FR3144990A1 - Organo-mineral binder, composition for roadway coatings, and road coatings - Google Patents

Abstract

The present invention refers to an organo-mineral binder composition comprising, by mass, relative to its total mass: (a) from 65% to 95% of an aqueous colloidal dispersion of (co)polymers having a basic pH ranging from 8.5 to 11, which is anionic and has a minimum film formation temperature, called TMFF, ranging from -10°C to 10°C, preferably from -5°C to 5°C and a glass transition temperature, called Tg, ranging from -10°C to 15°C, preferably from 0°C to 10°C VS ; (b) from 3% to 30% of a cationic mineral compound; (c) from 0.05% to 5% of an anionic thickening agent. The present invention also relates to a composition for road surface coverings comprising said organo-mineral binder, as well as to a road surface intended for regular traffic of light vehicles and which may be of the permeable (draining) or non-permeable type. Figure for abstract: no figure

Description

Organo-mineral binder, composition for road surface coating and road surface coating Technical field of the invention

The present invention relates to the field of road surfaces intended for regular traffic of light vehicles, such as wearing courses, produced cold.

In particular, the present invention relates to an organo-mineral binder composition. The invention also relates to a composition for road surfacing comprising said organo-mineral binder, as well as a road surfacing made from this composition for road surfacing intended for regular traffic of light vehicles. In addition, the road surfacing obtained will make it possible to produce, depending on the type of aggregates chosen, permeable (draining) or non-permeable roads.

State of the art

By definition, a road surface, such as asphalt, is made up of a granular fraction and a binder. The granular fraction is a mixture of gravel, fines and sand. It is most often derived from massive or sedimentary rocks, but it can also be derived from recycled products (such as asphalt aggregates, AE) or synthetic products. The binder is used to bond the aggregates together and ensure good mechanical strength of the asphalt layer. The binder, in general, can be, for example, a hydrocarbon binder, a synthetic binder or a plant binder.

The asphalt mixes are completely covered with binder during their manufacture, then applied by spreading and compacted to obtain road surfaces, also called pavements.

Today, many, if not most, roads are covered with bituminous coatings that have proven their ability to meet the constraints of the application on the one hand and the stresses related to traffic and climatic conditions on the other hand. These coatings are considered suitable for this use and their durability is recognized. Among the properties that give bitumen its qualities of use as a binder, viscoelasticity plays a fundamental role. It is this which makes it possible to find a good compromise between flexibility and rigidity.

Bitumen is a material resulting from the transformation of oil. As such, it is one of the so-called non-renewable raw materials since oil is a fossil material.

In addition, conventional bitumen-based coatings are most often applied hot. However, the production of hot coatings imposes significant energy costs.

Solutions have been proposed in the state of the art in order to replace all or part of the use of bitumen in road surface compositions, while presenting a quality of use that is substantially equivalent or close to it.

Document FR 2 853 647 describes in particular a binder for the production of a layer and/or coating for road construction and/or civil engineering comprising, relative to the total weight of (a) and (b):

(a) from 2 to 98% by weight of at least one natural or modified natural resin, of plant origin, having a softening point measured according to standard EN 1427 of 30 to 200°C;

(b) from 98 to 2% by weight of at least one oil of vegetable origin having a viscosity at 25°C of 50 mPa.s to 1000 Pa.s,

(c) said binder having: (c1) either a penetrability at 25°C, measured according to standard NF EN 1426, of 20 to 300 1/ ^10th of a mm and a softening point of 30 to 75°C, measured according to standard NF EN 1427; (c2) either a penetrability at 15°C, measured according to standard NF EN 1426, of 300 to 900 1/ ^10th of a mm and a viscosity at 60°C, measured according to standard NF EN 12596 of 2 to 20Pa.s; and

(d) said binder being free from any natural or synthetic elastomer and any thermoplastic polymer.

Natural resin can be natural rosin and vegetable oil can be crude or refined oil. It can also be modified by chemical reactions, such as esterification.

Document FR 3 095 661 describes the use of an aqueous polymer dispersion for the preparation of a binder intended for the manufacture of road or urban asphalt.

In particular, the aqueous dispersion comprises at least:

- an anionic surfactant and

- Π1 particles based on at least two polymers having distinct glass transition temperatures, such that the polymer having the highest glass transition temperature, greater than or equal to 10°C, is at the centre of the Π1 particle and the polymer having the lowest glass transition temperature, less than or equal to 0°C, is at the surface of the Π1 particle, for the preparation of a binder intended for the manufacture of a road or urban coating.

Although these technical solutions are satisfactory, there is a need in the state of the art to have new binder compositions which are more environmentally friendly compared to traditional binders, in particular those derived from petroleum, while retaining technical performances which are substantially comparable.

In particular, there is a need in the state of the art to have new binder compositions for cold forming road surfaces, in particular intended to be subjected to regular traffic of light vehicles, having good mechanical strength, such as good compressive strength Rc.

There is also a need in the state of the art to have new binder compositions, having adequate technical performances, while being easy to implement, namely while being easily achievable at the level of its preparation process, the process being capable of or configured to provide stable compositions having identical or at least similar technical characteristics from one batch to another.

The aim of the present invention is thus to propose a new binder composition which meets at least in part the aforementioned needs.

Presentation of the invention

For this purpose, the present invention relates to an organo-mineral binder composition comprising, by mass, relative to its total mass:

(a) from 65% to 95% of an aqueous colloidal dispersion of (co)polymers which is anionic and which has

- a basic pH ranging from 8.5 to 11, preferably ranging from strictly greater than 8.5 to 10.0,

- a minimum film formation temperature, called TMFF, ranging from - 10°C to 10°C, preferably ranging from - 5°C to 5°C and

- a glass transition temperature, called Tg, ranging from -10°C to 15°C, preferably ranging from 0°C to 10°C;

(b) from 3% to 30% of at least one cationic mineral compound;

(c) from 0.05% to 5% of an anionic thickening agent.

Other non-limiting and advantageous characteristics of the binder composition according to the invention, taken individually or in all technically possible combinations, are as follows:

- the binder composition comprises, by mass, relative to its total mass: (a) from 70% to 90% of said aqueous colloidal dispersion of (co)polymers; (b) from 10% to 25% of said aqueous dispersion comprising at least one cationic mineral compound; (c) from 0.05% to 1% of said thickening agent;

- (a) the aqueous colloidal dispersion of (co)polymers comprises a carboxylated styrene-butadiene copolymer;

- (a) the aqueous colloidal dispersion of (co)polymers also comprises an anionic emulsifier and/or an anionic initiator;

- (a) the aqueous colloidal dispersion of (co)polymers comprises:

- an average particle size ranging from 100 nm to 250 nm, preferably from 120 nm to 220 nm and in particular from 150 nm to 190 nm, and/or

- a dry extract of active products including the (co)polymers and, where appropriate, the anionic emulsifier and/or the anionic initiator ranging from 30 to 60%, preferably from 40 to 50%, relative to the total mass of the aqueous colloidal dispersion of (co)polymers (a);

- said at least one cationic mineral compound (b) is in the form of powder or in the form of an aqueous dispersion;

- said at least one cationic mineral compound (b) is in the form of an aqueous dispersion in which it has an average particle size ranging from 0.1 µm to 50 µm, preferably ranging from 0.5 µm to 20 µm and typically ranging from 1 µm to 5 µm;

- said at least one cationic mineral compound (b) is calcium carbonate;

- (c) the anionic thickening agent belongs to the same chemical family as (a) the aqueous colloidal dispersion of (co)polymers and has an acidic pH of the order of 3 to 6, preferably 4 to 5;

- (c) the anionic thickening agent is an anionic dispersion in aqueous phase, preferably comprising a carboxylated styrene-butadiene copolymer;

- the binder composition comprises at least one of the following characteristics, preferably all of the following characteristics:

- a pH ranging from 7.0 to 11.0, preferably ranging from 8 to 10 and typically ranging from 8.5 to 9.5;

- a viscosity measured at 22°C ± 2°C with a Brookfield viscometer (RV DV II+, 60 rpm) according to ISO 2555:2018 ranging from 100 mPa.s to 10,000 mPa.s, preferably ranging from 200 mPa.s to 5,000 mPa.s and typically ranging from 500 mPa.s to 200 mPa.s;

- a dry extract in mass in active products comprising:

the (co)polymers, where applicable the anionic emulsifier and/or the anionic initiator,

the cationic mineral compound and

the thickening agent

ranging from 40% to 70%, preferably from 45% to 60% and typically of the order of 50% to 53% relative to the total mass of the organo-mineral binder;

- an average particle size ranging from 100 nm to 50 µm, preferably ranging from 120 nm to 3 µm.

