IL268653A - Lightweight concrete with a polymeric filler and method of making same - Google Patents

Description

268653/3 LIGHTWEIGHT CONCRETE WITH A POLYMERIC FILLER AND METHOD OF MAKING SAME FIELD OF THE INVENTION

[001] The present invention generally relates to concrete and methods of making concrete.

More particularly, the present invention relates to a lightweight concrete with a polymeric filler and methods of making such lightweight concrete.

BACKGROUND OF THE INVENTION

[002] Concrete is a structural composite material composed from an aggregate bonded together with cement and water. The first recorded use of concrete floors is dated 1400- 1200 BC in the city of Tiryns, Greece. The first concrete that included hydraulic lime, was developed by John Smeaton in Devon in England, between 1756 and 1759. Hydraulic lime is the basis for the commonly used modern days “Portland cement” which was developed and patented in England by Joseph Aspdin in 1824.

[003] Since the development of the Portland cement many admixtures have been developed in order to control various properties of the cement, for example, accelerators, such as, calcium chloride, calcium nitrate and sodium nitrate to speed up the hydration (hardening) of the concrete; air entraining agents for adding and entraining small air bubbles in the concrete; plasticizers to increase the workability of the wet concrete, allowing it to be placed more easily, with less consolidating effort; and retarders to slow the hydration of concrete to be used in large or difficult pours where partial setting before the pour is complete is undesirable.

[004] However, regardless to the admixtures added, the type of cement used and type of 3 3 aggregates, the density of the solid concrete is at least 2.2 metric ton/m (2200 Kg/ m ). The higher the reinforcing/aggregate percentage the higher is the density. Standard concrete has 3 a density of 2.4 metric ton/m , while highly reinforced (with iron) concrete may have a 3 density of up to 6 metric ton/m . Accordingly, the use of concrete adds to the weight of the building and requires higher reinforcing.

[005] Not all construction element requires high strength. Some elements, for example, floors or internal/external design elements requires medium to low strength, for example, 1 268653/3 up to 15 MPa. These elements may benefit from a lightweight concrete, that may save weight of the total building, and further save the amount of required reinforcing.

[006] U.S. Patent No. 3,764,357 discloses lightweight concrete and a plaster that includes concreate and aggregates including expanded polystyrene beads configured to be expanded in hot water. The lightweight concrete and a plaster are prepared by wetting the surfaces of particles of a lightweight aggregate with an aqueous medium, and then admixing the particles of wet aggregate with dry finely divided cementitious material to coat the particles therewith. The expanded polystyrene beads are prepared from small pellets or beads of polystyrene containing admixed therewith a heat activated expanding agent such as a volatile hydrocarbon. Upon mixing with water the polystyrene beads will expand due to the chemical reaction of a volatile hydrocarbon with the water. The polystyrene beads will expand to about 2060 times their original size.

[007] Accordingly, there is a need for a lightweight concrete having medium to low strength that can use non-expandable polymer particles and specifically polymeric waste SUMMARY OF THE INVENTION

[008] Aspects of the invention may be directed to a method of making lightweight concrete. The method may include adding at least 50 volumetric % of filler comprising non- 3 expandable polymer particles to at least 200 Kg of water to be included in each m of wet mixture; and adding cement to the wet mixture until the pH of the wet mixture reaches a target pH level, to receive a wet concrete mixture.

[009] In some embodiments, the target pH level of the wet mixture may be higher than 12.

In some embodiments, the target pH level of the wet mixture may be between 12-13. In some embodiments, the filler may be at least 70 volumetric % of the non-expandable polymer particles. In some embodiments, the filler may be one of: non-biological waste, a Refuse-Derived Fuel (RDF) and a mixture of non-recyclable polymers. In some embodiments, the filler’ particles have average particle size of between 2 mm to 50 mm.

[010] In some embodiments, adding the filler may include: adding a first type of filler particles having a first average particles size; and adding a second type of filler particles having a second average particles size. In some embodiments, the first average particles size is at least 30% larger than the second average particles size. 2 29 March 2020 29 March 2020 268653/3

[011] In some embodiments, the method may include adding at least 200 Kg of sand to be 3 included in each m of wet mixture. In some embodiments, the added sand may be selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof. In some embodiments, the method may include adding at least one type of admixture to the wet mixture. In some embodiments, the at least one type of admixture is selected from: a thickener, an air entraining admixture, superplasticizer, and cement accelerator admixture.

