can e.g., be combusted to generate electricity and/or heat. Biogas can also be used, either directly or after upgrading, as renewable natural gas and/or transportation fuels. Biogas can be injected into a natural gas and/or biogas grid.

Binder when used in asphalt mixture compositions binds the aggregate particles into a cohesive mixture, whilst also lubricating the particles when hot to assist in compaction. According to the type of mixture and its end use, the amount of binder used will typically vary between 3 and 11 percent by mass of the mixture. Bituminous binders are characterised by being the residue from distilling raw oil and are black, sticky and thermoplastic, i.e. , they become softer and more fluid when they are heated and harden again when they cool. Bituminous binders are categorised after their penetration at 25°C. A Bitumen 40/60 is a bitumen with a penetration of 4-6 mm penetration at 25°C and a bitumen 70/100 is a bitumen with at penetration of 7-10 mm at 25°C measured according to EN 1426:2015.

Biodegradable matter refers to organic material that can be partly or completely degraded into simple chemical compounds such as mono-, di- and/or oligo-saccharides, amino acids and/or fatty acids by microorganisms and/or by enzymes. Biodegradable matter is generally organic material that provides a nutrient for microorganisms, such as mono-, poly- or oligosaccharides, fat and/or protein. These are so numerous and diverse that a huge range of compounds can be biodegraded, including hydrocarbons (oils), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pharmaceutical substances. Microorganisms secrete biosurfactant, an extracellular surfactant, to enhance this process.

Bioliquid is the liquefied and/or saccharified biodegradable components obtained by enzymatic treatment of waste comprising organic matter. Bioliquid also refers to the liquid fraction obtained by enzymatic treatment of waste comprising organic material once separated from non-fermentable solids. Bioliquid comprises water and organic substrates such as protein, fat, galactose, mannose, glucose, xylose, arabinose, lactate, acetate, ethanol and/or other components, depending on the composition of the waste (the components such as protein and fat can be in a soluble and/or insoluble form). Bioliquid comprises also fibres, ashes and inert impurities. The resulting bioliquid comprising a high percentage of solubles provides a substrate for gas production, a substrate suitable for anaerobic digestion e.g., for the production of biogas and digestate.

“Digestate”, sometimes called, and used interchangeably with “anaerobic digestate”, “AD digestate” or “solid digestate” is the residual output from an anaerobic digestion (AD). Usually, the digestate has alkaline pH and comprises mainly water, but also suspended solids and dissolved matter such as salts which may include both inorganic salts and organic salts. It is the material remaining after anaerobic digestion of a biodegradable feedstock such as bioliquid from an enzymatic and/or microbial treatment of waste or other substrates suitable for anaerobic digestion. The digestate may advantageously be dewatered by separation means, such as filters, sedimentation tanks or the like into "dewatered digestate" or solid digestate and "reject water".

Dry matter, also appearing as “DM” or “TS”, refers to total solids, both soluble and insoluble, and effectively means "non-water content." Dry matter content is measured by drying at approximately between 60 to 105°C until constant weight is achieved. In a preferred embodiment, dry matter content is measured by drying at approximately 105 °C. The lower temperature range may be used, when analysing substrates containing volatile compounds, which may escape when boiling the water and decrease the accuracy of the analysis result.

Filler or filler aggregate refers to a fraction of a mineral most of which passes a 63 pm sieve. The main function of a filler is that of filling voids in coarse aggregates, which intensification the density, stability and toughness of a conventional bituminous paving mix. Another is the formation of a fillerasphalt mastic in which the particles of dust either may be individually coated with asphalt/bitumen or are fused into the asphalt/ bitumen in mechanically and colloidal suspension. The term bitumen may be used, and are indeed commonly used, instead of the term asphalt, e.g., in USA. In the present context “asphalt composition” refers to a composition comprising digestate, bitumen, and aggregates. The term “bitumen” in this context thus refers to the binder of the asphalt composition. Excess amounts of fillers lead to, brittleness and tendency to cracking. Deficiency of filler leads to increased void content, lower stability and softens the mix. In a typical dense asphalt mixture, the aggregate occupies around 85% of the total volume (of which about 5% is filler), with about 10% bitumen and 5% air voids. If the filler is considered as a binder additive, the aggregate skeleton represents about 80% of the volume and threequarters of the remaining space is filled with bitumenfiller mortar (Institution of Civil Engineers, ICE Manual of Construction Materials, Section 3, edited by Airey and Collop, page 285).

Hydrolysis is meant to be related to the context wherein the waste, such as municipal solid waste material is hydrolysed to break down cellulose and/or hemicellulose and other substrates to fermentable sugars or other components, such as glucose, cellobiose, xylose, xylulose, arabinose, mannose, galactose, and/or soluble oligosaccharides (also known as saccharification). The hydrolysis is performed enzymatically by one or more enzyme compositions in one or more stages. In the hydrolysis step, the waste, such as municipal solid waste material, e.g., pre-treated, is hydrolysed to break down proteins and lipids (e.g., triglycerides) found in the waste. The hydrolysis can be carried out as a batch process or series of batch processes. The hydrolysis can be carried out as a fed batch or continuous process, or series of fed batch or continuous processes, where the waste, such as municipal solid waste material is fed gradually to, for example, a hydrolysis solution comprising an enzyme composition. The hydrolysis may be continuous hydrolysis in which a waste material, such as municipal solid waste (MSW), and an enzyme composition are added at different intervals throughout the hydrolysis and the hydrolysate is removed at different intervals throughout the hydrolysis. The removal of the hydrolysate may occur prior to, simultaneously with, or after the addition of the cellulosic material and the cellulolytic enzymes composition. Municipal solid waste (MSW) refers to waste fractions which are typically available in a city, but that need not come from any municipality per se, i.e. , MSW refers to every solid waste from any municipality but not necessarily being the typical household waste - could be waste from airports, universities, campus, canteens, general food waste, among others. MSW may be any combination of one or more of cellulosic, plant, animal, plastic, metal, or glass waste including, but not limited to, any one or more of the following: Garbage collected in normal municipal collections systems, optionally processed in a central sorting, shredding or pulping device, such as e.g., a Dewaster® or a reCulture®; solid waste sorted from households, including both organic fractions and paper rich fractions; Generally, municipal solid waste in the Western part of the world normally comprise one or more of: animal food waste, vegetable food waste, newsprints, magazines, advertisements, books and phonebooks, office paper, other clean paper, paper and carton containers, other cardboard, milk cartons and alike, juice cartons and other carton with alu-foil, kitchen tissues, other dirty paper, other dirty cardboard, soft plastic, plastic bottles, other hard plastic, non-recyclable plastic, yard waste, flowers etc., animals and excrements, diapers and tampons, cotton sticks etc., other cotton etc., wood, textiles, shoes, leather, rubber etc., office articles, empty chemical bottles, plastic products, cigarette buts, other combustibles, vacuum cleaner bags, clear glass, green glass, brown glass, other glass, aluminium containers, alu-trays, alu-foil (including tealight candle foil), metal containers (-AI), metal foil (-AI), other sorts of metal, soil, rocks, stones and gravel, ceramics, cat litter, batteries (botton cells, alkali, thermometers etc.), other non-combustibles and fines.

"Organic" refers to materials/matter that comprises carbon and are bio-degradable and include materials/matter derived from living organisms. The terms “materials” and “matter” have the same meaning in this context and can be used interchangeably. Organic material/matter can be degraded aerobically (with oxygen) or anaerobically (without oxygen). Decomposition of biodegradable substances may include both biological and abiotic steps.

Rut depth is the measure of the depth of the rut a wheel makes in the asphalt after running back and forth a set number of times and is thus the reduction in the thickness of a test specimen asphalt mixture composition, in millimetres or percentage, relative to the specimen original thickness, caused by repeated passes of a loaded wheel according to EN 12697-22:2020.

Softening point of a binder is the temperature at which a material under standardised test conditions described in EN 1427:2015 attains a specific consistency. Solid/liquid separation refers to an active mechanical process, and/or unit operation(s), whereby liquid is separated from solid by application of some force through e.g., pressing, centrifugation, sedimentation, decanting or the like. Commonly, a solid/liquid (s/l) separation provides a liquid and solid fraction.

Sorted waste (and "sorted MSW') as used herein refers to waste, such as MSW, in which approximately less than 30%, preferably less than 20% and most preferably less than 15% by weight of the dry weight is not biodegradable material.

Stiffness modulus is a parameter expressing the relationship between stress and strain when submitting a linear viscoelastic material to a sinusoidal load wave. Stiffness modulus can be determined according to EN 12697-26:2012.

Unsorted waste (and “unsorted” MSW”) refers to waste that is not substantially sorted into separate fractions such that organic material is not substantially separated from plastic and/or other inorganic material, notwithstanding removal of some large objects or metal objects and not withstanding some separation of plastic and/or other inorganic material may have taken place. The terms "unsorted waste" (or "unsorted MSW'), as used herein, refers to waste comprising a mixture of biodegradable and non-biodegradable material in which 15% by weight or greater of the dry weight is non- biodegradable material. Waste that has been briefly sorted yet still produce a waste (or MSW) fraction that is unsorted. Typically, unsorted MSW may comprise organic waste, including one or more of food and kitchen waste; paper- and/or cardboard-comprising materials; recyclable materials, including glass, bottles, cans, metals, and certain plastics; burnable materials; and inert materials, including ceramics, rocks, and debris. The recyclable material might be before or after source sorting.

Waste comprises, sorted and unsorted MSW, agriculture waste, hospital waste, industrial waste, e.g., waste fractions derived from industry such as restaurant industry, food processing industry, general industry; waste fractions from paper industry; waste fractions from recycling facilities; waste fractions from food or feed industry; waste fraction from the medicinal or pharmaceutical industry; waste fractions from hospitals and clinics, waste fractions derived from agriculture or farming related sectors; waste fractions from processing of sugar or starch rich products; contaminated or in other ways spoiled agriculture products such as grain, potatoes and beets not exploitable for food or feed purposes; or garden refuse. DETAILED DESCRIPTION OF THE INVENTION

Environmentally friendly waste processing methods using biologically based technology, wherein e.g., waste or sewage sludge comprising organic material is converted to energy have been developed, however, depending on the composition and source of the substrate, some fractions cannot be converted by enzymes and/or microorganism into energy or other valuable products and needs to be disposed. One such fraction is the solids remaining after anaerobic digestion (AD), such as the digestate by-product.

One way of disposing digestate in an environmentally beneficial way is to formulate it into asphalt, such as described in W020002153A1 (Renescience A/S), which is incorporated herein by reference. When formulating the digestate into asphalt compositions, the digestate may act as a filler or fine aggregate replacement and when mixed with bitumen the glue-like substance binds the digestate in the composition, thereby making it less exposed to the environment. However, adding digestate to asphalt compositions, is only feasible if the quality of the asphalt composition will not be compromised. This may be a concern with regards to digestate as it comprises a high amount of organic material, compared to the material it replaces, as organic material is prone to oxidation and may cause the asphalt composition to degrade during long-term usage. This is disadvantageous economically, as the asphalt need to be replaced more often, and environmentally since production of asphalt requires use of natural resources and heat, which cause emissions of CCh-equivalents in the atmosphere. The concern relating to using material having higher organic content than asphalt material normally present in asphalt compositions are even more pronounced at higher amounts of digestate present in the asphalt composition.

Deteriorating roads are a constant problem for cities and countries and therefore the asphalt composition needs to be strong and be able to withstand long term usage e.g., resistance to rutting and cracking of road surfaces, abrasion stability, suitability to weather and climatic changes.

