# US 2018/0022653 A1 · Lightweight foamed cement, cement board, and methods for making same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0022653 A1 - Document ID: US20180022653A1 - Status: Published application - Kind: A1 - Application number: 15/213,751 - Filed: 2016-07-19 - Published: 2018-01-25 - Earliest claimed: 2016-07-19 - Assignees: United States Gypsum Company - Applicants: United States Gypsum Company - Inventors: Marianela Perez-Pena - Web page: https://patentgrep.com/patent/US20180022653A1 ## CPC - C04B 38/10: by using foaming agents (C04B38/02 takes precedence){or by using mechanical means, e.g. adding preformed foam} - C04B 24/04: Carboxylic acids; Salts, anhydrides or esters thereof - C04B 24/16: Sulfur-containing compounds - C04B 24/26: obtained by reactions only involving carbon-to-carbon unsaturated bonds {(C04B24/243 takes precedence)} - C04B 24/2623: {Polyvinylalcohols; Polyvinylacetates} - C04B 28/141: {containing dihydrated gypsum before the final hardening step, e.g. forming a dihydrated gypsum product followed by a de- and rehydration step} - C04B 38/106: {by adding preformed foams} - C04B 40/0028: {Aspects relating to the mixing step of the mortar preparation} - C04B 2103/20: Retarders - C04B 2103/32: Superplasticisers - C04B 2103/48: Foam stabilisers - C04B 2111/10: Compositions or ingredients thereof characterised by the absence or the very low content of a specific material - Y02W 30/91: Use of waste materials as fillers for mortars or concrete - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE - Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT ## Abstract Disclosed is a foamed cementitious composition which limits or eliminates aggregate, especially porous lightweight aggregate and uses a lower than usual water to cementitious composition weight ratio. The stable cementitious foam mixtures may be employed to make cement boards and other cement products. The foamed cementitious composition was made with additions of PVOH foaming stabilizer and surfactant foaming agents to make foam water or by entrain air into cementitious slurry mixtures. The cementitious mixtures have a limited amount or preferably no perlite and no lightweight aggregate. The resulting foamed mixture had foam bubbles with size in the range of 50 to 200 μm. After setting the foamed cementitious composition the resulting set board has air cells with size in the range of 50 to 200 μm. ## Claims ### Claim 1 A method of providing a lightweight cementitious product comprising: mixing a cementitious foamed mixture comprising 65-75 wt. % hydraulic cementitious reactive powder, 20-35 wt. % water 0.05-1 wt. surfactant as a foaming agent; 0.1 to 1.0 wt. % polyvinyl alcohol as a foam stabilizing agent; 0-0.5 wt. % a retarder selected from the group consisting of citric acid, alkali metal salt of citric acid, 0.15-1.0 wt. % superplasticizer; at least one member selected from the group consisting of aggregate and filler, wherein a weight ratio of total aggregate and filler to hydraulic cementitious reactive powder is 0 to 0.5:1, wherein all aggregate and filler of the cementitious foamed mixture is only lightweight non-porous aggregate and lightweight non-porous filler, wherein the lightweight non-porous aggregate and lightweight non-porous filler have a particle density of less than or equal to 40 lbs/cubic foot, wherein the lightweight non-porous filler and the lightweight non-porous aggregate have an open porosity of at most 0.10; water, wherein the foamed mixture weight ratio of water to hydraulic cementitious reactive powder is 0.3 to 0.5:1; and air in the form of foam bubbles with diameter in the range of 50 to 200 μm, wherein the foamed mixture has air volume content of 20 to 55 volume %; wherein the hydraulic cementitious reactive powder comprises in % by weight relative to the weight of the hydraulic cementitious reactive powder: 75 to 95% Portland cement, 0 to 21% high alumina cement, (also known as calcium aluminate cement), 0 to 10% calcium sulfate, and 0 to 25 pozzolanic material; casting the cementitious foamed