[012] Some other aspects of the invention may be directed to a lightweight concrete. The lightweight concrete may include at least 50 volumetric % of a filler particles; and a hardened cement. In some embodiments, the filler particles may include at least 70 volumetric % of non-expandable polymer particles.

[013] In some embodiments, the filler particles may be selected from: non-biological waste particles, a Refuse-Derived Fuel (RDF) particles and a mixture of non-recyclable polymers particles. In some embodiments, the filler’ particles may have average particle size of between 2 mm to 50 mm. In some embodiments, the filler may include: a first type of filler particles having a first average particles size; and a second type of filler particles having a second average particles size. In some embodiments, the first average particles size may be at least 30% larger than the second average particles size.

[014] In some embodiments, the lightweight concrete may further include sand. In some embodiments, the sand may be selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof.

[015] Some other aspects of the invention may be directed to a lightweight dry mortar. In some embodiments, the lightweight dry mortar may include: at least 50 volumetric % of a filler particles; and a cement. In some embodiments, the filler particles may include at least 70 volumetric % of non-expandable polymer particles. In some embodiments, the filler may be one of: non-biological waste, a Refuse-Derived Fuel (RDF) and a mixture of non- recyclable polymers.

[016] In some embodiments, the lightweight dry mortar may further include sand. In some embodiments, the sand may be selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof.

[017] In some embodiments, the filler’ particles may have average particle size of between 2 mm to 50 mm. In some embodiments, the filler may include: a first type of filler particles 3 29 March 2020 29 March 2020 268653/3 having a first average particles size; and a second type of filler particles having a second average particles size. In some embodiments, the first average particles size may be at least % larger than the second average particles size.

BRIEF DESCRIPTION OF THE DRAWINGS

[018] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[019] Fig. 1 is a flowchart of a method of making lightweight concrete according to some embodiments of the invention; and

[020] Figs. 2A, 2B and 2C are illustrations of structures of a lightweight concrete according to some embodiments of the invention.

[021] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[022] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components, modules, units and/or circuits have not been described in detail so as not to obscure the invention.

Some features or elements described with respect to one embodiment may be combined with features or elements described with respect to other embodiments. For the sake of clarity, discussion of same or similar features or elements may not be repeated.

[023] Aspects of the invention may be directed to a lightweight concrete having a density 3 of about 0.9 Ton/m and a method of making such a lightweight concrete, using for example, a lightweight dry mortar. A lightweight concrete according to embodiments of the invention 4 268653/3 may be used for forming floors or any other internal/external design elements that may require medium to low strength. A lightweight concrete according to embodiments of the invention may include a filler that includes at least 70 volumetric (vol.) % non-expandable polymer particles. In some embodiments, the filler may fill at least 50 vol.% of the final dry concrete. In some embodiments, the lightweight concrete may further include a cement to bind together the filler’s particles to form a uniform composite material. The cement may be any cement know in the art and may include any admixture known to be added to a cement.

[024] As used herein the term “non-expandable polymer’ may include any polymeric material that is not configured to expand in volume or swollen due to chemical or physical processes. A non-expandable polymer according to embodiments of the invention can slightly expand due to thermal expansion. Some examples for non-expandable polymers are: polyethylene, polyaniline, polypropylene, polyvinylchloride and the like.

[025] Reference is now made to Fig. 1 which is a flowchart of a method of making lightweight concrete according to some embodiments of the invention. In step 10, a filler that include non-expandable polymer particles may be added to at least 200 Kg of water to 3 be included in each m of wet mixture, the filler may be added at an amount that will occupy at least 50 vol. % of the final wet mixture. The filler and water may be introduced in to any commercial or known concrete mixer. In some embodiments, the filler may include at least 70 vol.% plastic particles (e.g., 75 vol. % or more), for example, polytene, polyaniline, polypropylene, polyvinylchloride and the like. In some embodiments, the filler may be a recycled waste, for example, non-biological waste, a Refuse-Derived Fuel (RDF), a mixture of non-recyclable polymers and the like. As used herein non-recyclable polymers may include any type of polymer that cannot be recycled due to any reason, for example, non- expandable polystyrene, PVD and the like.

[026] In some embodiments, less than 30 vol.% (e.g., less than 20 vol. %) of the filler may include at least one of: paper cardboard, labels, and other corrugated materials. In some embodiments, the filler’s particles may have average particle size of between 2 mm to 50 mm. An example for filler’s particles 120 is illustrated and discussed with respect to Figs. 2A-2C. In some embodiments, the method may include adding a first type of filler’s particles (e.g., filler’s particles 120 illustrated in Fig. 2C) having a first average particles size and adding a second type of filler’s particles (e.g., filler’s particles 122 illustrated in 29 March 2020 268653/3 Fig. 2C) having a second average particles size. In some embodiments, the first average particles size may be at least 30% larger than the second average particles size.

