Composition for road construction and rehabilitation

Abstract

The invention regards a bitumen stabilized material (BSM) composition, wherein the composition is a solid granular mixture before consolidation, comprising aggregates, glass fibre material, water, and foamed bitumen, wherein the bitumen is dispersed and does not form a continuous phase in the consolidated structure.

Description

[0001] P6428PC00

[0002] 1

[0003] Composition for road construction and rehabilitation

[0004] Technical field

[0005] The present invention relates to a composition suitable for road construction and / or road rehabilitation, a road structure comprising the composition, as well as methods of producing the road structure.

[0006] Background

[0007] The building and construction industries are responsible for a major fraction of the global energy consumption and greenhouse gas emissions. Consequently, technologies for reducing the carbon footprints of the industries, such as the road construction sector, are of high relevance.

[0008] Road construction and rehabilitation is conventionally based on liquid asphalt compositions, where coarse and fine aggregate particles are mixed and bonded together by a liquid binder comprising bitumen, and the structure consolidated by drying, curing, and / or compression.

[0009] The energy consumption and carbon emission from a road construction may be reduced by using recycled materials, particularly reclaimed asphalt (RA) or reclaimed asphalt Pavement (RAP). Reclaimed asphalt is where an old existing pavement layer comprising first aggregate particles, is disintegrated and crushed to form second aggregate particles, and the resulting crushed second aggregate particles recovered and used as aggregates in a new road construction. Use of reclaimed asphalt is specifically relevant for road rehabilitation or road renovation, where the disintegrated old asphalt is readily available. The demand for road rehabilitation generally exceeds the demand for new roads, and reclaimed asphalt may accordingly provide a significantly reduced carbon footprint or total CO2 emission.

[0010] In addition, the carbon footprint in road construction may be reduced by asphalt mixtures produced at lower temperatures. Conventional hot mix asphalt (HMA) and warm mix asphalt (WMA) are produced at temperatures at or above 100 °C, where the binder including bitumen is liquid. The energy consumption and corresponding carbon emission may be reduced by replacing HMA and WMA with cold mix asphalt (CMA) P6428PC00

[0011] 2 and bitumen stabilized material (BSM), which are unheated mixtures produced at ambient temperatures, i.e. around 21-25 °C.

[0012] For example, a cold mix asphalt may be based on a bitumen emulsion, i.e. bitumen mixed with water and an emulsifying agent to form a liquid emulsion. An example of a structure based on a bitumen emulsion is shown in Figure 1A. The structure comprises aggregate particles 1 which may be coarse 1.1 and fine 1.2 aggregates, where the inter particle space 2 is initially filled with the liquid emulsion bitumen, and upon drying and evaporation of the water, the bitumen 3 remains in the structure to bond the aggregate particles together, as indicated in Figure 1A.

[0013] Despite the advances, there is a need for more efficient and long-term durable road construction and rehabilitation technologies, to facilitate further improvements in the carbon footprint of the construction industry.

[0014] Summary

[0015] The present disclosure provides a composition suitable for road construction and / or road rehabilitation, which have a surprisingly low carbon footprint over the lifecycle of the road structure. The surprisingly low energy consumption and corresponding greenhouse gas emission may be obtained for a composition comprising bitumen stabilised material (BSM) with foamed bitumen and glass fibre material, where BSM provides an alternative construction material to traditional asphalt materials. It is found that the combination of foamed bitumen and glass fibre material results in a consolidated granular microstructure with a specific distribution of bitumen particles, fibres, and void / porosity, providing improved mechanical properties (e.g. improved tensile strength, stiffness, Marshall stability, rutting and / or fatigue). The improved mechanical properties are seen to facilitate reduced layer thickness of the road construction, as well as more long-term durable road constructions, and thus a significant reduction in the carbon footprint over the lifetime of a road structure.

[0016] Generally, alternative construction materials to asphalt materials or asphalt concrete materials, such as bitumen emulsion based materials, imply reduced or deteriorated mechanical properties. Consequently, when the alternative construction materials are used as layers in road structures, the reduced or deteriorated mechanical properties are compensated by an increased layer thickness, such as up to 25 % thicker layers. P6428PC00

[0017] 3

[0018] Accordingly, the potential reduction in energy consumption of an alternative road structure is opposed by the increase in consumed resources and material, since a correspondingly shorter distance may be paved due to the thicker layers. Further, when using reclaimed asphalt, the increased layer thickness requires higher amounts of aggregates. It is surprisingly found that the improved mechanical properties of compositions based on BSM with foamed bitumen and glass fibre material, may reduce or eliminate the need of thicker layers in road structures, thereby significantly improving the cost efficiency and carbon footprint, particularly for maintenance and rehabilitation of existing road structures that are dimensioned to the existing surroundings. Moreover, since BSM with foamed bitumen and glass fibre material advantageously is synthesized decentralized, e.g. in-situ (i.e. production on the final site for the road itself) or in proximity to the road construction (e.g. in a KMA plant at a road side), the transportation costs and associated carbon footprint may be further reduced.

[0019] It is further found that the distribution of bitumen particles, fibres, and porosity in the consolidated granular microstructure, facilitates adjustable mechanical properties. Specifically, it may be found that the contact forces between the foamed bitumen and the glass fibre material may be controlled by the glass fibre surface friction, which again may be controlled by a glass fibres coating, i.e. glass fibre sizing and / or re-sizing.

[0020] A first aspect of the disclosure relates to a bitumen stabilised material (BSM) composition, wherein the composition is a solid granular mixture before consolidation, comprising aggregates, glass fibre material, water, and foamed bitumen, and wherein the bitumen is dispersed and does not form a continuous phase in the consolidated structure.

[0021] Due to the improved and adjustable mechanical properties, the composition may advantageously be used as a layer in a road structure. The road structure comprising BSM supplemented with glass fibre material, further has the advantage of being less susceptible to fractures, due to inherent limited fracture propagation in the non- continuous microstructure. Hence, the composition may facilitate road structures with improved long-term durability and lower maintenance costs, and as a result, reduced carbon footprint. P6428PC00

[0022] 4

[0023] A second aspect of the disclosure relates to a road structure comprising one or more layers, wherein at least one layer comprises the BSM composition according to the first aspect.

[0024] The glass fibre material advantageously comprises glass fibre waste material or recycled glass fibre waste materials, providing further reduction of the carbon footprint. The glass fibre waste material may include recycled glass fibre production waste, i.e. waste from a process (e.g. off-cut virgin glass fibre including off-cut rovings and glass fibre fabric), as well as recovered or extracted glass fibre material from worn out structures (e.g. decommissioned wind turbine blades). Recovered glass fibre material from wind turbine blades may have reduced mechanical properties due to the fibre extraction process, typically involving high temperatures or harsh chemicals (e.g. pyrolysis or solvolysis) degrading the fibres. However, it is surprisingly found that the foamed bitumen advantageously may be combined with any glass fibre material, providing improved and / or adjustable mechanical properties.

[0025] In a preferred embodiment, the glass fibre material is virgin glass fibre, glass fibre waste material or recycled glass fibre material, such as recycled glass fibre production waste or extracted glass fibre waste, optionally extracted glass fibres from decommissioned end-of-life wind turbine rotor blades.