Thus, long term stability of asphalt compositions is crucial, and the components comprised in the asphalt compositions may, no matter how beneficial they are, not compromise the asphalt e.g., by making it prone to fracture or cracking and thereby promoting aging of the asphalt. As organic material is subject to oxidation having organic material in concrete or asphalt would seem detrimental to the composition for the above-mentioned reasons. However, in this application it is shown, that incorporating digestate having at least 15% LO c on dry matter basis according to EN 1744- 1 :2009 in moderate concentrations in the asphalt had no negative impact on the asphalt and did not result in an asphalt, which were inferior to an asphalt without digestate. Asphalt compositions comprising digestate having at least 15%, such as at least 20%, such as at least 30%, such as at least 40% LOI 95o°c may even result in an asphalt which are superior to asphalt without digestate, e.g., by making the asphalt less prone to cracking and fracturing as well as making the asphalt softer and more flexible. As shown in the Examples, the effect of the adding digestate with high organic content compared to conventional asphalt material resulted in an asphalt composition which was not inferior and was in some cases even improved compared to conventional asphalt compositions not comprising digestate.

Thus, one embodiment of the present invention provides in a first aspect an asphalt composition comprising, a) 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, b) 1-10 wt% bitumen with respect to total weight of composition, and c) 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

A second aspect of the invention provides in an asphalt composition comprising, a) 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, b) 5-15 wt% bitumen with respect to total weight of composition, and c) 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

A third aspect of the invention provides in an asphalt composition comprising, a) 2-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, b) 5-15 wt% bitumen with respect to total weight of composition, and c) 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

A fourth aspect of the invention provides in an asphalt composition comprising, a) 5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, b) 5-15 wt% bitumen with respect to total weight of composition, and c) 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm. In one aspect the asphalt composition comprises 1-20 wt% digestate, such as 1.5-20 wt%, 2-20 wt%, 5-20 wt%, 10-20 wt%, 15-20 wt%, 5-15 wt%, 5-10 wt%, preferably 2-8 wt%, preferably 3-8 wt%, or 4-8 wt% by weight of the total composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of least 15%, such as least at 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 % or such as at least 60 %.

The digestate of the invention is a by-product from an AD process. Preferably, the digestate is a byproduct from an AD process performed on a substrate resulting from treatment of waste, such as bioliquid. The bioliquid is obtained when liquifying waste e.g., by use of enzymes and/ microorganisms. The liquified waste is an excellent substrate for an AD process as the sugars are more accessible for the microorganisms in the AD process, compared to e.g., a wheat substrate. The main product of the AD process is biogas, and green energy derived therefrom. There is a huge need in the world for green energy and solutions which lower the CO2 emissions. In this respect fuel, such as bioethanol and green energy such as biogas are preferred alternatives to fossil fuels and natural gas. However, during the productions of such environment friendly alternatives some byproducts are produced, hereunder digestate, which are not easily recycled and thus end up being disposed, without harvesting any potential these by-products may have.

The digestate used in the asphalt composition of the invention are preferably derived from a waste treatment process, where waste is liquified to produce bioliquid, which is subsequently subjected to an AD process producing biogas and digestate. Whatever the source, the digestate is usually dewatered to produce solid digestate, in the present application, also termed digestate, and in one aspect of the invention the digestate is dried to at least 70 % dry matter (DM), such as at least 75% dry matter, such as at least 80% dry matter, such as at least 85% dry matter, such as at least 90% dry matter, such as at least 95% dry matter. Digestate is usually dewatered by separation means such as filters, sedimentation tanks, filter presses, screw presses, decanters (with or without polymers and/out other chemicals such as flocculants) or the like into "dewatered digestate" and "reject water".

In one embodiment, the digestate is dried in an oven at 105 °C until constant mass to obtain at least 90 wt % dry matter digestate.

Usually, digestate comprises mainly water, wherein the digestate from the AD has a total solid content of about 4-8 percent and after the dewatering the digestate has a total solid content of 25- 45 percent by weight, the rest being water. The digestate comprises non-biodegradable and biodegradable organics, suspended solids and dissolved matter such as dissociated salts and has alkaline pH value. Reject water is defined as the liquid fraction obtained after one or more solid-liquid separations of the AD digestate. The standard of digestate produced by AD process can be assessed at least on three criteria, chemical, biological and physical aspects. Chemical quality needs to be considered in terms of inorganic contaminants, persistent organic compounds, and the content of macro-elements such as nitrogen, phosphorus, and potassium.

The physical standards of composts and by-products such as digestate include mainly appearance and odour factors. Whilst physical contamination does not generally present a problem with regards to human, plant or animal health, contamination (in the form of plastics, metals, and ceramics) can cause a negative public perception. There is, currently, a public debate regarding both micro and visible plastics ending in natural resources and being eaten by animals or getting entangled, which may cause health problems. Also, sharp materials (such as glass or metals) are considered an issue when used in nature (for fertiliser or land restoration applications) due to the risk of cutting. Even if the compost and end products such as digestate is of high quality and all standards are met, a negative public perception of waste-based composts still exists. The presence of visible contaminants, such as plastic fragments, reminds users of this.

Digestate comprises mostly ash and biodegradable organic materials such as carbohydrates and proteins together with non-biodegradable organic materials such as plastic, lignin, and derivatives thereof, the biodegradable and non-biodegradable organic materials are hereinafter referred to as “organic materials” or “organic matter”. In a preferred aspect of the invention the digestate comprises at least 5% organic material of dry matter digestate, such as at least 10% organic matter, such as at least 15% organic matter, such as at least 20% organic matter, such as at least 25% organic matter, such as at least 30% organic matter, such as at least 35% organic matter, such as at least 40% organic matter, such as at least 45% organic matter, such as at least 50% organic matter, preferably the organic material content of the digestate is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, preferably at least 20% or preferably at least 30%. In one aspect the organic material is estimated as volatile solids by LO c according to EN 15935:2021.

Thus, one embodiment of the invention relates to an asphalt composition comprising 1-20 wt % or 1.5-20 wt % digestate, having a LOhso-con dry matter basis according to EN 1744-1 :2009 of at least 15 % of dry matter.

Another embodiment of the invention relates to an asphalt composition comprising 1-20 wt % digestate, having a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15 %, such as at least 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 %, such as at least 60 %, preferably at least 15 %, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 %.

Another embodiment of the invention relates to an asphalt composition comprising 1.5-20 wt % digestate, having a LOhso-con dry matter basis according to EN 1744-1 :2009 of at least 15%, such as at least 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 %, such as at least 60 %, preferably at least 15 %, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 %.

Another embodiment of the invention relates to an asphalt composition comprising 2-20 wt % digestate, having a LOhso-con dry matter basis according to EN 1744-1 :2009 of at least 15%, such as at least 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 %, such as at least 60 %, preferably at least 15 %, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 %.

Another embodiment of the invention relates to an asphalt composition comprising 5-20 wt % digestate, having a LOhso-con dry matter basis according to EN 1744-1 :2009 of at least 15%, such as at least 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 %, such as at least 60 %, preferably at least 15 %, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 %.

The volatile solids in digestate comprises mostly organic material as defined above, where part of the material measured by LOIsso-c according to EN 15935:2021 or LOhso-c according to EN 1744- 1 :2009, comprises plastic or derivates and lignin, which are not biodegradable and mostly inactive and thus are less prone to induce e.g., fractioning and cracking in asphalt.

The major fraction of digestate is ash, which accounts for 40 to 70 wt %, such as 45 - 50 wt % of the digestate. This is the ash fraction obtained after a standard method by thermogravimetric analysis at 550°C. The ash fraction may comprise carbonate and carbonate are often used as an inert filler in asphalt compositions generally. The amount of carbonate may be estimated from the difference between LO c and LOIsso-c and is approximately around 10% to 50% of the ash.

The biodegradable organic matter fraction of the digestate comprises a protein fraction. The protein fraction can for instance be estimated by determining the nitrogen content of the composition by multiplying with the Jones’ factors for a specific foodstuff. The standard, default conversion factor normally applied for mixed materials is 6.25 and has been used for nearly a century to estimate the nitrogemprotein ratio. If, for example the digestate is derived from a method comprising enzymatic degradation of municipal solid waste as the initial waste source for a subsequent AD process, then the 6.25 factor would be suitable for estimating the protein content because waste normally comprises proteins from various sources. A model substrate for instance comprises 41% mixed food waste of vegetable origin, 13% mixed food waste of animal origin and 46% mixed cellulosic waste. If, on the other hand, the waste source is mainly from cereals, the Jones factors applied for cereals could be applied instead to determine the protein content of the digestate. In one embodiment, the nitrogen content corrected for ammonium nitrogen content in the digestate is found by multiplying with factor 6.25.

The protein fraction of the digestate as estimated from the nitrogen content corrected for ammonium nitrogen content is usually between 7 and 20 wt % by weight of the digestate, such as 10 - 17 wt % or such as 12 - 15 wt % by weight of the digestate.

The digestate moreover comprises a carbohydrate fraction as estimated from the monomeric carbohydrate content after degradation in sulphuric acid and is usually between 5 and 20 wt %, such as between 7 and 16 wt %, such as between 9 and 14 wt %, such as between 10 and 13 wt % by weight of the digestate.

The digestate may be obtained from anaerobic digestion of one or more types of waste/feed stocks selected from the group consisting of: bioliquid from household waste, sewage sludge, general food waste, industrial waste, cellulosic waste, plant waste, animal waste, animal food waste, vegetable food waste, paper and/or carton waste, textile waste, waste fractions derived from agriculture or farming related sectors, waste fractions from processing of sugar or starch rich products, contaminated or in other ways spoiled agriculture products such as grain, potatoes and beets not exploitable for food or feed purposes, garden refuse, argent feed stock such as fatty acid rich feed stock, and starch industry feed stock.

The asphalt composition further comprise filler and/or fine aggregates and aggregates. To qualify as a fine aggregate the fine content should be above 3%, evaluated according to EN 933-9. To qualify as a filler in accordance with the European standard EN 13043:2003, 100% of the particles should be 2 mm or less in size, 85 - 100% of the particles should 0.125 mm or less in size and 70 - 100% should be 0.063 mm or less in size. Aggregates or typically crushed rock, slag, gravel and/or sand. Asphalt compositions can be specified according to national or regional standards, such as EN 13043 (BSI, 2002). This standard defines aggregate as a 'granular material used in construction', and separates this into one of three types (i) natural, (ii) manufactured, (iii) recycled aggregates, described as follows: (i) natural aggregate: aggregate from mineral sources that has been subjected to nothing more than mechanical processing (e.g. crushed rock, sands and gravel, often referred to as primary aggregate); (ii) Manufactured aggregate: aggregate of mineral origin resulting from an industrial process involving thermal or other modification (e.g. blast furnace slag); and (iii) recycled aggregate: aggregate resulting from the processing of inorganic or mineral material previously used in construction (e.g. reclaimed asphalt).

Further categorisation of aggregates can, as for filler, be given by the description for particle size: (i) coarse aggregate: substantially retained on a 2 mm test sieve; (ii) fine aggregate: substantially passing a 2 mm test sieve; (iii) all-in aggregate: a combination of course and fine aggregates; and (iv) filler aggregate: substantially passing a 0.063 mm test sieve, herein termed filler.

In one embodiment the asphalt composition comprises 1-20 wt % digestate, having a LOhso-con dry matter basis according to EN 1744-1 :2009 of at least 15%, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 %, further comprises 10-95 % aggregates, with respect to total weight of composition, wherein the aggregates comprise 1-40 % filler or fine aggregates, defined by size below 2 mm.

In one embodiment the asphalt composition comprising 1.5-20 wt % digestate, having a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 % further comprises 10-95 % aggregates, with respect to total weight of composition, wherein the aggregates comprise 1-40 % filler or fine aggregates, defined by size below 2 mm.

In one embodiment the asphalt composition comprising 2-20 wt % digestate, having a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 % further comprises 10-95 % aggregates, with respect to total weight of composition, wherein the aggregates comprise 1-40 % filler or fine aggregates, defined by size below 2 mm.

