Technical Field

The invention is related to cold asphalt additives.

The invention is particularly related to cold asphalt additives with waste oil.

Prior Art

Bitumen is a substance that can be found in solid, semi-solid, or liquid forms with hydrocarbon composition obtained by natural precipitation of crude petroleum or by distillation in refineries. The main use of bitumen is asphalt mixtures. Asphalt mixtures, which is a mixture of mineral aggregates and bitumen, is a widely used engineering material in the construction industry. Asphalt has a wide range of uses, especially in road construction, road maintenance, and insulation material.

Asphalt applications are generally carried out at high temperatures such as 150-200°C. Asphalt, which can be applied at temperatures of 25°C and below, is called cold asphalt. Cold asphalt applications include repair of deterioration and potholes on roads, manhole covers, chimneys and grids, manholes, and ramps. Some additives are added to asphalt mixtures so that asphalt can be processed at 25°C and below temperatures. Said additives must be compatible with bitumen.

The present cold asphalt additives either cannot provide sufficient processibility for the asphalt at room temperature or are softer than desired, therefore cannot be compressed and provide sufficient endurance after the asphalt mixture is laid cold asphalt mixtures which do not have sufficient processability harden in the bags and cannot be laid. Since cold asphalt additives are generally used for asphalt repair works and patching, and they are intended to be laid rapidly in short periods such as 30 minutes to open for traffic, good processibility is one of the most important criteria. In the USA patent application number US 2011/0041728 A1 , cold bitumen mixtures are described. In the said mixtures, polymerized fatty acids are used to improve the processibility of cold asphalt. Some of the present cold asphalt additives contain chemicals such as kerosene that may be harmful to human health. Cold asphalt additives are needed that do not contain chemicals harmful to human health and the environment and provide optimum processibility at low temperatures during the process are needed.

Another problem experienced in the use of present cold asphalt additives is the fact that asphalt costs increase since the additives are added to bitumen at high percentages. Using wastes for a more sustainable manufacturing process and products is important in terms of utilizing natural resources more efficiently. Also, a lot of manufacturing firms supply their raw materials from abroad. Logistics and customs costs are added because of the raw materials supplied from abroad and it is reflected in the costs of the end product. Therefore, solutions for decreasing additive costs are needed.

As a result, an improvement in the related technical field is needed due to the inadequacy of the present solutions on the subject.

Purpose of the Invention

The present invention is related to cold asphalt mixtures that meet the aforementioned requirements and bring further additional advantages, comprising a cold asphalt additive for use in cold asphalt applications and the said additive.

The primary purpose of the invention is to provide cold asphalt mixtures which have sufficient processibility during asphalt laying and patching operations of the asphalt at low temperatures.

Another purpose of the invention is to provide cold asphalt mixtures that do not harden in the packaging or during storage.

Another purpose of the invention is to provide cold asphalt mixtures that provide for sufficient compressibility and endurance levels after the laying.

Another purpose of the invention is to provide cold asphalt mixtures that do not contain volatile or unsavory chemical substances that harm human health or the environment.

Another purpose of the invention is to provide cold asphalt mixtures whose costs are reduced and additives whose asphalt additive raw material input costs are reduced. Another purpose of the invention is to provide cold asphalt mixtures which contribute to the recycling of waste oils. It is known that around 350 thousand tons of waste oil are discharged annually in the food industry. The used oils create waste after usage and most of these wastes are immediately destructed or used to manufacture products that have low economical value (such as animal feed, fertilizer, etc.). Today, with the developing technology, increasing the usage area of the wastes and recycling the same in the industry is aimed and therefore, the losses are minimized in the way to gain the maximum benefit from the raw material. Apart from that, the mixing of the household oil wastes into the drain waters affects the quality of the used water and the ecosystem negatively and poses a threat to human health as well. Household oil waste collection centers enable the use of household waste oils as raw materials. Collection of the waste oils to prevent their effect on environmental damage, reuse them, and raising environmental consciousness is the most reasonable precaution to be taken. In this way, producing different chemical products which will bring added value will be possible.

Structural and characteristic features of the invention, as well as all the advantages, will be understood more clearly thanks to the figures below and the detailed description written about these figures, and the evaluation should be made in consideration of these figures and the detailed description.

Detailed Description of the Invention

In this detailed description, the preferred embodiments of the subject cold asphalt additive and the cold asphalt mixture are described only for better understanding the subject and in a way not to create any limiting effect on the same.

A cold asphalt additive suitable for the present invention comprises vegetable waste oil and at least one ester obtained from the esterification reaction of a fatty acid with an alkanol amine. The additive also comprises at least one amidoamine obtained from the condensation reaction of the said fatty acid with a polyamine.

