Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
  • C04B20/10—Coating or impregnating
  • C04B20/1055—Coating or impregnating with inorganic materials
  • C04B20/1066—Oxides, Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B18/02—Agglomerated materials, e.g. artificial aggregates
  • C04B18/021—Agglomerated materials, e.g. artificial aggregates agglomerated by a mineral binder, e.g. cement
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C7/00—Coherent pavings made in situ
  • E01C7/08—Coherent pavings made in situ made of road-metal and binders
  • E01C7/10—Coherent pavings made in situ made of road-metal and binders of road-metal and cement or like binders
  • E01C7/14—Concrete paving
  • E01C7/142—Mixtures or their components, e.g. aggregate
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/0075—Uses not provided for elsewhere in C04B2111/00 for road construction
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/0081—Uses not provided for elsewhere in C04B2111/00 as catalysts or catalyst carriers
  • C04B2111/00827—Photocatalysts
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/20—Resistance against chemical, physical or biological attack
  • C04B2111/2038—Resistance against physical degradation
  • C04B2111/2061—Materials containing photocatalysts, e.g. TiO2, for avoiding staining by air pollutants or the like

Definitions

• the present invention relates to a synthetic granulate with photocatalytic properties for road application, as well as its production method, and a wearing course which incorporates it.
• the wearing course of a roadway must have particular mechanical and physicochemical properties, such as, for example, traffic resistance and suitability. tire adhesion in dry or wet conditions.
• An object of the invention is to provide a synthetic granulate having excellent microroughness which is maintained over time, so as to ensure permanent adhesion properties.
• This goal is achieved by the production of a synthetic granulate with photocatalytic properties. Indeed, its photocatalytic properties give the granulate a superhydrophilic and self-cleaning surface with respect to any organic pollution, and thus allow the maintenance of its excellent microroughness over time.
• superhydrophilic surface is meant a surface that has a total affinity with water, which has the effect of detaching the soil that is deposited on the surface, whether mineral or organic.
• a wearing course is particularly exposed to pollution: combustion residues, tire marks or other dirt are deposited on its surface and contribute to its fouling. It has been observed that particles of photocatalyst can completely or partially decompose these soils, and facilitate their evacuation. Despite its high resistance to abrasion, the synthetic aggregate with catalytic properties will undergo, like any granulate, an inevitable polishing of its surface over time, especially under the action of traffic. The presence of photocatalyst particles in the matrix of the granulate allows it to retain its self-cleaning and superhydrophilic properties over time, by renewing the surface as wear. As the roughness of the surface is not clogged with dirt, the micro-roughness of the granulate is maintained, and the adhesion properties of the tires on the wearing course also remain.
• the synthetic granulate of the invention consists of a set of grains, each comprising, included in a matrix formed by a binder, at least photocatalyst particles and a particulate mineral material.
• the invention therefore relates to a synthetic granulate with photocatalytic properties for road application, consisting of a set of grains, each comprising, included in a matrix formed by a hydraulic binder or pozzolanic, at least photocatalyst particles and a particulate mineral material. which is a sand, the synthetic granulate having a particle size d / D with D between 4 and 10.
• the matrix formed by a first binder which comprises the particulate mineral material and the photocatalyst particles, constitutes the heart of the grains of the synthetic granulate.
• the matrix formed by a second binder which comprises the particulate mineral material and the photocatalyst particles, is on the surface of the grains of the synthetic granulate, where it constitutes a layer of coating, the heart of the grains of the synthetic granulate then being constituted by the grains of a starting granulate.
• the photocatalyst is advantageously a semiconductor compound, preferably titanium dioxide.
• a semiconductor compound preferably titanium dioxide.
• the preferred forms are rutile, anatase and brookite, and more particularly the anatase form.
• Hombikat® UV100 (Sachtleben), Kronos® VLP7000 (Kronos), Kronos® VLP7500 (Kronos), Kronos® VLP7101 (Kronos) and Aeroxide® P25 (Evonik).
• the photocatalyst Hombikat® UV100 (Sachtleben) will be used.
• the synthetic granulate when the photocatalyst is titanium dioxide, preferably comprises between 0.5 and 50% by weight of photocatalyst particles relative to the total weight of the grains, and advantageously between 5 and 15% by weight relative to the total weight of the grains.
• the synthetic granulate when the photocatalyst is titanium dioxide, preferably comprises between 0.02 and 40% by weight of photocatalyst particles relative to the total weight of the grains, and advantageously between 0.2 and 12% by weight relative to the total weight of the grains.