In one embodiment the asphalt composition comprising 5-20 wt % digestate, having a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, preferably at least 15 %, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 % further comprises IQ- 95 % aggregates, with respect to total weight of composition, wherein the aggregates comprise 1- 40 % filler or fine aggregates, defined by size below 2 mm.

In one embodiment the asphalt composition comprises 1-20 wt % digestate, having a LOhso-con dry matter basis according to EN 1744-1 :2009 of at least 15%, wherein the composition further comprises 10-95 % aggregates, such as 10-80 %, such as 10-70 %, such as 10-60 %, such as IQ- 50 %, such as 10-40 %, such as 10-30 %, such as 10-20 %, such as 20-70 %, such as 30-70%, such as 40-70 %, such as 50-70 %, such as 60-70 %, with respect to total weight of composition, wherein the aggregates comprise 1-20 % filler or fine aggregates, such as 5-15 %, such as 5-10 %, such as 1-15 %, such as 1-10%, such as 1-5 % filler or fine aggregates defined by size below 2 mm.

Increasing environmental awareness in recent years has generated considerable interest not only in recycling but also in the use of so called ‘secondary aggregates’ - materials such as slate waste, china clay waste and PFA/fly ash - in road construction. Many of these materials, with appropriate technical properties, are used as fill, capping or sub-base aggregates and recent developments have seen slate and china clay wastes used as aggregate in asphalt compositions.

In order for the small particles of filler and aggregates to stick together a glue needs to be added, and such glue or binder is usually bitumen, when asphalt compositions are produced. Further, to increase the strength of the asphalt and ensure the aggregates, are not loosened from the asphalt by repeatably passing of traffic, most of the roads globally are paved with bitumen. Today the world’s demand for bitumen accounts for more than 100 million tons per year. The viscosity of bitumen is similar to that of cold molasses while the material obtained from the fractional distillation of crude oil boiling at 525 degrees centigrade is sometimes referred to as "refined bitumen". For a general overview of the state of the art concerning bitumen and asphalt, including any compositions comprising bitumen, provision of such compositions, as well as uses and applications, standards, definitions and the like, reference is e.g., made to "The Shell Bitumen Handbook, 6th edition (SHB#6; ISBN 978-0-7277-5837-8), which is incorporated herein by reference. The chemistry of bitumen is very complex, and the properties of produced bitumen are closely related to the crude oil sources and the refinery processes. By selecting appropriate crude oil and/or proper refinery processes, desired bitumen properties can be obtained.

Normally, the ratio between filler and bitumen is from 0.6 - 1.2 and the ratio between bitumen and aggregate 0.03 to 0.12.

In one embodiment of the invention the asphalt composition comprising 1-20 wt % digestate, having a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15 %, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 % further comprises 1-10 % bitumen, with respect to total weight of the composition.

In one embodiment of the invention the asphalt composition comprising 1.5-20 wt % digestate, having a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15 %, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 % further comprises 5-10 % bitumen, with respect to total weight of the composition. In one embodiment of the invention the asphalt composition comprising 5-20 wt % digestate, having a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15 %, preferably at least 20 %, preferably at least 30 %, or even more preferably at least 40 % further comprises 5-10 % bitumen, with respect to total weight of the composition.

In one embodiment of the invention the asphalt composition comprising 1-20 wt% digestate, having a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15 %, further comprises 1-10 % bitumen, such as at least 2-10 %, such as at least 3-10 %, such as at least 4-10 %, such as at least 5-10 %, such as at least 6-10 %, such as at least 7-10 %, such as at least 8-10 %, such as at least 2-8 %, such as at least 3 - 7% or such as at least 4-6 % bitumen, with respect to total weight of the composition.

In one embodiment of the invention the asphalt composition comprising 1.5-20 % digestate, having a LOWc on dry matter basis according to EN 1744-1 :2009 of at least 15 %, further comprises 1-10 % bitumen, such as at least 2-10 %, such as at least 3-10 %, such as at least 4-10 %, such as at least 5-10 %, such as at least 6-10 %, such as at least 7-10 %, such as at least 8-10 %, such as at least 2-8 %, such as at least 3 - 7% or such as at least 4-6 % bitumen, with respect to total weight of the composition.

In one embodiment of the invention the asphalt composition comprising 5-20 % digestate, having a LOWc on dry matter basis according to EN 1744-1 :2009 of at least 15 %, further comprises 1-10 % bitumen, such as at least 2-10 %, such as at least 3-10 %, such as at least 4-10 %, such as at least 5-10 %, such as at least 6-10 %, such as at least 7-10 %, such as at least 8-10 %, such as at least 2-8 %, such as at least 3 - 7% or such as at least 4-6 % bitumen, with respect to total weight of the composition.

Most road pavements consist of several courses of different materials which in combination make the road strong and durable. Asphalt pavements are frequently described as flexible pavements, implying their ability to absorb the stresses imposed by traffic and weather without cracking. The asphalt composition of the present invention is suitable for use in one or more of these courses. In one embodiment of the invention the asphalt composition is applied in the subgrade course. In one embodiment of the invention the asphalt composition containing digestate is incorporated in the binder course. In one embodiment of the invention the asphalt composition containing digestate is incorporated in the surface course. In one embodiment of the invention the asphalt composition containing digestate is incorporated in the regulating course.

The function of each of the courses is as follows: The subgrade course is typically the natural soil, on old roads usually well compacted by traffic, on new roads carefully shaped and compacted to the appropriate level and profile. Subgrade improvement may be possible by treatment of soils with lime, cement and Ground Granulated Blastfurnace Slag (GGBS) or by adding a ‘capping course’ of lower quality aggregate. The sub-base is the lowest course, put down to help build up the strength of the pavement. It also provides a working platform for the machinery used in laying and compacting the courses above. It is usually made from crushed stone and/or gravel.

The base is typically the main component of an asphalt pavement and provides most of the strength and load distributing properties of the pavement. For very lightly trafficked roads, car parks and pedestrian footways, it is usually made from graded crushed stone and/or hardcore and/or it may be crushed stone bound with a small proportion of cement (cement- bound granular base or lean-mix concrete) and other Hydraulically Bound Materials (HBMs). For most roads and areas carrying heavy vehicles, however, an asphalt base is used to provide a pavement of high strength and durability, to achieve the desired load-bearing capacity and absorb traffic loads so that the underlying subgrade is not deformed.

The regulating course is typically of variable thickness and is applied to an existing course or surface to provide the necessary profile for a further course of consistent thickness.

The binder course typically further contributes to the strength of the pavement, and at the same time provides an even, well-regulated surface to carry the uppermost course of the pavement. This will be an asphalt mixture composition.

The surface course typically provides an even and weather-resistant surface which can withstand the abrasive forces of traffic and provide appropriate skid resistance for the particular circumstances. Roads are exposed to particularly high stresses, e.g., when the water contained in the pavement structure begins to freeze. Water expands when freezing, which can lead to frost damage that will sooner or later have an impact also on the road surface. This is prevented by a so-called frost blanket which usually consists of a mixture of gravel and sand, supplemented by crushed mineral aggregate. When compacted, these courses of frost-resistant materials conduct water away from the upper pavement courses, reducing tensions very effectively at the same time.

The asphalt mixture compositions used for base, regulating, binder and surface courses are for example mixtures of aggregate (crushed rock, slag, gravel and/or sand), a binder e.g., of petroleum bitumen and/or modified bitumen to provide particular additional properties. These components are carefully proportioned and mixed to the required specification. The asphalt compositions are laid and compacted, usually whilst hot or warm, although cold laid mixtures such as foam mixtures are available.

The digestate may be applied in any of the above courses, depending on the desired properties. The digestate is typically replacing the filler and/or fine aggregate material and/or the bitumen/binder material, which provides several direct and indirect positive benefits. The direct benefits being e.g., softening and anti-aging effects and the indirect effects being e.g., reduction of CO2 footprint by replacing natural stone and gravel with a recycled by-product, produced in a process transforming e.g., waste into green energy or fuel. Or by replacing fossil material such as binder/bitumen.

Thus, one aspect of the present invention provides the use of the digestate according to the invention in the sub-course, binder course, regulating course and/or in the surface course of asphalt compositions.

In view of practical handling and storage of the digestate composition as well as in view of its use in asphalt compositions, it is preferred that the digestate is dried until constant mass before use due to the mechanical strength of the asphalt risk being compromised if course and fine aggregates and filler and other additives cannot be distributed evenly due to lumping. However, the dewatered digestate may be used as is in cold mixes such as foam mixes.

As disclosed in the examples herein, the digestate was added to an asphalt surface composition and provided an impact on the softening of the asphalt surface composition by reducing the softening point temperature of the asphalt surface composition. The addition of the digestate to an asphalt surface composition moreover provided an improved anti-ageing effect. Moreover, the addition of the digestate to an asphalt surface composition provided a rejuvenating effect to the asphalt surface composition. Here it is shown, that incorporating digestate having at least 15% LO c on dry matter basis according to EN 1744-1 :2009 in high to moderate concentrations in the asphalt had no negative impact on the asphalt and did not result in an asphalt, which was inferior to an asphalt without digestate. The digestate comprises at least 15 wt% LO c but may comprise up to 60 wt% LOl95o°c. The amount of digestate in the asphalt composition is 1.5 wt% - 20 wt% of the total asphalt composition. Accordingly, in one embodiment the asphalt composition comprises 0.22 wt% - 9 wt% of the weight total asphalt composition, such as 0.5 - 8 wt%, such as 1 - 7 wt%, such as 2 - 5 wt%, such as 3 -4.5 wt%, or such as 0.22 - 3 wt%, such as 0.22 - 2.5 wt%, such as 0.22 - 2 wt% or such as 0.22 - 1 wt%, thus significantly higher amount than previously tested in asphalt compositions. These results are surprising as it would be expected that material added e.g., a filler or fine aggregate material having more than 6 to 10 % organic material of dry matter, would deteriorate the asphalt, (e.g. Deterioration of modern concrete structures and asphalt pavements by respiratory action and trace quantities of organic matter | PLOS ONE, O. Olubajo and A. Osha, International Conference on Sustainable Development, Benue State University, Makurdi, 2015 ) and/or make it prone to aging due to oxidation of the organic material. Also, the Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete ASTM C618 stipulates an upper limit for LO c at 6%.

It is shown here that asphalt surface compositions comprising quite a large amount of the digestate according to the invention showed increased softening, anti-ageing and rejuvenation while upholding sufficient tensile strength.

In a preferred embodiment, the digestate is used in the sub-course, binder course, regulating course and/or in the surface course of asphalt compositions of the invention wherein 1 .5 to 20 wt% by weight of the total asphalt composition is digestate according to the invention. Accordingly, such use include use wherein 1-20 wt %, 1.5-20 wt %, 2-20 wt %, 5-20 wt %, 10-20 wt %, 15-20 wt %, 5-15 wt %, 5-10 wt %, preferably 2-8 wt %, preferably 3-8 wt %, or 4-8 wt % by weight of the total composition in the sub-course, binder course regulating course and/or in the surface course is digestate.

In another preferred embodiment, the digestate is used in the sub-course, binder course, regulating course and/or in the surface course of the asphalt compositions of the invention, wherein 0,1-5% by weight of the total filler aggregate components in the sub-course, binder course, regulating course and/or in the surface course is digestate.

In another preferred embodiment, the digestate is used in the sub-course, binder course, regulating course and/or in the surface course of the asphalt compositions of the invention, wherein 1-70 wt%, such as 1- 60 wt%, such as 1- 50 wt%, such as 1- 40 wt%, such as 1- 30 wt%, such as 1-20 wt%, such as 2-20 wt%, preferably such as 5-20 wt% by weight of the total bitumen/binder in the subcourse, binder course, regulating course and/or in the surface course is digestate.