[0026] The combination of foamed bitumen and glass fibre material may provide a more flexibly produced road structure. For example, the manufacture of foamed bitumen combined with the density of glass fibre material facilitates that a road structure may be produced in-situ more independent of the weather conditions. Hence, the composition may be applied even under moist and windy conditions.

[0027] A third aspect of the disclosure relates to a method of producing a road structure, comprising the steps of:

[0028] - paving the composition according to the first aspect to form one or more road layers.

[0029] A fourth aspect of the disclosure relates to use of glass fibre material for bitumen stablised material (BSM) compositions, wherein the composition is a solid granular mixture before consolidation, and wherein the bitumen is dispersed and does not form a continuous phase in the consolidated structure. P6428PC00

[0030] 5

[0031] Description of Drawings

[0032] The invention will in the following be described in greater detail with reference to the accompanying drawings.

[0033] Figures 1 shows embodiments of road structures, where (A) shows a structure based on a bitumen emulsion binder, and (B) shows a structure based on bitumen stabilised material (BSM) binder with foamed bitumen.

[0034] Figure 2 shows an embodiment of (A) the manufacture of foamed bitumen in a reaction chamber, and (B) the solid mixture obtained in the reaction chamber.

[0035] Figure 3 shows an embodiment of BSM in-situ paving and compaction.

[0036] Detailed description

[0037] The invention is described below with the help of the accompanying figures. It would be appreciated by the people skilled in the art that the same feature or component of the device / product are referred with the same reference numeral in different figures. A list of the reference numbers can be found at the end of the detailed description section.

[0038] Asphalt compositions

[0039] Road construction and rehabilitation is conventionally based on asphalt compositions. The term “asphalt” as used herein refers to a mixture comprising aggregates and bitumen binder, where bitumen is a thermoplastic mixture of hydrocarbon compounds, typically naphthalene aromatics, high molecular weight phenols and carboxylic acids, saturated hydrocarbons, and asphaltenes, corresponding to an elemental composition with around 80 wt% carbon and 10 wt% hydrogen. Bitumen occurs as natural deposits and is a constituent of petroleum, and may thus be refined from petroleum. The terms “asphalt” and “bitumen” are often used interchangeably, however herein the terms are distinguished as described above.

[0040] Asphalt compositions are conventionally based on liguid products. Hot mix asphalt (HMA), warm mix asphalt (WMA), and emulsified asphalt (e.g. BSM emulsion) are initially liguid products, where the aggregate particles 1.1 and 1.2 are surrounded or suspended in a continuous liguid phase and the inter particle space 2 between the aggregates filled with the liguid binder including bitumen 3, as sketched in Figure 1A. P6428PC00

[0041] 6

[0042] Following drying, cooling / curing, and / or compression, the asphalt composition is hardened and consolidated by the aggregates being bonded together by the hardened bitumen, as sketched in Figure 1A.

[0043] BSM with foamed bitumen

[0044] Bitumen stabilised material (BSM) is an alternative construction material to conventional asphalts, asphalt materials or asphalt concrete materials. In contrast to conventional asphalt, BSM is produced at ambient temperatures, i.e. around 21-25 °C, with a low content of bitumen, such that the bitumen is dispersed in the consolidated structure and does not form a continuous phase. Accordingly, BSMs are defined by the dispersed bitumen particles and the non-continuous binding of the aggregate particles.

[0045] As described above, BSM emulsion materials are based on an unheated liquid mixture of aggregates and a liquid emulsion binder comprising bitumen. In contrast to BSM emulsion materials, the BSM may be based on foamed bitumen. BSM with foamed bitumen differs from the emulsified material by being a solid granular mixture, and not a liquid product before consolidation.

[0046] Figure 2A shows an embodiment of the manufacture of foamed bitumen. The foamed bitumen is produced in a reaction chamber or mixing chamber, e.g. an expansion chamber, where water and / or air is / are injected under pressure (e.g. > 3 bar) into hot (e.g. > 160 °C) bitumen at a chamber inlet (upper part of image). Upon injection, the water instantly evaporates and expands approximately 1500 times in volume when turning into steam, thereby generating a foam (lower part of image). The foam bubbles will burst and collapse when coming into contact with aggregates present in the chamber, and bitumen splinters are then created and distributed between the aggregates.

[0047] Figure 2B shows an embodiment of the produced solid granular mixture present in the reaction chamber, where the bitumen splinters / particles 3 are seen as “spot welds” between the aggregate particles 1. The inter particle spaces may comprise residual water and / or air from the manufacture process.

[0048] Figure 1B also shows an embodiment of a structure based on bitumen stabilised material (BSM) binder with foamed bitumen. The non-continuous binding of the P6428PC00

[0049] 7 aggregate particles by the bitumen particles 3 is also seen here, and it is further seen that the splinters / particles of bitumen 3 are concentrated around the finer aggregate particles 1.2 that are speculated to be more prone to foam bubble collapse. The spatial distribution of the bitumen particles results in a specific void distribution, porosity and microstructure of structures based on foamed bitumen, which is different from structures obtained from BSM emulsion, as indicated in Figure 1A.

[0050] It is further surprisingly found that BSM compositions comprising foamed bitumen and glass fibre material result in a solid granular microstructure with a specific distribution of bitumen particles, fibres, and void / porosity. It is speculated that the presence of glass fibres together with aggregates in the reaction chamber results in a specific distribution of the bitumen splinters / particles due to the effect of the glass fibres on the collapse of the foam bubbles. The resulting consolidated granular microstructure is further surprisingly seen to have improved mechanical properties, as further described in the Examples. Moreover, it may be found that the mechanical properties may be controllable by adjusting the glass fibre material, such as by adjusting the glass fibre coating or sizing, and / or length.

[0051] An embodiment of the disclosure relates to a bitumen stabilised material (BSM) composition comprising aggregates, glass fibre material, water, and foamed bitumen. BSM may be defined as a solid granular mixture before consolidation, and the bitumen is dispersed and does not form a continuous phase in the consolidated structure.

[0052] The adhesion between bitumen and aggregate particles and / or fibres may be improved by the presence of an active filler in the reaction chamber. By the term “active filler” is meant an agent that may improve the surface adhesion by changing the surface charge of a solid particle. Examples of active fillers include cement, lime such as hydrated lime, Ca(OH)2, and fly ash. Advantageously, the amount of active filler does not exceed 1 wt% and / or does not exceed the amount of bitumen in weight percent.

[0053] In an embodiment of the disclosure, the composition further comprises an active filler. In a further embodiment, the active filler is cement, lime such as hydrated lime, and / or fly ash.

[0054] Aggregates P6428PC00

[0055] 8

[0056] It follows that the compositions may comprise any type of aggregate particles. By the term “aggregate particle” is meant a particle which may be an agglomerate of multiple primary particles compacted together to form an individual aggregate particle. Hence, the terms aggregates and aggregate particles are used interchangeably herein. Examples of aggregates include sand, gravel, and reclaimed asphalt, e.g. disintegrated pavement crushed by milling. Natural aggregates that have not previously been part of a produced structure, such as sand and gravel, may also be referred to as virgin aggregates, whereas aggregates that are recycled from existing structures, such as concrete structures and reclaimed asphalt, may be referred to as recycled granular layers.