mixture and leaving the cast mixture to set to form the lightweight cementitious product, wherein the set cementitious foamed mixture has, measured 14 days after casting, a nominal density of 45-60 pounds per cubic foot and a nail pull value of greater than 90 pounds-force; wherein the set cementitious foamed mixture has a compressive strength, measured 7 days after casting of 500 psi to about 5000 psi. ### Claim 2 (depends on 1) The method of claim 1, wherein the air is added by aerating a blend of a first portion of the water, the surfactant, and the polyvinyl alcohol with entrainment of air to form foam water, wherein the surfactant is 1 to 15% by weight of the foam water; wherein the polyvinyl alcohol is 1 to 5 wt % of the foam water of the foam water; blending the foam water and a slurry comprising the hydraulic cementitious composition, a second portion of the water, an optional second portion of the polyvinyl alcohol, and an optional second portion of the surfactant, to produce the cementitious foamed mixture; wherein the foamed mixture weight ratio of said foam water to said cementitious composition is 0.01 to 0.05:1, wherein the set cementitious foamed mixture has air cells volume content of 20 to 55 volume %, wherein the set cementitious foamed mixture has air cells with diameter in the range of 50 to 200 μm. ### Claim 3 (depends on 2) The method of claim 2, wherein the foam water adds a first potion of the air to the slurry to form a foamed slurry, further comprising mixing the foamed slurry in the presence of air to entrain a second portion of the air into the foamed slurry. ### Claim 4 (depends on 1) The method of claim 1, wherein the air is added by entraining the air into a slurry comprising the hydraulic cementitious composition, the surfactant, the polyvinyl alcohol, the retarder, the superplasticizer, and the water. ### Claim 5 (depends on 1) The method of claim 1, wherein the mixture further comprises an alkali metal silicate, triethanol amine, and a phosphate selected from the group consisting of sodium trimetaphosphate, potassium tripolyphosphate, sodium tripolyphosphate, tetrasodium pyrophosphate, tetrapotassium pyrophosphate, monopotassium phosphate, dicalcium phosphate, and mixtures thereof. ### Claim 6 (depends on 1) The method of claim 1, wherein at least 80% of the total aggregate and filler is coated perlite. ### Claim 7 (depends on 1) The method of claim 1, wherein the surfactant comprises an anionic surfactant selected from the group consisting of alkyl benzene sulfonate, fatty acid salts, sodium lauryl sulfate, alkyl sulfate salts, sodium lauryl ether sulfate, sodium alkyl ether sulfate, (sodium C14-16 olefin sulfonate, alpha-olefin sulfonates, phosphate esters, sulphosuccinates, alkyl phenol ether sulfates, and isethionates. ### Claim 8 (depends on 1) The method of claim 1, wherein the water to hydraulic cementitious reactive powder weight ratio is 0.32 to 0.38:1, wherein the Portland cement ranges from about 75% to about 90% of the hydraulic cementitious reactive powder, the high alumina cement ranges from about 0% to about 10%, and the calcium sulfate ranges from about 2% to about 5% of the hydraulic cementitious reactive powder. ### Claim 9 (depends on 1) The method of claim 1, further comprising wherein the cast mixture forms into a sheet, and wherein setting comprises setting the sheet to an initial set condition; further comprising cutting the initial set condition sheet to form a pre-cured board; and wherein the pre-cured board is cured to a final set condition to form the board product; wherein the board product has a density of 40-90 pcf and a nail pull value greater than or equal to 90 pounds-force, wherein the board has air cells with diameter in the range of 50 to 200 μm. ### Claim 10 (depends on 1) The method of claim 1, wherein the cementitious foamed mixture has an absence of calcium chloride, calcium formate, and calcium nitrate. ### Claim 11 (depends on 1) A foamed cement product comprising the set foamed mixture produced according to the method claim 1. ### Claim 12 (depends