In a preferred embodiment, the present invention provides use of digestate, having LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, for one or more of softening, anti-ageing, and rejuvenation of the sub-course, binder course, regulating course and/or the surface course of an asphalt composition.

One embodiment of the invention relates to an asphalt composition comprising 1-20 wt% digestate, having a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, such as at least 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 %, such as at least 60 %, preferably at least 15 %, preferably at least 20 %, or even more preferably at least 30 % and comprises 1-20 wt% filler or fine aggregates, such as 5-20 wt%, such as 5-15 wt%, such as 5-10 wt%, such as 1-15 wt%, such as 1-10 wt%, such as 1-5 wt% filler or fine aggregates defined by size below 2 mm, and 10-70 wt% aggregates, such as 10-60 wt%, such as 10-50 wt%, such as 10-40 wt%, such as 10-30 wt%, such as 10-20 wt%, such as 20-70 wt%, such as 30-70 wt%, such as 40-70 wt%, such as 50- 70 wt%, such as 60-70 wt%, and further comprises 1-10 wt% bitumen, such as at least 2-10 wt%, such as at least 3-10 wt%, such as at least 4-10 wt%, such as at least 5-10 wt%, such as at least 6- 10 wt%, such as at least 7-10 wt%, such as at least 8-10 wt%, such as at least 2-8 wt%, such as at least 3 - 7wt% or such as at least 4-6 wt% bitumen, with respect to total weight of composition.

One embodiment of the invention relates to an asphalt composition comprising 1.5-20 % digestate, having a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, such as at least 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 %, such as at least 60 %, preferably at least 15 %, preferably at least 20 %, or even more preferably at least 30 % and comprises 1-20 wt% filler or fine aggregates, such as 5-20 wt%, such as 5-15 wt%, such as 5-10 wt%, such as 1-15 wt%, such as 1-10wt%, such as 1-5 wt% filler or fine aggregates defined by size below 2 mm, and 10-70 wt% aggregates, such as 10-60 wt%, such as 10-50 wt%, such as 10-40 wt%, such as 10-30 wt%, such as 10-20 wt%, such as 20-70 wt%, such as 30-70 wt%, such as 40-70 wt%, such as 50- 70 wt%, such as 60-70 wt%, and further comprises 1-10 wt% bitumen, such as at least 2-10 wt%, such as at least 3-10 wt%, such as at least 4-10 wt%, such as at least 5-10 wt%, such as at least 6- 10 wt%, such as at least 7-10 wt%, such as at least 8-10 wt%, such as at least 2-8 wt%, such as at least 3 - 7 wt% or such as at least 4-6 wt% bitumen, with respect to total weight of composition.

One embodiment of the invention relates to an asphalt composition comprising 2-20 % digestate, having a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at least 15%, such as at least 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 %, such as at least 60 %, preferably at least 15 %, preferably at least 20 %, or even more preferably at least 30 % and comprises 1-20 wt% filler or fine aggregates, such as 5-20 wt%, such as 5-15 wt%, such as 5-10 wt%, such as 1-15 wt%, such as 1-10wt%, such as 1-5 wt% filler or fine aggregates defined by size below 2 mm, and 10-70 wt% aggregates, such as 10-60 wt%, such as 10-50 wt%, such as 10-40 wt%, such as 10-30 wt%, such as 10-20 wt%, such as 20-70 wt%, such as 30-70wt%, such as 40-70 wt%, such as 50- 70 wt%, such as 60-70 wt%, and further comprises 1-10 wt% bitumen, such as at least 2-10 wt%, such as at least 3-10 wt%, such as at least 4-10 wt%, such as at least 5-10 wt%, such as at least 6- 10 wt%, such as at least 7-10 wt%, such as at least 8-10 wt%, such as at least 2-8 wt%, such as at least 3 - 7wt% or such as at least 4-6 wt% bitumen, with respect to total weight of composition.

As mentioned, it is surprising that moderate amounts of digestate, i.e. preferably above 1.5% by weight of total composition can replace bitumen/binder and fine aggregates (D>2mm) and filler material (D>0.063 mm) due to the relatively high organic content without significantly influencing the strength and water stability of the asphalt pavement as it is commonly accepted within the asphalt industry that materials with a high organic content cannot be used e.g., as an aggregate, filler or bitumen replacement in asphalt compositions. This is suspected to be caused by the unique process by which the organics remaining inaccessible to degradation by enzymatic hydrolysis and bacterial degradation as is used in the waste treatment and/or AD process. In addition, it’s assumed that the lignin and plastic derivates, which together with the biodegradable organic material comprises the volatile solids which are measured as e.g., LOIsso-c and LO 1950-0 on dry matter basis according to EN 15935:2021 and EN 1744-1 :2009 respectively, and that these materials are inert and beneficial for the asphalt composition.

Furthermore, the addition of digestate is not restricted to a single asphalt application but has been tested in Asphalt Concrete (AC), both binder and surface course and in Stone Mastic Asphalt (SMA) mixtures, suggesting that the addition of digestate, having a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, can be used in any asphalt application when the recipe is optimized towards application.

Further, non-dried digestate (15<DM<45 wt%) may be used in some asphalt applications such as cold mix and foamed asphalt mixtures where aggregates can be incorporated when wet. This would reduce the CO2 footprint of the overall process and asphalt composition even further when not utilizing energy for drying digestate and heating the asphalt composition.

Asphalt Concrete (AC) compositions with dig estate

As mentioned above it is shown in the present application that digestate may be applied in AC compositions. Therefore, one embodiment of the invention relates to an AC composition e.g., prepared according to European Standard EN13108-1 for AC mixtures, wherein the composition comprises 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 3-15% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

One embodiment of the invention relates to an AC composition e.g., prepared according to European Standard EN 13108-1 for AC mixtures, wherein the composition comprises 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO 1950-0 on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 3-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

The AC composition may comprise 1-20 wt% digestate, such as 1 .5-20 wt%, 2-20 wt%, 5-20 wt%, 10-20 wt%, 15-20 wt%, 5-15 wt%, 5-10 wt%, preferably 2-8 wt%, preferably 3-8 wt%, or 4-8 wt% by weight of the total composition, wherein the digestate may a LO c on dry matter basis according to EN 1744-1 :2009 of at 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 % or such as at least 60 %.

The AC composition may be any of, but not limited to: AC4, AC6, AC8, AC10, AC11 , AC12, AC14, AC20, AC30, AC32, ACBE, prepared according to the standard EN13108-1. AC10 is an Asphalt Concrete with a nominal maximum stone size of 10 mm, AC14, which is an Asphalt Concrete with nominal maximum aggregate size in the asphalt mixture is 14 mm or AC20, which is an Asphalt Concrete with a nominal maximum stone size of 20 mm and so forth. Some of the AC compositions above comprises of crushed rock (or recycled aggregates) of e.g., 10, 14 and 20 mm, wherein crushed rock (or recycled aggregates) is bound together with bitumen, which act as a binder. The AC compositions with lower AC numbers e.g., 10 are suitable for low stress areas, such as cycle tracks and estate roads and vice versa with AC compositions having higher AC numbers. In one embodiment the Asphalt Concrete composition of the invention is prepared according to the standard EN 13108-1 :2016 for AC.

In one embodiment the AC composition comprising digestate is an ACBE Asphalt Concrete, prepared according to the standard EN 13108-31.

In one embodiment the AC composition comprising digestate is prepared according to the standard EN 13108-2 for AC for Very Thin Layers (BBTM) or according to EN 13108-9 for Ultrathin layers (UTL). UTL is a hot mix asphalt road surface course laid on a bonding layer, at a nominal thickness between 10 mm and 20 mm.

In one embodiment of the invention the asphalt composition comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 3-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm, is an AC with emulsions, prepared according to the European Standard EN 13108-31 AC with emulsions. This European Standard specifies requirements for plant mixtures of the mix group AC with bituminous emulsion for use on roads, and other trafficked areas (EN 13108-31). In one embodiment of the invention the asphalt composition comprising 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 3-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm, is an AC with emulsions, prepared according to the European Standard EN 13108-31 AC with emulsions. This European Standard specifies requirements for plant mixtures of the mix group AC with bituminous emulsion for use on roads, and other trafficked areas (EN 13108-31).

The European Standards above specifies requirements for mixtures of AC compositions suitable for use on roads, airfields, and other trafficked areas. The Asphalt Concrete compositions may be used in surface course, binder courses and base course. The AC compositions may be mixed with 1-10 % of bitumen of 10/20, 15/25, 30/45, 40/60, 70/100, 100/150, 160/220 or250/330 penetration grade, the amount and type depending on the intended use of the asphalt composition.

Hot Rolled Asphalt (HRA) compositions with digestate

As mentioned above it is shown in the present application that digestate may be applied in a HRA compositions. Therefore, one embodiment of the invention relates to an HRA composition e.g., prepared according to European Standard EN 13108-4 for HRA mixtures comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 5-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

One embodiment of the invention relates to an HRA composition e.g., prepared according to European Standard EN 13108-4 for HRA mixtures comprising 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 5-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

The HRA composition may comprise 1-20 wt% digestate, such as 1.5-20 wt%, 2-20 wt%, 5-20 wt%, 10-20 wt%, 15-20 wt%, 5-15 wt%, 5-10 wt%, preferably 2-8 wt%, preferably 3-8 wt%, or 4- 8 wt% by weight of the total composition, wherein the digestate may a LO c on dry matter basis according to EN 1744-1 :2009 of at 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 % or such as at least 60 %.

In one embodiment the HRA composition comprising digestate is prepared according to the standard EN 13108-2 for AC for Very Thin Layers (BBTM) or according to EN 13108-9 for Ultrathin layers (UTL). UTL is a hot mix asphalt road surface course laid on a bonding layer, at a nominal thickness between 10 mm and 20 mm.

The European Standards above specifies requirements for mixtures of HRA compositions suitable for use on roads, airfields, and other trafficked areas. The HRA compositions may be used in surface course, binder course and base course. The HRA compositions may be mixed with 1-10 % of bitumen of 10/20, 15/25, 30/45, 40/60, 70/100, 100/150, 160/220 or 250/330 penetration grade, the amount and type depending on the intended use of the asphalt composition.

Stone mastic asphalt (SMA) compositions with digestate

As mentioned above it is shown in the present application that digestate may be applied in a SMA compositions. Therefore, one embodiment of the invention relates to an SMA composition e.g., prepared according to European Standard EN 13108-5 for SMA mixtures comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 5-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

One embodiment of the invention relates to an SMA composition e.g., prepared according to European Standard EN 13108-5 for SMA mixtures comprising 1 .5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 5-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

The SMA composition may comprise 1-20 wt% digestate, such as 1.5-20 wt%, 2-20 wt%, 5-20 wt%, 10-20 wt%, 15-20 wt%, 5-15 wt%, 5-10 wt%, preferably 2-8 wt%, preferably 3-8 wt%, or 4- 8 wt% by weight of the total composition, wherein the digestate may a LO c on dry matter basis according to EN 1744-1 :2009 of at 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 % or such as at least 60 %. The European Standards above specifies requirements for mixtures of SMA compositions suitable for use on roads, airfields, and other trafficked areas. The SMA compositions may be used in surface course, binder course and base course. The SMA compositions may be mixed with 1-10 % of bitumen of 10/20, 15/25, 30/45, 40/60, 70/100, 100/150, 160/220 or 250/330 penetration grade, the amount and type depending on the intended use of the asphalt composition.

In one embodiment the SMA asphalt comprises 1-20 wt%, such as 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 5-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm is prepared according to any of the two older standards EN 13108-5:2006 or EN 13108-5/AC:2008.