The present invention also relates to a composition for road surface coating intended for regular light vehicle traffic comprising at least one organo-mineral binder as defined above, at least one aggregate and added water.

Preferably, the aggregate comprises at least sands, preferably of calcareous nature, having a granular fraction of 0/2 and/or 0/4 mm and gravels having a granular fraction of 0/20.

The present invention also refers to a road surface, characterized in that it comprises the road surface composition as defined above, and that it has a thickness ranging from 3 to 8 cm, preferably ranging from 3 to 5 cm and typically ranging from 4 to 4.5 cm. Depending on the road surface composition developed, the road surface will be of the permeable or non-permeable type.

Typically, the road surface coating composition is placed between a base layer and a sealant layer.

Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

For the remainder of the description, unless otherwise specified, the indication of an interval of values "from X to Y" or "between X and Y", in the present invention, is understood as including the values X and Y. Also, unless otherwise specified, the indication "strictly greater than X", does not include this value X.

For the purposes of this application, a traffic lane intended for regular traffic of light vehicles is a roadway on which the vehicles that circulate are only vehicles whose Gross Vehicle Weight is limited to 3.5 Tonnes. Thus, the traffic lanes concerned may be pedestrian paths, cycle paths, but also lanes intended for the regular traffic of cars and other utility vehicles, as well as parking areas. Road surfaces intended for private individuals, such as access roads to garages, etc. also fall within the scope of this definition.

According to the invention, unless otherwise stated, the various characteristics of the invention have been measured according to the standards mentioned below.

Detailed description of the invention

In addition, various other features of the invention emerge from the attached description which illustrate non-limiting embodiments of the invention.

A. Composition of organo-mineral binder

The Applicant company has focused on developing new organo-mineral binder compositions, in particular bitumen-free, which are environmentally friendly and intended for cold application to form, in particular, porous road surfaces, suitable for light vehicles.

For this purpose, the organo-mineral binder composition according to the invention comprises, by mass, relative to its total mass:

(a) from 65% to 95% of an aqueous colloidal dispersion of (co)polymers which is anionic and which has:

- a basic pH ranging from 8.5 to 11, preferably ranging from strictly greater than 8.5 to 10.0,

- a minimum film formation temperature, called TMFF, ranging from - 10°C to 10°C, preferably ranging from - 5°C to 5°C and

- a glass transition temperature, called Tg, ranging from -10°C to 15°C, preferably ranging from 0°C to 10°C;

(b) from 3% to 30% of an aqueous dispersion comprising at least one cationic mineral compound;

(c) from 0.05% to 5% of an anionic thickening agent.

Due to its characteristics, the organo-mineral binder composition according to the invention can be applied cold and without odor. It makes it possible to form road surface compositions that can also be applied cold, offering real energy and environmental savings (in particular the absence of Volatile Organic Compounds, VOCs).

The organo-mineral binder composition according to the invention also has the advantage of being substantially transparent. This characteristic thus makes it possible to form urban coatings that highlight the natural color of the selected aggregates. In the absence of an expansion joint, the coating thus produced has perfect integration into the urban or landscaped environment.

The coating thus formed from the organo-mineral binder according to the invention also has physical properties enabling it to contribute effectively to certain problems encountered in urban environments, such as the fight against the increasing waterproofing of urban surfaces as well as the reduction of urban heat islands (UHI).

As mentioned above, the binder composition according to the invention is an aqueous-phase organo-mineral binder based on a composition of at least three starting constituents which will be described in more detail below:

(a) an aqueous colloidal dispersion of organic (co)polymers which is anionic, intended to form a polymer film allowing cohesion between the aggregates used in order to manufacture a road surface,

(b) a cationic mineral agent, generally in the form of an aqueous dispersion comprising at least one cationic mineral compound and which is capable of stabilizing the binder composition according to the invention, of reinforcing the bonds between the aggregate and the binder during the preparation of a road surface and of improving the resistance of said surface thus prepared;

(c) an anionic thickening agent capable of and/or configured to increase the viscosity of the binder composition according to the invention (and which is different from the aforementioned colloidal dispersion (a)).

A1. Aqueous colloidal dispersion of anionic (a) (co)polymers

First of all, the organo-mineral binder composition according to the invention mainly comprises an aqueous colloidal dispersion of anionic (co)polymers.

Indeed, this aqueous colloidal dispersion of (co)polymers (a) represents, by mass, from 65% to 95%, preferably from 80% to 90% relative to the total mass of the organo-mineral binder according to the invention.

According to the invention, a range of values from 65% to 95% includes the following values (in %) and any interval between these values: 65; 66; 67; 68; 69; 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83; 84; 85; 86; 87; 88; 89; 90; 91; 92; 93; 94; 95.

In addition, the aqueous colloidal dispersion of (co)polymers (a) has the following characteristics.

First, as mentioned above, the aqueous colloidal dispersion of (co)polymers (a) is anionic (i.e.: negatively charged).

The Applicant has discovered that in order to create strong bonds between the (co)polymer and the aggregates (sand, gravel, fillers, etc.) used, it is necessary to have a negatively charged (co)polymer. Indeed, the Applicant has found that when the aqueous colloidal dispersion of (co)polymer is added to the aggregates (in grain form), bonds will be created between these aggregates and the (co)polymer. However, the grains of the aggregates are generally characterized by the presence of positive charges on their surface: presence of cations K ⁺ , Ca ²⁺ , Mg ²⁺ , Al ³⁺ , Fe ³⁺ , as well as protons H ⁺ . These positive charges added to the protons contained in the supply water will provide a lot of positive ions that it is preferable to counterbalance with a negatively charged (co)polymer.

Then, the aqueous colloidal dispersion of (co)polymers (a) has a basic pH ranging from 8.5 to 11, preferably ranging from strictly greater than 8.5 to 10.5. According to the invention, a “pH ranging from 8.5 to 11” includes the following values and any interval between these values: 8.5; 8.6; 8.7; 8.8; 8.9; 9; 9.1; 9.2; 9.3; 9.4; 9.5; 9.6; 9.7; 9.8; 9.9; 10; 10.1; 10.2; 10.3; 10.4; 10.5; 10.6; 10.7; 10.8; 10.9; 11.

The Applicant has also discovered that it is necessary for the (co)polymer used to form the binder composition according to the invention to have a minimum film formation temperature, called TMFF, ranging from -10°C to 10°C, preferably ranging from -5°C to 5°C and typically ranging from -1°C to 2°C, such as 0°C. According to the invention, a TMFF ranging from -10°C to 10°C includes the following values and any interval between these values (in °C): -10; -9; -8; -7; -6; -5; -4; -3; -2; -1; 0; 1; 2; 3; 4; 5; 6; 7; 8; 9; 10.

Also, she discovered that the glass transition temperature, Tg, was important and should range from -10°C to 15°C, preferably from 0°C to 10°C and typically from 5°C to 10°C. According to the invention, a Tg ranging from -10°C to 15°C includes the following values and any interval between these values (in °C): -10; -9; -8; -7; -6; -5; -4; -3; -2; -1; 0; 1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15.

In general, it is preferable that one of the temperatures between TMFF and Tg, but not both, be less than or equal to 3°C, particularly less than or equal to 2°C and typically less than or equal to 1°C, such as 0°C.

An aqueous colloidal dispersion of (co)polymers (a) having such a TMFF or Tg, makes it possible to use the binder according to the invention when applied at temperatures higher than the higher of the two temperatures between TMFF and the Tg, namely at temperatures which can drop to -10°C. The binder according to the invention can thus be used to form coatings in all seasons (i.e.: the outside temperatures must be higher than the Tg or the TMFF of the aqueous colloidal dispersion of (co)polymers (a)).