[0057] In an embodiment of the disclosure, the aggregates are virgin aggregates, recycled granular layers or reclaimed asphalt. In a further embodiment, the aggregates are asphalt granulate, for example made from milled, recycled asphalt. In a further embodiment, the aggregates comprise concrete or gravel.

[0058] For road structures, aggregates of bimodal size distribution comprising a coarse and fine fraction, may advantageously be used to obtain a high density packing of the aggregates. Specifically for BSM with foamed bitumen and glass fibre material, a high density packing of the aggregates, glass fibres, and bitumen splinters may be obtained if bimodal aggregates are present in the reaction chamber.

[0059] The resulting microstructure of a granular BSM with foamed bitumen may further be affected by the type of bitumen as well as the presence of additional particles and / or agents. For example, the spatial distribution of the bitumen splinters / particles, and thus the distribution of voids / porosity and the resulting mechanical properties, are affected by the type of bitumen used in the reaction chamber. Advantageously, a penetration grade bitumen is used, such as grade 40 / 60 or 70 / 100.

[0060] In an embodiment of the disclosure, the bitumen is penetration grade bitumen, for example of grade 30 / 40, 40 / 50, 50 / 70, 60 / 70, 80 / 100, or 100 / 120, preferably 40 / 60 or 70 / 100. P6428PC00

[0061] 9

[0062] It follows that the spatial distribution of agglomerates, glass fibres, bitumen splinters, and voids may be affected by the presence of additional particles or fillers with different electrical surface charges and / or the presence of agents affecting the surface charges of the agglomerates / fibres, such as antistatic agents. Examples of additional particles include elastic particles, such as rubber particles, pozzolan, silica, celluloses, or silica fume.

[0063] In an embodiment of the disclosure, the composition further comprises elastic particles such as rubber particles, pozzolan, silica, celluloses, or silica fume.

[0064] In an embodiment of the disclosure, the composition further comprises an antistatic agent.

[0065] As described above, improved adhesion between bitumen and aggregate particles and / or fibres is facilitated by the amount of active filler not exceeding 1 wt% and / or not exceed the amount of bitumen in weight percent. It is further surprisingly found that improved mechanical properties as well as adjustable mechanical properties may be obtained for BSM compositions with a low content of foamed bitumen, such as between 1-3 wt% foamed bitumen, or more preferably between 2-2.5 wt% foamed bitumen. The composition may comprise 1-10 v / wt% water, where the term “v / wt%” either means volume percent (v% or vol%) or weight percent (wt%) water. Within the field of BSM, the amount of water in a composition is commonly referred to as weight percent. For example, the composition may include 1-10 wt% water or 1-10 mL of water for every 100 g of composition. By the term weight percent is meant the relative mass to the total mass of the composition.

[0066] In an embodiment of the disclosure, the composition comprises: 80-98 wt% aggregates, 0.1 -1.0 wt% glass fibres, such as 0.25 wt% glass fibres, up to 1 wt% active filler, 1-10 v / wt% water, and 1-3 wt% foamed bitumen.

[0067] In a further embodiment, the composition comprises: 90-95 wt% aggregates, P6428PC00

[0068] 10

[0069] 0.1 -1.0 wt% glass fibres, such as 0.25 wt% glass fibres,

[0070] 0.5-1 wt% active filler,

[0071] 3-5 v / wt% water and

[0072] 2-2.5 wt% foamed bitumen.

[0073] Glass fibre material

[0074] It follows that the compositions may comprise any type of glass fibre material. By the term “glass fibre material” is meant a material comprising one or more glass fibres, where a glass fibre is defined as an individual fibre or filament of glass.

[0075] The glass fibres may be present as individual elements or arranged in bundles as roving, and the fibres / rovings may further be assembled into a glass fibre fabric or glass fibre cloth. For example, multiple rovings may be arranged in defined orientations and stitched bonded together by a stitching thread, such as a polyester thread, as further defined below. Alternatively, multiple fibres / roving may be woven to form a defined orientation and / or pattern.

[0076] G / ass fibre

[0077] By the term “glass fibre” is meant fibres of glass. The spellings “fiber” and “fibre” are used interchangeably. Glass fibres typically comprise spun or extruded glass filaments that are coated, or sized, with a chemical solution (a sizing), where the sizing provides mechanical strength for the filaments to be handled and further processed. The coating / sizing is typically a surface treatment process carried out immediately upon the shaping of the glass fibres. Accordingly, a glass fibre comprising sizing may also be referred to as a “virgin glass fibre”.

[0078] Common types of glass fibres used in wind turbines include E- glass, S-glass, R-glass, H-glass, D-glass, AR-glass (alkali resistant), and ECR-glass. Common types of sizing of glass fibres used in wind turbines include silanes and silicones having melting points or ignition points below 450-650 °C.

[0079] Roving

[0080] The manufacture of the glass fibres, e.g. glass fibre spinning, may imply that the glass fibres are produced as bundles of essentially parallel oriented fibres / filaments. A bundle is also referred to as a roving. It follows that the diameter and number of P6428PC00

[0081] 11 filaments in a roving may vary. The diameter of a roving is also referred to as “TEX size of roving” or “micronsize”.

[0082] G / ass fibre fabric

[0083] By the term "glass fibre fabric" is meant one or more layers of rovings that are assembled into a fabric or cloth, i.e. a kind of a textile normally being flexible and bendable. The rovings may be assembled into a fabric by any suitable method, such as by stitching, and / or weaving.

[0084] Assembly by stitching involves that the rovings are assembled and stitched together by a stitching thread. For example, the stitching thread may be a polyester thread, and thus the thread constitutes a minor amount of the fabric, typically 0.1 -2.5 wt%, such as 0.5-2.5 wt%, of the fabric. Further, typically the stitching thread comprises a material having a melting point or ignition point below 450-650 °C. The non-woven fabric is also referred to as “technical fabric”.

[0085] The fibres / rovings may be assembled in defined orientations and / or patterns, such as unidirectional or multiaxial arrangements. By the term "unidirectional" is meant that the fibres / rovings in one layer of the fabric are parallel. By the term "muitiaxial reinforcements" or simply "multiaxial" is meant fabric made up of multiple plies or layers of parallel fibres, each lying in a different orientation or axis. Preferably the glass fibre fabric comprises muitiaxial reinforcements, wherein layers of unidirectional fibres / rovings are assembled and stitched together. Thus, they provide strength and stiffness in multiple directions depending on the controlled orientation of the fibres. Multiaxials include unidirectional, biaxial, and triaxial and quadraxial fabrics, for example tailored to have the reinforcement in four main directions of 0 degrees, 90 degrees, +45 and -45 degrees. Furthermore, special reinforcement in directions between 45 degrees and 90 degrees may occur depending on the number and orientation of the layers. Glass fibre fabric with multiaxial reinforcement normally range in weight from 200 g / m2to 2500 g / m2, such as from 1000 g / m2to 1300 g / m2.

