Lightweight concrete compositions

Abstract

A lightweight concrete composition containing from 10 to 90 volume percent of a cement composition, from 10 to 90 volume percent of particles having an average particle diameter of from 0.2 mm to 8 mm, a bulk density of from 0.03 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3, and from 0 to 50 volume percent of aggregate; where the sum of components used does not exceed 100 volume percent, and where after the lightweight concrete composition is set it has a compressive strength of at least 1700 psi as tested according to ASTM C39 after seven days. The concrete composition can be used to make concrete masonry units, construction panels, road beds and other articles.

We claim: 
     
       1. A pre-cast and pre-stressed construction article containing a lightweight concrete composition comprising
 from 10 to 90 volume percent of a cement composition,   from 10 to 90 volume percent of particles having an average particle diameter of from 0.2 mm to 3 mm, a bulk density of from 0.028 g/cc to 0.48 g/cc, an aspect ratio of from 1 to 3, and have a continuous outer layer,   from 0 to 50 volume percent of aggregate, and   less than one percent by weight with respect to total weight of the composition of air-entraining agents;   
       wherein the sum of components used does not exceed 100 volume percent; wherein the concrete composition has a density of from about 90 to about 130 lb./ft 3 ; and 
       wherein after the lightweight concrete composition is set for seven days, has a compressive strength of at least 1700 psi as tested according to ASTM C39. 
     
     
       2. A lightweight concrete article made according to a method comprising:
 identifying the density and strength properties of a set lightweight concrete composition;   determining the type, size and density of polymer beads to be expanded for use in the lightweight concrete composition;   determining the size and density the polymer beads are to be expanded to;   expanding the polymer beads to form expanded polymer beads;   dispersing the expanded polymer beads in a cementitious mixture containing a hydraulic cement composition to form the lightweight concrete composition; and   allowing the lightweight concrete composition to set in a desired form;   
       wherein the lightweight concrete composition comprises
 from 10 to 90 volume percent of a cement composition, 
 from 10 to 90 volume percent of particles having an average particle diameter of from 0.2 mm to 3 mm, a bulk density of from 0.028 g/cc to 0.48 g/cc, an aspect ratio of 
 from 1 to 3, and have a continuous outer layer, 
 from 0 to 20 volume percent of coarse aggregate, 
 from 10 to 50 volume percent of fine aggregate, and 
 less than one percent by weight with respect to total weight of the composition of air-entraining agents; 
 
       wherein the sum of components used does not exceed 100 volume percent; 
       wherein the concrete composition has a density of from about 90 to about 130 lb./ft 3 ; and 
       wherein after the lightweight concrete composition is set for seven days, has a compressive strength of at least 1700 psi as tested according to ASTM C39. 
     
     
       3. A pre-cast construction article containing a concrete composition comprising
 from 10 to 90 volume percent of a cement composition,   from 10 to 90 volume percent of particles having an average particle diameter of from   0.2 mm to 3 mm, a bulk density of from 0.028 g/cc to 0.48 g/cc, an aspect ratio of from 1 to 3, and have a continuous outer layer,   from 0 to 50 volume percent of aggregate, and   less than one percent by weight with respect to total weight of the composition of air-entraining agents;   
       wherein the sum of components used does not exceed 100 volume percent; wherein the concrete composition has a density of from about 90 to about 130 lb./ft 3 ; and 
       wherein after the lightweight concrete composition is set for seven days, has a compressive strength of at least 1700 psi as tested according to ASTM C39. 
     
     
       4. The construction article according to  claim 3 , wherein the particles comprise expanded polymer particles having an inner cell wall thickness of at least at least 0.15 μm. 
     
     
       5. The construction article according to  claim 3 , wherein the particles comprise expanded polymer particles comprising one or more polymers selected from the group consisting of homopolymers of vinyl aromatic monomers; copolymers of at least one vinyl aromatic monomer with one or more of divinylbenzene, conjugated dienes, alkyl methacrylates, alkyl acrylates, acrylonitrile, and/or maleic anhydride; polyolefins; polycarbonates; polyesters; polyamides; natural rubbers; synthetic rubbers; and combinations thereof. 
     