Mastic asphalt (MA) compositions with digestate

As mentioned above it is shown in the present application that digestate may be applied in MA compositions. Therefore, one embodiment of the invention relates to an MA composition e.g., prepared according to European Standard EN 13108-6 for MA mixtures comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 5-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

One embodiment of the invention relates to an MA composition e.g., prepared according to European Standard EN 13108-6 for MA mixtures comprising 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LOIgso-c on dry matter basis according to EN 1744- 1 :2009 of at least 15%, 1-10 wt% or preferably 5-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

The MA composition may comprise 1-20 wt% digestate, such as 1 .5-20 wt%, 2-20 wt%, 5-20 wt%, 10-20 wt%, 15-20 wt%, 5-15 wt%, 5-10 wt%, preferably 2-8 wt%, preferably 3-8 wt%, or 4-8 wt% by weight of the total composition, wherein the digestate may a LOhso-c on dry matter basis according to EN 1744-1 :2009 of at 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 % or such as at least 60 %. In one embodiment the MA composition comprising digestate is prepared according to the standard EN 13108-2 for AC for Very Thin Layers (BBTM) or according to EN 13108-9 for Ultrathin layers (UTL). UTL is a hot mix asphalt road surface course laid on a bonding layer, at a nominal thickness between 10 mm and 20 mm.

The European Standards above specifies requirements for mixtures of MA compositions suitable for use on roads, airfields, and other trafficked areas. The MA compositions may be used in surface course, binder course and base course. The MA compositions may be mixed with 1-10 wt%, such as 2-10 wt %, 3-15 wt %, such as 4-15 wt %, such as 5-15 wt %, preferably 5-10 wt % of bitumen of 10/20, 15/25, 30/45, 40/60, 70/100, 100/150, 160/220 or 250/330 penetration grade, the amount and type depending on the intended use of the asphalt composition.

In one embodiment the MA asphalt comprises 1-20 wt%, such as 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% or preferably 5-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm is prepared according to any of the two older standards EN 13108-6:2006 or EN 13108-6/AC:2008.

Porous Asphalt (PA) compositions with dig estate

As mentioned above it is shown in the present application that digestate may be applied in PA compositions. Therefore, one embodiment of the invention relates to an PA composition e.g., prepared according to European Standard EN EN 13108-7 for PA mixtures comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

One embodiment of the invention relates to an PA composition e.g., prepared according to European Standard EN EN 13108-7 for PA mixtures comprising 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and IQ- 95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1- 40 wt% filler or fine aggregates, defined by size below 2 mm.

The PA composition may comprise 1-20 wt% digestate, such as 1.5-20 wt%, 2-20 wt%, 5-20 wt%, 10-20 wt%, 15-20 wt%, 5-15 wt%, 5-10 wt%, preferably 2-8 wt%, preferably 3-8 wt%, or 4-8 wt% by weight of the total composition, wherein the digestate may a LO c on dry matter basis according to EN 1744-1 :2009 of at 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 % or such as at least 60 %.

In one embodiment the PA composition comprising digestate is prepared according to the standard EN 13108-2 for AC for Very Thin Layers (BBTM) or according to EN 13108-9 for Ultrathin layers (UTL). UTL is a hot mix asphalt road surface course laid on a bonding layer, at a nominal thickness between 10 mm and 20 mm.

In one embodiment the PA asphalt comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm is prepared according to any of the two older standards EN 13108-7:2006 or EN 13108-7/AC:2008.

In one embodiment the PA asphalt comprising 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm is prepared according to any of the two older standards EN 13108-7:2006 or EN 13108-7/AC:2008.

Soft asphalt (SA) compositions with digestate

As mentioned above it is shown in the present application that digestate may be applied in SA compositions. Therefore, one embodiment of the invention relates to an SA composition e.g., prepared according to European Standard EN 13108-3 for SA mixtures comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt%, preferably 1-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

One embodiment of the invention relates to an SA composition e.g., prepared according to European Standard EN 13108-3 for SA mixtures comprising 1 .5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LOIgso-c on dry matter basis according to EN 1744- 1 :2009 of at least 15%, 1-10 wt%, preferably 1-15 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm.

The SA composition may comprise 1-20 wt% digestate, such as 1.5-20 wt%, 2-20 wt%, 5-20 wt%, 10-20 wt%, 15-20 wt%, 5-15 wt%, 5-10 wt%, preferably 2-8 wt%, preferably 3-8 wt%, or 4-8 wt% by weight of the total composition, wherein the digestate may a LO c on dry matter basis according to EN 1744-1 :2009 of at 20 %, such as at least 25 %, such as at least 30 %, such as at least 35 %, such as at least 40 %, such as at least 45 %, such as at least 50 %, such as at least 55 % or such as at least 60 %.

In one embodiment the SA composition comprising digestate is prepared according to the standard EN 13108-2 for AC for Very Thin Layers (BBTM) or according to EN 13108-9 for Ultrathin layers (UTL). UTL is a hot mix asphalt road surface course laid on a bonding layer as a surface later, at a nominal thickness between 20 mm and 30 mm.

The European Standards above specifies requirements for mixtures of SA compositions suitable for use on roads, airfields, and other trafficked areas. The SA compositions may be used in surface course, binder course and base course. The SA compositions may be mixed with 1-10 % of bitumen of 250/330 330/430, 500/650, 650/900, V1500, V3000 or V12000 penetration grade, the amount and type depending on the intended use of the asphalt composition.

Foamed or cold mix Asphalt compositions with digestate

In one embodiment the asphalt composition comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and IQ- 95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1- 40 wt% filler or fine aggregates, defined by size below 2 mm is a cold mixed, produced with unheated aggregate and bitumen emulsion or foamed bitumen to produce e.g., a foamed asphalt mix.

In one embodiment the asphalt composition comprising 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and IQ- 95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1- 40 wt% filler or fine aggregates, defined by size below 2 mm is a cold mixed, produced with unheated aggregate and bitumen emulsion or foamed bitumen to produce e.g., a foamed asphalt mix. Foamed mixed asphalts are typically produced by one of the following methods, which are for example described in The voice of the European Asphalt Industry - What is Asphalt? (eapa.org) which may be prepared with digestate.

1. The direct method of foaming is to inject a small, controlled amount of water to hot bitumen via foaming nozzles. This results in a large but temporary increase in the effective volume of the binder which facilitates coating at lower temperatures. Some vapor remains in the bitumen during compaction reducing effective viscosity and facilitating compaction. On cooling the binder reverts to normal, as the amount of water is insignificant. This technique can enable a temperature reduction of the asphalt mix of about 20 to 40°C.

2. An indirect foaming technique uses a mineral as the source of foaming water. Hydrophilic minerals from the zeolite family are commonly used. They contain about 20 percent of crystalline water, which is released above 100 °C. This release of water creates a controlled foaming effect, which can provide an improved workability for a 6- to 7-hour period, or until the temperature drops below 100 °C. The foaming results in an improved workability of the mix which can subsequently allow a decrease in the mix temperature by approximately 30° C with equivalent compaction performance.

A second indirect foaming technique uses the moisture on the sand (or RAP) to generate naturally created foam. It is a sequential technique. The coarse aggregate which represents about 80% of the mix design is dried/heated to 130-160° C, it is then coated by the bitumen and thereby creating a thick binder film on the coarse particles. The next stage involves the addition of the cold/wet fraction. The moisture in contact with the hot bitumen causes foaming which facilitates easy coating of the cold and wet RAP or fine aggregate.

This technique enables the same temperature reduction as the direct foaming through nozzles, about 20 to 40°C.

Preparing Asphalt Compositions with digestate

One embodiment of the invention relates to an the asphalt composition comprising 1-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm, wherein the composition comprises Reused Asphalt Preparation (RAP) e.g., prepared according to the European Standard EN 13108-8 for RAP, wherein the RAP is incorporated in 10% or below of the total weight of composition in an MA or wherein the RAP is incorporation in 20% or below in other surface asphalt or wherein the RAP is incorporation in 50% or below in any other asphalt.. One embodiment of the invention relates to an the asphalt composition comprising 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm, wherein the composition comprises Reused Asphalt Preparation (RAP) e.g., prepared according to the European Standard EN 13108-8 for RAP, wherein the RAP is incorporated in 10% or below of the total weight of composition in an MA or wherein the RAP is incorporation in 20% or below in other surface asphalt or wherein the RAP is incorporation in 50% or below in any other asphalt..

The European Standards above specifies requirements for the classification and description of reclaimed asphalt as a constituent material for asphalt mixtures. This European Standard only specifies reclaimed asphalt with bituminous binders, such as: paving grade bitumen, modified bitumen or hard grade bitumen, according to EN 13108-8. The RAP compositions may be mixed with a bitumen of 70/100 penetration grade or 40/60 penetration grade, depending on the intended use of the asphalt composition.

Preferably the asphalt compositions of the invention are in accordance with EN 13108-21 , relating to Factory Production Control and/or EN 13108-20 relating to Type Testing procedure for use in Assessment and Verification of the Constancy of Performance (AVCP), bituminous mixtures.

Unless the asphalt composition is prepared by cold mixing and with the exception of the Hot Rolled Asphalt (which is prepared at high temperatures), the asphalt composition of the invention may be prepared at different warm temperatures.

The asphalt composition comprising 1-20 wt%, preferably 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and IQ- 95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1- 40 wt% filler or fine aggregates, defined by size below 2 mm may be a Half Warm Asphalt, produced between around 70 °C to around 100 °C.

One aspect of the invention relates to a method of producing an asphalt composition comprising 1- 20 wt%, preferably 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1 :2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm and wherein the asphalt composition is produced between around 70 °C to around 100 °C.

The asphalt composition comprising 1-20 wt%, preferably 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1:2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and IQ- 95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1- 40 wt% filler or fine aggregates, defined by size below 2 mm is preferably a Warm Mix Asphalt, produced between around 100°C to around 150°C.

One aspect of the invention relates to a method of producing an asphalt composition comprising 1- 20 wt%, preferably 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1:2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm and wherein the asphalt composition is produced between around 100 °C to around 150 °C.

The asphalt composition comprising 1-20 wt%, preferably 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1:2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and IQ- 95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1- 40 wt% filler or fine aggregates, defined by size below 2 mm is preferably a Hot Mix Asphalt, produced between around 120°C to around 190°C.

One aspect of the invention relates to a method of producing an asphalt composition comprising 1- 20 wt%, preferably 1.5-20 wt% digestate with respect to total weight of composition, wherein the digestate have a LO c on dry matter basis according to EN 1744-1:2009 of at least 15%, 1-10 wt% bitumen with respect to total weight of composition, and 10-95 wt% aggregates with respect to total weight of composition, wherein the aggregates comprise 1-40 wt% filler or fine aggregates, defined by size below 2 mm and wherein the asphalt composition is produced between around 120 °C to around 200 °C.

One aspect relates to an asphalt composition according to the invention, wherein the bitumen is a 10/20, 15/25, 30/45, 40/60, 70/100, 100/150, 160/220 or 250/330 penetration grade bitumen.

One aspect relates to an asphalt according to the invention, wherein the bitumen is a 250/330 330/430, 500/650, 650/900, V1500, V3000 or V12000 penetration grade bitumen. The asphalt compositions of the invention are preferably prepared after the newest standards for mixing asphalt compositions. Any of the above compositions may be produced according to the corresponding US or any other standard applying for a relevant region.

Source of the digestate

The digestate can be obtained from various suitable AD substrate, i.e. , any biomass which may be subjected to AD processing. Such substrates include but are not limited to lignocellulosic material, such as straw, household waste, sewage sludge, manure, straw beddings containing manure, cellulosic material, such as paper and pulp, industrial waste such as cuttings from slaughterhouses or floor sweepings from dairies, residues from food or beverage industry or other materials with biogas potential.