• the particulate mineral material has a hardness greater than that of the matrix in which it is included and forms hard inclusions in the grains of the granulate. These inclusions form asperities on the surface of the grains of the aggregate, and are responsible for the micro-roughness of the granulate. In order to allow optimum adhesion of the tires on the wearing course, it is desirable that the relief of the grains conforms to the surface of the tires, thus creating a large contact surface.
• the particulate mineral material comprises particles having a size of less than 1.5 mm, preferably of between 1 and 1.2 mm, thus forming indentations of about 200 ⁇ m at the surface of the grains.
• the particulate mineral material is preferably derived from a source rock having good mechanical properties, and in particular good resistance to wear and fragmentation. Any naturally occurring rock with a Los Angeles coefficient value less than 12 and a Micro-Deval coefficient of less than 20 is preferred.
• the particulate mineral material is preferably sand, particularly gneiss sand or dioritic sand.
• the particulate mineral material may also be a mixture of several particulate mineral materials.
• the starting granulate used in the second embodiment of the invention may be any granulate, natural or synthetic, in accordance with a use in a wearing course according to standard NF EN 13043.
• the first binder forming the core matrix of the grains of the synthetic granulate is a hydraulic binder or pozzolanic in the sense of the standard NF P15-108.
• the second binder forming the matrix of the coating layer on the surface of the grains of the synthetic granulate is also a hydraulic binder or pozzolanic in the sense of the NF P15-108 standard. It may or may not be identical to the first binder forming the matrix of the heart of the grains of the synthetic granulate.
• these first and second binders preferably comprise a cement and a silica fume.
• all the additional constituents which form the grains are preferably of a mineral nature.
• Step (d) curing said mortar grains; whereby said synthesis granulate is obtained.
• Step (a) of the process can be implemented according to two methods.
• step a) said photocatalyst particles are mixed simultaneously with firstly said first binder and with said particulate mineral material.
• a particulate mineral material is provided on the one hand, and on the other hand elements for forming a first binder are provided, on the other hand, particles of photocatalyst are also provided, and then a quantity of photocatalyst is mixed simultaneously.
• predetermined said particulate mineral material with a predetermined amount of said photocatalyst particles and with a predetermined amount of each of said elements for forming a first binder, whereby a mortar comprising, in a matrix formed by a first binder, both photocatalyst particles and inclusions corresponding to the particulate mineral material.
• step a) said photocatalyst particles are mixed with said first binder prior to mixing with said particulate mineral material.
• a particulate mineral material is provided, on the other hand, elements are provided for forming a first binder, which elements comprise particles of photocatalyst, and then a predetermined quantity of said particulate mineral material is mixed with a predetermined amount of each of said elements for forming a first binder, whereby a mortar comprising, in a matrix formed by a first binder, both photocatalyst particles and inclusions corresponding to the particulate mineral material is obtained.
• the main elements intended to form the first binder of the mortar are chosen from cements, silica fume, superplasticizers and water.
• the matrix formed by the first binder comprises a cement, thus making it possible to obtain a mortar with a high compressive strength.
• the superplasticizer makes it possible to limit the water / cement ratio.
• the photocatalyst particles are either incorporated in the elements intended to form a first binder, or mixed simultaneously with the other constituents of the mortar.
• the amount of photocatalyst is determined such that the photocatalyst particles represent between 0.5 and 50% by weight, advantageously between 5 and 15% by weight, relative to the total weight of the synthetic granulate obtained.
• Step (b) of the process is a curing step which corresponds to a treatment of the mortar to manage the exchange of water and / or heat with the external environment. In practice, a cure prevents dehydration of the matrix and instead promotes hydration that tends to consolidate.
• the conditions (time and temperature) in which a cure is practiced determine the consolidation of the matrix and therefore of the mortar.
• time and temperature determine the consolidation of the matrix and therefore of the mortar.
• the cure for this hydration is not too long. Indeed, a crushing after a cure of short duration allows to expose a number of inclusions and thus to obtain a high roughness.
• the mortar is advantageously hydrated by a cure which corresponds to a succession of two courses.
• the duration of the second treatment is limited, so that the consolidation of the matrix is just sufficient so that, on the one hand, the inclusions adhere sufficiently in the matrix without being detached during the crushing and that, on the other hand, the fractures caused by crushing can reveal a rugged facies.
• the sand inclusions combine with the cement to form lime silicates within the mortar.
• a second too long cure would lead to an extremely strong adhesion between the inclusions and the matrix, thus favoring the appearance of intergranular ruptures within the inclusions, synonymous with facies much smoother and therefore lower roughness.
• Step (c) of the process is a crushing step of the mortar, performed after the second cure. The crushing is carried out several times, then the crushed mortar is screened in a sieve making it possible to select grains of size between 0 and 10 mm.
