Manufacturing processes for organic or organic / mineral aggregates, organic or organic / mineral aggregates, and applications of these aggregates.

Abstract

The present invention relates to an aggregate manufacturing process characterized by obtaining a substance in the form of a wet powder by mixing at least one granular organic or organic / mineral starting material for aggregate with water and at least one mineral binder that can be hardened in the presence of water and / or at least one system that can form a mineral binder hardened in an aqueous medium, compressing this by an extrusion or pressing method to closely mix the binder and / or system that can form a binder / granular starting material / water, increasing the intrinsic density of the substance, reducing the intrinsic porosity, and hardening one or more binders, resulting in a hardened solid mass in the form of aggregate of a desired size and / or shape, or a hardened solid mass converted into aggregate of a desired size and / or shape by cutting or crushing immediately after or in a subsequent step after compression.

Description

Technical Field

[0001] The present invention relates to a process for manufacturing organic or organic / mineral aggregates, the organic or organic / mineral aggregates obtainable by this process, and the use of these aggregates.

Background Art

[0002] As part of the current drive for resource conservation and waste limitation, especially to save on new aggregates, circular economy solutions are widely adopted in the construction and public works sectors. Recently, crushed concrete, incinerator bottom ash, and crystallized slag, which replace natural aggregates extracted from quarries, have been used as aggregates.

[0003] However, these aggregate production methods are insufficient to solve the problems of overproduction of waste and shortage of aggregate resources.

Summary of the Invention

[0004] The aim of the present invention is to meet this need, and the process proposed for this purpose consists of selecting at least one organic or organic / mineral granular substrate having a large specific surface area or increasing its specific surface area by crushing at least one organic or organic / mineral granular substrate so as to achieve such a particle size, adding at least one binder and water, applying pressure to the aggregate, and shaping it to form the desired aggregate.

[0005] Therefore, the first object of the present invention is an aggregate manufacturing process characterized by obtaining a substance in the form of a wet powder by mixing at least one granular organic or organic / mineral starting material for aggregate with water and at least one system capable of forming at least one mineral binder that can be hardened in the presence of water and / or a mineral binder that is hardened in an aqueous medium, compressing this by an extrusion or pressing method to closely mix the binder and / or system capable of forming the binder / granular starting material / water, increasing the intrinsic density of the substance, reducing the intrinsic porosity, and hardening one or more binders, resulting in a hardened solid mass in the form of aggregate of a desired size and / or shape, or a hardened solid mass converted into aggregate of a desired size and / or shape by cutting or crushing immediately after or in a subsequent step after compression.

[0006] The granular organic starting material may be selected from wood, paper, cardboard, plastics, plant-based materials such as flax fibers, hemp fibers or cellulose fibers, insulating materials such as wood wool, household waste, biogenic waste, bituminous waste, and mixtures thereof.

[0007] Granular organic / mineral starting materials may be selected from non-hazardous, non-inert waste such as construction waste, general industrial waste, household waste, or tertiary waste, as well as from mixtures of the organic materials listed above with at least one granular mineral material selected from sand such as silica sand and basalt sand, non-reactive clay, sediments such as dredged deposits, glass, gypsum, coal, crushed concrete, crushed aggregate, insulating materials such as glass wool and rock wool, quarrying granules, industrial process granules, and mixtures thereof.

[0008] In particular, non-hazardous, non-inert waste constituting a mixture of organic / mineral materials directly used as a starting material in the process according to the present invention can be cited. In particular, building waste such as demolition or construction waste from buildings containing wood, plastics, glass wool, metals, or general industrial waste, household waste, or tertiary waste can be cited.

[0009] To make it clear, waste materials originating from various sources represent a direct mixture of starting materials according to the present invention, and their proportions vary depending on the source.

[0010] Granular organic or organic / mineral starting materials or mixtures of granular mineral starting materials are as follows: A D90 value of -2mm or less, preferably 1.5mm or less, and more preferably 1.1mm or less. A D10 value of -0.01 mm or more, preferably 0.02 mm or more, and more preferably 0.03 mm or more, and D50 value of -0.1 mm or more, preferably 0.2 mm or more, more preferably 0.35 mm or more and 1.1 mm or less, preferably 0.8 mm or less. The substance or mixture of substances may have a particle size as defined by [the relevant law], and the substance or mixture of substances may be ground as necessary to obtain this particle size.

[0011] D90, D10, and D50 mean that 90% by mass, 10% by mass, and 50% by mass of the particles must have their minimum projection plane in each of the indicated sizes.