[0086] Recycled glass fibre material

[0087] Large structures such as wind turbine blades are conventionally manufactured based on technical glass fibre fabric that is stitched with polyester thread. The glass fibre fabric is cut into the desired shape and the cut fabric embedded in a polymeric resin or P6428PC00

[0088] 12 matrix of for example epoxy, polyester resin or a vinylester resin. The embedded fabric is then cured and shaped to form a glass fibre reinforced product, such as a wind turbine blade.

[0089] At the end of the product life, e.g. when the wind turbine is decommissioned, the blade is typically dismantled from the construction and disposed of as waste in a landfill. For example, wind turbine blades have an expected lifetime of 20-25 years, after which they may be dismantled and deposited at a landfill.

[0090] It is desirable to exploit glass fibre waste material and to recycle any type of glass fibre material, since the manufacture of virgin glass fibres typically involves high temperature melts, which is an energy consuming and CO2 polluting process. Accordingly, use of recycled glass fibre material may significantly reduce the environmental impact of a product life cycle.

[0091] Glass fibre waste materials, which are advantageously recycled include off-cuts of rovings and glass fibre fabric, as well as worn out glass fibre reinforced structures, such as wind turbine blades. Off-cut rovings and glass fibre fabric are not embedded in polymeric resin, and may thus be directly applied in a composition, such as a BSM composition. However, for glass fibre reinforced structures, the glass fibres, rovings or fabric are embedded in a polymeric matrix.

[0092] Glass fibres of discarded glass fibre reinforced structures may be recycled by partly extracting the glass fibres from the polymeric matrix. The extracted glass fibres may also be referred to as extracted glass fibre waste. Hence, the term “extracted glass fibres” means glass fibres that are extracted from a cured matrix material. The glass fibers may be extracted by removing the matrix material, for example by thermal treatment of the matrix (pyrolysis, gasification, incineration, oxygen combustion), or by chemical dissolution of the matrix material (solvolysis). Depending on the extraction process, the extracted glass fibres may comprise no or minor amounts of matrix, and possibly the stitching thread and sizing may be removed simultaneously with the matrix. Accordingly, the extracted glass fibres may be present as fabric, rovings or individual glass fibres absent sizing. P6428PC00

[0093] 13

[0094] Recovered glass fibre material from wind turbine blades may have reduced mechanical properties due to the fibre extraction process, typically involving high temperatures or harsh chemicals (e.g. pyrolysis or solvolysis) degrading the fibres, e.g. due to the removal of sizing. Accordingly, a sizing may advantageously be reapplied before the extracted glass fibre material is recycled in a BSM composition.

[0095] In an embodiment of the disclosure, the glass fibre material is virgin glass fibre, glass fibre waste material or recycled glass fibre material, such as recycled glass fibre production waste or extracted glass fibre waste, optionally extracted glass fibres from decommissioned end-of-life wind turbine rotor blades.

[0096] Adjustable mechanical properties of BSM with foamed bitumen and glass fibre material may be obtained for a composition comprising individually arranged or loosely distributed glass fibres and / or rovings, particularly without stitching thread. It is further found that the mechanical properties of the BSM may be further controlled by the type of sizing on the glass fibres / roving. Accordingly, the glass fibres advantageously comprise a sizing, and optionally the glass fibres have been subjected to one or more surface treatments for applying or re-applying one or more coating layers of sizing.

[0097] In an embodiment of the disclosure, the glass fibres comprise individually arranged glass fibres and / or rovings, such as such as non-stitched glass fibres and / or rovings. In a further embodiment, the glass fibres comprise a sizing.

[0098] In an embodiment of the disclosure, the glass fibres are extracted glass fibres obtained by solvolysis or pyrolysis, optionally wherein a sizing is reapplied after solvolysis or pyrolysis. In a further embodiment, the glass fibre material is extracted glass fibre waste, and preferably the extracted glass fibres are selected from the group of: pyrolyzed or solvolyzed wind turbine blades, pyrolyzed or solvolyzed glass fibre reinforced plastics, and combinations thereof.

[0099] By the term “fibre length” is meant the average fibre length or fibre size.

[0100] By the term “average particle size” is meant the average particle size as determined by common particle size measurements techniques. The particle size of a spherical particle is unambiguously defined by its diameter or radius. However, for most cases, P6428PC00

[0101] 14 the particle shapes are not spherical, and for a batch of particles, e.g. a powder, the particles will differ in sizes and have a distribution of different sizes. Thus, when applying the common techniques as known to the skilled person for evaluating particle sizes, the particle size is often quantified in terms of a representative particle diameter or radius, such as the average particle diameter, or the average fiber length.

[0102] The size of non-spherical particles may be quantified as the diameter of an equivalent sphere, such as the sphere having the same volume as the non-spherical particle, the sphere having the same surface area as the non-spherical particle, the sphere having the same sedimentation rate as the non-spherical particle, the sphere having a diameter corresponding to the length of the major axis (maximum length) of the non- spherical particle, or the sphere having a diameter corresponding to the minor axis (or minimum length) of the non-spherical particle. Despite this is not a proper quantification from a geometrical point of view, it is applied to provide a quantitative description of the characteristic sizes.

[0103] In most cases, a particle size distribution exists. The average particle size may then refer to the particle diameter of the equivalent spherical particle as evaluated by laser diffraction. This particle diameter and the associated particle size distributions are evaluated using laser diffraction, where the liquidly dispersed particles are passed through a focused laser beam, such that the particles scatter the light. The scattering angle is proportional to the particle size, and a map of the scattering intensity versus the angle may then be obtained and used to calculate the particle sizes and the distribution. The calculation of the particle size distribution may be based on Mie theory, which is based on assuming spherical particles. The Mie theory includes comparison of the obtained scattering pattern with scattering patterns derived from theory (assuming spherical particles). Based on the particle size distribution, the average particle size may be determined.

[0104] Similar a fiber length distribution may exist. Thus, a fiber length range means the range of the average distribution. The distribution may be multimodal, meaning that the fiber lengths are distributed in a number of fractions. For example, the distribution may be bimodal. By the term “bimodal size distribution” is meant a particle size / length distribution having at least two modes or peaks, corresponding to two different particle size fractions. For example, a mixture of a powder fraction with a finer average particle P6428PC00

[0105] 15 size, and a powder fraction with a coarser average particle size, will form a bimodal size distribution with a fine and a coarse peak. Also, a mixture of fibers having a first fraction with a smaller average fiber length, and a second fraction with a larger average fiber length will form a bimodal size / length distribution.

[0106] It is found that BSM compositions comprising foamed bitumen and glass fibres with an average fibre length between 5-40 mm, and / or two length fractions within the range of 5-40 mm, may result in solid granular microstructure having advantageous mechanical properties.

[0107] In an embodiment of the disclosure, the glass fibres have an average fibre length range between 5-40 mm, such as 6-25, for example 6-15, 6-20, or 9-12 mm. In a further embodiment, the fibre lengths are distributed in at least two length fractions within said range.

[0108] It is further found that BSM compositions comprising foamed bitumen and glass fibres may result in solid granular microstructure having advantageous mechanical properties, when the amount of glass fibre material is between 0.1-1 wt%,.

