Lightweight concrete compositions
A lightweight ready-mix concrete composition that contains 8-20 volume percent cement, 11-50 volume percent sand, 10-31 volume percent prepuff particles, 9-40 volume percent coarse aggregate, and 10-22 volume percent water, where the sum of components used does not exceed 100 volume percent. The prepuff particles have an average particle diameter of from 0.2 mm to 8 mm, a bulk density of from 0.02 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3. The slump value of the composition measured according to ASTM C 143 is from 2 to 8 inches. After the lightweight ready-mix concrete composition is set for 28 days, it has a compressive strength of at least 1400 psi as tested according to ASTM C39.
1. A lightweight ready-mix concrete composition comprising
8-20 volume percent cement,
11-50 volume percent sand,
10-31 volume percent prepuff particles,
9-40 volume percent coarse aggregate,
10-22 volume percent water, and
less than one percent by weight with respect to total weight of the composition of air-entraining agents;
wherein the prepuff particles have
an average particle diameter of from 0.2 mm to 3 mm,
a bulk density of from 0.02 g/cc to 0.64 g/cc,
an aspect ratio of from 1 to 3, and
a continuous outer layer,
wherein the sum of components used does not exceed 100 volume percent;
wherein the concrete composition has a density of from 90 to about 130 lb./ft 3 ;
wherein the slump value measured according to ASTM C 143 is from 2 to 8 inches; and
wherein after the lightweight ready-mix concrete composition is set for 28 days, has a compressive strength of at least 1700 psi as tested according to ASTM C39.
2. The lightweight concrete composition according to claim 1 , wherein the prepuff particles comprise expanded polymer particles having an inner cell wall thickness of at least at least 0.15 μm.
3. The lightweight concrete composition according to claim 1 , 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 an hydride; polyolefins; polycarbonates; polyesters; polyamides; natural rubbers; synthetic rubbers; and combinations thereof.
4. The lightweight concrete composition according to claim 1 , wherein the prepuff 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.
5. The lightweight concrete composition according to claim 1 , wherein the 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, slag cements, Type I cement, Type IA cement, Type II cement, Type IIA cement, Type III cement, Type IIIA cement, Type IV cement and Type V cement.
6. The lightweight concrete composition according to claim 1 , wherein the composition comprises plasticizers and/or fibers.
7. The lightweight concrete composition according to claim 6 , 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.
8. The lightweight concrete composition according to claim 1 , wherein the coarse aggregate is 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, tuff, macrolite, slate, expanded blast furnace slag, sintered fly ash, coal cinders, and combinations thereof.
9. The lightweight concrete composition according to claim 1 set in the form of a construction panel.
10. The lightweight concrete composition according to claim 1 wherein the water to cement ratio is greater than 0.40.
11. A lightweight ready-mix concrete composition prepared by combining sand, coarse aggregate, cement, prepuff particles, water, less than one percent by weight with respect to total weight of the composition of air-entraining agents, and optionally a water reducer in a pan or drum style mixer, wherein the prepuff particles have an average particle diameter of from 0.2 mm to 3 mm, a bulk density of from 0.02 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3, and a continuous outer layer; wherein the concrete composition has a density of from 90 to about 130 lb./ft 3 ; and wherein after the lightweight ready-mix concrete composition is set for 28 days, has a compressive strength of at least 1700 psi as tested according to ASTM C39.
12. The lightweight concrete composition according to claim 11 having a slump value measured according to ASTM C 143 of from 2 to 8 inches.
13. The lightweight concrete composition according to claim 11 , wherein the cement comprises Type I cement, Type II cement, or Type III cement.
14. The lightweight concrete composition according to claim 11 , wherein the water reducer is selected from the group consisting of lignosulfonates, sodium naphthalene sulfonate formaldehyde condensates, sulfonated melamine-formaldehyde resins, sulfonated vinylcopolymers, urea resins, and salts of hydroxy- or polyhydroxy-carboxylic acids, and combinations thereof.