Without being bound by any theory, the Applicant has discovered that the use in the majority quantity of an aqueous colloidal dispersion of anionic (co)polymers (a) as described above made it possible, during the formation of the final coating, to ensure the cohesion of all the aggregates between them, while being the most neutral with regard to the final aesthetic appearance of said coating.

Thus, generally, the aqueous colloidal dispersion of (co)polymers (a) is translucent after drying (barely perceptible once setting is complete) and is resistant over time. In addition, preferably, it does not comprise or only in trace amounts (i.e.: less than 10%, preferably less than 5% and typically less than 2%, by mass, relative to the total mass of the dispersion (a)), of toxic compounds, such as polychlorinated biphenyl PCB, volatile organic compounds VOC, polycyclic aromatic hydrocarbons PAH, heavy metals, endocrine disruptors, or other carcinogenic elements.

Preferably, the aqueous colloidal dispersion of (co)polymers (a) contains one or more carboxyl groups and is characterized by anionic polymerization.

For example, the aqueous colloidal dispersion of (co)polymers may be chosen from aqueous dispersions based on (co)polymers of carboxylated styrene butadiene, carboxylated styrene butadiene acrylate, carboxylated styrene butadiene acrylonitrile, 2-ethylhexyl acrylate or methyl methacrylate as well as a mixture of each of these carboxylated styrene butadiene copolymers in proportions ranging from 0.01 to 99.9%.

The aqueous dispersion may also correspond to an acrylic styrene, a pure acrylic, a modified acrylic, a butyl acrylate or a mixture of each of these copolymers in proportions ranging from 0.01 to 99.9%.

In general, the aqueous colloidal dispersion of (co)polymers also comprises a stabilizer, such as ammonia (NH4 ⁺ ). The stabilizer represents, by mass, relative to the total mass of the dispersion, less than 1%, preferably less than 0.5%.

Also, the aqueous colloidal dispersion of (co)polymers also comprises an anionic emulsifier and/or a setting initiator.

The anionic emulsifier makes it possible in particular to accentuate the negative charge of the aqueous colloidal dispersion of (co)polymers (a) since it is negatively charged on its surface. Another role of this anionic emulsifier is to allow the copolymerization of several different monomers. The anionic emulsifier can, for example, be chosen from surfactants of the alkylbenzene sulfonate type, such as sodium dodecylbenzenesulfonate (or sodium lauryl sulfate), as well as other surfactants such as sodium stearate, sodium lauryl ether sulfate, dehydrogenated resin acids and their alkali metal salts, as well as a mixture thereof. Preferably, the anionic emulsifier is chosen from sodium dodecylbenzenesulfonate, known as SBDS (presence of sulfonate groups (-SO ₃ ^- ) on its surface).

The setting initiator may, for example, be chosen from among the conventional water-soluble radical anionic setting initiators of solution polymerization, such as alkali persulfates, water-soluble diazo derivatives or redox systems based on oxidants such as hydrogen peroxide, organic peroxides or hydroperoxides and reducing agents such as alkali sulfites and bisulfites, amines, metal formaldehyde sulfoxylates, etc. These setting initiators may be used alone or as a mixture. Preferably, the setting initiator is anionic and notably comprises persulfate groups (-O-SO3^-).

Therefore, the entire structure of the styrene-butadiene copolymer/optionally anionic emulsifier + setting initiator is negatively charged. In addition, the electrostatic stabilization (suspension in aqueous phase of the (co)polymers) prevents any possible flocculation or precipitation of the (co)polymer solution.

Generally, the concentration of budadiene, by mass, relative to the total mass of the aqueous colloidal dispersion of (co)polymers (a) ranges from 25% to 50%, preferably from 30% to 45% and typically from 35% to 40%, such as 37%.

According to this embodiment, the styrene-butadiene copolymer comprises a [styrene]:[butadiene] ratio ranging from 4:1 to 1:1 and is typically 2:1.

In particular, the aqueous colloidal dispersion of (co)polymers (a) comprises an average particle size ranging from 100 nm to 250 nm, preferably from 120 nm to 220 nm and in particular from 150 nm to 190 nm.

According to the invention, “an average particle size ranging from 100 nm to 250 nm” includes the following values (in nm) and any interval between these values: 100; 110; 120; 130; 140; 150; 160; 170; 180; 190; 200; 210; 220; 230; 240; 250.

Typically, the aqueous colloidal dispersion of (co)polymers (a) comprises a dry extract of active products including the (co)polymers and, where appropriate, the anionic emulsifier and/or the anionic initiator ranging from 30% to 60%, preferably from 40% to 50%, relative to the total mass of the aqueous colloidal dispersion of (co)polymers (a).

For the purposes of the present invention, a range of “from 30% to 60%” includes the following values (in %) and any interval between these values: 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60.

In general, the dynamic viscosity of the aqueous colloidal dispersion of (co)polymers (a) measured at 22°C ± 2°C with a Brookfield viscometer (RV DV II+, 60 rpm) according to ISO 2555:2018 ranges from 20 to 500 mPa.s, preferably from 25 to 400 mPa.s and typically from 50 to 300 mPa.s. As an example, the colloidal dispersion (a) having the characteristics illustrated in Table 1 below is suitable for forming the binder according to the invention.

Characteristic of colloidal dispersion (a) Percentage of dry extract 49.0 ± 1.0% Butadiene concentration 37% pH 9.0 -10.0 Relative density (density of dispersion (a)/density of pure water at 4°C) 1.01 Dynamic viscosity 50-300 mPa.sec TMFF 0°C Tg 7°C Particle size 170 nm

A2. Cationic mineral compound (b)

The Applicant has discovered that in order to reinforce the mechanical resistance of the polymer film formed by the aqueous dispersion (a) and to improve the bonding forces between the polymer and the aggregates (sand, gravel), it was necessary to add a cationic mineral compound which can advantageously be in the form of an aqueous dispersion.

Without being bound by any theory, the Applicant discovered that the addition of this positively charged mineral compound made it possible to reduce the elasticity of the final binder composition (intrinsic characteristic of the aqueous colloidal dispersion of (co)polymers (a)) and to preserve the mechanical strengths of the latter, in particular in contact with humidity. Indeed, most polymers, such as the styrene-butadiene copolymer, present in the organic colloidal dispersion (a) tend to relax in contact with water and in a humid environment, consequently affecting, and quite significantly, the mechanical performance of the final binder composition. However, here, the Applicant discovered that the use of a specific mineral compound, namely positively charged, made it possible to create sufficiently strong covalent bonds with the negatively charged (co)polymers of the colloidal dispersion (a) and was capable of reducing its elasticity. In addition, the mineral compound has the advantage of increasing the viscosity of the final binder composition.

Thus, the addition of a mineral compound to the binder composition according to the invention makes it possible to improve the durability of the coating formed from this binder, particularly with regard to climatic aggression.

In order to obtain the required mechanical performances, the Applicant has further discovered that it is necessary for the cationic mineral compound to be combined with the colloidal dispersion of organic (co)polymers during the preparation of the binder composition according to the invention. The latter cannot be added subsequently, for example at the time of manufacturing the road surface composition (binder mixture according to the invention with the granular mixture). Indeed, if this were the case, the mixture obtained (i.e. the binder comprising only the colloidal dispersion (a) + the anionic thickening agent (c), the aggregates (such as sand and gravel) and the mineral compound added subsequently) would not be optimal. The mineral compound, such as calcium carbonate, would not be sufficiently “bound” to the aqueous dispersion of (co)polymers (a) and would therefore not make it possible to obtain the desired final performances for coating it (rutting resistance, etc.). The good performance over time of this final coating would therefore be directly impacted.

According to the invention, the cationic mineral compound (b) represents, by mass, relative to its total mass, from 3% to 30%, preferably from 10% to 30%. In the context of the present invention, a value range of “3% to 30%” includes the following values (in %) and any interval between these values: 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30.

In general, the mineral compound can be any type of mineral fillers such as kaolinite or smectite clays treated, crushed and calcined at different cooking temperatures, calcium carbonate, talc, titanium or zinc dioxide, calcium or barium sulfates or sulfoaluminates, and is preferably calcium carbonate.

According to one embodiment of the invention, the cationic mineral compound (b) is in powder form.

According to another embodiment of the invention, the cationic mineral compound (b) is in the form of an aqueous dispersion.