[0109] In an embodiment of the disclosure, the composition comprises between 0.1-1 wt% glass fibre material, more preferably between 0.2-0.5 wt%, such as 0.25 or 0.30 wt%.

[0110] Road structure

[0111] A road structure may advantageously comprise multiple layers to accommodate sufficient durability for high traffic loads. The layers typically include a subbase layer immediately superjacent to the ground, and a surface layer, also referred to as wearing course, in direct contact with the traffic. A base layer is sandwiched between the subbase layer and surface layer, and the base layer thus often constitutes the main load bearing structure. Consequently, the mechanical properties and the mechanical integrity of the base layer is crucial. Hence, if fractures are formed in the base layer, it may be necessary to replace the entire base layer upon maintenance.

[0112] Due to the improved and adjustable mechanical properties of BSM comprising foamed bitumen and glass fibre material, a road structure advantageously comprises a layer comprising BSM supplemented with glass fibre material. BSM supplemented with glass P6428PC00

[0113] 16 fibre material further has the advantage of being less susceptible to fractures. Due to the microstructure including non-continuous distribution of the bitumen particle, the propagation of generated fractures are limited, and fractures will be local in extend. Thus, when fractures are formed, it may be sufficient to remove only a part of the layer and complete replacement of the layer may be avoided. The road structure may therefore have lower maintenance costs and carbon footprint over a lifecycle. Thus, preferably, the base layer is based on a BSM composition comprising foamed bitumen and glass fibre material.

[0114] An embodiment of the disclosure relates to a road structure comprising one or more layers, wherein at least one layer comprises BSM supplemented with a glass fibre material.

[0115] An embodiment of the disclosure relates to use of glass fibre material for BSM compositions, thereby forming BSM compositions with glass fibre material in the composition.

[0116] Production of road structure

[0117] It follows that a BSM composition comprising glass fibre material and foamed bitumen may be used for producing one or more layers in a road structure, e.g. by paving. After paving, the final consolidated granular microstructure of the BSM may be formed by compacting by compression and / or curing of the layer.

[0118] An embodiment of the disclosure relates to a method of producing a road structure, comprising the step of: paving a BSM composition to form one or more road layers. In a further embodiment, the method further comprises compacting and / or curing the layer.

[0119] As described above, the BSM may preferably form a base layer located subjacent to a wearing course. Since the wearing course is in direct contact with the traffic and subjected to wheel friction on breaking, the wearing course advantageously comprises asphalt with a continuous bitumen binder phase. Hence, the wearing course is preferably made from hot mixed asphalt. P6428PC00

[0120] 17

[0121] In an embodiment of the disclosure, the method further comprises adding a wearing course made from hot melt asphalt on top of the BSM layer.

[0122] The paving of BSM provides a more flexibly produced road structure, which may be paved more independent of the weather conditions due to the low moisture susceptibility of the foamed bitumen present in small amounts, and the density of the glass fibre material. Hence, the BSM may be paved in-situ even under moist and windy conditions, as shown in Figure 3.

[0123] Figure 3 shows an embodiment of BSM in-situ paving and compaction. The in-situ process provides continuous paving carried out by passing a coupled combination of vehicles. The first vehicle distributes active filler, e.g. cement onto the substrate or ground. The following vehicles may provide a source of water and bitumen for the BSM machine, which comprises the reaction chamber or mixing chamber for the foamed bitumen. The mixing chamber may further be provided with agglomerates, and comprise a nozzle configured for mixing the BSM product with the pre-deposited active filler, such that the deposited BSM forms a uniform mixture. The last vehicles may be rollers for compacting and consolidating the BSM layer.

[0124] The aggregates of the BSM may also be produced in-situ, e.g. by a further vehicle comprising a miller removing and crushing the old existing asphalt layer. Accordingly, the aggregates of the BSM may be reclaimed asphalt aggregates.

[0125] Alternatively, the BSM composition may be mixed ex-situ (e.g. in remote plant) in a reaction chamber supplied with foamed bitumen, aggregates, and glass fibre material. Both the in-situ and ex-situ process imply a low carbon footprint due to the mixing at ambient temperatures. To further reduce the carbon footprint, the BSM is preferably produced in-situ or in a mobile reaction chamber (e.g. in a “Kalt Misch Anlage” KMA plant) placed in proximity to the road structure, since transportation is reduced significantly. It is further advantageous that the BSM is paved within 4 hours of mixing the foamed bitumen to reduce collapse of the foamed bitumen before paving.

[0126] In an embodiment of the disclosure, the aggregates have been provided by removing and milling one or more asphalt layers above the road foundation. P6428PC00

[0127] 18

[0128] In an embodiment of the disclosure, the reclaimed asphalt aggregates are mixed in-situ or in a mobile cold recycling plant with foamed bitumen. In a further embodiment, the reclaimed asphalt aggregates are mixed with foamed bitumen at ambient temperature.

[0129] In an embodiment of the disclosure, the BSM layer is applied to the road within 4 hours of mixing with foamed bitumen.

[0130] The miller producing the reclaimed asphalt aggregates may further facilitate that active filler and / or glass fibre material spread on an existing road before the miller is passed, may be more uniformly mixed with the aggregates and the foamed bitumen.

[0131] In an embodiment of the disclosure, the active filler is spread on the road before it is recycled and milled, optionally wherein active filler and glass fibres are spread on the road so that the materials are mixed with asphalt during the milling.

[0132] Reference numbers

[0133] 1 - Aggregate particles

[0134] 1.1 - Coarse aggregate

[0135] 1.2 - Fine aggregate

[0136] 2 - Inter particle space

[0137] 3 - Bitumen

[0138] Examples

[0139] The invention is further described by the examples provided below.

[0140] Example 1 - BSM where glass fibre is glass fibre waste as glass fibre roving

[0141] Bitumen Stabilized Material (BSM) is a construction material used mainly for road construction or renovation, e.g. for base layers of road structures. BSM is produced in an unheated process, which saves large amounts of CO2 emissions compared to a similar construction with a base layer made from hot mix asphalt (HMA).

[0142] BSM is typically made from almost 100% recycled asphalt (or reclaimed asphalt as aggregates), with only a small amount (about 2.2 wt%) of new bitumen, which is foamed in a special process. Additionally, around 0.8 wt% cement (as an active filler) P6428PC00

[0143] 19 and some water are typically added to optimize the material's workability during application.

[0144] BSM provides an alternative construction material to conventional liquid asphalts, such as hot mix asphalt and cold mix asphalt. In contrast to asphalts, BSM has a granular microstructure with voids / porosity facilitating permeability and a low content of bitumen, due to the BSM production temperatures and method. Thus, BSM provides a cost efficient alternative with a significant lower carbon footprint.

[0145] A challenge for BSM is that the material is somewhat weaker than traditional HMA. Therefore, when the asphalt base layer is converted to BSM, a layer thickness increase of about 25% is normally required to achieve the same load-bearing capacity against traffic load.

[0146] It is therefore highly desirable to strengthen BSM, increasing its load-bearing capacity, so the necessary extra layer thickness can be reduced or possibly avoided altogether. Thus, in recent years, work has focused on improving BSM pavement properties, including the material's cohesion and bonding strength.