A substrate suitable for AD processes comprises organic matter which is converted to e.g., biogas, digestate and inerts. The digestate may thus come from different sources, however as the AD process is overall the same the end products are rather similar. In one preferred embodiment the digestate is derived from a waste treatment processes. Since the specific composition of asphalt can be analysed by standard methods available in the art, the method applied for obtaining the digestate is of less relevance.

However, in one aspect of the invention, the digestate is obtained from a method comprising: a) Subjecting waste to enzymatic and/or microbial treatment b) Subjecting the treated waste from step a) to one or more separation step(s) whereby a bioliquid fraction and a solid fraction is provided; and c) Subjecting the bioliquid fraction to anaerobic digestion.

Optionally one or more of the following steps may be performed, d) Separating the solid fraction from the liquid fraction of the digestate obtained in step c) e) Subject the digestate fraction obtained in step d) to anti-lumping treatment and/or passing digestate through 2 mm sieve, or f) Optionally subjecting the digestate obtained in e) to drying and/or milling to reduce particle size.

In another embodiment, the digestate is obtained from an AD process wherein the substrate is not subjected to microbial and/or enzymatic treatment (i.e. step a) and separation (i.e. step b). Accordingly, in another preferred embodiment, the digestate is obtained from a method comprising: c) Subjecting a substrate to anaerobic digestion.

Optionally one or more of the following steps may be performed, d) Separating the solid fraction from the liquid fraction of the digestate obtained in step c) e) Subject the digestate fraction obtained in step d) to anti-lumping treatment and/or passing digestate through 2 mm sieve, or f) Optionally subjecting the digestate obtained in e) to drying and/or milling to reduce particle size.

The methods can be performed within a single waste processing plant comprising one or more bioreactors and/or one or more downstream AD reactors or the waste treatment process providing the digestate can be performed at two or more different and possibly independent waste processing and/or biogas production sites.

Step a, b and c in the method are commonly applied steps in waste treatment methods, and details regarding one or more of these steps have been disclosed in for example WO2014/198274, WO2013/18778, WO 2022/096406 and WO 2022/096517.

The steps of the method can be described as follows:

The enzymatic and/or microbial treatment of the waste in step a) can for instance be performed in a bioreactor. The treatment is performed by optionally adding one or more enzymes and/or by the bacteria present in the waste. Optionally, standard, cultivated, or manipulated yeast, bacteria, or any other microorganism capable of converting the organic material present in the waste into compositions suitable for subsequent biogas production in an anaerobic digestion process may be added to the bioreactor. The enzymes are supplied in either native form or in form of microbial organisms expressing the enzymes.

The enzymatic and/or microbial treatment in step a) may be performed by adding one or more enzymes, supplied in either native form and/or in form of microbial organisms giving rise to the expression of such enzymes; and/or by the bacteria present in the waste and/or optionally by adding standard, cultivated, or manipulated yeast, bacteria, or any other microorganism capable of converting the organic material present in the waste into organic acids or other compositions, such as lactic acid, 3-hydroxypropionic acid (3-HPA), 1 ,4-butanediol (BDO), butanedioic acid (succinic acid), ethane-1 ,2-diol (ethylene glycol), butanol or 1 ,2-propanediol (propylene glycol), suitable for subsequent biogas production in an anaerobic digestion process.

Microorganisms that may be added to the bioreactor in step a) include yeasts, and/or fungi and/or bacteria.

Other microorganisms that may be added to the bioreactor in step a) include bacteria that can efficiently ferment hexose and pentose including but not limited to cellobiose, glucose, xylose and arabinose to short chain organic acids including but not limited to citric acid, lactic, formic acid, acetic acid, butyric acid, valeric acid, isovaleric acid and propionic acid as well as alcohols including but not limited to ethanol.

The fermenting microorganisms may have been genetically modified to provide the ability to ferment pentose sugars, such as xylose utilizing, arabinose utilizing, and xylose and arabinose co-utilizing microorganisms.

The fermenting organisms may comprise one or more polynucleotides encoding one or more cellulolytic enzymes, hemicellulolytic enzymes, and accessory enzymes described herein.

The microorganisms present in the waste or added to the bioreactor, may produce fermentable sugars and organic acid or other compositions, such as lactic acid, 3-hydroxypropionic acid (3-HPA), 1 ,4-butanediol (BDO), butanedioic acid (succinic acid), ethane-1 ,2-diol (ethylene glycol), butanol or 1 ,2-propanediol (propylene glycol), that may be used as feed in a subsequent anaerobic digestion process. These organic acids or other compositions further include acetate, propionate and butyrate. Substrates, such as waste that is suitable for treatment normally comprises, at least, lactic acid producing bacteria.

The treatment in step a) may comprise addition of cellulase activity by inoculation with one or more microorganism(s) that exhibits extracellular cellulase activity.

In step a) the waste may also be treated with an enzyme composition wherein the enzymes are added to the waste independently from the enzymes present within the microorganisms already present or added to the waste. Suitable enzyme compositions are well known in the art and are commercially available.

Suitable enzyme blends are cellulolytic background composition (CBC) comprising a commercial cellulolytic enzyme preparation. Examples of commercial cellulolytic enzyme preparations suitable for use in the method according to the present invention include but is not limited to, for example, CELLIC® CTec (Novozymes A/S), CELLIC® CTec2 (Novozymes A/S), CELLIC® CTec3 (Novozymes A/S), CELLUCLAST® (Novozymes A/S), NOVOZYM™ 188 (Novozymes A/S), SPEZYME™ CP (Genencor Int.), ACCELLERASE™ TRIO (DuPont), FILTRASE® NL (DSM); METHAPLUS® S/L 100 (DSM), ROHAMENT™ 7069 W (Rohm GmbH), or ALTERNAFUEL® CMAX3™ (Dyadic International, Inc.).

In addition to the CBC, further enzyme activity may be added from individual sources or together as part of enzyme blends. Suitable blends include but are not limited to the commercially available enzyme compositions Cellulase PLUS, Xylanase PLUS, BrewZyme LP, FibreZyme G200 and NCE BG PLUS from Dyadic International (Jupiter, FL, USA) or Optimash BG from Genencor (Rochester, NY, USA).

For treatment of MSW suitable CBCs comprises enzymatic activity in accordance with the activity of ACCELLERASE® TRIO™ (Genencor Int.), Cellic CTec2 (Novozymes A/S) or Cellic CTec3 (Novozymes A/S) or Cellic CTec3 (Novozymes A/S).

The enzymatic treatment of the biodegradable parts of the substrate, e.g., waste optionally concurrently with microbial fermentation according to step a) may be performed at a temperature above 20°C and up to 75°C resulting in liquefaction and/or saccharification of biodegradable parts of the waste and accumulation of sugars and other soluble degradation products.

Depending on the substrate the Dry Matter content may vary. Waste, e.g., MSW, may have a Dry Matter (DM) content in the range 10%-90%; 20%-85%; 30%-80%; 40%-75%; 50%-70%; or 55%-65 % (w/w); and/or around 10%; 15%; 20%; 25%; 30%; 35%; 40%; 45%; 50%; 55%; 60%; 65%; 70%; 75%; 80%; 85%; or 90% (w/w). Other substrates may have different dry matter (DM) content such as 3 to 30% for manure.

In order for the enzymatic and/or microbial liquefaction of the substrate, e.g., waste in the bioreactor in step a) to provide a bioliquid comprising an optimum amount of short chain carboxylic acids and sugars such as glucose, xylose, arabinose, lactic acid/lactate, acetic acid/acetate and/or ethanol, the pH in the bioreactor should generally remain within a pH range of between pH 2 - 6.5.

Step b) is a separation step where the bioliquid is separated from the non-degradable solid waste fractions. Clean and efficient use of the degradable component of waste, such as MSW, combined with recycling typically requires some method of sorting or separation to separate degradable from non-degradable material. The separation in step b) may be performed by any means known in art, such as in a ballistic separator, washing drums and/or hydraulic presses. In one embodiment the separation is performed before the enzymatic treatment. Separation of liquid and solids can e.g., be done in different presses (such as screw and/or piston presses) or e.g., using a simpler sieve function. A ballistic separator is typically used to separate the solids into fractions and only secondarily a liquid separation.

In step c), the bioliquid fraction obtained in step b) is subjected to anaerobic digestion (AD) process. However, the AD substrate need not be bioliquid. Suitable AD substrate can be any biomass which may be subjected to AD processing. Such substrates include but are not limited to lignocellulosic material, such as straw, household waste, sewage sludge, manure, straw beddings containing manure, cellulosic material, such as paper and pulp, industrial waste such as cuttings from slaughterhouses or floor sweepings from dairies, residues from food or beverage industry or other materials with biogas potential.

In a preferred embodiment the AD substrate is obtained from a process where the substrate was generated by biologic treatment such as enzymatic treatment and/or microbial treatment of a waste composition. In another preferred embodiment, the AD substate is generated by enzymatic treatment and/or microbial treatment of MSW.

In some embodiment of the invention the substrate for the AD process has not been subjected to enzyme and/or microbial treatment as described above. The substrate may not be pre-processed, the substrate may have been subjected to various types of mechanical pre-treatment or the substrate may have been subjected to other treatments before entering the AD process, including sorting, mechanical and/or manual sorting,

A range of AD technologies exists in the state of the art for converting various substrates including waste, such as municipal solid waste, municipal wastewater solids, food waste, high strength industrial wastewater and residuals, fats, oils and grease (FOG), and various other organic waste streams into biogas. Many different anaerobic digester systems are commercially available, and the skilled person will be familiar with how to apply and optimize the anaerobic digestions process. The metabolic dynamics of microbial communities engaged in anaerobic digestion are complex.

In typical AD for production of methane biogas, biological processes mediated by microorganisms achieve four primary steps - hydrolysis of biological macromolecules into constituent monomers or other metabolites; acidogenesis, whereby short chain hydrocarbon acids and alcohols are produced; acetogenesis, whereby available nutrients are catabolized to acetic acid, hydrogen and carbon dioxide; and methanogenesis, whereby acetic acid and hydrogen are catabolized by specialized archaea to methane and carbon dioxide. The hydrolysis step is typically rate-limiting and dependent on the biomass type. In the bioliquid i.e. , from enzymatic and/or microbial treatment of waste, it is the methanogens that limits the processing rate. From the AD plant is furthermore obtained digestate, comprising a solid fraction and a liquid fraction (reject water), thus the digestate used in asphalt may sometimes be termed solid digestate, in particular comprising a water-like liquid with separable suspended particles. Such solid digestate is, in one embodiment of the present invention, the digestate used in the asphalt composition according to the invention.

The anaerobic digestion step c), may comprise one or more reactors operated under controlled aeration conditions, eliminating or minimizing the available oxygen, in which methane gas is produced in each of the reactors comprising the system. The AD reactor(s) can, but need not, be part of the same waste processing plant as the bioreactor in step a) and can, but need not, be connected to the bioreactor in step a). Moreover, the AD process may be in the form of a fixed filter system. A fixed filter anaerobic digestion system is a system in which an anaerobic digestion consortium is immobilized, optionally within a biofilm, on a physical support matrix.

In step d) the digestate obtained from step c) is separated into a liquid phase and a solid digestate and the solid digestate is dried until constant mass.

The digestate comprises both solids and liquids and these fractions may be used for various purposes. The solid-liquid separations can for instance be done by decantation, centrifugation and/or sedimentation. Usually, the anaerobic digestate comprises mainly water, wherein the digestate has a total solid content of about 4-8% and after the dewatering the solid digestate has a total solid content of 25-30% by weight, the rest being water.