The Applicant has discovered that it is preferable to use the cationic mineral compound (b), such as calcium carbonate, in the form of an aqueous dispersion. Indeed, on the one hand, the aqueous dispersion makes it possible to limit the risks of exposure of the user/personnel when handling the mineral compound such as CaCO ₃ compared to its use in powder form (more dispersible). On the other hand, the Applicant has discovered that when the cationic mineral compound and in particular calcium carbonate is in the form of an aqueous dispersion, also called slurry, this makes it possible to significantly increase, compared to the powder form, the viscosity of the mixture "aqueous colloidal dispersion of anionic (co)polymers (a) + cationic mineral compound".

According to this embodiment, said at least one cationic mineral compound represents, by mass (dry extract), relative to the total mass of the aqueous colloidal dispersion (b) from 50% to 95%, preferably from 60% to 85% and typically from 70% to 80%. For the purposes of the present invention, a value range of “50% to 95%” includes the following values (in %) and any interval between these values: 50; 55; 60; 65; 70; 75; 80; 85; 90; 95.

In general, according to this embodiment, the cationic mineral compound has an average particle size ranging from 0.1 µm to 50 µm, preferably ranging from 0.5 µm to 20 µm and typically ranging from 0.5 µm to 8 µm. According to the invention, a value range of “0.1 µm to 50 µm” includes the following values (in µm) and any interval between these values: 0.1; 0.5; 1; 1.5; 2; 2.5; 3; 3.5; 4; 4.5; 5; 5.5; 6; 6.5; 7; 7.5; 8; 8.5; 9; 9.5; 10; 10.5; 11; 11.5; 12; 12.5; 13; 13.5; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50.

Typically, the dynamic viscosity of the mineral compound (b) in the form of an aqueous dispersion measured at 23°C ± 2°C with a Brookfield viscometer (RV DV II+, 100 rpm) according to ISO 2555:2018, ranges from 100 to 1500 mPa.s, preferably ranges from 200 to 800 mPa.s and typically ranges from 250 to 500 mPa.s.

In particular, the aqueous dispersion comprising at least one cationic mineral compound (b) has a basic pH ranging from 7.5 to 13, preferably ranging from 8 to 10.5. According to the invention, a “pH ranging from 7.5 to 13” includes the following values and any interval between these values: 7.5; 7.6; 7.7; 7.8; 7.9; 8; 8.1; 8.2; 8.3; 8.4; 8.5; 8.6; 8.7; 8.8; 8.9; 9; 9.1; 9.2; 9.3; 9.4; 9.5; 9.6; 9.7; 9.8; 9.9; 10; 10.1; 10.2; 10.3; 10.4; 10.5; 10.6; 10.7; 10.8; 10.9; 11; 11.1; 11.2; 11.3; 11.4; 11.5; 11.6; 11.7; 11.8; 11.9; 12; 12.1; 12.2; 12.3; 12.4; 12.5; 12.6; 12.7; 12.8; 12.9; 13.

For example, calcium carbonate having the characteristics illustrated in Table 2 below is suitable for producing the binder composition according to the invention. This is a calcium carbonate of fairly high purity produced by wet grinding of a specific calcite. The size of the calcium carbonate particles is relatively small and is of the order of 3 µm.

This product has the following characteristics in particular:

Characteristic of the cationic mineral compound (b) (calcium carbonate) Percentage of dry extract 75% ± 1.0% Particle size (d50%) 3 µm pH 9.0 ± 0.5 Relative density (density of dispersion (b)/density of pure water at 4°C) 1.80 ± 0.20 Specific surface area 4.2 m².g ^-1 Dynamic viscosity (at 25°C) 250-500 mPa.s

A3. Anionic thickening agent

Finally, the binder composition according to the invention comprises, by mass, relative to its total mass, from 0.05% to 5%, preferably from 0.05% to 1% of an anionic thickening agent (c).

According to the invention, a range of values from “0.05% to 5%” includes the following values and any interval between these values (in %): 0.05; 0.06; 0.07; 0.08; 0.09; 0.10; 0.15; 0.2; 0.25; 0.30; 0.35; 0.4; 0.45; 0.5; 0.55; 06; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95; 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; 4.0; 4.5; 5.

The Applicant has discovered that it is preferable to further increase the viscosity of the binder composition based on the colloidal dispersion of organic (co)polymers (a) and the mineral compound (b) via the addition of a thickening agent (rheological agent). As mentioned above, the viscosity of the binder (without the use of this thickening agent) is mainly linked to the viscosity of the colloidal dispersion (a) which is relatively low (generally of the order of 50-250 mPa.s).

However, in order not to destabilize the role played by the aqueous dispersion of negatively charged organic (co)polymers, the Applicant has also discovered that it is important to add a rheological agent also negatively charged (such as the (co)polymers).

On the other hand, it is preferable for the thickening agent according to the invention to have a high thermoplastic (rheo-fluidifying) power so as to limit the mass content of starting reagent other than compounds (a) and (b) according to the invention and in particular so as not to alter the function of the colloidal dispersion of organic (co)polymers (a). Thus, the use of a low mass content of thickening agent is preferred so as not to disturb the stability of the binder according to the invention.

For this purpose, and in order to obtain a homogeneous and stable binder composition over time, the anionic thickening agent (c) preferably belongs to the same chemical family as (a) the aqueous colloidal dispersion of (co)polymers. In addition, the anionic thickening agent (c) has an acidic pH of the order of 3 to 6, preferably 4 to 5.

Indeed, the Applicant has discovered that these additional characteristics make it possible to restrict the quantity of thickening agent and to obtain a high thermoplastic power. Without being bound by any theory, it would seem that the acid thickening agent would form an acid-base “shock” between the latter and the aqueous dispersion of (co)polymers (a) which would make it possible to rapidly increase, and with a low dose of product, the final viscosity of the binder composition.

Generally, the anionic thickening agent (c) is an anionic dispersion in aqueous phase, preferably comprising a carboxylated styrene-butadiene copolymer, a butadiene acrylate copolymer, a butadiene acrylate polymer comprising styrene units, a mixture of each of the three preceding compounds.

According to this embodiment, in which the anionic dispersion in aqueous phase comprising the thickening agent (c) comprises an average particle size ranging from 50 nm to 250 nm, preferably from 80 nm to 220 nm and in particular from 100 nm to 150 nm.

Also, according to this embodiment, the mass concentration of butadiene within the anionic dispersion in aqueous phase of carboxylated styrene-butadiene copolymer ranges from 10 to 20%, preferably from 13% to 18%.

The anionic thickening agent (c) may also be any other type of additive for modifying the viscosity of a polymer such as natural thickeners such as agar agar, artificial polymers based on cellulose such as cellulose ethers of the HEC (hydroxyethylcellulose) or HMHEC (hydrophobically modified hydroxyethylcellulose) type, non-associative acrylic thickeners (ASE) and associative acrylic thickeners (HASE), thickening polyurethanes (HEUR), as well as any other water-soluble or water-dispersible polymers.

For example, the anionic thickening agent (c) having the characteristics illustrated in Table 3 below is suitable for producing the binder composition according to the invention. It is a thickening agent in the form of an anionic dispersion in aqueous phase of a highly carboxylated styrene-butadiene copolymer having a pH of the order of 4-5. It is characterized by a high thermoplastic (rheofluidifying) power and is perfectly compatible with the aqueous dispersion of anionic organic (co)polymer (a). Insofar as it is acidic, this product is also capable of creating an acid-base shock with the colloidal dispersion of (co)polymers (a) as described above.

This product has the following characteristics in particular:

Characteristics of the thickening agent (c) Percentage of dry extract 35.5% ± 1.0% pH 4.5 Relative density (density of the dispersion (c)/density of pure water at 4°C) 1.05 Dynamic viscosity (at 25°C) 25 mPa.s Butadiene concentration 15% Particle size 120 nm

The anionic thickening agent (c) according to the invention thus makes it possible to increase the viscosity of the final binder composition and in particular to prevent the creep of the binder composition during its storage/transport and, on the other hand, during the manufacture of the road surface composition (i.e.: manufacture of the asphalt).

A.4 Characteristics of the organo-mineral binder according to the invention

In general, the organo-mineral binder according to the invention is in the form of an aqueous dispersion and generally has the following physicochemical characteristics.