[027] In step 20, cement may be added to the wet mixture (e.g., inside the concrete mixer) until the pH of the final wet mixture reaches a target pH level, to receive a wet concrete mixture. In some embodiments, the target pH level of the final wet mixture may be higher than 12. In some embodiments, the target pH level of the final wet mixture may be between 12-13. In some embodiments, the cement may be added until the required pH level is achieved. In some embodiments, the pH level of the wet mixture may be measured using any method known in the art, for example, according to ASTM C 25, “Standard Test Methods for Chemical Analysis of Limestone, Quicklime, and Hydrated Lime” which may require : mixing 10 g (0.35 oz) of sample with 200 mL (6.8 fl oz) of deionized water. Stirring for 30 minutes and letting the solution stand for 30 minutes. Measuring the pH with a pH probe and meter and/or Lackmus paper.

[028] In some embodiments, the cement may be any know cement, for example, a Portland cement, or any other lime or calcium silicate based cements known in the art. In some embodiments, the cements may be characterized as either hydraulic or non-hydraulic, depending on the ability of the cement to set in the presence of water. In some embodiments, other types of cements may be used as well , for example, Pozzolan-lime cements which are mixtures of ground pozzolan and lime and calcium aluminate cements which are hydraulic cements made primarily from limestone and bauxite. An example, of a cement 110 in a lightweight concrete according to some embodiments of the invention is illustrated and discussed with respect to Figs. 2A-2C.

[029] In some embodiments, the method may include adding at least 200 Kg of sand to be 3 included in each m of wet mixture. In some embodiments, the added sand may be selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof.

[030] In some embodiments, the method may include adding at least one type of admixture to the wet mixture. In some embodiments, the at least one type of admixture is selected from: a thickener, an air entraining admixture, superplasticizer, and cement accelerator admixture. In some embodiments, the thickener may be one of: Hydroxyethyl Cellulose, Methyl 2-hydroxyethyl cellulose, micro-silica and the like. In some embodiments, the air entraining admixture may be aluminum powder and the like. In some embodiments, the 6 268653/3 superplasticizer may be selected from: Polycarboxylate, lignosulfonates as their sodium salt, sulfonated naphthalene formaldehyde condensate, sulfonated melamine formaldehyde condensate, acetone formaldehyde condensate and polycarboxylate ethers and the like. In some embodiments, the cement accelerator admixture may be selected form: calcium nitrate (Ca(NO ) ), calcium nitrite (Ca(NO ) ), calcium format (Ca(HCOO) ), aluminum 3 2 2 2 2 compounds and the like. 3

[031] An example, 1 cubic meter (m ) of a wet mixture according to some embodiments of the invention may include: 200-500 Kg Portland cement, 150-400 Kg RDF, 100-300 Kg quarry sand and 100-250 Kg water. In some embodiments, the wet mixture may further include up to 300 Kg aggregate. In some embodiments, the wet mixture may include at least one of the following admixtures: 0.1-2 Kg thickener, up to 2 Kg air entraining admixture and 1-20 Kg superplasticizer.

[032] Additional experimental results are listed in the table given below. From the water added to the wet mixture, approximately 80% evaporates and 20% participates in the hydration process of the concreate. Accordingly, a dry concreate will weight less than the wet mixture, however the shrinking due to water evaporation is neglectable, since most of the volume taken by the water is replaced with air.

[033] The Calculations in the below table were conducted according to the method thought in “Dr. Itzhak Soroka, Building Materials and their properties use, pages 608 and 609, publisher, The Technion, 1989”. The information regarding the average density of Portland cements were taken from “Helsel et al., Comparative study of methods to measure the density of Cementitious powders, J Test Eval. 2016 Nov; 44(6): 10.1520/JTE20150148”.

Concrete with at Concrete with at Concrete with at least 50% filler least 60% filler least 70% filler Material Density Weight Volume Weight Volume Weight Volume 3 3 3 3 [Kg/m ] [Kg] [m ] [Kg] [m ] [Kg] [m ] Portland 3000 450 0.15 350 0.117 270 0.09 cement RDF filler Max. 250 0.5 300 0.6 350 0.7 500 water 1000 200 0.2 180 0.18 180 0.18 7 09 June 2020 09 June 2020 09 June 2020 268653/3 Soil+ 2550 350 0.137 250 0.098 0 0.0 aggregates Additives 1200 15.6 0.013 6 0.005 22 0.02 Total of 1265.6 1 1086 1 924 1 wet mixture % vol of 50% 60% 70% filler In both dry and wet concreate

[034] In some embodiments, the wet mixture may be mixed for at least 5 minutes, for example, 7 minutes, 10 minutes, 12 minutes or more. In some embodiments, the concreate may be prepared according to the required standards.

