Patent Application
20220106228
The present invention relates to the field of building and public works and, more particularly, to materials of the aggregate type which enter into the composition of building materials.
Known aggregates have as their basic component an assembly of minerals and sometimes fossils. They are often derived from massive or fragmented rock and can be monomineral or polymineral.
Aggregates are commonly referred to as rock fragments intended to be used as components of materials necessary for the manufacture of public works, civil engineering works and building works.
Currently, aggregates are classified into three main families:
In the field of aggregates, wastes such as clinker, kaolin sands, mine waste rock, crushed concrete, etc. have already been used.
The purpose of the present invention is to propose aggregates that incorporate waste, such as household waste, organic waste, industrial waste, sludge and sediment waste, thus responding to the problem of waste treatment, while presenting mechanical and physico-chemical characteristics suitable for use in the construction, public works and civil engineering sector, in particular by meeting the standard currently required in this sector.
The present invention therefore relates firstly to base grains to be assembled together to form granules for a composition of construction materials useful in the field of building, public works and civil engineering, characterised in that each base grain consists of a core formed by an agglomerate of fragments of compressed waste and associated with each other by a micro-concrete with carbonated hydraulic binder which has undergone hydraulic setting, the core being enclosed in a shell formed by a reactive powder micro-concrete (RPMC) which has undergone hydraulic setting.
The waste fragments can in particular be derived from waste selected from among household waste (HW), household refuse (HR), residual household refuse (RHR), mixtures of at least two of HW, HR and RHR, organic waste, industrial waste, sludge waste, or mixtures of these wastes, the fragments having in particular been subjected to an inerting treatment, in particular by a quicklime-based composition.
Household waste (HW) refers to waste resulting from the daily domestic activity of households and economic activities collected under the same conditions as these ones. This waste is collected by traditional residual household waste collection, by selective collections, by waste collection centres, by bulky waste collection and by green waste collection.
Household refuse (HR) refers to the waste resulting from the daily domestic activity of households and economic activities collected under the same conditions as these ones. This waste is collected by the traditional collection of residual household waste and by selective collections.
Residual household refuse (RHR) refers to the portion of mixed household waste after selective collection.
Household waste, household refuse and residual household refuse are, for France, products listed and standardised by the French Environment and Energy Management Agency (ADEME).
For example, the composition of RHR in France is as follows according to ADEME:
Organic material waste can be, among other things, beet pulp and other processing waste from the agri-food industry.
Industrial waste can be constituted, among other things, by hyperbaric water jet cutting sands.
Sludge and sediment waste can be, among other things, sludge and sediment from dredging of harbours and channels, or sludge and sediment from wastewater treatment plants.
In accordance with particular embodiments of the present invention, the micro-concrete with a carbonated hydraulic binder, having undergone hydraulic setting during the formation of the grain cores, comprises the following components:
and the hydraulically set reactive powder micro-concrete (RPMC) for shell formation consists of the following components:
The admixtures for concrete that can be used in the composition of micro-concretes and reactive powder micro-concretes (RPMC) can be selected from set accelerators, set retarders, air entrainers, plasticizers, including super-plasticizers, pigments, grinding agents, colloids and mass water repellents.
The micro-concrete binding the waste fragments can also be a reactive powder micro-concrete (RPMC) as defined above.
The weight ratio of waste fragments to micro-concrete for binding the waste fragments is in particular between 10:1 and 1:3.
The weight ratio of core to shell of a grain is in particular between 15:1 and 1:3, being in particular from 1:1 to 2:1.
In particular, the waste fragments can each have a larger dimension of at most 30 mm, being in particular 100 μm-5 mm; the cores can have a larger dimension of 100-500 mm; and the shells can have a thickness of 0.3 to 10 mm.
The grains can have any shape, such as spherical, spheroidal, parallelepipedic, cylindrical.
The present invention also relates to granules consisting in the assembly of at least two, in particular two to twenty, base grains as defined above, wherein the granules can take dimensions selected to form one of a set of granules whose dimensions are distributed according to a granulometric curve to form an aggregate advantageously complying with the NFP18-545 standard, and a set of granules, which added to another aggregate, such as a natural aggregate, form a mixed aggregate advantageously complying with the NFP18-545 standard.
Examples include the preparation of the following aggregates with a granulometric curve in accordance with NFP18-545:
The base grains of a granule can be assembled by one of pressing, gluing and bonding with a hydraulically set, carbonated hydraulic binder concrete, such as a micro-concrete or a reactive powder micro-concrete (RPMC), e.g. a RPMC as defined above, the assembly having in particular a lower compressive/impact strength than the base grains.
The skilled person knows how to select micro-concretes according to their compressive/impact strength.
Advantageously, the cores can have a compressive strength of at least 15 MPa, in particular at least 25 MPa; the grains can have a compressive strength of at least 25 MPa, in particular of at least 60 MPa; and the granules can have a compressive strength of at least 20 MPa, in particular of at least 45 MPa.