[0012] To achieve the best properties of the aggregate, the mixture of granular starting material and binder or binder-forming system must be optimal within the composite forming the aggregate; that is, the contact surface between the material and the binder / binder-forming system must be as large as possible. However, if this surface area is too large, it will absorb excess water and / or binder, and therefore the composite will be weakened. The specific values ​​of D90, D10, and D50 mentioned above are favorable for such optimization.

[0013] The following may be selected as the curable mineral binder(s): (a) Hydraulic cementitious binders, such as NF EN206 standard cements like Portland CEM I and Portland CEM III, (b) A mixture based on at least three components selected from clinker, metakaolin, gypsum, slag, limestone filler, silica fume, ash, pozzolanes, and pozzolanes, and (c) A mixture of at least one binder as defined in (a) and at least one component of the mixture as defined in (b).

[0014] One or more systems capable of forming a cured mineral binder in an aqueous medium are: - At least one precursor that forms a geopolymer or activated alkali, selected particularly from kaolin, metakaolin, shale, clay, slag, ash and mixtures thereof (kaolin, shale and clay can be subjected to heat treatment such as calcination or flash treatment), - May consist of at least one activator selected from soda, potassium, and sodium silicate and / or potassium silicate to form an activating binder.

[0015] especially, - Petroleum-based polymers, such as polyamides, polyacrylamides, and concrete plasticizers and superplasticizers, - Biopolymers, such as corn starch or cellulose ether, - Mineral plasticizers, such as bentonite and non-reactive ash, At least one molding aid selected from the above can be incorporated into the mixture to produce a wet powder.

[0016] In a particularly preferred method, the mixture is (A) 50 to 95 parts by weight, particularly 65 to 90 parts by weight of one or more of the granular starting materials, and (B) 5 to 50 parts by weight, particularly 10 to 35 parts by weight of the binder (multiple parts are possible) and / or binder forming system (multiple parts are possible), Water added in a ratio of 2 to 40 parts by weight, and molding aids (multiple may be added) up to a maximum of 5 parts by weight, are obtained in the form of a wet powder. All of these parts by weight are obtained for 100 parts by weight of (A) + (B).

[0017] Water helps to harden the binder either by participating in a hydraulic manner in the case of hydraulic mineral binders or by constituting the medium in which geopolymers or activated alkalis are formed. Water can also help with compression by liquefying the mass to be compressed.

[0018] It is advantageous to adjust the amount of the mixture before compression to obtain a wet powder rheology corresponding to classes S1 to S3, in particular class S1 (slump of 10 to 40 mm according to Abrams cone), of concrete compliant with the standard NF EN12 350-2.

[0019] Mixing can be carried out in a paddle mixer, a pan mixer, a ribbon mixer or a planetary mixer for between 3 seconds and 3 minutes.

[0020] The wet powder is advantageously compressed by an extrusion method in a single-screw or twin-screw extruder or by a pressing method using a piston press or a vibrating compression press to directly obtain the desired aggregate or to obtain strands which are then cut into the desired aggregate or to utilize a compression wheel which makes it possible to directly obtain the desired aggregate.

[0021] Compression enables several phenomena: - an increase in the intrinsic density of the material, - a close mixing of the binder, the material and water, - a reduction in the intrinsic porosity of the material, and - the production of a minimum of cohesion before the end of the curing stage.

[0022] This means that without compression, during the curing process, the composite cannot maintain the form of the aggregate and at best the pores are only filled with non-activated binder and in the worst case it collapses before completely solidifying.

[0023] After compression, or after molding, or after compression and / or molding, the hardened product or aggregate can be advantageously cured in a sealed chamber at a temperature of 15-70°C for a period of 1 hour to 10 days.

[0024] The present invention also relates to aggregates obtained by the process defined above, having at least one of the following characteristics: -A water absorption rate of less than 37% by weight, conforming to the standard NF EN 1097-6. -1.4~3g / cm 3 Preferably 1.6 to 2.5 g / cm³ 3 The density conforms to the standard NF EN 1097-6, and A Los Angeles coefficient less than -85, preferably between 10 and 70, conforming to standard EN 1097-2.

[0025] The aggregate defined above preferably has a particle size of 4 to 70 mm, more preferably 4 to 31.5 mm.