The binder composition according to the invention firstly has a final pH which is basic and which generally ranges from 7.0 to 11, preferably from 8 to 10 and is typically 9 ±0.5. According to the invention, a “pH ranging from 7.0 to 11” includes the following values and any interval between these values: 7; 7.1; 7.2; 7.3; 7.4; 7.5; 7.6; 7.7; 7.8; 7.9; 8; 8.1; 8.2; 8.3; 8.4; 8.5; 8.6; 8.7; 8.8; 8.9; 9; 9.1; 9.2; 9.3; 9.4; 9.5; 9.6; 9.7; 9.8; 9.9; 10; 10.1; 10.2; 10.3; 10.4; 10.5; 10.6; 10.7; 10.8; 10.9; 11.

As mentioned above, the pH is an important characteristic of the binder. Its stability over time is due to the fact that at least one of the two main compounds included in its composition, and preferably both, are aqueous phase dispersions, one being organic in nature, the other mineral in nature – whose pH is close to 9. The addition of a small quantity of the anionic thickening agent, generally having an acidic pH, causes a relatively limited acid-base shock. This will ensure very long-term stability of the binder composition thus developed.

In particular, the dynamic viscosity of the binder according to the invention measured at 22°C ± 2°C with a Brookfield viscometer (RV DV II+, 60 rpm) according to the ISO 2555: 2018 standard ranges from 100 mPa.s to 10,000 mPa.s, preferably from 200 mPa.s to 5,000 mPa.s and typically from 500 mPa.s to 2,000 mPa.s.

Such viscosity will in particular ensure optimal homogenization of the aggregates with the binder during the manufacture of a road surface composition and during its installation.

Typically, the binder composition according to the invention comprises, relative to its total mass, a mass content of dry extract (i.e., of particles present in compounds (a) to (c) according to the invention) ranging from 30% to 70%, preferably from 40% to 60% and in particular from % to 55%.

For the purposes of the present invention, a range of “30 to 70%” includes the following values and any interval between these values: 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60; 61; 62; 63; 64; 65; 66; 67; 68; 69; 70.

Generally, the binder composition comprises an average particle size ranging from 100 nm to 50 µm, preferably from 110 nm to 10 µm and in particular from 120 nm to 5 µm.

According to the invention, an average particle size of “from 100 nm to 10 µm” includes the following values and any interval between these values: 100 nm; 200 nm; 300 nm; 400 nm; 500 nm; 600 nm; 700 nm; 800 nm; 900 nm; 1 µm; 2 µm; 3 µm; 4 µm; 5 µm; 6 µm; 7 µm; 8 µm; 9 µm; 10 µm; 11 µm; 15 µm; 20 µm; 25 µm; 30 µm; 35 µm; 40 µm; 45 µm; 50 µm.

In particular, the binder has a density at 22°C ranging from 1.01 to 1.15, preferably from 1.04 to 1.12 and typically from 1.080 ± 0.02.

Due to its characteristics and in particular its composition, the appearance of the binder according to the invention is generally a milky white liquid which becomes transparent after drying.

By way of example, the organo-mineral binder composition according to the invention may comprise, by mass, relative to its total mass,

- from 70% to 95%, preferably from 80% to 90% and typically 84.65% of the aqueous colloidal dispersion of (co)polymers (a), in particular that illustrated in Table 1;

- from 3% to 25%, preferably from 8% to 20% and typically 15% of the cationic mineral compound, in particular that illustrated in Table 2 above; and

- from 0.05% to 2%, typically 0.35% of the anionic thickening agent as illustrated in Table 3 above.

The Applicant has thus developed a transparent, cold-applicable organo-mineral binder which also has the following advantages:

- the product is ready to use - it does not require any dilution or addition of raw material before use;

- the product is translucent, allowing the natural colour of the aggregate to be preserved when manufacturing a road surface;

- the product is in aqueous phase and odorless upon application

- cleaning of equipment and installations can be done only with water (the use of organic solvent is not necessary, or even desirable).

- the product is mixed or used as a spray at room temperature;

- the product is not considered a hazardous mixture within the meaning of Regulation No. 1272/2008 on the classification, labelling and packaging of dangerous substances and mixtures (CLP);

- no raw material used (and as described above) is included in the list of products subject to authorization;

- the transport, storage and implementation of the finished product (i.e.: organo-mineral binder) is not subject to ICPE (Classified Installation for Environmental Protection);

- absence of organic solvents (VOCs).

- absence of CMR substances (carcinogenic, mutagenic and reprotoxic), cat 1, of PBT (polybutylene terephthalate) and vPvB (from the English, “very persistent and very bioaccumulative” are substances known to be very persistent and very bioaccumulative) in particular heavy metals, substances of the “endocrine disruptor” type, of PAHs and of PCBs;

- the product is not dangerous for the surrounding flora and fauna: it is not likely to pollute water and soil at the end of its life; and

- the coating installed is recyclable.

Thus, the organo-mineral binder according to the invention can be used to form road construction coatings for light vehicles and/or civil engineering, as a total replacement for bitumen.

A.5 Process for preparing the organo-mineral binder according to the invention

1. le mélange des constituant de départ (a) à (c) tels que décrit ci-dessus.

The process for preparing the organo-mineral binder according to the invention generally comprises at least the following step:

1. the mixture of starting constituents (a) to (c) as described above.

Generally, the mixture is made at room temperature (ranging from around 15°C to 25°C). It is not necessary to heat it.

A conventional mixing device, such as a stainless steel tank equipped with a motor and a stirring blade, may be suitable for preparing the binder according to the invention.

For example, the mixing step can be carried out in a conventional mixer with a rotation speed ranging from 200 to 400 revolutions per minute for a duration ranging from 10 to 20 minutes.

B. Road surface composition for regular light vehicle traffic

B.1 Structure of the road surface composition

• un liant organo-minéral tel que défini ci-dessus, et
• au moins un granulat (i.e. : mélange granulaire),
• de l’eau d’apport.

The present invention also relates to a composition for coating traffic lanes intended for regular traffic of light vehicles comprising at least:

• an organo-mineral binder as defined above, and
• at least one aggregate (ie: granular mixture),
• of the supply water.

The road surface composition according to the invention in fact requires the addition of water in order to ensure optimal diffusion of the organo-mineral binder according to the invention on the surface of said at least one aggregate and to increase the open time of the mixture.

In general, the road surface coating composition comprises, by mass, relative to the dry mass of said at least one aggregate, from 0.5% to 6%, preferably from 1% to 5% and typically from 1.5% to 4% of added water. According to the invention, a range of values from “from 0.5% to 6%” includes the following values (in %) and any interval between these values: 0.5; 0.6; 0.7; 0.8; 0.9; 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; 4.0; 4.5; 5; 5.5; 6.0.

The adjustment of the dosage of added water may be conventionally carried out by a person skilled in the art: the rate of added water must be sufficient to ensure the quality of the dispersion of binder according to the invention within the aggregates, but without excess so as not to harm the desired aesthetic quality of the surface of the final traffic surface (risk of fines rising and cushioning). Conventionally, the person skilled in the art will also take into account the initial water content of the aggregates used in order to adjust the dosage of added water.

Also, the road surface coating composition comprises, by mass, relative to the dry mass of said at least one aggregate of 2% to 8%, preferably 3% to 7% and typically 4% to 6% of the organo-mineral binder.

Similarly, the adjustment of the dosage of organo-mineral binder according to the invention may be carried out conventionally by a person skilled in the art, in particular depending on the type of aggregates chosen and the type of traffic lanes desired (i.e.: permeable type roads, namely draining or non-permeable type). In general, it is around 5.0% by mass relative to the dry mass of all the aggregates. After curing of the coating and evaporation of the water, the fraction of binder typically represents approximately 2.5%, by mass, relative to the total mass of the coating thus formed.

In general, said at least one aggregate corresponds to materials usually used in the field of road surfaces, such as "classic" natural mineral aggregates, generally virgin (not recycled). As mentioned in the previous paragraph, depending on the materials incorporated in the mixture, the traffic lane produced may be of the permeable or non-permeable type.

Preferably, said at least one aggregate does not comprise recycled aggregates and only comprises virgin natural mineral aggregates.

