Lightweight concrete compositions
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.
1. A concrete masonry unit made from a concrete composition comprising:
from 10 to 90 volume percent of a cement composition;
from 10 to 90 volume percent of expanded particles having an average particle diameter of from 0.2 mm to 3 mm, an aspect ratio of from 1 to 3, and 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 concrete composition has a density of from about 40 to about 130 lb./ft 3 ; and
wherein after the concrete composition is set for seven days, has a compressive strength of at least 1700 psi as tested according to ASTM C39.
2. The concrete masonry unit according to claim 1 , wherein the expanded particles comprise expanded polymer particles having an inner cell wall thickness of at least at least 0.15 μm.
3. The concrete masonry unit according to claim 1 , wherein the expanded 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.
4. The concrete masonry unit composition according to claim 1 , wherein the expanded 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 concrete masonry unit according to claim 1 , wherein the cement composition comprises a hydraulic cement composition.
6. The concrete masonry unit according to claim 5 , 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.
7. The concrete masonry unit according to claim 1 , wherein the concrete composition comprises coarse aggregate, plasticizers and/or fibers.
8. The concrete masonry unit according to claim 7 , 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.
9. The concrete masonry unit according to claim 7 , 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.
10. The concrete masonry unit according to claim 1 , wherein a standard 2½ inch drywall screw, screwed into the concrete masonry unit to a depth of 1½ inches, is not removed by applying 500 pounds of force perpendicular to the surface screwed into for one minute.