As per the natural composition of the bitumen, asphaltene is a material having a dispersion form with different phases comprised of aromatic oil and resins. Due to its hydrophobic nature and the polar functional groups in the asphaltene, it is a compatible material with the hydrocarbon-based solvents having hydrophobic structure, fatty acids, and vegetable waste oils. In this application, the expressions of “vegetable waste oil” and “waste oil” mean vegetable waste oils that are obtained after the vegetable oils are used once or more than once, soap- stocks from the vegetable crude oil refining industry (the byproduct separated after the neutralization of the free fatty acids with caustic and washing process in the refinery of vegetable crude oils), tank floor sediments, oily soils, used frying oils, oils obtained from the oil retainers of various facilities and expired vegetable oils. Vegetable oils can be oils obtained from oily plant seeds such as olive, sunflower, corn, cotton, soybean, canola, and safflower. Also, as vegetable waste oil, waste oils obtained from coconut oil, palm oil industry can be used.

Waste oils obtained with the invention can be filtered only to remove the remaining solid particles within. Apart from that, the waste oils obtained can be used in the preparation of the cold asphalt additive of the invention without being subjected to any pre-treatment.

In this application, “cold asphalt” and “cold asphalt additive" are used to mean an asphalt mixture that can be processed at lower temperatures than 25°C and an additive that provides for the processibility of asphalt mixtures at lower temperatures than 25°C respectively.

The subject cold asphalt additive comprises at least one fatty acid chosen from fatty acids which have 10 carbon to 20 carbon and ester or esters obtained from the reaction of at least one alkanol amine chosen from monoethanolamine (MEA), trisopropanol amine (TIPA), triethanolamine (TEA), diethanolamine (DEA) and monoethanolamine (MEA). Among the suitable fatty acids, capric acid; undeconic acid, myristic acid, stearic acid, linoleic acid, arachidic acid, behenic acid, elaidic acid, lauric acid, oleic acid, palmitic acid, and sunflower fatty acid are present. The esterification reaction is performed at a particular temperature, preferably at 140-180°C. In the present invention, it was found that due to the compatible interaction between the fatty acid and amine compounds with bitumen, the esters obtained from alkanol amines effectively improve the performance of the cold asphalt additives. Alkanol amines are more cost-effective compared to amine compounds such as polyamines. By this means, the cold asphalt additives are rendered economically efficient. The obtained esters strengthen the compatibility between the bitumen and the aggregate by interacting with both the polar carboxylic groups in the bitumen and the active groups on the aggregate surface, with the help of the amine groups they have along the carbon main chain of the alkanol amines. The esters obtained thanks to the long hydrocarbon chain and hydrophobic structure of the fatty acids have a high affinity with bitumen and they are embedded in the bitumen to strengthen the compatibility with bitumen.

Among the preferred fatty acids, fatty acids that have 12 to 18 carbon are present. Among the said fatty acids with 12 to 18 carbon, lauric acid; oleic acid, palmitic acid, and sunflower fatty acid are present respectively.

In a preferred embodiment of the invention, the fatty acid is lauric acid and the said alkanol amine is chosen from monoethanolamine (MEA), trisopropanol amine (TIPA), triethanolamine (TEA) diethanolamine (DEA), and monoethanolamine (MEA).

In a preferred embodiment of the invention, the fatty acid is oleic acid and the said alkanol amine is chosen from monoethanolamine (MEA), trisopropanol amine (TIPA), triethanolamine (TEA), diethanolamine (DEA), and monoethanolamine (MEA).

In a preferred embodiment of the invention, the fatty acid is palmitic acid and the said alkanol amine is chosen from monoethanolamine (MEA), trisopropanol amine (TIPA), triethanolamine (TEA), diethanolamine (DEA), and monoethanolamine (MEA).

In another preferred embodiment of the invention, the fatty acid is sunflower fatty acid and the said alkanol amine is chosen from monoethanolamine (MEA), trisopropanol amine (TIPA), triethanolamine (TEA) diethanolamine (DEA), and monoethanolamine (MEA).

In a preferred embodiment of the invention, the fatty acid comprises a mixture of the fatty acids that have 12 to 18 carbon and the said alkanol amine is chosen from monoethanolamine (MEA), trisopropanol amine (TIPA), triethanolamine (TEA) diethanolamine (DEA) and monoethanolamine (MEA).

The most preferred alkanol amine is triethanolamine (TEA). Triethanolamine (TEA) is less expensive than trisopropanol amine (TIPA) and more available, less volatile than diethanolamine (DEA) and monoethanolamine (MEA), and more reliable in terms of process.

The most preferred alkanol amine is triethanolamine (TEA). Triethanolamine (TEA) is less expensive than trisopropanol amine (TIPA) and more available, less volatile than diethanolamine (DEA) and monoethanolamine (MEA), and more reliable in terms of process. The general structure of the ester obtained from the reaction of fatty acids and TEA is shown in the following.

The additive can also comprise an amidoamine compound or its compounds obtained from the said reaction of at least one fatty acid chosen from fatty acids that have 10 carbon to 20 carbon and at least one polyamine chosen from diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA). Among the suitable fatty acids, capric acid; undeconic acid, myristic acid, stearic acid, linoleic acid, arachidic acid, behenic acid, elaidic acid, lauric acid, oleic acid, palmitic acid, and sunflower fatty acid are present. Amidoamines obtained from the said fatty acids and polyamines interact with both the polar functional groups in the asphaltene structure and the active positively charged groups on the aggregate surface to increase the compatibility of the bitumen in the asphalt mixture with both the additive and the aggregate.