The present invention also relates to a process for manufacturing base grains, granules and aggregates as defined above, characterised in that it comprises the following successive steps:
coating, in order to obtain the grains, the grain cores obtained with the composition of the reactive powder micro-concrete (RPMC), the possible admixtures, and the quantity of water necessary for hydraulic setting of the latter, the coating being carried out, for example, by one of tumbling in a drum and spraying on the grain cores; storing the grains obtained at least for the time necessary for their maturation, for example between 10 and 30 days;
The invention also relates to the use of base grains, granules and aggregates as defined above, or prepared by the method as defined above, as components of a composition of construction materials in the field of building, public works and civil engineering, in particular for the construction of walls, floors, road metalling and all concrete works.
The following Examples illustrate the present invention without limiting its scope.
In these Examples, seven reactive powder micro-concretes (RPMC) with the compositions shown in Table 1 were used.
(1)“Millisil C400” from SIFRACO/SIBELO
(2)“Farsil 10” from Silmer or “Christoballite” from Como Céramique
In these Examples, the super-plasticizer marketed as “DYNAMON NRG 1045” by the Company “MAPEI” was also used as a liquid admixture to each RPMC, and, for the formation of the shells of the base grains, a mass water repellent marketed as “SIKACEM Hydrofuge liquide” by the Company “SIKA”.
The maturation times described in these Examples are each of the order of 28 days, as it is well known in the field of building and public works.
In a hopper, the product of HR and RHR waste collection was introduced. This waste was transferred by conveyor belt to a shredder line with 2-axis rotary shears in order to obtain a material made up of pieces each with a maximum size of 2 cm.
The shredded material was then transferred to a drum mixer where it was combined with a quicklime composition to treat the organic parts of the HR and RHR to make them as inert as possible.
The processed material was then transferred to a series of industrial shredder lines with a maximum passing of 5 mm to obtain HR/RHR fragments with a larger size of 5 mm.
The HR and RHR fragments were then transferred by auger to a mixer wherein they were associated by mixing with RPMC1+ superplasticizer and water in the following proportions, in parts by weight:
The resulting mixture was then transferred to an automated moulding line to produce 1 m×1 m slabs of 18mm thickness and 2.5 density under hydraulic press.
The resulting slabs were stored for use after a period of time at least equal to their maturation time.
The slabs were then cut into parallelepipedic pieces of 18 mm side length.
These pieces constitute the base grain cores according to the present invention.
Each of the resulting cores was coated by rolling in a Rotomat-type drum with a 1 mm thick shell of RPMC1, evenly distributed over the surface of each grain core.
For this purpose, the grain cores were mixed with a mixture of RPMC1+ superplasticizer+mass water repellent and water in the following proportions, in parts by weight:
The resulting basic grains were stored for use after a period of time at least equal to their maturation time.
The base grains obtained in C were transferred by conveyor belt to a refusal mixer in which a mixture of RPMC2+ superplasticizer and water was added in the following proportions, in parts by weight
The resulting aggregates were stored for use after a period of time at least equal to their maturation time.
As RPMC2 is less resistant than MBPR1, the base grains do not disintegrate if the aggregate breaks.
The procedure was as in Example 1,A, except that after treatment with the quicklime composition, the treated material was transferred to a series of industrial shredders with a maximum passing of 1 mm, to obtain HR/RHR fragments with a larger size of 1 mm.
The procedure was the same as in Example 1, B, except that RPMC3 was used, the mixing proportions in the mixer being:
and that once the mixture was made, it was transferred to a hydraulic press extruder with a 3 mm grid to make cylindrical grain cores of 3 mm thickness and 2.5 density.
The resulting grain cores were stored for use after a period of time at least equal to their maturation time.
The procedure was as in Example 1,C, except that the mixing proportions were as follows:
The procedure was as in Example 1,D, except that RPMC4 was used and the mixing proportions were as follows:
As RPMC4 is less resistant than RPMC3, the base grains do not disintegrate if the aggregate breaks.
The procedure was as in Example 1,A, except that after treatment with the quicklime composition, the treated material was transferred to a series of industrial shredders with a maximum passing of 1 mm.
The procedure was as in Example 1,B, except that
MBPRS was used, the mixing proportions in the mixer being :
and that once the mixture was made, it was transferred to a 2 mm diameter tabletting machine to make cylindrical grain cores of 2 mm thick and 2.5 density.
The resulting grain cores were stored for use after a period of time at least equal to their maturation time.
The procedure was the same as in Example 1,C, except that RPMC6 was used and the mixing proportions were as follows:
The procedure was as in Example 1,D, except that RPMC7 was used and the mixing proportions were as follows:
As RPMC7 is less resistant than RPMC6, the base grains do not disintegrate if the aggregate breaks.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1901351 | Feb 2019 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/051023 | 2/10/2020 | WO | 00 |