     
       6. The construction article according to  claim 3 , wherein the particles comprise expanded polymer particles prepared by expanding a polymer bead having an unexpanded average resin particle size of from about 0.2 mm to about 2 mm. 
     
     
       7. The construction article according to  claim 3 , wherein the cement composition comprises one or more materials selected from the group consisting of Portland cements, pozzolana cements, gypsum cements, aluminous cements, magnesia cements, silica cements, and slag cements. 
     
     
       8. The construction article according to  claim 3 , wherein the concrete composition comprises sand, fine aggregate, coarse aggregate, plasticizers and/or fibers. 
     
     
       9. The construction article according to  claim 8 , wherein the fibers are selected from the group consisting of glass fibers, silicon carbide, aramid fibers, polyester, carbon fibers, composite fibers, fiberglass, combinations thereof, fabric containing said fibers, and fabric containing combinations of said fibers. 
     
     
       10. The construction article according to  claim 3 , wherein a standard 2 ½ inch drywall screw, screwed into the formed and set concrete composition to a depth of 1 ½ inches, is not removed by applying 500 pounds of force perpendicular to the surface screwed into for one minute. 
     
     
       11. The construction article according to  claim 2 , wherein the particles comprise expanded polymer particles prepared by expanding a polymer bead having an unexpanded average resin particle size of from about 0.2 mm to about 2 mm. 
     
     
       12. The construction article according to  claim 11 , wherein the particles comprise polystyrene. 
     
     
       13. The construction article according to  claim 2 , wherein the coarse aggregate is selected from the group consisting of stone, gravel, ground granulated blast furnace slag, fly ash, glass, expanded slate, clay; pumice, perlite, vermiculite, scoria, diatomite, expanded shale, expanded clay, expanded slag, pelletized aggregate, extruded fly ash, tuft, macrolite, slate, expanded blast furnace slag, sintered fly ash, coal cinders, and combinations thereof. 
     
     
       14. The construction article according to  claim 2 , wherein the fine aggregate comprises sand. 
     
     
       15. The construction article according to  claim 2 , wherein the lightweight concrete composition comprises from 0.1 to 1 volume percent of one or more additives selected from the group consisting of anti-foam agents, water-proofing agents, dispersing agents, set-accelerators, set-retarders, plasticizing agents, superplasticizing agents, freezing point decreasing agents, adhesiveness-improving agents, colorants and combinations thereof. 
     
     
       16. The construction article according to  claim 1 , wherein the particles comprise expanded polymer particles prepared by expanding a polymer bead having an unexpanded average resin particle size of from about 0.2 mm to about 2 mm. 
     
     
       17. The construction article according to  claim 1 , wherein the construction article comprises prestressing tendons. 
     
     
       18. The construction article according to  claim 1 , wherein the lightweight concrete composition comprises from 0.1 to 1 volume percent of one or more additives selected from the group consisting of anti-foam agents, water-proofing agents, dispersing agents, set-accelerators, set-retarders, plasticizing agents, superplasticizing agents, freezing point decreasing agents, adhesiveness-improving agents, colorants and combinations thereof. 
     
     
       19. The construction article according to  claim 1 , wherein the lightweight concrete composition is free of air entraining agents. 
     
     
       20. The concrete article according to  claim 2 , wherein the lightweight concrete composition is free of air entraining agents. 
     
     
       21. The construction article according to  claim 3 , wherein the lightweight concrete composition is free of air entraining agents. 
     
     
       22. A dry mixture comprising:
 10 to 90 volume percent of a cement composition,   10 to 90 volume percent of expanded particles having an average particle diameter of from 0.2 mm to 3 mm, a bulk density of from 0.028 g/cc to 0.52 g/cc, an aspect ratio of from 1 to 3, and a continuous outer layer,   0 to 50 volume percent of one or more aggregates, and   0 to 1 volume percent of one or more additives;   wherein the sum of components used does not exceed 100 volume percent;   wherein the dry mixture is packaged for future use;   wherein after the dry mixture is mixed with a sufficient amount of water to cause the mixture to set and bind, the resulting concrete composition has a density of from 90 to about 130 lb./ft 3  and a seven day compressive strength of at least 1700 psi as determined according to ASTM C39.   
     