After separation of the liquid phase, the digestate fraction obtained in step d) may be subjected to anti-lumping treatment and/or passing digestate through 2 mm sieve. The purpose of this step is to avoid lumping of the digestate. The particles tend to aggregate to each other forming lumps of various sizes. When the digestate is used in asphalt compositions as filler it is, however, important that the filler composition is added and distributed evenly in(to) the asphalt composition. Therefore, an anti-lumping step may be required. Anti-lumping can be performed using any suitable means and methods known in the art. One such method is normally obtained when drying the digestate until constant mass. This is normally obtained when the digestate has between 0-20% moisture, such as 0%, 2.5%, 5%, 7.5%, 10% 12.5%, 15%, 17.5% or 20%. Preferably, the digestate is dried until having between 0-10% moisture, such as 5% or such as 0%, 2%, 4%, 6%, 8% or 10%. The digestate can be dried by subjecting to temperatures of up to about 105°C, such as 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C or 105°C for a period of time sufficient to obtain constant mass. Normally, the time required is from 20 to 30 hours, such as 24 hours.

Step f) is an optional step that is to be selected when particles of smaller sizes are desirable for the specific use of the digestate. If step f) is selected, the digestate obtained from step e) is subjected to drying and/or milling to reduce particle size. Depending on the milling method applied to reduce particle size a previous drying step may be required. Some milling means can only be applied on dry material whereas other means for milling provides sufficient particle size reduction when applied on wet material. The intensity of the milling can be adjusted, for example by adjusting the duration of time of subjecting the digestate and thereby provide various particle size fractions.

The enzymatic and/or microbial waste treatment process described in step a) is applicable to a wide range of waste comprising organic matter. Agricultural material/waste, household waste and municipal waste are examples of sources containing usually a high content of dry matter and a certain content of organic material. Since it is the organic fraction when waste is subjected to enzymatic and/or microbial treatment in a bioreactor in step a) that provide a bioliquid substrate suitable for the anaerobic digestion in step c), waste comprising organic material is a suitable feed. Examples of suitable waste includes MSW, agriculture waste, industrial waste, waste fractions from recycling facilities, and garden refuse. The process is applicable to unsorted as well as to sorted waste. In preferred embodiments, the waste is sorted or unsorted MSW.

In one embodiment step a) to b) is not performed and the digestate is a by-product from an AD process performed on another organic comprising substrate than bioliquid. Such substrate may be source separated household waste, sewage sludge, manure, straw beddings containing manure, cellulosic material, such as paper and pulp, industrial waste such as cuttings from slaughterhouses or floor sweepings from dairies, residues from food or beverage industry or other materials with biogas potential.

The digestate according to the invention can also be obtained from other waste treatment processes that are different from the method described above. Regardless of the method applied to provide the digestate, water, such as municipal solid waste is a preferred waste source due to its composition of mixed organic waste fractions. Thus, the digestate composition obtained appears very robust and it is therefore believed that the same composition of ingredients and their amounts, will be in line with the digestate disclosed herein regardless of the specific organic waste it is obtained from.

EXAMPLES

Preparation of samples composition and size distribution

Example 1 Preparation of composition and size distribution

1. 1 Preparation of di gestate

Samples of starting material for the digestate was obtained from a waste treatment process wherein waste, i.e. , MSW was subjected to enzymatic degradation, and the liquid fraction thus obtained was subjected to anaerobic digestion. The first steps applied for preparing the samples were made as described in WO 2020/002153 A1 Example - Preparation of Digestate additives point 1.1 step 1 , step 2, and 3 three (page 65 line 23 to page 67 line 24) hereby incorporated by reference.

The produced bioliquid was used for biomethane production in a full-scale anaerobic digester. The anaerobic digesters were four 4.300 cubic meter liquid filled tanks (0 31 x 8 m) where the biological conversion took place. The tanks were equipped with four agitators for each tank. The effluent was discharged by bottom extraction to a hygienisation system where the digestate is heated to 70°C for 1 hour. The hygienised digestate was dewatered with decanter centrifuges to produce the solid digestate (here termed digestate) with a suspended dry matter of approximately 25-45 wt%. A cationic polyacrylamide flocculant was used to aid the de-watering process. The concentrated digestate from anaerobic digestion periods with stable biogas production was collected in 500 L pallet tanks and transported to the Renescience laboratory in Denmark by currier.

The 300-400 kg monthly samples were subjected to drying in a EMMERT UF 750 conventional oven at 105 °C for 24 hours. The material was loosened to brake up lumps created by agglomeration during batch drying by running it through an Retsch SM300 mill with a 2.0 mm screen inserted.

The product thus obtained was analysed by laser diffraction on a HELOS/KF Particle Size Analyser at 1 .5 bar with vibrational in feeder with 65% feed rate in order to determine the particle size fractions of the composition.

Samples were collected monthly in August 2021 , September 2021 , October 2021 , December 2021 , January 2022, February 2022, March 2022, April 2022, May 2022, June 2022 and August 2022.

7.2 Size distribution determination

All samples were analysed by laser diffraction in order to determine the size fractions of the composition. Table 1 discloses the percentage of composition passing through various sieve sizes after milling from the samples collected in August 2021 (1), September 2021 (2), October 2021 (3), November 2021 (4), December 2021 (5), January 2022 (6), February 2022 (7), March 2022 (8), April 2022 (9), May 2022 (10), June 2022 (11) and August 2022 (12) respectively.

Table 1 Size fractions of the particles in the digestate of samples loosened through a mill with a 2 mm screen Sample 1 2 3 4 5 6 7 8 9 10 11 12

1.2 Loss on ignition

Table 2 discloses the loss on ignition, LOI, at 550°C and 950°C after a method adapted from EN 1744-1 :2019. The digestate samples were dried at 105°C until constant weight and milled on a

Retsch SM300 mill with a 2.0 mm screen inserted to loosen agglomerates formed by batch drying. Porcelain crucibles was dried at 550°C overnight, placed in a desiccator to cool, weighed and approx.

2.5 g digestate sample was added to a crucible in triplicate for each sample. The digestate samples were subsequently placed in a muffle furnace at 550±25°C until constant weight, placed in a desiccator to cool and weighed. The digestate samples were then placed in a muffle furnace at 950±25°C until constant weight, placed in a desiccator to cool and weighed. The loss of ignition was calculated from the data according to EN 1744-1 :2019 and the results is seen from Table 2.

Table 2: Volatile solids (loss on ignition) at 550 and 950°C

Asphalt Concrete mixture

Example 2 Mixing the aggregate(s), filler(s) and binder(s) with digestate to obtain an asphalt concrete (AC) mixture

Two standard samples of asphalt mixture were prepared. The recipe used was to produce an AC surf 11 top course asphalt, one with 6.2 wt% penetration grade 70/100 and one with 5.8 wt% penetration grade 40/60 bitumen as shown in Table 3. Two samples where 50% filler material was replaced with dried digestate (AC Sample 1 : Sample 9, April 2022, AC Sample 2: Sample 6, October 2021 and AC Sample 3: Sample 3, January 2022) was produced. The dried digestate is used as a mixed filler and replaces both 50% filler and some fine aggregates (natural sand and crushed sand). The aggregate grading is shown in Table 3 and the recipes with binder is shown in Table 4.

For sample set a, 6.2 wt% bitumen penetration grade 70/100 was used and for sample set b, 5.8 wt% bitumen penetration grade 40/60 was used. In Table 4 are the composition of the entire mixture seen with both aggregates and bitumen included. Table 4: Asphalt concrete sample recipes with binder

AC AC AC

AC Sample

Sample Sample Sample

1 b, 2b, 3b

0a 1a 0b

Before the mixing begins, mixing containers were pre-heated to 155 ± 25 °C. Then aggregates, preheated to 155 ± 25 °C, were weighed into the containers. Aggregates were mixed together.

Bitumen used in this assay was then added until reaching the desired binder content in the asphalt mixture composition. Filler was then added. All components were then thoroughly mixed for approximately 3-5 minutes and continuously mixed in said containers, until a uniform mixture was obtained, with the aggregate(s) being entirely coated with the binder(s). The mixture was poured into a suitable form and manually dispersed before it was compacted. The asphalt was left to cool to 90- 100°C, measured by an IR handheld thermometer, before the final compacting. The mixture was then allowed to cool to room temperature over night before the slab is unmoulded and stored in a climate chamber at 15°C to allow the binder(s) to harden before preparing test specimens. 2.2 Indirect Tensile Strength (ratio) of asphalt compositions provided in Example 2

The asphalt compositions described in Example 2 comprising the digestate described in Examples 1 and 2 are subjected to test for indirect tensile strength according to EN 12697-23:2017.

Four batches a 25 kg batch of the above asphalt composition (AC 11 Surf course) was made with 70/100 or 40/60 penetration grade bitumen. The test was performed within 42 days after production of the test specimens. Three produced test specimens were cut from each of the produced asphalt slap and analysed as is and the indirect tensile strength of the dry specimens was recorded, ITSdry. Three test specimens were soaked in water at 40°C for 72 hours and the indirect tensile strength was recorded for these specimens, ITSwet- The indirect tensile strength ratio was calculated as ITSwet relative to ITSdry.

Table 5: Indirect tensile strength (ratio) for AC samples

SAMPLE DRY SAMPLE WET SAMPLE RATIO

DESCRIPTION (ITSDRY) (ITSWET) (ITSR)

The tensile strength of the samples tested are comparable to the control sample and within commonly accepted standard. The indirect tensile strength ratio is higher than the 80% required for all samples.

2.3 Tri-Axial rutting tests of asphalt compositions provided in Example 2

The asphalt compositions comprising the digestate described are subjected to Tri-Axial rutting tests according to EN 12697-25:2016, method B.

Table 6; Tri-axial rutting of AC samples

The tested samples with 50% replacement of filler material with dried digestate shows improved rutting performance compared to the reference samples, both in mixtures with 6.2% 70/100 penetration grade and 5.8% 40/60 penetration grade bitumen

2.4 Rheology of binder from asphalt compositions provided in Example 2

The stiffness and phase angles were tested for the bitumen extracted from the samples. A master curves at 20°C was constructed for the Effect on stiffness (G*), Figure 1 and 2 and for the effect on phase angle, Figure 3 and 4, according to EN 12697-22:2018. Figure 1 shows master curves with shear stress modulus (G*) [Pa] as a function of angular frequency for fresh and aged sample 0a; reference sample with wigras 40 filler in an AC11 surf asphalt sample with 6.2% 70/100 bitumen, and 1a; sample with 50% filler material replaced by digestate. Figure 2 shows master curves with shear stress modulus (G*) [Pa] as a function of angular frequency for fresh and aged sample 0b; reference sample with wigras 40 filler in an AC11 surf asphalt sample with 5.8% 40/60 bitumen, and 1b; sample with 50% filler material replaced by digestate. Figure 3 shows master curves with phase shift angle (6) [°] as a function of angular frequency for fresh and aged sample 0a; reference sample with wigras 40 filler in an AC11 surf asphalt sample with 6.2% 70/100 bitumen, and 1a; sample with 50% filler material replaced by digestate. Figure 4 shows master curves with phase shift angle (6) [°] as a function of angular frequency for fresh and aged sample 0b; reference sample with wigras 40 filler in an AC11 surf asphalt sample with 5.8% 40/60 bitumen, and 1b; sample with 50% filler material replaced by digestate. An investigation of the master curve shows whether the tested samples provide an equally balanced effect over the whole width of the spectrum of complex shear modulus G*, measured in Pascal (Pa), and the phase shift angle 6, measured in degrees (°), vs. angular frequency measured in radian per second (co or rad/s). The change from fresh to aged samples shows the effect of aging on the sample and the shorter the distance between the master curve for the fresh and aged sample, the less effect aging has on the sample. In relation to the effect on phase angle, values above the master curve for the sample used for comparison means that the tested sample is more liquid than the reference and such samples are accordingly less elastic than the reference. If the samples shown an equally balanced effect over the whole width of the spectrum, it can be concluded that the bitumen samples were not influenced in a similar way to that experienced when polymer modifying bitumen with addition of various polymers.