[035] Some aspects of the invention may be related to a ready to mix dry lightweight mortars. In some embodiments, a dry lightweight mortar may include at least some of the dry components (e.g., ingredients) of the wet mixture disclosed herein above. In some embodiments, the dry lightweight mortar may include a cement and at least 50 vol % of a filler. In some embodiments, the filler may include at least 70 vol. % of non-expandable polymer particles (e.g., 80 vol. % or more), for example, polytene, polyaniline, polypropylene, polyvinylchloride and the like. In some embodiments, the filler may be a recycled waste, for example, non-biological waste, a Refuse-Derived Fuel (RDF), a mixture of non-recyclable polymers and the like. As used herein non-recyclable polymers may include any type of polymer than cannot be recycled due to any reason, for example, non- expandable polystyrene, PVD and the like.

[036] In some embodiments, less than 30 vol.% (e.g., less than 20 vol. %) of the filler may include at least one of: paper cardboard, labels, and other corrugated materials. In some embodiments, the filler’s particles may have average particle size of between 2 mm to 50 mm. An example for filler’s particles 120 is illustrated and discussed with respect to Figs. 2A-2C. In some embodiments, the filler material may include a first type of filler’s particles 8 7a 29 March 2020 09 June 2020 268653/3 (e.g., filler’s particles 120 illustrated in Fig. 2C) having a first average particles size and a second type of filler’s particles (e.g., filler’s particles 122 illustrated in Fig. 2C) having a second average particles size. In some embodiments, the first average particles size is at least 30% larger than the second average particles size.

[037] In some embodiments, the dry lightweight mortar may further include sand. In some embodiments, the added sand may be selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof.

[038] Reference is now made to Figs. 2A-2C which are illusration of a lightweight concrete according to some embodiments of the invention. Fig. 2A is an illusration of a dry lightweight concrete element 100 according to some embodiments of the invention. Dry lightweight concrete element 100 may be a part of a floor or any other internal/external design element that may require medium to low strength of, for example, less than 15 MPa.

In some embodiments, dry lightweight concrete element 100 may be formed using embodiments of the method disclosed herein above with respect to Fig. 1.

[039] In some embodiments, dry lightweight concrete element 100 may include: a hardened cement 110 and at least 50 volumetric % of filler particles 120, for example, 60 vol. %, 70 vol.%, 80 vol. % and more. In some embodiments, at any vol. % of filler particles, hardened cement 110 may form a continuous matrix. In some embodiments, the density of 3 3 dry lightweight concrete element 100 may be at most 1000 Kg/m , for example, 900 Kg/m , 3 800 Kg/m or less. An enlarged view of a cut in concrete 100 showing filler’s particles 120 in the continuous matrix made from dry cement 110 is illustrated in Fig. 2B.

[040] In some embodiments, hardened cement 110 may include any known cement, for example, a Portland cement, or any other lime or calcium silicate based cements. In some embodiments, hardened cement 110 may include other cements, for example, Pozzolan- lime cements which are mixtures of ground pozzolan and lime and Calcium aluminate cements, Calcium sulphate cements, or any pozzolan cement, which are hydraulic cements made primarily from limestone and bauxite.

[041] In some embodiments, filler 120 may include at least 70 volumetric % of non- expandable polymer particles (e.g., 75 vol. % or more). Some example for optional polymers may include, polytene, polyaniline, polypropylene, polyvinylchloride (PVC) and the like. In some embodiments, filler particles 120 may include recycled waste particles, for example, non-biological waste particles, a Refuse-Derived Fuel (RDF), a mixture of non- 8 9 29 March 2020 268653/3 recyclable polymers and the like. As used herein non-recyclable polymers may include any type of polymer that cannot be recycled due to any reason, for example, non-expandable polystyrene, PVC and the like.

[042] In some embodiments, less than 30 vol.% (e.g., less than 20 vol. %) of the filler may include at least one of: paper cardboard, labels, and other corrugated materials. In some embodiments, filler’s particles 120 may have average particle size of between 2 mm to 50 mm, for example, 2- 22 mm, 3-10 mm.