[0147] The following includes tests and documentation of the improving effect achieved by adding Ucomposite’s recycled glass fibers to a typical Danish BSM material.

[0148] The study aimed to use the same BSM formula with 0 / 16 mm recycled asphalt from Gammelrand, without fibers, as previously tested by the Danish Technological Institute for the Danish Road Directorate.

[0149] G / ass fibre material

[0150] In this task, a similar mixture of BSM was made, but this time with the addition of 0.25 wt% Ucomposite’s glass fibers. Ucomposites’ glass fibers are E-glass fiber rovings with sizing obtained from glass fiber waste material. The glass fibre rovings are non-stitched rovings.

[0151] The non-stitched rovings are cut using a double cut method using two guillotine cutters, which perform a cutting corresponding to cutting planar squares of e.g. 16 x 16 mm. The material is fed into a reinforced guillotine cutting machine, equipped with a P6428PC00

[0152] 20 tungsten carbide mobile knife which is able to cut the hard glass fibre materials with a speed of 400 cuts per minute. This enables a range of cutting lengths of 6 mm to 160 mm, and for example 16 mm. The cutting machine may be driven by a three phase enclosed motor with cooled housing with a total installed power of 9.2 Kw / 50 Hz - 10.6 Kw / 60 Hz. The cutting width may be 280 mm effective for a 700 mm table infeed width. The production capacity may be about 1000 kg / hour.

[0153] The material is first conveyed on a feeding belt to an awaiting hardened steel roll assembly. The rolls compresses the material on the feed table and draws it efficiently toward the knives. Depending on the material and the material compressibility, the compressed material thickness is from 30 mm to 50 mm, and the maximum material thickness at infeed is + / - 100 mm. The scissor effect produced between the carbide mobile knife and the fixed knife may ensure a clean edged cut of e.g. 16 mm.

[0154] The material is then conveyed into another similar cutting machine with a 90 degrees angle to the machine direction. The cutting machine is set at a similar setting producing cuts of e.g. 16 mm. The square pieces of fabric will then be of a size of 16 x 16 mm.

[0155] The rovings have an average glass fibre length between 9-12 mm, where 83% of the fibres have a length of between 6-15 mm.

[0156] The tests were carried out in accordance with the Danish Road Directorate's work description for BSM-CMA, as well as underlying test protocols (prVD).

[0157] The task included:

[0158] • Laboratory production of BSM based on 0 / 16 mm crushed recycled asphalt from Gammelrand, with 2.2 wt% 40 / 60 foamed bitumen and 0.8 wt% cement, as well as a water content determined by previous modified Proctor tests on the recycled asphalt, so the BSM mixture's water content became 5.6 wt%.

[0159] • Vibration compaction of 10 0150x60 mm test specimens.

[0160] • Marshall compaction of at least 3x3 0100 mm Marshall specimens for fatigue testing.

[0161] • Production of rutting test plates for rutting tests, at 45°C and TSRST tests.

[0162] • Curing of specimens for 72 hours at 40°C in a ventilated oven.

[0163] • Measurement of dimensions and density. P6428PC00

[0164] 21

[0165] • Determination of the material's maximum density and calculated voids.

[0166] • Tensile strength testing on both dry and water-stored specimens (0150 mm) and calculation of the water sensitivity index.

[0167] • Stiffness modulus determination at 20°C (0150 mm specimens).

[0168] • Marshall stability testing at 25°C (0150 mm specimens from stiffness modulus determination).

[0169] • TSRST cold crack resistance testing on sawn beams from the compacted plate.

[0170] • Fatigue resistance testing at 10°C on a series of at least 3x3 test specimens (0100 mm).

[0171] The data were processed and compared with reference data.

[0172] The testing program mentioned in the previous section was carried out for both a reference mixture of BSM without fibers and a mixture with the addition of 0.25 weight percent of Ucomposite’s glass fibers.

[0173] The fibers were added to the laboratory mixture immediately before the foamed bitumen was dosed into the mixer. Optimization of the foamed bitumen was carried out in accordance with the Road Directorate's testing method prVD 32-1-2021. The mixing procedure followed prVD 32-2-2021.

[0174] Test specimens with a diameter of 150 mm and a height of 60 mm were produced for both the fiber and reference mixtures, in accordance with prVD 32-3-2021. The same standard also served as the basis for producing material plates for rutting tests and producing beams for TSRST cold crack tests.

[0175] All tests were conducted according to the Road Directorate's applicable AAB for BSM- KMA / BSM-in situ.

[0176] The obtained data are shown in Table 1 and are discussed below. P6428PC00

[0177] 22

[0178] Table 1 : Obtained data for various functional properties of BSM with / without fiber addition, compared with the requirements according to the Danish Road Directorate's

[0179] Work Description AAB for BSM. P6428PC00

[0180] 23

[0181] Review of Individual Parameters

[0182] Material Composition

[0183] The lines marked A-C in Table 1 indicate the percentage composition of the two BSM materials used. For the mixture with fiber addition, the amount of binder (foamed bitumen) was increased by 0.1% to account for the extra volume of fibers. Both mixtures were given a water content corresponding to the optimal value determined by a modified Proctor test, minus 2%.

[0184] Tensile Strength and Water Sensitivity

[0185] The tensile strength of the dry-stored specimens is shown in line D, and the tensile strength of the water-stored specimens is shown in line E. The tensile strength represents the material's internal cohesion and bonding strength. As can be seen from the table, the fiber-modified variant shows a 30% increase in tensile strength.

[0186] Line F shows the water sensitivity index, which is calculated as the percentage ratio between the tensile strength of the wet and dry-stored specimens. As shown in Table 1 , the water sensitivity resistance (adhesion) improves by 7% (relatively).

[0187] Density, Maximum Density, and Voids P6428PC00

[0188] 24

[0189] Line G of Table 1 indicates the density of the laboratory-compacted specimens. Line H shows the respective maximum density of the materials, and line I gives the calculated void content based on the aforementioned densities.

[0190] As can be seen from line I, the addition of 0.25% glass fibers reduces the built-in voids of the material from 16.9% to 15.2%, which, all else being equal, suggests a more robust material with the fiber dosage.

[0191] Stiffness Modulus

[0192] Line J of Table 1 shows the stiffness modulus determined for the test specimens, which can be viewed as an indicator of the material's load-bearing capacity. As shown in line J of Table 1 , the fiber modification results in a 30% increase in the stiffness modulus, indicating that the same load-bearing capacity as the reference material could likely be achieved with a reduced layer thickness, which was one of the primary goals of the test series.

[0193] Marshall Stability

[0194] Line K of Table 1 shows the compressive strength of the materials in the so-called Marshall stability test, which has been used for hot-mixed asphalt for many years. For testing BSM, a test temperature of 25°C is used in accordance with the AAB for BSM- KMA / BSM-in situ. As shown in the table, the stability (compressive strength) increases by 13% with fiber addition. (Line L of the table provides deformation measurements corresponding to the compressive test, which are supplementary values accompanying the compressive test and are only marginally relevant for assessing the materials.)

[0195] Rutting Resistance

[0196] Lines M, N, and O of Table 1 show the values obtained from rutting tests, where a loaded wheel passes over a 10 cm thick plate 20,000 times at a test temperature of 45°C. Line M indicates the total rut depth in millimeters.