• Step (d) of the process is a curing step of the mortar grains obtained after crushing. This third treatment advantageously makes it possible to complete the hydration of the cement which began during the second treatment, to perfect the hardening of the matrix within the crushed mortar and thus to consolidate the grains obtained after crushing.
• the production of the synthetic granulate according to the second embodiment of the invention is carried out by the following steps: (e) coating a starting granulate with a coating composition comprising a particulate mineral material, a second binder, and photocatalyst particles; (f) recovery of the grains obtained by an anti-gluing agent or mobilization of the grains during the first days; and (g) curing said coating composition; whereby said synthesis granulate is obtained.
• the starting granulate used in step (e) of the process is preferably characterized by a particle size d / D with d representing the smallest dimension in mm and D the largest dimension in mm such that d is between 0 and 4 and D is between 4 and 10.
• the starting granulate is identical to the synthetic granulate produced according to the first embodiment of the invention, except that the mortar is not loaded with particulate matter. photocatalyst. This therefore amounts to carrying out the following steps: (a) manufacturing a mortar comprising a particulate mineral material and a first binder;
• step (d) curing said mortar grains; whereby said starting granulate used in step (e) of the process is obtained.
• steps (b), (c) and (d) above are identical to steps (b), (c) and (d) of the method corresponding to the first embodiment of the invention, and step (a) above is carried out as follows: on the one hand, a particulate mineral material is provided, on the other hand, elements are provided for forming a first binder, and then a predetermined quantity of said particulate mineral material is mixed with a predetermined quantity of each of said elements intended to form a first binder. whereby a mortar comprising, in a matrix formed by a first binder, inclusions corresponding to the particulate mineral material is obtained.
• the coating composition used in step (e) of the process can be obtained by two methods.
• said coating composition is obtained by simultaneous mixing of said photocatalyst particles with said second binder and with said particulate mineral material.
• a particulate inorganic material is provided on the one hand, and elements for forming a second binder are provided on the other hand.
• Photocatalyst particles are also provided on the other hand and a predetermined quantity is then mixed simultaneously.
• said particulate mineral material with a predetermined amount of said photocatalyst particles and with a predetermined amount of each of said elements for forming a second binder, whereby a coating composition comprising a particulate mineral material, a second binder, and photocatalyst particles.
• said coating composition is obtained by simultaneously mixing said photocatalyst particles with said second binder prior to mixing with said particulate mineral material.
• a particulate mineral material is provided
• elements are provided for forming a second binder, which elements comprise photocatalyst particles, then a predetermined quantity of said particulate mineral material is mixed with a predetermined amount of each of said elements for forming a second binder, whereby a coating composition comprising a particulate mineral material, a second binder, and photocatalyst particles is obtained.
• the main elements for forming the second binder of the coating composition are selected from cements, silica fume, superplasticizers and water.
• the second binder is identical to the first binder.
• the photocatalyst particles are either incorporated in the elements for forming a second binder, or mixed simultaneously with the other constituents of the coating composition.
• the quantity of photocatalyst is determined so that the photocatalyst particles represent either between 0.5 and 50% by weight, advantageously between 5 and 15% by weight, relative to the total weight of the coating composition, or between 0 , 02 and 40% by weight, advantageously between 0.2 and 12% by weight, relative to the total weight of the synthetic granulate obtained.
• Step (e) of the process is carried out as follows: a starting granulate is provided on the one hand, and on the other hand a coating composition obtained according to one of the two methods described above is provided. above, - mixing in a kneader a predetermined amount of said starting granulate with a predetermined amount of said coating composition, whereby grains are obtained coated by said coating composition.
• the amount of the coating composition to be introduced into the kneader is calculated from the specific surface of the starting granulate. This is to cover each grain of the starting granulate with a coating layer of thickness preferably between 0.1 and 3 mm and preferably between 0.5 and 1.5 mm.
• Step (g) of the method is a curing step, identical to step (d) of the method corresponding to the first embodiment of the invention.
• step (f) is carried out in which the grains coated with the coating composition are covered with an anti-adhesive agent. This step is necessary to prevent grain agglomeration during the subsequent cure step (g).
• This anti-slip agent may be chosen from mineral powders such as calcareous or siliceous fillers. It can also be liquid, and corresponds for example in this case to silicone oil or paraffin oil. Finally, they may be concrete deactivating agents capable of blocking the setting phenomenon on the surface.
• the synthetic granulate is obtained whose grains consist of a core coated with a consolidated coating layer.
• the synthetic granulate is then screened in a sieve to select the size of the grains.
• the present application finally relates to the use of synthetic granulate with photocatalytic properties in a de-polluting wearing course.
• the present invention relates to a cleansing surface layer obtained by mixing a granulate and a bituminous binder of which part of the granulate, preferably all, is a synthetic aggregate as defined above.
