FIELD OF THE INVENTION

The present invention is in the field of an inductive bituminous waterproofing, a road structure comprising said waterproofing, a method of applying a sheet of waterproofing to a surface, removing the sheet of waterproofing from said surface, repairing said waterproofing, wherein the surface is selected from a multilayer civil engineering system, such as a flexible surfacing layer on orthotropic steel deck bridge, a roof, a roadway pavement, and combinations

thereof .

BACKGROUND OF THE INVENTION

Waterproofing relates to making an object or structure waterproof or water-resistant so that it remains relatively unaffected by water and that it resists ingress of water typically under specified conditions for a specific case. Waterproof typically refers to a lack of penetration of water through said waterproofing, possibly under pressure. Permeation of water vapor through a waterproofing is

preferably limited or prevented. Items may also be

waterproofed by applying water-repellent coatings. In construction, a building or structure is waterproofed with the use of so-called membranes or coatings to protect it and to preserve it's structural integrity.

A bituminous waterproofing is often used in road structures. A waterproofing is typically applied on a road structure by heating with a gas burner or the like.

Waterproofing, which are often referred to as waterproofing membranes, typically consist of thermoplastic, rubber, or coated-fabric materials. The

materials are used in a system to which the waterproofing is applied to prevent the ingress of water, such as into foundations, roofs, walls, basements, buildings, and steel deck bridge structures when properly installed. The most common type of sheet based waterproofing is a bituminous waterproofing membrane. This type of waterproofing is typically adhered to a substrate surface using blowtorches. The waterproofing comprises a hot polymer modified

bituminous binder functioning as adhesive. An important requirement for the application of a waterproofing is in addition to a waterproofing capacity it also provides sufficient bonding or adhering to the surrounding materials. Earlier investigations have shown that the bonding

strength of waterproofing layers to the surrounding

materials has a strong influence on the structural response thereof .

A disadvantage of existing waterproofings in road structures is that it is difficult to apply such

waterproofings , and even more difficult to maintain and remove such waterproofings .

Some documents relate to bituminous coatings, but no so much to waterproofings . US 4,849,020 A1 recites an improved asphalt composite utilizing a mixture of asphalt and a lossy microwave absorptive material normally in a granular form and dispersed homogeneously throughout the asphalt matrix. The use of a microwave material enhances removal,

reconditioning and reforming the asphalt during patching or repair operations which rely upon microwave radiation heating. WO 2002/050375 A1 recites a road construction and a method for realizing such a road construction comprising a foundation layer, a road surface provided on top of the foundation layer, and a binder course provided between the foundation layer and the road surface for bonding the road surface to the foundation layer. In the binder course metal particles are incorporated. The metal particles form threads and are iron particles. The binder course comprises bitumen that is incorporated in a fleece. WO 2010/031530 A1 recites a method for the production of a thin road surface that can be installed in sheets and comprises high-strength, hard chips, embedded in a bitumen-based carrier layer. It further relates to a method for installing such a pre-manufactured road surface that can be installed in sheets.

The present invention therefore relates to an improved waterproofing and methods of handling this waterproofing, which solves one or more of the above problems and drawbacks of the prior art, providing reliable results, without jeopardizing functionality and advantages.

SUMMARY OF THE INVENTION

It is an object of the invention to overcome one or more limitations of waterproofings of the prior art and methods of handling these waterproofings and at the very least to provide an alternative thereto. Thereto inductive agents, such as metallic fibres or other metallic particles, which may be of various sizes and nature, are incorporated into the modified and non-inductive bituminous binder, which may be coated on the outer-surfaces of a waterproofing sheet, which is also referred to as membrane, or

waterproofing membrane. Such a waterproofing may typically have a thickness of <10 cm, preferably <1 cm, such as 2-5 mm. The present waterproofing is typically a multilayer structure comprising a reinforcement layer (4), and at least one waterproofing (2a) layer, the waterproofing comprising an electromagnetically inductive agent (2c) , at least one bituminous material (2b) layer, the bituminous material comprising at least one bituminous binder, and at least one carrier sheet (9) . When for instance an induction heating apparatus or a microwave apparatus generates a typically alternating electromagnetic field heat is generated thereby in the inductive agents of the waterproofing. The

electromagnetic field may be applied by a source using 0.1- 10 kV of power, preferably 0.2-5kV, such as 0.55 kV supplied power, and using an alternating electromagnetic field with a frequency of 10-300 kHz, preferably 20-200 kHz, such as of 64.5 kHz. Thereby adhesive characteristics of the

waterproofing with its surrounding surface are activated. In addition the waterproofing is found to heal itself and to repair debonding damage between the waterproofing and surrounding substrate surface and hence improve the

structural integrity of e.g. a road structure and improve the structures service life. Also, when the inductive waterproofing is applied at the surface of a typically non- inductive top layer, preferably a flexible top layer, the waterproofing can be attached and detached using the induction heating apparatus. The method provides the

opportunity of contactless heating of a waterproofing at various depths mostly independently of the inductive

characteristics of surrounding materials/layers.