     
       23. The mixture according to claim 22, wherein the expanded particles comprise one or more polymers selected from the group consisting of homopolymers of vinyl aromatic monomers; copolymers of at least one vinyl aromatic monomer with one or more of divinylbenzene, conjugated dienes, alkyl methacrylates, alkyl acrylates, acrylonitrile, and/or maleic anhydride; polyolefins; polycarbonates; polyesters; polyamides; natural rubbers; synthetic rubbers; and combinations thereof. 
     
     
       24. The mixture according to claim 22, wherein the particles comprise expanded polymer particles prepared by expanding a polymer bead having an unexpanded average resin particle size of from about 0.2 mm to about 2 mm. 
     
     
       25. The mixture according to claim 22, wherein the cement composition comprises a hydraulic cement composition. 
     
     
       26. The mixture according to claim 25, wherein the hydraulic cement comprises one or more materials selected from the group consisting of Portland cements, pozzolana cements, gypsum cements, gypsum compositions, aluminous cements, magnesia cements, silica cements, and slag cements. 
     
     
       27. The mixture according to claim 22, wherein the cementitious mixture comprises fine aggregate, coarse aggregate, plasticizers and/or fibers. 
     
     
       28. The mixture according to claim 27, wherein the fibers are selected from the group consisting of glass fibers, silicon carbide, aramid fibers, polyester, carbon fibers, composite fibers, fiberglass, combinations thereof, fabric containing said fibers, and fabric containing combinations of said fibers. 
     
     
       29. The mixture according to claim 22 comprising one or more materials selected from the group consisting of stone, gravel, ground granulated blast furnace slag, fly ash, glass, silica, expanded slate, clay; pumice, perlite, vermiculite, scoria, diatomite, expanded shale, expanded clay, expanded slag, fumed silica, pelletized aggregate, extruded fly ash, tuft, macrolite, slate, expanded blast furnace slag, sintered fly ash, coal cinders, and combinations thereof. 
     
     
       30. The mixture according to claim 22, wherein the additives are selected from the group consisting of anti-foam agents, water-proofing agents, dispersing agents, set-accelerators, set-retarders, plasticizing agents, superplasticizing agents, freezing point decreasing agents, adhesiveness-improving agents, colorants and combinations thereof. 
     
     
       31. The mixture according to claim 22, wherein the expanded particles are expanded polystyrene particles. 
     
     
       32. The mixture according to claim 31, wherein the cement composition is present at from 10 to 60 volume percent and comprises a Portland Cement; the expanded polystyrene particles are present at from 20 to 78 volume percent, the aggregates are present at from 5 to 35 volume percent, and one or more additives are present at from 0.1 to 1 volume percent. 
     
     
       33. A dry mixture for mixing later with water to form a concrete structure comprising:
 22 to 90 volume percent of cement;   10 to 90 volume percent of expanded particles having
 an average particle diameter of from 0.2 mm to 3 mm, 
 a bulk density of from 0.028 g/cc to 0.52 g/cc, 
 an aspect ratio of from 1 to 3, and 
 a continuous outer layer, 
   0.5 to 5 volume percent of fibers;   0 to 60 volume percent of one or more aggregates,   0 to 3 volume percent by weight of an ethylene/vinyl acetate copolymer;   0 to 3 volume percent of an anti-foam agent;   0 to 3 volume percent of a water reducer; and   0 to 3 volume percent of a plasticizer;   wherein the sum of components used does not exceed 100 volume percent;   wherein after the dry mixture is mixed with a sufficient amount of water to cause the mixture to set and bind, the resulting concrete composition has a density of from 90 to about 130 lb./ft 3  and a seven day compressive strength of at least 1700 psi as determined according to ASTM C39.   
     
     
       34. The mixture according to claim 33, wherein the cement composition comprises a hydraulic cement composition. 
     
     
       35. The mixture according to claim 33, wherein the hydraulic cement comprises one or more materials selected from the group consisting of Portland cements, pozzolana cements, gypsum cements, gypsum compositions, aluminous cements, magnesia cements, silica cements, and slag cements.