In general, "classic" natural aggregates can be, without limitation, gravel, chippings, sand, fillers, sandstone (very fine grain sand), dust or a mixture thereof. The aggregates used can be road aggregates, meeting the standards: NF EN 13043 in Europe and ASTM C33 in North America or even the NF P18 545 standard.

Generally, the aggregates used have a Los Angeles coefficient less than or equal to 30 measured according to the NFEN 1097-2 standard.

Fillers, also called fines, correspond to a mineral powder generally having a particle size of less than 63 µm.

Sands correspond to any rock in the state of small unbound grains with a dimension of up to 5 mm and generally ranging from 0 to 4 mm, typically having the following granular fractions 0/2 mm or 2/4 mm. Preferably, the sands are of calcareous nature. They generally have a real density measured according to standard NF EN 1097-6 greater than 2000 kg/m ³ and even greater than 2500 kg/m ³ and a relative bulk density measured according to standard NF EN 1097-3 between 1.2 and 1.7.

The gravel may be of a calcareous, silico-calcareous nature, or even of another harder rock. They have a granular fraction preferably ranging from 0 to 20 mm. For example, the following fractions of gravel are suitable for producing the coating composition according to the invention: 2/6; 4/6; 6/10; 6/14 or one of their combinations.

According to a preferred feature of the invention, said at least one aggregate does not comprise fillers and is composed of sand and gravel. Obviously, it is known to those skilled in the art that the 0/2 mm or 2/4 mm sand fractions may have a (minor) granular percentage having a particle size of less than 63 µm (this depends on the particle size distribution of the sand used).

The use of an aggregate based on sand and gravel has the advantage of reducing the mass quantity of fillers/fines that may be present, while having a sufficiently dense granular mixture to promote inter-granular embedding and thus promote the setting kinetics of the organo-mineral binder according to the invention.

• de 15% à 50%, de préférence de 20% à 45% de sables,
• de 50% à 5%, de préférence de 55% à 80% de gravillons.

Thus, advantageously, the aggregate comprises, by mass, relative to its total mass:

• from 15% to 50%, preferably from 20% to 45% of sand,
• from 50% to 5%, preferably from 55% to 80% gravel.

• de 15% à 50%, de préférence de 20% à 45% de sables 0/4 mm,
• de 20% à 40%, de préférence de 25% à 35% de gravillons présentant une fraction 2/6 mm et/ou 4/6 mm ;
• de 20% à 50%, de préférence de 25% à 45% de gravillons présentant une fraction 6/10 mm et/ou 6/14 mm.

In particular, the aggregate comprises, by mass, relative to its total mass:

• from 15% to 50%, preferably from 20% to 45% of 0/4 mm sand,
• from 20% to 40%, preferably from 25% to 35% of gravel with a fraction of 2/6 mm and/or 4/6 mm;
• from 20% to 50%, preferably from 25% to 45% of gravel with a fraction of 6/10 mm and/or 6/14 mm.

B.2 Manufacturing process for road surface coating

In general, the method of manufacturing the roadway coating composition described above comprises the following steps:

(i) cold mixing in a conventional mixer of an initial mixture comprising at least: the organo-mineral binder according to the invention, at least one aggregate and the added water, so as to obtain a final mixture (corresponding to said road surface coating composition);

(ii) where applicable, transport of the final mixture to the location where the road surface will be installed.

According to the invention, the mixing step (i) is carried out cold, i.e. at room temperature. Thus, no heating step is necessary/required in order to form a road surface according to the invention, unlike a warm or hot asphalt mix.

This mixing stage can be carried out, for example, in a concrete plant, a cold mixing plant or even a mobile mixing unit (such as a mobile batching plant).

In general, if it is necessary to transport the final mixture, this step has a fairly limited duration, generally less than or equal to 1 hour and will generally be 30 minutes to 1 hour, so as to best preserve the humidity of the final mixture before its arrival at the place of implementation.

C. Road surface for light vehicles

C.1 Structure of the road surface

The present invention also relates to a road surface intended for regular traffic of light vehicles, comprising the composition for road surface treatment described above, characterized in that it has a thickness of 3 to 8 cm, preferably 3 to 5 cm and typically 4 to 4.5 cm.

Thus, the road surface according to the invention has a low thickness.

Typically, the density of the road surface composition (also called final mix) placed after compaction is in the range of 1.80 to 2.0 tm ^{- 3} .

The Applicant has thus developed a binder which makes it possible to seal the aggregates, not by coating, as is typically done with bitumen-based coatings, but by intergranular contact point. The increase in cohesion and the stiffening of the final mixture is based on the intergranular adhesive properties which is made possible by simple evaporation of the water contained in the binder composition according to the invention. Thus, the performance of the road surface will be achieved by simple dehydration and drying of the composition for road surface coating (also called, final mixture).

In particular, the Applicant has developed a binder and a coating composition whose setting mechanism is carried out in two stages:

- initially, the setting begins with rapid drying of the coating surface - in this phase, only external conditions (contact surface, temperature, relative humidity, wind) have an influence on the drying speed;

- in a second stage, the setting continues from the surface towards the core of the coating – however, the kinetics decrease because the surface of the coating becomes denser, leading to a slowdown in the exchanges between the ambient air and the binder contained at the core of the coating.

Preferably, the road surface coating composition is disposed between a base layer and a sealing layer.

For example, the composition for road surface coating may be applied to a base layer of the GNT 0/20 cm or 0/31.5 cm type which is porous and draining and which has a minimum bearing capacity of 50 MPa. This base layer may for example have a thickness of 15 cm. It is also possible to apply the composition for road surface coating to a base layer of the type, hydraulic concrete, bituminous concrete or even a coating.

The sealing layer suitable for the present invention may comprise, for example, another organo-mineral binder in aqueous phase.

For example, it may be an aqueous phase binder which is derived from the combination of a siliceous mineral matrix grafted with an organic matrix.

Advantageously, the organic matrix may correspond to an acrylic polymer while the siliceous mineral matrix may be a colloidal silica suspended in water. A coupling agent is added to the composition of this other binder in order to graft the siliceous matrix with the organic matrix.

In particular, the composition of the other organo-mineral binder forming the sealing layer may be as follows and comprise, by mass, relative to its total mass:

- from 60% to 95%, preferably from 70% to 90% and typically from 75% to 85% of organic matrix (polymer);

- from 2% to 10%, preferably from 3% to 8% and typically from 3% to 5% of the siliceous matrix in aqueous phase;

- from 0.1% to 3%, preferably from 0.15% to 2% and typically from 0.20% to 0.4% of the coupling agent;

- from 5% to 30%, preferably from 8% to 25% and typically from 10% to 20% of water.

For example, the composition of the other binder may be as follows, by mass, relative to the total mass of the composition:

- 80.40% acrylic polymer;

- 4.25% colloidal silica suspended in water;

- 0.35% coupling agent; and

- 15% water (input).

This other organo-mineral binder has the advantage of reinforcing the stability of the final coating (surface reinforcement of the coating by enriching the surface with binder - over a few millimeters - thus ensuring optimal cohesion forces). The stiffening of this other binder is carried out by simple evaporation of the water contained in it, leaving a cohesive and continuous film on the granular surface. This other binder thus provides lasting cohesion at the mineral surface, while preserving the natural appearance of the aggregates. This other binder is preferably translucent after drying. In general, it provides the coating with high UV resistance, thus guaranteeing significant durability against climatic (rain, sun) and mechanical aggressions. In addition and advantageously, it is also environmentally friendly: it does not generate any pollution and/or production of VOCs during its implementation and has the same environmental characteristics as the organo-mineral binder according to the invention.

In general, the road surface according to the invention is intended to form a roadway for light vehicles.

Finally, the road surface according to the invention, depending on the composition used, is of the permeable type or the non-permeable type.

By "permeable type coating" is meant a coating permeability greater than 10 ^-5 ms ^-1 . In situ , and as indicated in the NF P 98-150-1 standard relating to class 1 permeable bituminous concrete (BBDr), the average percolation speeds Vp measured on this type of coating will, for all of them, be greater than 0.6 cm.s ^-1 for coatings made with 0/6 mm materials and greater than 0.8 cm.s ^-1 for coatings made with 0/10 mm materials.