• a wearing course is obtained from a mix comprising a mixture of a granulate, a bituminous binder and optionally additives and / or fillers.
• at least a portion of the aggregates are synthetic aggregates with photocatalytic property.
• the synthetic granulate has a particle size d / D with d is between 0 and 8, preferably between 0 and 4 and D is between 4 and 10, preferably between 5 and 10, and better between 6 and 10.
• the layer In general, the rolling composition comprises 3 to 10% by weight of bituminous binder and 60 to 95% by weight of aggregate relative to the total weight of the wearing course.
• compositions indicated in Table 1 below are given by way of example of compositions making it possible to obtain a synthetic granulate with photocatalytic properties according to the first embodiment of the invention.
• compositions are expressed in kg of material for one cubic meter of concrete.
• Table 1 Compositions making it possible to obtain a synthetic granulate with photocatalytic properties according to the first embodiment of the invention.
• a quantity substantially equal to 943 kg / m 3 of gneiss sand is mixed simultaneously with an amount equal to 210 kg / m 3 of photocatalyst particles and with a total amount substantially equal to 1021 kg / m 2.
• the gneiss sand Prior to mixing, the gneiss sand has preferably undergone sieving on a sieve of 1.5 mm to retain as particles only sand grains of size preferably less than or equal to 1.5 mm.
• the mortar is obtained by mixing the aforementioned quantities, and by performing the first cure, then the second cure. It is then crushed and sieved to select grain size preferably between 6.3 and 10 mm. These are then subjected to the third cure.
• Example 2 a quantity substantially equal to 840 kg / m 3 of dioritic sand is mixed simultaneously with an amount equal to 280 kg / m 3 of photocatalyst particles and with a total amount substantially equal to 101 1 kg / m 2. 3 elements for forming the first binder and water.
• the dioritic sand has preferably undergone sieving, but rather on a sieve of 1 mm to retain as particles only sand grains of size preferably less than or equal to 1 mm.
• the same steps as those carried out for the mortar of Example 1 are then carried out.
• Such a synthetic granulate with photocatalytic properties has extremely interesting properties which allow it to be used in wearing courses which are both depolluting and having excellent adhesion properties of the tires.
• compositions indicated in Table 2 below are given by way of example of compositions making it possible to obtain a synthetic granulate with photocatalytic properties according to the second embodiment of the invention.
• Table 2 Compositions making it possible to obtain a synthetic granulate with photocatalytic properties according to the second embodiment of the invention.
• a coating composition is prepared by mixing an amount equal to 990 kg / m 3 of gneiss sand with a quantity equal to 240 kg / m 3 of photocatalyst particles and with a substantially equal total amount. at 1015.2 kg / m 3 of elements intended to form the second binder and water.
• Example 1 prior to mixing, the gneiss sand was preferably sieved on a sieve of 1.5 mm.
• the synthetic granulate A is obtained by mixing one ton of 4/6 chippings of dioritic nature in a kneader with 1200 kg of the coating composition of Example 3, and then covering the coated grains obtained with an anti-gluing agent such as Formwork oils or the like and the agents for inactivating the concrete, by effecting the final cure of the coating composition.
• an anti-gluing agent such as Formwork oils or the like and the agents for inactivating the concrete
• a coating composition is prepared by mixing an amount equal to 910 kg / m 3 of sand with diorite an amount equal to 180 kg / m3 of photocatalyst particles and a total amount substantially equal to 1079 kg / m 3 of elements intended to form the second binder and water.
• the dioritic sand was preferably screened on a 1 mm sieve.
• Synthetic granulate B obtained by mixing one ton of chippings 2/8 in a kneader which is coated with 1600 kg of the coating composition of Example 4, and then covering the coated grains obtained with an anti-adhesive agent as defined above, by effecting the final cure of the coating composition, and finally by sieving to select grains of size preferably between 6.3 and 10 mm.
• Such a synthetic granulate with photocatalytic properties has extremely interesting properties which allow it to be used in depolluting wearing courses which have excellent tire adhesion properties.
• the necessary quantities of photocatalyst are less important than for the first embodiment.

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• 2009
  • 2009-03-25 FR FR0951938A patent/FR2943664A1/fr active Pending
• 2010
  • 2010-03-25 EP EP10715981A patent/EP2411580A1/de not_active Withdrawn
  • 2010-03-25 CA CA2756644A patent/CA2756644A1/fr not_active Abandoned
  • 2010-03-25 US US13/257,671 patent/US20120006231A1/en not_active Abandoned
  • 2010-03-25 WO PCT/FR2010/050546 patent/WO2010109146A1/fr active Application Filing

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