[0026] Another object of the present invention is the use of aggregate produced by the process defined above, or the aggregate defined above, as aggregate for concrete (such as ready-mixed concrete and precast concrete), aggregate for asphalt mix, backfill material for geotechnical use, road base material, or decorative aggregate, the granular material being used alone or in combination with other aggregates, such as natural aggregates, artificial aggregates, or even conventional aggregates, particularly recycled aggregates based on crushed concrete.

[0027] The following examples illustrate the present invention without limiting its scope.

[0028] In these examples, unless otherwise specified, percentages and parts are expressed in weight.

[0029] Example 1: Production of aggregates from construction waste and inert mineral materials A mixture of construction and public works waste, consisting of 30% wood, paper, and cardboard-based organic materials and 70% crushed concrete and gypsum-based inert materials, was pulverized to particle sizes specified by D90 (0.6 mm), D10 (0.04 mm), and D50 (0.2 mm).

[0030] Next, a mixture in the form of a wet powder was prepared with the following composition: - The resulting pulverized mixture (64.2 parts) - CEM III cement (binding agent) (35.8 parts) -Water (15 parts) -Visco crete sika Dynamon NG (MBS) Superplasticizer (Molding Aid) (0.5 part)

[0031] Next, the mixture prepared in this manner was subjected to compression by passing it through a single-screw extruder, and at the outlet of the single-screw extruder, the anhydrous adhesive mixture in the form of strands thus formed was cut to obtain aggregates with a particle size of [10;14] mm.

[0032] Next, the aggregate was cured in a sealed chamber at 20°C for three days.

[0033] This aggregate exhibited the following: -1.8g / cm 3 density, -20% water absorption rate, Los Angeles coefficient of -70.

[0034] Example 2: Production of aggregate from quarried stone granules and flax fibers A mixture of 90% quarrying granules and 10% flax fibers was crushed to obtain particle sizes defined by D90 (1 mm), D10 (0.06 mm), and D50 (0.2 mm).

[0035] Next, a mixture in the form of a wet powder was prepared with the following composition: - The resulting pulverized mixture (75 parts) A mixture of -59.5% clinker, 22.5% limestone, 1.5% blast furnace slag, and 18% limestone filler (25 parts) -Water (15 parts) -Visco crete sika superplasticizer Dynamon NG (MBS) (molding aid) (partial)

[0036] Next, the mixture was compressed in a piston extruder to obtain a block of the anhydrous adhesive mixture, which was then cured in a sealed chamber at 25°C for three days.

[0037] At the end of the curing process, the resulting blocks were crushed to obtain aggregate with a particle size of [4-30 mm].

[0038] This aggregate exhibited the following: -1.6 g / cm³ 3 density, -20% water absorption rate, Los Angeles coefficient of -50.

[0039] Example 3: Production of aggregates from general industrial waste (CIW) A mixture of construction and public works waste, consisting of 30% wood, paper, and cardboard-based organic materials and 70% crushed concrete and gypsum-based inert materials, was pulverized to particle sizes specified by D90 (0.7 mm), D10 (0.1 mm), and D50 (0.25 mm).

[0040] Next, a mixture in the form of a wet powder was prepared with the following composition: - Grinding mixture (54.2 parts) -CEM I cement (45.8 parts) -Water (25.4 parts) - Bentonite (molding aid) (1.7 parts)

[0041] Next, the mixture prepared by this method was compressed using a compression wheel and cured at 45°C for 5 days to obtain aggregate with a particle size of 10-14 mm.

[0042] This aggregate exhibited the following: -1.6 g / cm³ 3 density, -25% water absorption rate, Los Angeles coefficient of -75.

Claims

1. A process for producing aggregate, characterized by: mixing at least one granular organic or organic / mineral starting material for aggregate with water and at least one system capable of forming at least one mineral binder that can harden in the presence of water and / or a mineral binder that hardens in an aqueous medium to obtain a substance in the form of a wet powder; compressing this by an extrusion or pressing method to closely mix the binder and / or the system capable of forming the binder / granular starting material / water, thereby increasing the intrinsic density of the substance, reducing the intrinsic porosity, and hardening one or more of the binders, resulting in a hardened solid mass in the form of aggregate of a desired size and / or shape, or a hardened solid mass converted into aggregate of a desired size and / or shape by cutting or crushing immediately after or in a subsequent step after compression.