By "non-permeable type coating" we mean a permeability of less than 10 ^-5 /10 ^-6 ms ^-1 . In situ , and as indicated in the NF P 98-150-1 standard relating to class 1 permeable bituminous concrete (BBDr), the average percolation speeds Vp measured on this type of coating will then be less than 0.6 cm.s ^-1 for coatings made with 0/6 mm materials and less than 0.8 cm.s ^-1 for coatings made with 0/10 mm materials.

In general, a permeable road surface has a granular fraction of sand (diameter less than or equal to 4 mm), by mass, relative to the total mass of the granular mixture, less than or equal to 50%, preferably less than or equal to approximately 45%.

On the contrary, a non-permeable road surface has a granular fraction of sand (diameter less than or equal to 4 mm), by mass, relative to the total mass of the granular mixture, strictly greater than 50%, preferably greater than or equal to approximately 55%.

C.2 Road surface manufacturing process

The method of manufacturing the road surface according to the invention at a place of implementation comprises the following steps:

(iii) spreading the final mixture as defined above at the place of implementation; and

(iv) compacting the spread mixture so as to obtain a road surface.

The spreading stage is traditionally carried out with a finisher or a grader. For example, the finisher is used with a cold table, generally using the pre-compaction of the table.

In general, the spreading step will be carried out under suitable weather conditions. Indeed, as mentioned above, the setting of the binder according to the invention is made possible by evaporation of the water it contains. It is therefore preferable that the following conditions are met:

- application temperature: between 10°C and 30°C;

- maximum humidity during application: HR 80%;

- relative humidity must be less than 80% also during the 48 to 72 hours following application of the mixture;

- no precipitation within 48 hours of application;

- in hot and dry weather, a surface mist of water on a fresh mixture is possible in order to maintain its water content and prevent surface crusting.

The compaction stage is carried out with a conventional compactor (static or vibrating cylinder compactors, pneumatic compactors, etc.).

The time to put into circulation is generally 72 hours to 96 hours.

After this period, the seal coat can be applied, usually by spraying. The seal coat is as described above and includes the other organo-mineral binder. Generally, the amount of this other organo-mineral binder will be between 200 and 600 gm ^- ², preferably 300 and 450 gm ^- ². The higher the dosage of this other binder, the more permeable the final road surface will be.

Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

According to the invention, unless otherwise stated, the various characteristics of the invention have been measured according to the standards mentioned below.

D. Examples

D.1 Example 1 : example of organo-mineral binder composition according to the invention

The Applicant has prepared an organo-mineral binder composition according to the invention which is as follows:

Constituent Kind Product Quantity (volume/volume) Aqueous colloidal dispersion of anionic copolymer Styrene butadiene Composition
Table 1 84.65% Cationic mineral compound (aqueous dispersion) Calcium Carbonate Slurry Composition
Table 2 15.00% Anionic thickening agent Anionic aqueous phase dispersion of a highly carboxylated styrene butadiene copolymer Composition
Table 3 0.35%

The binder composition according to the invention is prepared by mixing in a mixer of the stainless steel stirring tank type set at a speed of 250 revolutions per minute for a period of 15 minutes at room temperature.

D.2 Example 2 : example of composition for road surface coating

The Applicant has prepared two compositions for road surface coatings which are summarised in Table 5 below (the contents of added water and binder according to Example 1 above are in percentage, by mass, relative to the total mass of the granular mixture).

The composition according to example A is intended to form a permeable type road surface, while the composition according to example B is intended to form a non-permeable type road surface.

Example A Example B Organo-mineral binder (example 1) 5% 5% Supply water 2.2% 2.5% Granular mixture
- calcareous sand 0/4 mm
- 2/6 mm limestone gravel
- 6/10 mm silico-calcareous gravel
25%
35%
40%
40%
30%
30%

The recomposition of the granular mixture is as follows for these two examples A and B:

Example A Example B Sieve in mm Recomposition curve in % 12.5
10
8
6.3
4
2
1
0.5
0.25
0.125
0.063 100.00
92.80
77.60
63.82
45.42
24.20
17.51
11.44
7.81
5.81
4.20 100.00
94.60
83.20
72.76
57.38
37.41
27.26
17.73
11.94
8.74
6.44

The compositions of Examples A and B are prepared in a mixer of the type planetary mixer similar to a mortar mixer described in standard NF EN 196-1, equipped with a 20 L tank, with a rotation speed of 140 rpm for a duration of 90 sec. The quantity of the mixture prepared is 5 to 10 kg per production.

The mixtures produced are then introduced into cylindrical stainless steel molds in order to produce test pieces for determining mechanical performance. The methodology for producing these test pieces is inspired by standard NF EN 13 286-53, with, in particular, an adaptation of the closing stress which is 4 MPa for this test (equivalent to slight compaction).

D.3 Example 3 : Mechanical performance of the compositions for road surface coating according to the invention (Examples A and B)

• Résistance à la compression simple Rc (NF EN 13286-41)

The following mechanical performances were tested for the compositions according to examples A and B according to the invention:

• Simple compressive strength Rc (NF EN 13286-41)

A test piece containing the composition according to Example A or Example B is subjected to compression until rupture. The maximum force supported by the test piece is recorded and the compressive strength is calculated. In particular, the test consists of stressing a cylindrical test piece with a diameter of Ø 5 cm and a height of h 5 cm (5 × 5) between two plates perpendicular to its main axis, on a computer-controlled press, with a constant force application speed of 0.1 kN.s ^-1 .

• Résistance à la traction indirecteRtb(NF EN 13286-42)

The higher the Rc value, the better the mechanical resistance of the tested composition.

• Indirect tensile strength Rtb (NF EN 13286-42)

The NF EN 13286-42 standard is used to determine the indirect tensile strength Rtb. This involves placing the plate in contact with the test piece, then applying a load continuously and uniformly at a speed not exceeding 0.2 MPa/s.

• Détermination du module d’élasticité E (NF EN 13286-43)

The higher the R _tb value, the better the mechanical resistance of the tested composition.

• Determination of the modulus of elasticity E (NF EN 13286-43)

The NF EN 13286-43 standard describes the method to follow for measuring E. The modulus of elasticity provides information on the behavior of the tested material subjected to constraints and characterizes the rigidity of the material.

The higher the modulus of elasticity, the less the material deforms under stress and therefore the more rigid it is.

The method of preserving the test pieces before crushing is as follows:

- 7 days at T=20°C (± 2°C) and HR (relative humidity) = 50% (± 10%)

- 7 days at T=20°C (± 2°C) and HR (relative humidity) = 50% (± 10%), then 2 days of immersion of the test pieces in water at 20°C.

Rc
7 days air
(MPa) Rtb
7 days air
(MPa) Rc
(7 days air + 2 days water)
(MPa) Rtb
(7 days air + 2 days water)
(MPa) E
7 days
(MPa) Example A 4.02 0.72 1.95 0.31 4000-5000 Example B 5.25 0.88 2.42 0.39 5000-6000

These results therefore show that coating compositions A and B can be used for gentle modes of transport (pedestrians, bicycles, etc.), but can also be implemented on roads and highways intended for the regular passage of light vehicles (weight < 3.5T).

The Applicant has thus developed a permeable, natural and recyclable road surface, capable of meeting the specific constraints of structures for soft modes of transport (cycle paths, greenways, etc.), but also of roads subject to regular traffic of light vehicles.

Also, the road surface according to the invention makes it possible to enhance the natural shapes and shades of the aggregates. Indeed, the organo-mineral binder used is practically transparent after drying. It is therefore the formulation conditions which directly determine the final aesthetics of the road surface.

Furthermore, the coating, due to its mechanical properties - satisfactory resistance and fairly low modulus of elasticity (4,000 to 6,000 Mpa), is a relatively flexible coating, requiring no expansion joints.

D.4 Example 4

A comparative study was carried out by the Applicant in order to validate in particular the characteristics of the colloidal dispersion of organic (co)polymer (a) included in the binder composition according to the invention.

Thus, various other polymers (also in aqueous phase) not having all the technical characteristics required to form the aqueous colloidal dispersion of organic (co)polymer (a) according to the invention were tested and the results are summarized in Table 8 below.