The present waterproofing may have a multilayer

structure, comprising a waterproof material, typically a thermoplastic or coated-fabric binder, that is mixed with an amount of inductive agents, such as metallic fibres, metallic particles, or materials which are able to generate heat when they are subjected to an alternating

electromagnetic field or microwave radiation. For instance, bitumen may be for making the inductive waterproofing membrane. The present invention provides use of

electromagnetic induction or microwave radiation techniques to melt the surface of the inductive membrane in order to quickly and non-destructively install, remove, or repair the waterproofing membranes on/in civil engineering structures, by using an external electromagnetic source to cause

induction into the present material. The heating temperature used is typically higher than the melting temperature of the thermoplastic binder used to make the surfaces of the membrane .

The present waterproofing may be applied in a road structure .

In a second aspect the present invention relates to a method of applying a sheet of waterproofing to a surface of road structure comprising providing the road structure and material adapted to provide electromagnetic induction according to the invention, applying the material to a surface by induction or microwave heating to a temperature of at least 70 °C during a period of time sufficient to adhere the material as a waterproofing, such as during 10-60 sec .

In a third aspect the present invention relates to a method of removing a sheet of waterproofing, comprising providing the road structure and sheet according to the invention on a surface, removing the material adapted to provide electromagnetic induction from the surface by induction or microwave heating.

In a fourth aspect the present invention relates to a method of repairing a sheet of waterproofing, comprising providing the road structure and sheet according to the invention on a surface, repairing the material adapted to provide electromagnetic induction from the surface by induction or microwave heating.

Advantages of the present description are detailed throughout the description.

DETAILED DESCRIPTION OF THE INVENTION

In an exemplary embodiment of the present multilayer structure and road structure the electromagnetically

inductive agents may be selected from metallic fibres, such as steel wool, and steel shavings, and from metallic particles, such as ferromagnetic material, iron powder and particles, steel slag, and steel grit. These may be of various sizes, and/or of various nature or source.

In an exemplary embodiment of the present multilayer structure and road structure the bituminous material in the typically flexible binder may be selected from natural binders, non-fossil derived binders, and fossil, such as petroleum, derived bitumen, ethylene propylene diene monomer EPDM rubber, hypalon, polyvinyl chloride, liquid roofing, and combinations thereof. The binder according to the invention may be any natural, non-fossil, or fossil derived binder, including straight run fractionation-derived

bitumen, cracked bitumens, bitumens derived from processing such as air blowing, propane de-asphalting, steam de

asphalting, chemically modifying and the like. The bitumen selected depends on the end-product properties desired.

Preferably, the bitumen is paraffinic or naphthenic bitumen. The fossil or non-fossil derived binders may be modified with multi-block co-polymers having an amino group and/or imino group on both ends of the molecule used. The co polymers can be available commercially from several

suppliers and can be incorporated in the multi-block co polymer by co-polymerizing a mix of conjugated diene and vinyl aromatic hydrocarbon monomers utilizing the difference in their co-polymerization reactivity rates. Exemplary polymers include those having the amino group and/or imino group introduced into both ends of the molecule having the skeleton of a conventional known diene rubber or its

hydrogenation product (i.e., natural rubber, epoxidated natural rubber, isoprene rubber, styrene-butadiene rubber, hydrogenated styrene-butadiene rubber, butadiene rubber (high cis butadiene rubber or low cis butadiene rubber) , acrylonitrile-butadiene rubber, or hydrogenated

acrylonitrile-butadiene rubber, olefin rubber (i.e.,

ethylene-propylene rubber, ethylene-propylene diene rubber, maleic modified ethylene-propylene rubber, butyl rubber, copolymer of isobutylene or an aromatic vinyl or diene monomer, acrylic rubber, or ionomer) , halogen containing rubber (i.e., brominated butyl rubber, chlorinated butyl rubber, brominated isobutylene-paramethyl styrene copolymer, chloroprene rubber, hydrine rubber, chlorosulfonated

polyethylene, chlorinated polyethylenes , or maleic modified chlorinated polyethylene), silicone rubber (i.e.,

methylvinyl silicone rubber, or methylphenylvinyl silicone rubber), sulfur-containing rubber (i.e., polysulfide

rubber), fluorocarbon rubber (i.e., vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, or fluorine- containing phosphazene rubber) , urethane rubber, liquid polyisoprene, liquid polybutadiene, liquid 1,2- polybutadiene, liquid styrene-butadiene rubber, liquid polychloroprene, liquid silicone rubber, liquid fluorocarbon rubber, thermoplastic elastomer (i.e., styrene-butadiene- styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene butylene styrene block

copolymer, or other styrene elastomers, olefin elastomer, ester elastomer, urethane elastomer, polyamide elastomer, polyvinyl chloride elastomer), or thermoset elastomer (i.e., urethane elastomer or silicone elastomer) , and combination thereof .