2. The process according to claim 1, characterized in that the granular organic starting material is selected from wood, paper, cardboard, plastics, plants such as flax fibers, hemp fibers, and cellulose fibers, insulating materials such as wood wool, household waste, biogenic waste, bituminous waste, and mixtures thereof, and the granular organic / mineral starting material is selected from non-hazardous, non-inert waste such as construction waste and general industrial waste, household waste, or tertiary waste, and from a mixture of the organic substances listed above and at least one granular mineral substance selected from sand such as silica sand and basalt sand, non-reactive clay, sediments such as dredged deposits, glass, gypsum, coal, crushed concrete, crushed aggregate, insulating materials such as glass wool and rock wool, quarrying granules, industrial process granules, and mixtures thereof.

3. The granular organic or organic / mineral starting material or mixture of granular mineral starting materials is as follows: A D90 value of -2 mm or less, preferably 1.5 mm or less, and more preferably 1.1 mm or less. A D10 value of -0.01 mm or more, preferably 0.02 mm or more, and more preferably 0.03 mm or more, and A D50 value of -0.1 mm or more, preferably 0.2 mm or more, more preferably 0.35 mm or more and 1.1 mm or less, preferably 0.8 mm or less. The process according to one of claims 1 and 2, characterized in that the substance or mixture of the substance has a particle size defined by, and the substance is pulverized as necessary to obtain this particle size.

4. One or more hardenable mineral binders, (a) Hydraulic cement-based binders, for example, NF EN206 standard cements such as Portland CEM I and Portland CEM III, (b) A mixture based on at least three components selected from clinker, metakaolin, gypsum, slag, limestone filler, silica fume, ash, pozzolanes, and pozzolanes, (c) A mixture of at least one binder as defined in (a) and at least one component of the mixture as defined in (b) The process according to one of claims 1 to 3, characterized by being selected from.

5. One or more of the above systems capable of forming a mineral binder cured in an aqueous medium are, - At least one precursor that forms a geopolymer or activated alkali, particularly selected from kaolin, metakaolin, shale, clay, slag, ash and mixtures thereof, wherein the kaolin, shale and clay are capable of undergoing heat treatment such as calcination or flash treatment, - At least one activator selected from soda, potassium, and sodium silicate and / or potassium silicate to form an activated binder, The process according to one of claims 1 to 4, characterized by comprising:

6. especially, - Petroleum-based polymers, such as polyamides, polyacrylamides, and concrete plasticizers and superplasticizers, - Biopolymers, such as corn starch or cellulose ether, - Mineral plasticizers, such as bentonite and non-reactive ash, The process according to one of claims 1 to 5, characterized in that at least one molding aid selected from is incorporated into the mixture to produce the wet powder.

7. The mixture (A) 50 to 95 parts by weight, particularly 65 to 90 parts by weight, of one or more of the granular starting materials, and (B) 5 to 50 parts by weight, particularly 10 to 35 parts by weight of the binder and / or binder forming system, The water, added in a ratio of 2 to 40 parts by weight, and the molding aid, which can be added up to a maximum of 5 parts by weight, are obtained in the form of a wet powder. The process according to one of claims 1 to 6, characterized in that all of these weight parts are obtained for 100 weight parts of (A) + (B).

8. The process according to one of claims 1 to 7, characterized in that the wet powder is compressed by an extrusion method using a single-screw or twin-screw extruder, or by a pressing method utilizing a piston press or a vibratory compression press to directly obtain the desired aggregate, or to obtain strands and then cut them into the desired aggregate, or to utilize a compression wheel that makes it possible to directly obtain the desired aggregate.

9. The process according to one of claims 1 to 8, characterized in that a hardened product or aggregate, either after compression, or after molding, or after compression and / or after molding, is appropriately cured in a sealed chamber at a temperature of 15 to 70°C for a period of 1 hour to 10 days.

10. - Water absorption rate of less than 37% by weight, in accordance with standard NF EN 1097-6. -1.4~3g / cm ３ Preferably 1.6 to 2.5 g / cm³ ３ The density conforms to the standard NF EN 1097-6, and Los Angeles coefficient less than -85, preferably 10 to 70, in accordance with standard EN 1097-2. Aggregate obtained by a process specified in one of claims 1 to 9, having at least one of the above.

11. The aggregate according to claim 10, characterized in that the particle size is 4 to 70 mm, preferably 4 to 31.5 mm.

12. Use of aggregate manufactured by a process described in any of claims 1 to 9 or the aggregate specified in any of claims 10 and 11 as aggregate for concrete, aggregate for asphalt, backfill material for geotechnical use, road base material, or decorative aggregate, wherein the aggregate is used alone or in mixture with other aggregates.

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