Among the preferred fatty acids, fatty acids which have 12 to 18 carbon are found. Among the said fatty acids which have 12 to 18 carbon, lauric acid; oleic acid, palmitic acid, and sunflower fatty acid are present.

In a preferred embodiment of the invention, the fatty acid is lauric acid and the said polyamine is chosen from diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA). In a preferred embodiment of the invention, the fatty acid is oleic acid and the said polyamine is chosen from diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA).

In another preferred embodiment of the invention, the fatty acid is palmitic acid and the said polyamine is chosen from diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA).

In another preferred embodiment of the invention, the fatty acid is sunflower fatty acid and the said polyamine is chosen from diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA).

In a preferred embodiment of the invention, the fatty acid comprises a mixture of the fatty acids that have 12 to 18 carbon and the said polyamine is chosen from diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA).

The most preferred polyamine is diethylenetriamine (DETA). The general structure of the amidoamine obtained by the reaction of fatty acids and DETA is shown in the following.

The obtained ester compound or compounds are mixed with vegetable waste oil and the final cold asphalt additive is obtained. Thanks to the use of vegetable waste oils, the use of solvent in the additive is decreased and the cost of the cold asphalt additive is reduced. In the additive suitable for the invention, the total percentage by weight of the ester compound or compounds is preferably 1-20%. Under this percentage, sufficient functional amine concentration which will strengthen the interaction with bitumen cannot be provided. Above this concentration, the slider property of the additive fades and the processability weakens. The total percentage of the ester compound or compounds by weight is more preferably 5-15%. The desired amine concentration and processability are found to have been provided in additives having this concentration.

The total percentage of the vegetable waste oil to the cold asphalt additive by weight is preferably 30-90%, more preferably 60-90%. It was found that the cold asphalt additive prepared in the said percentages shows a synergic performance in terms of both processability and endurance.

Also, at least one hydrocarbon-based solvent can be added to the additive before or after adding the vegetable waste oil or together with the vegetable waste oil. The said hydrocarbon-based solvent is preferably linear alkylbenzene and/or heavy alkyl benzene having the formula C ₆ H ₅ CnH _2n+i . Alkylbenzene is preferred since it has an apolar hydrophobic long hydrocarbon chain and it is a solvent compatible with bitumen. The additive can also contain mineral oils.

The subject cold asphalt additive is used in the preparation of the cold asphalt mixtures. Therefore, the obtained additive is mixed with bitumen. Preferably, the percentage of the cold asphalt additive to the cold asphalt mixture is 25-35% by total weight, and more preferably 30%.

Sample 1

Fatty acid and an alkanol amine are reacted through esterification for 8 hours at 160°C, atmospheric pressure. 9 gr each was taken from the products obtained with this reaction and these were mixed with particular amounts of C12-C15 linear alkyl benzene at room temperature. Two of the mixtures prepared to prepare the waste oil additive were added with vegetable waste oil at 60 and 90% percentages by total weight respectively, and the Additive III and Additive IV were obtained. The waste oil used is mostly comprised of sunflower waste oil supplied from dining halls. Waste oils that have an acid index of 10-20 mg KOH/g, iodine number of 70-80 mg l ₂ /100 g, and saponification index between 200-220 were used.

The amounts of fatty acid, alkanol amine, solvent, and waste oil used in the preparation of the additives are given in Table I. able

Sample 2

70 gr each additive-free bitumen with 160/220 penetration degree (Bitumen 160/220) were taken and each of them was heated up to 120°C. 30 gr each was taken from the obtained additives (Additives l-IV) and heated up to 60°C, then mixed separately with the bitumen samples taken at room temperature. The temperatures of each one of the obtained mixtures were measured to be 100°C. As the temperatures go down to 25°C from 100°C, the viscosities of the mixtures and therefore their resistance to mixing were measured as they get colder. With the purpose of comparison, the viscosity of the Bitumen 160/220 was measured at varying temperatures. In this way, the viscosity of the additive-free bitumen and doped bitumen mixtures was measured and their processability was tested quantitatively. The obtained results are given in Table II in the cP unit.

Table 2

Results

Since additive-free bitumen becomes unmixable after 70°C, its viscosity values could not be measured. In the doped bitumen samples, measurements can be taken even at temperature falls up to 30°C. The processability of the additives was determined by the comparison of viscosities at downward temperatures. Parallel results would be obtained for temperatures lower than 30°C.

Esters provide surprise processability for the bitumen due to their hydrophobic structure and amine content. Esters interact with both the polar functional groups and the active positively charged groups on the aggregate surface and increase the processability of the bitumen in the asphalt mixture. There is no quantitative testing method for better processability in the literature. With the viscosity measurement method at various temperatures developed with this invention, the bitumen processability was measured and the performance of the additives was determined.

Even though the costs of the vegetable waste oil additives (Additive II and Additive IV) are very low, it was shown the processibility of the same surprisingly increases and it shows a better performance than the other additives when used with the esters suitable for the invention, compared to plain bitumen. Since recycling unused waste oils is possible with this method, the present invention provides economical gain. Also, the subject additives do not comprise high volatility components and therefore, less savory products can be obtained.