[0197] In any case, both materials exhibit a very high degree of rutting resistance. In line N of the table, the requirement for tracking rate as specified in the Work Description for hot- mixed asphalt is given in parentheses, for hot-mixed ABB type 16, designed for heavy traffic, with ZE10 (number of 101 equivalent standard axle loads) > 500 per day. It is noted that the tracking rate for the fiber-modified BSM, with a value of 0.026 pm per P6428PC00

[0198] 25 double pass (cycle), is only about one-third of the maximum value required for a particularly strong polymer-modified base layer in the Work Description for HMA. Thus, it can be concluded that both tested BSM variants have excellent rutting resistance.

[0199] Fatigue Resistance

[0200] The fatigue test can be likened to the "IKEA test," where a drawer or door is opened and closed a million times to demonstrate robustness and durability. In the case of asphalt and BSM materials, the expected durability is determined by a fatigue test, where a cylindrical specimen is subjected to repeated loading up to a million times, with varying forces that create a certain deformation of the specimen. The loading continues until the specimen breaks down (or the stiffness is reduced to less than half of the initial value). Based on the obtained data, the initial strain that the material can withstand while still enduring one million loads can be calculated by extrapolation for each material.

[0201] As seen from line P of Table 1, the initial strain (deformation) that the fiber-modified BSM can tolerate after one million loads is 63.7 microstrain, which is 23% better than the reference. This indicates that fiber modification of the BSM material can likely result in a significantly greater durability improvement.

[0202] TSRST Cold Crack Resistance

[0203] To ensure that an asphalt or BSM material has sufficient resistance to cracking in cold weather, the so-called TSRST test (Thermal Stress Restrained Specimen Test) is performed. A sawn beam of BSM is mounted in a test setup where the end surfaces of the specimen are fixed in the longitudinal direction. The specimen is then cooled at a rate of -10°C per hour. The colder the specimen gets, the more it will try to contract, until it breaks at a relatively low temperature. The fracture temperature and the associated internal tensile stress are recorded. (The lower the fracture temperature, the better the crack resistance.)

[0204] The test series for both tested materials show an absolute fracture temperature in the range of -35°C. However, the internal tensile stress of the material shows a peak at a higher test temperature, after which the internal tensile stress decreases due to the progressive breakdown of more and more of the BSM material's point bonds.

[0205] Therefore, it is most relevant here to look at the temperature at which the first point P6428PC00

[0206] 26 bonds begin to break. The fiber-modified BSM shows a low fracture temperature of minus 23°C, which experience suggests indicates good cold crack resistance. The reference material (BSM without fibers) showed a slightly higher (worse) temperature of -21 °C.

[0207] The addition of 0.25% (by weight) of Ucomposite’s glass fibers to a BSM material has, according to the conducted test series, clearly improved several functional parameters.

[0208] • The internal cohesion of the BSM material improved by approximately 30%.

[0209] • The adhesion under water exposure improved.

[0210] • The stiffness modulus of the BSM material (an indicator of load-bearing capacity) improved by 30%.

[0211] • The compressive strength (Marshall stability) of the BSM material improved by about 13%.

[0212] • The fatigue resistance (an indicator of durability) of the BSM material improved by about 23%.

[0213] • The low-temperature crack resistance of the BSM material in freezing conditions also improved, though the improvement was more marginal.

[0214] Thus, clear improvements are achieved with the applied fiber addition, which also indicates potential for reducing the necessary thickness of the BSM layers. This, in turn, suggests potential material savings.

[0215] Documentation of the effect of adding fibers to the BSM mixture

[0216] (Fibers: Glass Fibre from Ucomposites). A mixture of BSM with the same recycled asphalt and the same recipe as previously used to document the effect of "16x16" fibers in BSM was produced. The dosage of fibers was set at 0.7% of the mixture.

[0217] The following testing program was conducted (methods in accordance with the Danish Road Directorate’s Work Description for BSM-CMA):

[0218] • Mixing of BSM with fiber addition

[0219] • Vibration compaction of 9 specimens, 60x0150 mm

[0220] • Curing of specimens for 72 hours at 40°C

[0221] • Determination of density and dimensions

[0222] • Determination of tensile strength in dry and wet stored specimens, and calculation of water sensitivity at 25°C

[0223] • Determination of stiffness modulus at 20°C P6428PC00

[0224] 27

[0225] • Determination of Marshall stability at 25°C

[0226] • Determination of the material’s maximum density

[0227] • Determination of void content

[0228] Laboratory Testing of the Effect of Fiber Reinforcement in BSM

[0229] BSM (Bitumen Stabilized Material) is a relatively new, cold-mixed, and CCh-saving material for road construction, which until now is mostly used to replace traditional hot- mixed asphalt base layers in road structures. BSM may typically be made from crushed recycled asphalt, which is mixed with a small amount of new, foamed bitumen, creating a point-bonded base layer. Due to this point-bonded structure, there is a desire to document that fiber reinforcement can improve cohesion, tensile strength, and loadbearing capacity (stiffness modulus).

[0230] In the previously reported test series, BSM was tested to evaluate the effect of fiber reinforcement with Ucomposites' fibers. The tests showed a significant improvement in properties with the addition of 0.25% of the glass fibers. Therefore, in this test series, a supplementary test was conducted with the same BSM material as previously used. The fibers were added in an amount of 0.25% by weight, which was deemed optimal based on visual assessment during mixing before the addition of the foamed bitumen.

[0231] Table 2: Data from laboratory testing of BSM with / without the addition of fibres (various types and amounts). P6428PC00

[0232] 28

[0233] It is evident from Table 2 that the addition of 0.25% of Ucomposites' glass fibers produces clear improvements in tensile strength, stiffness, Marshall stability, rutting and fatigue compared to reference mixture without fibers.

[0234] Example 2 - BSM with extracted glass fibre material

[0235] BSM compositions similar to Example 1 were produced, but where the glass fibre roving was replaced with extracted glass fibres obtained by pyrolysis. The fibres were added in amounts of 0.25 wt% or 0.8 wt%. For comparison, a reference without fibres is included. The BSMs were tested similar as in Example 1, and the results are summarized in Table 3.

[0236] Table 3: Data from laboratory testing of BSM with / without the addition of extracted fibres (various types and amounts). P6428PC00

[0237] 29

[0238] It is seen that addition of 0.25 wt% extracted glass fibres may improve the tensile strength. Further, it is seen that addition of 0.80 wt% extracted glass fibres may further P6428PC00

[0239] 30 improve the mechanical properties, e.g. 20% higher dry tensile strength and 7% higher wet tensile strength.

[0240] Items

[0241] The presently disclosed may be described in further detail with reference to the following items.

[0242] 1. A bitumen stabilised material (BSM) composition comprising aggregates, glass fibre material, water, and foamed bitumen.

[0243] 2. The composition of item 1 , further comprising an active filler.

[0244] 3. The composition according to item 2, wherein the active filler is cement, lime such as hydrated lime, and / or fly ash.

[0245] 4. The composition of any of the preceding items, wherein the aggregates are virgin aggregates, recycled granular layers or reclaimed asphalt.