[043] In some embodiments, two or more different sizes of filler particles may be used, as illustrated in Fig. 2C. Such an arrangement may allow to use larger vol. % of filler particles while maintaining a continuous matrix of hardened cement 110. In some embodiments, the filler may include a first type of filler particles 120 having a first average particles size and a second type of filler particles 122 having a second average particles size. In some embodiments, the first average particles size may be at least 30% larger than the second average particles size. For example, first type of particles 120 may have average particles size of 10 mm and second type of particles 122 may have average particles size of 3 mm. In some embodiments, dry concrete 100 may further include a third type of filler particles (not illustrated), for example, having average particles size of 5 mm.

[044] In some embodiments, dry lightweight concrete element 100 may further include sand. In some embodiments, the sand may be selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof.

[045] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents may occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

[046] Various embodiments have been presented. Each of these embodiments may of course include features from other embodiments presented, and embodiments not specifically described may include various features described herein. 9

Claims (25)

268653/2 CLAIMS

1. A method of making lightweight concrete, comprising: adding filler comprising non-expandable polymer particles to at least 200 Kg of water 3 to be included in each m of wet mixture; and adding cement to the wet mixture until the pH of the wet mixture reaches a target pH level, to receive a wet concrete mixture, wherein the filler occupies at least 50% of the volume of the wet mixture.

2. The method of claim 1, wherein the target pH level of the wet mixture is higher than 12.

3. The method of claim 1, the filler is a Refuse-Derived Fuel (RDF) .

4. A method according to any one of the preceding claims, wherein the filler comprises at least 70 volumetric % of non-expandable polymer particles.

5. A method according to any one of the preceding claims, wherein the filler is one of: non-biological waste, and a mixture of non-recyclable polymers.

6. A method according to any one of the preceding claims, wherein the filler’ particles have average particle size of between 2 mm to 50 mm.

7. A method according to any one of the preceding claims, wherein adding the filler comprises: adding a first type of filler particles having a first average particles size; and adding a second type of filler particles having a second average particles size, and wherein the first average particles size is at least 30% larger than the second average particles size.

8. A method according to any one of the preceding claims, further comprising: 3 adding at least 200 Kg of sand to be included in each m of wet mixture. 10 268653/2

9. The method of claim 8, wherein the added sand is selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof.

10. A method according to any one of the preceding claims, further comprising adding at least one type of admixture to the wet mixture.

11. The method of claim 10, wherein the at least one type of admixture is selected from: a thickener, an air entraining admixture, superplasticizer, and cement accelerator admixture.

12. A lightweight concrete comprising: filler particles; and a hardened cement, wherein the filler particles comprise at least 70 volumetric % of non-expandable polymer particles, and wherein the filler particles occupy at least 50% of the volume of the lightweight concrete.

13. The lightweight concrete of claim 12, wherein the filler particles are Refuse-Derived Fuel (RDF) particles.

14. The lightweight concrete of claim 12, wherein the filler particles are selected from non-biological waste, and a mixture of non-recyclable polymers

15. A lightweight concrete according to any one of claims 12-14, wherein the filler’ particles have average particle size of between 2 mm to 50 mm.

16. A lightweight concrete according to any one of claims 12-15, wherein the filler includes: a first type of filler particles having a first average particles size; and 11 268653/2 a second type of filler particles having a second average particles size, and wherein the first average particles size is at least 30% larger than the second average particles size.

17. A lightweight concrete according to any one of claims 12-16, further comprising sand.

18. The lightweight concrete of claim 17, wherein the sand is selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof.

19. A lightweight dry mortar, comprising: at least 60 volumetric % of a filler particles; and a cement, wherein the filler particles comprises at least 70 volumetric % of non-expandable polymer particles.

20. The lightweight dry mortar of claim 19 wherein the filler is a Refuse-Derived Fuel (RDF).

21. The lightweight dry mortar of claim 19 wherein the filler is one of: non-biological waste and a mixture of non-recyclable polymers.

22. The lightweight dry mortar according to any one of claims 19-21, further comprising sand.

23. The lightweight dry mortar of claim 22, wherein the sand is selected from a group consisting of: quarry sand, natural sand, aggregates, coil ash and any combination thereof.

24. A lightweight dry mortar according to any one of claims 19-23, the filler’ particles have average particle size of between 2 mm to 50 mm. 12 268653/2

25. A lightweight dry mortar according to any one of claims 19-24, wherein the filler includes: a first type of filler having a first average particles size; and a second type of filler having a second average particles size, and wherein the first average particles size is at least 30% larger than the second average particles size. 13