In an exemplary embodiment of the present multilayer structure and road structure the reinforcement layer, may be selected from woven and non-woven materials, synthetic polymers, such as polyethylene, polypropylene, polyethylene terephthalate, and nylon, blends and copolymers thereof, and mineral, wood, glass, aluminum, and combinations thereof.

In an exemplary embodiment of the present multilayer structure and road structure the material adapted to provide electromagnetic induction may comprise 50-95 vol.%

waterproofing, 0.5-25 vol.% binder, 0.2-20 vol.%

electromagnetically inductive agent, the remainder being reinforcement layer (4), carrier sheet and optionally 1-10% filler .

In an exemplary embodiment the present multilayer structure and road structure may comprise a reinforcement layer located in the middle of the material adapted to provide electromagnetic induction, parallel to the top and bottom surface, preferably wherein the layer is a membrane.

In an exemplary embodiment the present multilayer structure and road structure may comprise a carrier sheet located at the top and at the bottom of the material adapted to provide electromagnetic induction, parallel to the top and bottom surface.

In an exemplary embodiment the present road structure may comprise 2-4 waterproofings , and/or independently may comprise 2-4 carrier sheets per waterproofing, and/or independently comprising 2-4 binding layers per

waterproofing, and/or independently may comprise 1-4 inlay layers per waterproofing,

wherein carrier sheets, binding layers, and inlay layers are preferably provided as a stack of layers.

In an exemplary embodiment of the present road structure the top layer may have a thickness of <20 cm, such as <10 cm.

In an exemplary embodiment the present road structure may comprise at least one top layer, at least one Guss Asphalt layer, and at least two waterproofings .

In an exemplary embodiment of the present method

induction heating may be provided by an alternating

electromagnetic field.

In an exemplary embodiment of the present method the surface may be selected from a multilayer civil engineering system, such as a flexible surfacing layer on orthotropic steel deck bridge, a roof, a roadway pavement, a foundation, a wall, a basement, a building, and combinations thereof.

In an exemplary embodiment of the present method on the material adapted to provide electromagnetic induction a further flexible surfacing layer may be applied.

In an exemplary embodiment of the present method the further flexible surfacing layer may have a thickness of less than 10 cm.

The invention will hereafter be further elucidated through the following examples which are exemplary and explanatory of nature and are not intended to be considered limiting of the invention. To the person skilled in the art it may be clear that many variants, being obvious or not, may be conceivable falling within the scope of protection, defined by the present claims.

SUMMARY OF THE FIGURES

Figs, la-e, 2-7 show some details.

DETAILED DESCRIPTION OF FIGURES

In the figures:

100 road structure

1 top layer

2 inductive material (membrane) layer

2a waterproofing layer

2b bituminous material layer

2c inductive agent

4 reinforcement layer

7 Guss asphalt

8 deck plate

9 inlay sheet/carrier layer

10 electromagnetic source

Figure la-e show common failure types with prior art (i.e., slippage in Fig. la, corrugation and shoving in Fig. lb, adhesive failure in Fig. lc, cracking in Fig. Id and rutting in Fig. le) .

Figure 2 shows a graphical representation of a

multilayer road structure 100 on a steel deck 8 comprising a top layer 1, the inductive membrane 2 and Guss asphalt 7.

Figure 3a shows a graphical representation of the inductive membrane 2, which is provided with a waterproofing 2a on the top and on the bottom of a reinforcement layer 4. The inductive membrane is able to absorb electromagnetic fields from an induction source 7.

Figure 3b shows a graphical representation of the cross section of the inductive membrane 2, in which the

waterproofing 2a comprises inductive agents 2b and a

bituminous material 2c. Between the two waterproofings , a reinforcement layer 4 is shown as well, which is in contact with waterproofings 2a via inlays 9.

Figure 4 shows a graphical representation of the cross section of a multilayer road structure 100 on a deck plate 5 comprising a top layer 1, two inductive membranes 2, one on the top of Guss asphalt 7 and one on the top of deck plate 8. Both membranes are induction heated via a mobile

electromagnetic induction source 7.

Figure 5 shows the results of induction heating of the inductive bituminous waterproofing membrane in the

laboratory. The details of the laboratory experiments are provided in the Examples section.

Examples

An inductive bituminous waterproofing membrane which comprises an waterproofing on the top and on the bottom of a polyester-based reinforcement layer was used herein to evaluate the rate of induction heating on the surface of membrane. Steel fibers were used as inductive agents, mixed together with bitumen modified with a styrene-butadiene- styrene block copolymer to form the waterproofing.

Induction heating tests were conducted at 20 °C for 30 sec by using an induction generator of 0.55 kV supplied power and under an alternating electromagnetic field of 64.5 kHz frequency. During the induction heating, the temperature increase on the surface of inductive membrane, which was the surface of waterproofing part of membrane, was monitored with an infrared camera. Fig. 5 shows the average

temperature developed over 30 sec of induction heating which increased from 20 °C to 110 °C in 30 seconds.