[0246] 5. The composition according to any of the preceding items, wherein the aggregates are asphalt granulate, for example made from milled, recycled asphalt.

[0247] 6. The composition according to any of the preceding items, wherein the aggregates comprise concrete or gravel.

[0248] 7. The composition according to any of the preceding items, wherein the bitumen is penetration grade bitumen, for example of grade 30 / 40, 40 / 50, 50 / 70, 60 / 70, 80 / 100, or 100 / 120, preferably 40 / 60 or 70 / 100.

[0249] 8. The composition of any of the preceding items, further comprising elastic particles such as rubber particles, pozzolan, silica, celluloses, or silica fume.

[0250] 9. The composition according to any of the preceding items, further comprising an antistatic agent.

[0251] 10. The composition of any of the preceding items, comprising 80-98 wt% aggregates, P6428PC00

[0252] 31

[0253] 0.1-1.0 wt% glass fibres, such as 0.25 wt% glass fibres, up to 1 wt% active filler, 1-10 v / wt% water and

[0254] 1-3 wt% foamed bitumen.

[0255] 11. The composition of any one of the preceding items, comprising 90-95 wt% aggregates,

[0256] 0.1 -1.0 wt% glass fibres, such as 0.25 wt% glass fibres,

[0257] 0.5-1 wt% active filler, 3-5 v / wt% water and

[0258] 2-2.5 wt% foamed bitumen.

[0259] 12. The composition of any of the preceding items, wherein the glass fibres have an average fibre length range between 5-40 mm, such as 6-25, for example 6-15, 6-20, or 9-12 mm.

[0260] 13. The composition of item 12, wherein the fibre lengths are distributed in at least two length fractions within said range.

[0261] 14. The composition according to any of the preceding items, wherein the glass fibre material is virgin glass fibre, glass fibre waste material or recycled glass fibre material, such as recycled glass fibre production waste or extracted glass fibre waste, optionally extracted glass fibres from decommissioned end-of-life wind turbine rotor blades.

[0262] 15. The composition according to any of the preceding items, wherein the glass fibres comprise individually arranged glass fibres and / or rovings, such as nonstitched glass fibres and / or rovings.

[0263] 16. The composition according to any of the preceding items, wherein the glass fibres comprise a sizing.

[0264] 17. The composition according to any of the preceding items, wherein the glass fibres are extracted glass fibres obtained by solvolysis or pyrolysis, optionally wherein a sizing is reapplied after solvolysis or pyrolysis, P6428PC00

[0265] 32

[0266] 18. The composition according to any of the preceding items, wherein the glass fibre material is extracted glass fibre waste, and preferably the extracted glass fibres are selected from the group of: pyrolyzed or solvolyzed wind turbine blades, pyrolyzed or solyolyzed glass fibre reinforced plastics, and combinations thereof.

[0267] 19. The composition according to any of the preceding items, comprising between 0.1-1 wt% glass fibre material, more preferably between 0.2-0.5 wt%, such as 0.25 or 0.30 wt%.

[0268] 20. A road structure comprising one or more layers, wherein at least one layer comprises BSM according to any of the items 1-19.

[0269] 21. A method of producing a road structure, comprising the steps of: paving the composition of any of the items 1-19 to form one or more road layers.

[0270] 22. The method of item 21 , further comprising compacting and / or curing the layer.

[0271] 23. The method of any of items 21-22, further comprising adding a wearing course made from hot mixed asphalt on top of the BSM layer.

[0272] 24. The method of any of items 21-23, wherein the aggregates have been provided by removing and milling one or more asphalt layers above the road foundation.

[0273] 25. The method of any of items 21-24, wherein the aggregates, optionally reclaimed asphalt aggregates are mixed in-situ or in a mobile cold recycling plant with foamed bitumen.

[0274] 26. The method of any of items 21-25, wherein the reclaimed asphalt aggregates are mixed with foamed bitumen at ambient temperature.

[0275] 27. The method of any of items 21-25, wherein the BSM layer is applied to the road within 4 hours of mixing with foamed bitumen.

[0276] 28. The method of any of items 21-25, wherein the active filler is spread on the road before it is recycled and milled, optionally wherein active filler and glass fibres P6428PC00

[0277] 33 are spread on the road so that the materials are mixed with asphalt during the milling.

[0278] 29. Use of glass fibre material for BSM compositions.

[0279] 30. The composition according to any one of the preceding items, wherein the BSM composition is a solid granular mixture before consolidation, and wherein the bitumen is dispersed and does not form a continuous phase in the consolidated structure.

Claims

P6428PC0034Claims1 . A bitumen stabilised material (BSM) composition, wherein the composition is a solid granular mixture before consolidation, comprising aggregates, glass fibre material, water, and foamed bitumen, and wherein the bitumen is dispersed and does not form a continuous phase in the consolidated structure.

2. The composition of claim 1 , further comprising an active filler, optionally wherein the active filler is cement, lime such as hydrated lime, and / or fly ash.

3. The composition of any of the preceding claims, wherein the aggregates are virgin aggregates, recycled granular layers or reclaimed asphalt.

4. The composition of any of the preceding claims, comprising 80-98 wt% aggregates,0.1-1.0 wt% glass fibres, such as 0.25 wt% glass fibres, up to 1 wt% active filler,1-10 wt% water and1-3 wt% foamed bitumen.

5. The composition according to any of the preceding claims, wherein the glass fibre material is virgin glass fibre, glass fibre waste material or recycled glass fibre material, such as recycled glass fibre production waste or extracted glass fibre waste, optionally extracted glass fibres from decommissioned end-of-life wind turbine rotor blades.

6. The composition according to any of the preceding claims, wherein the glass fibres comprise individually arranged glass fibres and / or rovings, such as nonstitched glass fibres and / or rovings.

7. The composition according to any of the preceding claims, wherein the glass fibres comprise a sizing.

8. The composition according to any of the preceding claims, wherein the glass fibres are extracted glass fibres obtained by solvolysis or pyrolysis, optionally wherein a sizing is reapplied after solvolysis or pyrolysis,P6428PC00359. The composition according to any of the preceding claims, comprising between 0.1-1 wt% glass fibre material, more preferably between 0.2-0.5 wt%, such as 0.25 or 0.30 wt%.

10. A road structure comprising one or more layers, wherein at least one layer comprises BSM according to any of the claims 1-9.

11. A method of producing a road structure, comprising the steps of: paving the composition of any of the claims 1-9 to form one or more road layers.

12. The method of claim 11 , wherein the aggregates have been provided by removing and milling one or more asphalt layers above the road foundation.

13. The method of any of claims 11-12, wherein the aggregates, optionally reclaimed asphalt aggregates, are mixed in-situ or in a mobile cold recycling plant with foamed bitumen.

14. The method of any of claims 11-13, wherein the active filler is spread on the road before it is recycled and milled, optionally wherein active filler and glass fibres are spread on the road so that the materials are mixed with asphalt during the milling.

15. Use of glass fibre material for bitumen stabilised material (BSM) compositions, wherein the composition is a solid granular mixture before consolidation, and wherein the bitumen is dispersed and does not form a continuous phase in the consolidated structure.

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