on 11) The foamed cement product of claim 11, having a nominal density of 48 to 53 pounds per cubic foot, nail pull values in the range of 90 to 110 pounds-force, and compressive strength of 600-900 psi. ### Claim 13 A cement product comprising a set cementitious foamed mixture comprising: 65-75 wt. % hydraulic cementitious reactive powder, 0.05-1 wt. % surfactant as a foaming agent; 1 to 1.0 wt. % polyvinyl alcohol as a foam stabilizing agent; 1-0.5 wt. % a retarder selected from the group consisting of citric acid, alkali metal salt of citric acid; 15-1.0 wt. % superplasticizer; at least one member selected from the group consisting of aggregate and filler, wherein a weight ratio of total aggregate and filler to hydraulic cementitious reactive powder is 0 to 0.5:1, wherein all aggregate and filler of the cementitious foamed mixture is only lightweight non-porous aggregate and lightweight non-porous filler, wherein the lightweight non-porous aggregate and lightweight non-porous filler have a particle density of less than or equal to 40 lbs/cubic foot, wherein the lightweight non-porous filler and the lightweight non-porous aggregate have an open porosity of at most 0.10; wherein the product has air cells with diameter in the range of 50 to 200 μm, wherein the product has air cells volume content of 20 to 55 volume %; wherein the hydraulic cementitious reactive powder comprises in % by weight relative to the weight of the hydraulic cementitious reactive powder: 75 to 95% Portland cement, 0 to 21% high alumina cement, 0 to 10% calcium sulfate, and 0 to 25 pozzolanic material, wherein the product was made with a weight ratio of water to hydraulic cementitious reactive powder of 0.3 to 0.5:1; wherein the product has a nominal density of 45-60 pounds per cubic foot, and a nail pull value of greater than 90 pounds-force; and wherein the product has a compressive strength, measured after setting 7 days of 500 psi to about 5000 psi. ### Claim 14 (depends on 13) The product of claim 13, having a nominal density of 48 to 53 pounds per cubic foot, nail pull values in the range of 90 to 110 pounds-force, and compressive strength of 600-900 psi. ### Claim 15 (depends on 13) The product of claim 13, wherein the mixture further comprises an alkali metal silicate, triethanol amine, and a phosphate selected from the group consisting of sodium trimetaphosphate, potassium tripolyphosphate, sodium tripolyphosphate, tetrasodium pyrophosphate, tetrapotassium pyrophosphate, monopotassium phosphate, dicalcium phosphate, and mixtures thereof. ### Claim 16 (depends on 13) The product of claim 13, wherein the surfactant is an anionic surfactant comprising a polar group selected from the group consisting of carboxylate, sulfate, sulfonate and phosphate, wherein the retarder is at least one member of the group consisting of sodium citrate, potassium citrates, citric acid, gluconates, and mixtures thereof. ### Claim 17 (depends on 13) The product of claim 13, further comprising at least one member of the group consisting of triethanolamine, sodium citrate, and sodium trimetaphosphate, wherein the superplasticizer comprises a polycarboxylate. ### Claim 18 (depends on 13) The product of claim 13, wherein the surfactant comprises an anionic surfactant selected from the group consisting of alkyl benzene sulfonate, fatty acid salts, sodium lauryl sulfate, alkyl sulfate salts, sodium alkyl ether sulfate, sodium lauryl ether sulfate, alpha-olefin sulfonates, sodium C14-16 olefin sulfonate, phosphate esters, sulphosuccinates, alkyl phenol ether sulfates, and isethionates. ### Claim 19 (depends on 13) The product of claim 13, wherein the water to hydraulic cementitious reactive powder weight ratio is 0.32 to 0.38:1, wherein the Portland cement ranges from about 73% to about 76%, the high alumina cement ranges from about 5% to about 10%, and the calcium sulfate ranges from about 2% to about 5%. ### Claim 20 (depends on 13) The product of claim 13, wherein the product is a sheet comprising the set foamed mixture, the sheet having a thickness of 0.25 to 2 inches.