The curves from all fresh bitumen samples extracted from asphalt samples with digestate incorporated provide the same shape as the bitumen extracted from the fresh reference sample without digestate. Thus, the tested samples are equally balanced over the whole width of the spectrum for both shear stress modulus, describing the stiffness of the binder, and the phase shift angle. In Table 7 are that values for shear stress modulus and phase shift angle at 1.59 Hz corresponding to 10 rad/sec seen for the fresh and the aged sample. 10 rad/sec corresponds to the influence of a truck tire travelling at 80 km/h. [The Shell Bitumen Handbook, 6 ^th Edition, 2015, page 141]

The ratio for shear stress modulus at 10 rad/sec between bitumen extracted from fresh and aged samples with digestate and without was smaller in a blend with a 70/100 bitumen and slightly larger in a blend with 40/60 bitumen. Thus, a tendency towards a less stiff asphalt when digestate interacts with the softer bitumen, indicating that the digestate has a rejuvenating effect on the bitumen.

The ratio for phase shift angle at 10 rad/sec between bitumen extracted from fresh and aged samples with digestate and without was slightly higher in a blend with a 70/100 bitumen and not significantly different in a blend with 40/60 bitumen. Thus, a tendency towards increased elasticity of the bitumen was observed when digestate interacts with softer bitumens. Table 7

AC samples prepared with reclaimed, limestone or Digestate

Example 3 Testing of AC samples prepared with reclaimed, limestone or novel filler

Three samples of asphalt mixtures were prepared. The recipe used was to produce an AC surf 11 asphalt as shown in Table 9 and 10. In the first sample, a limestone filler - Wigras 40K - was used as filler material. Further, a sample was prepared where reclaimed filler from the bag house fines from the dust collection devices in an asphalt production plant consisting mainly of milion and quartz filler material, was used. The third sample was prepared with a 50/50 % mixture of reclaimed filler and digestate (sample 9) from example 1 and 2 as filler material and sand equivalents (fine aggregates). The recipes were adjusted to have the same amount of fines in the mix, the particle size distribution was analysed with laser diffraction prior to preparing the recipes.

Table 8: Amount of fine aggregates in filler products

* Standard product value (Materials Science, Engineering, 2013)

The aggregate grading is seen from Table 3 in Example 1. The fines content was kept constant in all samples. The aggregate amounts are seen from Table 9.

Table 9

Table 10

Before the mixing begins, mixing containers were pre-heated to 155 ± 25 °C. Then aggregates preheated to 155 ± 25 °C, were weighed into the containers. Aggregates were mixed together. Bitumen used in this assay was then added until reaching the desired binder content in the asphalt mixture composition. Filler and in asphalt sample 1d also digestate were then added. All components were then thoroughly mixed for approximately 3-5 minutes and continuously mixed in said containers, until a uniform mixture was obtained, with the aggregate(s) being entirely coated with the binder(s). The mixture was poured into a suitable form and manually dispersed before it was compacted. The asphalt was left to cool to 90-100°C, measured by an IR handheld thermometer, before the final compacting. The mixture was then allowed to cool to room temperature over night before the slab is unmolded and stored in a climate chamber at 15°C to allow the binder(s) to harden before preparing test specimens.

3. 1 Indirect tensile strength and tri-axial rutting test of asphalt compositions comprising the filler composition in combination with reclaimed filler

The asphalt samples produced in Example 3 were analysed for indirect tensile strength according to EN 12697-23:2017 and Tri-Axial rutting tests according to EN 12697-25:2016, method B. The results are apparent from Table 11.

Table 11

It is seen from Table 11 that none of the samples fail at 10.000 loading cycles. Further, when comparing using limestone as filler material and reclaimed aggregates from the filter unit used for aggregate drying during asphalt production, the latter stiffens the asphalt giving a higher indirect tensile strength, but also a higher creep rate (f _c ) and cumulative axial strain after 1000 loading cycles (£1000) showing that asphalt with reclaimed filler is more susceptible to permanent deformation compared to an asphalt with the premium limestone as filler. If replacing 50% of of the reclaimed filler with digestate, the softening

Thus, when having aggregates readily available, having an asphalt plant with or near a stone quarry, continuously producing dust which can be collected and used as filler material, but needing or wanting a slightly softer, less stiff asphalt, reclaimed filler can with advantage be mixed with dried digestate, rather than using the premium limestone as softener. If an ITSR target of 90%, at least 85% and a cumulative axial strain of target 0.8%, maximum 1 % is needed for a certain recipe, a mixture of 30% dried digestate and 70% reclaimed filler would be optimal in an AC 11 surface course recipe bound by 5.9% 40/60 grade bitumen. This calculation is visualised in Figure 5. Figure 5 shows response optimization of mixture of limestone (LS), reclaimed filler (RF) and digestate (digestate) for ITSR value of 90% and permanent deformation after 1000 cycles as low as possible based on modelling of predictions of ITSR [%] and £1000 [%] from data in Example 3 as a stepwise mixtures regression performed in statistical software: Minitab 21.1.

3.2 Penetration and softening point of bitumen extracted from fresh and aged asphalt composition comprising the filler composition

Penetration and softening point of bitumen extracted from an asphalt composition were tested. Two references and two samples with 50% replacement of filler with dried digestate (Sample 9 from Example 1) of 25 kg batches of the above asphalt composition (AC 11 Surf) was made. The test was performed within 1.5 hours after filling the moulds with liquid bitumen for both virgin and aged test samples. The aging was performed by leaving a sample for 3 weeks aging in a closed internal ventilated oven at 85°C. This corresponds to approximately 6 years of service life. The aging can be made by other commonly applied aging methods, such as the Rolling Thin Film Oven Test (RTFOT), temperature ageing and the Pressurised Ageing Vessel (PA ) test. The bitumen from the fresh and aged samples was extracted with dichloromethane prior to analysis according to EN 12697-1 :2020 soxhlet extractor method.

The penetration tests were performed using the needle penetration test in accordance with EN 1426:2015. The penetration is expressed as the distance in tenths of a millimetre that a standard needle will penetrate vertically into a sample of the material under specified conditions of temperature, load and loading duration.

The softening point tests were performed using the Ring and Ball test in accordance with EN 14271427:2015. The softening point is defined as the mean of the temperatures at which two discs of bituminous binders, cast in shouldered brass rings, heated at a controlled rate in a liquid bath while each support a brass ring, softens enough to allow each ball to fall a distance of 25.0±0.4 mm.

As shown in Figure 4 these tests showed that penetration of the binders extracted from the asphalt composition comprising digestate are softer than the penetration of binders extracted from the reference. The softening point numbers are matching with penetration expressed in the Penetration Index (PI) relating to the temperature susceptibility, as described in The Shell Bitumen Handbook by Hunter, Self and Read (2003) and therefore meets the requirement of value of -1.5 to 0.7 with bitumen of lower and negative PI softening more readily than those with higher PI. T 500 ■ log(P25°c) ^— 1952 - 50 ■ log(P ₂₅ = _c ) + 120

The softening points in all samples were far above the minimum value of -1.5.

The below Table 12 shows the results obtained in the penetration and softening point tests for the reference sample and for the asphalt samples with 50% filler replaced with dried digestate (Sample 9), respectively, shortly (within 1.5 hours) after addition of the filler composition and after ageing.

Table 12: Penetration and softening point data for AC samples Stone Mastic Asphalt mixture

Example 4 Mixing the aggregate(s), filler(s) and binder(s) with digestate additive to obtain a stone mastic asphalt (SMA) mixture composition to evaluate filler properties

Three standard samples of mastic asphalt mixture were prepared. The recipe used was to produce an SMA 10 asphalt, with 6.6 wt% penetration grade 40/60 bitumen as shown in Table 14. 5.0 wt% of the total aggregate, Bardon Hill fine aggregate (with a density of 2800 kg/m ³ ) amount was replaced with dried digestate in the SMA sample produced. The digestate used was an equal mixture of Sample 1 , 2 and 3 sieved on a 1.0 mm sieve prior to usage. The particle size distribution of the mixture was analysed by dry sieving and is shown in Table 13.

Table 13: Particle size distribution for mixture of Sample 1 , 2 and 3 sieved through 1 mm sieve

Table 14: Grading for SMA samples with and without digestate replacement of filler

The combined density for each aggregate size of granite aggregates and digestate combined was calculated as the density of the dried digestate was measured to be 1770 kg/m ³ . A volumetric gradation was produced for each SMA mixture based on the different densities of the aggregates to provide an accurate fit to the volume gradation of the control SMA mixture.

The volumetric proportions of the SMA mixtures were calculated as the VMA, Voids in mineral aggregate [% of bulk volume], is calculated from the bulk specific gravity of the aggregate, G _S b, and the bulk specific gravity of the compacted mixture, G _m b, and the aggregate in total percent of total dry weight of the total mixture, P _s .

VMA = 100 The aggregates were heated to approximately 160°C and then mixing the aggregates with hot bitumen. The bitumen was preheated to approximately 160°C. The aggregates and the bitumen were then mixed in a hot mixing bowl and afterwards, the bitumen coated material was transferred to a cylindrical mould with an internal diameter of 100 mm. The SMA samples was compacted to the target void content using a gyratory compactor. The target air void content was set to 7.4% for the sample with 5.0% dried digestate. The target density was set to 2283 for the sample with 5% digestate. The sample was gyrated for approximately 310-25 times as the density of the mixture did not meet the target. The air void content is therefore higher for the sample containing digestate. The stiffness was determined according to EN 12697-26:2018. The test determines the stiffness modulus based on a sequence of haversine waveform loading pulses applied along the vertical diameter of the specimen. In addition, two linear LDVTs were attached to record the amplitude of the peak horizontal deformation during the test. Once an initial value has been recorded, the cylindrical sample is rotated to find the second modulus value along the perpendicular diameter. The mean stiffness modulus is then determined as the mean value of the two results. The stiffness modulus was calculated according to the equation below, where the stiffness modulus, S _m [MPa], is calculated from the peak vertical load, F [N], the Poisson’s ratio, v, assumed to be 0.35, the mean amplitude of the horizontal deformation obtained from the five load pulse applications, z [mm], and the thickness of the test sample, h [mm]:

Table 15

It is seen that the air void content is slightly higher for a SMA Sample 1a with 4.7 wt% digestate, but the stiffness is within the same range as a sample of reference SMA, with a tendency towards the sample being stronger due to the digestate reaction with bitumen and strengthening the mixture. The results show that it is possible to produce good SMA with digestate. Two samples of SMA mixture of unmilled, unsieved digestate, Sample 6 (Jan22), were produced with 2.5 and 5 wt% digestate in the mixtures. The samples were prepared with the same procedure. The sample particle size distribution analysed by dry sieving is seen from Table 16.

Table 16: Particle size distribution for mixture of Sample 1, 2 and 3 sieved through 1 mm sieve

The graduation is similar to the sieved sample and is expected to behave similarly. The aggregate grading for the produced SMA samples is seen from Sample 17.

Table 17: Grading for SMA samples with and without digestate replacement of filler The target air void content was set to 7.4% for both the sample with 2.5 and 5% dried digestate. The target density was set to 2310 and 2283 kg/m3 for the sample with 2.5 and 5% dried digestate respectively.

The indirect tensile strength was conducted in triplicate at 20°C following the EN 12697-23 standard.

The results show that although the unsieved digestate modified SMA mixtures were harder to compact and obtained a higher final air voids content compared to the reference, the mechanical properties (stiffness and strength) are similar for the digestate-SMA mixtures compared to the control SMA mixture and it is feasible and may even be beneficial to replace 0-5% aggregates with dried digestate in SMA mixtures.