These technical characteristics required for the aqueous dispersion of (co)polymers are as follows:

- an anionic character;

- a basic pH ranging from 8.5 to 11, preferably ranging from 9 to 10,

- a minimum film formation temperature, called TMFF, ranging from - 10°C to 10°C, preferably ranging from - 5°C to 5°C and

- a glass transition temperature, called Tg, ranging from -10°C to 15°C, preferably ranging from 0°C to 10°C,

For this comparative study of different colloidal dispersions of (co)polymers (a),

- the dosage in aqueous colloidal dispersion of polymer (%), by mass, relative to the total dry mass of the granular mixture is 3.40% (i.e., absence of the cationic mineral compound (b) and of the thickening agent (c) according to the invention);

- the granular mixture comprises, by mass, in relation to its total mass: 70% of calcareous sand 0/4 mm (Gontero) and 30% of gravel 2/6.3 mm (Gontero);

- the different mixtures “aqueous dispersion of (co)polymer + granular mixture” were prepared according to the process described in Example 2;

- the performance measurements are similar to those described above for Example 3. In particular, the method of preserving the test pieces before crushing is as follows:

- 7 days (“days”) at T=20°C (± 2°C) and RH (relative humidity) = 50% (± 10%);

- 7 days (“days”) at T=20°C (± 2°C) and RH (relative humidity) = 50% (± 10%), then 2 days of immersion of the specimens in water at 20°C (for measurements of simple compressive strength after immersion “Rc im” and indirect compressive strength after immersion “Rtb im”).

As shown in Table 8, the aqueous colloidal dispersion of (co)polymers according to the invention exhibits better performances, whether in terms of simple compressive strength Rc and indirect tensile strength Rtb, whether immersed or not.

Polymers Performance (MPa) Ex. Aqueous dispersion type TMFF
Tg (°C) Anionic 7.0<pH<11 Rc
(7 days air) Rc im.
(7 days air + 2 days water) Rtb
(7 days air) Rtb im.
(7 days air + 2 days water) Ex.C
(inv) Styrene-butadiene (SBR) 0°C 7°C Yes 9.0-10.0 12.36 4.25 1.26 0.57 Ex.D
(inv) Styrene-butadiene (SBR) 0°C 7°C Yes 9.7 11.45 3.25 1.26 0.39 Comp.1 Acrylic 19°C 33°C Yes 8.3 9.09 2.42 1.23 0.54 Comp.2 Acrylic 4°C 14°C Yes 8.0 8.09 1.75 0.75 0.35 Comp.4 Acrylic 10°C 25°C Yes 8.5 8.55 3.25 0.96 0.46 Comp.5 Styrene acrylic 3°C 10°C No 7.8 7.18 1.50 0.96 0.43 Comp.6 Styrene acrylic -2°C 0°C Yes 7.5 6.09 1.25 0.83 0.38 Comp.7 Styrene acrylic 4°C 12°C Yes 7.5 4.18 0.92 0.48 0.217 Comp.8 Styrene-butadiene (SBR) -51°C 0°C No 11 7.36 2.42 0.99 0.37 Comp.9 Styrene acrylic 4°C 10°C Yes 7.5 7.18 2.17 0.90 0.33 Comp.10 Acrylic 14°C 15°C Yes 8.5 6.18 1.75 0.60 0.30 Comp.11 Styrene acrylic 0°C - Yes 7.0- 8.5 8.91 1.98 0.87 0.27 Comp.12 Acrylic 0°C - - 8.5-9.5 3.36 0.83 0.52 0.12 Comp.13 Styrene Acrylic 12°C - - 7.5- 8.5 3.82 1.33 0.53 0.18 Comp.14 Acrylic 17°C - - 8.0 -9.0 9.73 2.33 1.01 0.35 Comp.15 Styrene-butadiene <1°C -7°C No 7.8 3.55 0.42 0.21 -

Claims (16)

Organo-mineral binder composition comprising, by mass, relative to its total mass:
(a) from 65% to 95% of an aqueous colloidal dispersion of (co)polymers which is anionic and which has
- a basic pH ranging from 8.5 to 11.0, preferably ranging from strictly greater than 8.5 to 10.0,
- a minimum film formation temperature, called TMFF, ranging from - 10°C to 10°C, preferably ranging from - 5°C to 5°C and
- a glass transition temperature, called Tg, ranging from -10°C to 15°C, preferably ranging from 0°C to 10°C;
(b) from 3% to 30% of at least one cationic mineral compound;
(c) from 0.05% to 5% of an anionic thickening agent. Organo-mineral binder composition according to claim 1, comprising, by mass, relative to its total mass:
(a) from 70% to 90% of said aqueous colloidal dispersion of (co)polymers;
(b) from 10% to 25% of said at least one cationic mineral compound;
(c) from 0.05% to 1% of said thickening agent. An organo-mineral binder composition according to any preceding claim, wherein (a) the aqueous colloidal dispersion of (co)polymers comprises a carboxylated styrene-butadiene copolymer. An organo-mineral binder composition according to any preceding claim, wherein (a) the aqueous colloidal dispersion of (co)polymers also comprises an anionic emulsifier and/or an anionic initiator. An organo-mineral binder composition according to any preceding claim, wherein (a) the aqueous colloidal dispersion of (co)polymers comprises:
- an average particle size ranging from 100 to 250 nm, preferably from 120 to 220 nm and in particular from 150 to 190 nm and/or
- a dry extract of active products including the (co)polymers and, where appropriate, the anionic emulsifier and/or the anionic initiator ranging from 30 to 60%, preferably from 40 to 50%, relative to the total mass of the aqueous colloidal dispersion of (co)polymers (a). Organo-mineral binder composition according to one of the preceding claims, in which said at least one cationic mineral compound (b) is in the form of a powder or in the form of an aqueous dispersion. Organo-mineral binder composition according to one of the preceding claims, in which said at least one cationic mineral compound (b) is in the form of an aqueous dispersion in which it has an average particle size ranging from 0.1 to 50 µm, preferably ranging from 0.5 to 20 µm and typically ranging from 1 to 5 µm. An organo-mineral binder composition according to one of the preceding claims, wherein said at least one cationic mineral compound (b) is calcium carbonate. Organo-mineral binder composition according to one of the preceding claims, in which (c) the anionic thickening agent belongs to the same chemical family as (a) the aqueous colloidal dispersion of (co)polymers and has an acidic pH of the order of 3 to 6, preferably 4 to 5. An organo-mineral binder composition according to any preceding claim, wherein (c) the anionic thickening agent is an anionic dispersion in aqueous phase, preferably comprising a carboxylated styrene-butadiene copolymer. Organo-mineral binder composition according to one of the preceding claims, comprising at least one of the following characteristics, preferably all of the following characteristics:
- a pH ranging from 7.0 to 11.0, preferably ranging from 8.0 to 10.0 and typically ranging from 8.5 to 9.5;
- a viscosity measured at 22°C±2°C with a Brookfield viscometer (RV DV II+, 60 rpm) according to ISO 2555:2018 ranging from 100 to 10,000 mPa.s, preferably ranging from 200 to 5,000 mPa.s, and typically ranging from 500 to 2,000 mPa.s;
- a mass content of dry extract in active products comprising the (co)polymers, where appropriate the anionic emulsifier and/or the anionic initiator, the cationic mineral compound and the thickening agent, ranging from 30 to 70%, preferably from 40 to 60% and typically of the order of 50 to 53% relative to the total mass of the organo-mineral binder;
- an average particle size ranging from 100 nm to 50 µm, preferably ranging from 120 nm to 3 µm. Composition for road surface coating comprising at least one organo-mineral binder according to one of the preceding claims, at least one aggregate and added water. A road surface composition according to claim 12, wherein the aggregate comprises at least
- sands, preferably of a calcareous nature, with a granular fraction of 0/2 and/or 0/4 mm,
- gravel preferably with a granular fraction of 0/20. Road surface intended for regular traffic of light vehicles comprising the road surface composition according to claim 12 or 13, having a thickness of 3 to 8 cm, preferably 3 to 5 cm and typically 4 to 4.5 cm. A road surface according to claim 14, wherein the road surface composition is disposed between a base layer and a seal layer. Use of a composition for road surface coating according to claim 12 or 13, for producing permeable or non-permeable road surfaces.