Composition for aerated or lightweight concrete

Patent metadata

Field	Value
Publication number	US-2023192545-A1
Application number	US-202117997770-A
Country	US
Kind code	A1
Filing date	May 18, 2021
Priority date	May 20, 2020
Publication date	Jun 22, 2023
Grant date	—

Abstract

Aqueous compositions may be used preparing special concretes like aerated concrete or lightweight concrete. Such an aqueous composition for preparing such concretes, may combine water, a hydraulic binder, and an aggregate that is ground in the presence of a particular anionic polymer. The ground aggregate is selected from slag, fly ash, sand, and combinations thereof.

First claim

1 . An aqueous composition (C) suitable for preparing aerated concrete or for preparing lightweight concrete, the composition (C) comprising:
water; an aggregate (A) comprising a silicon dioxide comprising material ground in the presence of an aid comprising a polymer (P) having a molecular weight M w , measured by SEC, of less than 20,000 g/mol and a polymolecularity index (PI) of less than 3.5, the polymer being prepared by a radical polymerization reaction in water or in a solvent, at a temperature of at least 20° C., of a polymerization mixture comprising (i) an anionic monomer (M) comprising a polymerizable olefinic unsaturation and a carboxylic acid group, (ii) a radical-generator comprising hydrogen peroxide, ammonium persulfate, tertiobutyl hydroperoxide, an alkaline metal persulfate, (iii) optionally, an ion comprising Fe II , Fe III , Cu I , and/or Cu II and (iv) optionally, sodium bisulfite, potassium bisulfite, ammonium bisulfite, sodium hypophosphite, potassium hypophosphite, ammonium hypophosphite, and/or disodium 2,2′-(thiocarbonylbisthio)dipropanoate (DPTTC); and a hydraulic binder (B).

2 . The composition of claim 1 , wherein the aggregate (A) comprises at least 10 wt. % of silicon dioxide.

3 . The composition of claim 1 , wherein the polymer (P):
has a weight-average molecular weight M w of less than 15,000 g/mol; or has a weight-average molecular weight M w greater than 1,000 g/mol; or has a polymolecularity index (PI) of less than 3.2.

4 . The composition of claim 1 , wherein the anionic monomer (M) comprises acrylic acid, methacrylic acid, an acrylic acid salt, and/or a methacrylic acid salt.

5 . The composition of claim 1 , wherein the polymerization reaction is carried out with:
100 wt. % of the anionic monomer (M); or the anionic monomer (M) in a range of from 70 to 99.5 wt. % and at least one further monomer in a range of from 0.5 to 30 wt. %.

6 . The composition of claim 1 , wherein the hydraulic binder (B) comprises cement, Portland cement, aluminous cement, calcium sulfoaluminate cement, and/or cement as defined in EN 197-1 standard.

7 . The composition of claim 1 , comprising:
the water in a range of from 20 to 45 wt. %; the aggregate (A), in ground form, in a range of from 35 to 70 wt. %; and hydraulic binder (B) in a range of from 10 to 20 wt. %.

8 . The composition of claim 1 , further comprising:
a further aggregate.

9 . The composition of claim 1 , that is:
an aqueous composition (C1) suitable for preparing an autoclaved aerated concrete and further comprising (v) an expansion agent and (vi-a) lime and/or (vi-b) a lime comprising material; or an aqueous composition (C2) suitable for preparing a foam concrete and further comprising (vii-a) a foaming agent or (vii-b) an air-entraining agent.

10 . The composition of claim 9 , wherein the composition (C1) is present and comprises:
the water in a range of from 20 to 45 wt. %, the aggregate (A), in ground form, in a range of from 35 to 65 wt. %, the hydraulic binder (B) in a range of from 10 to 20 wt. %, the lime comprising material (vi-b) in a range of from 3 to 9.98 wt. %, and the expansion agent (v) in a range of from 0.02 to 2 wt. %.

11 . The composition of claim 9 , wherein the composition (C2) is present and comprises:
the water in a range of from 20 to 45 wt. %, the aggregate (A), in ground form, in a range of from 35 to 65 wt. %, the hydraulic binder (B) in a range of from 10 to 20 wt. %, the foaming agent (vii-a) or air-entraining agent (vii-b) in a range of from 5 to 10 wt. %.

12 . An aerated or lightweight concrete item that is:
an autoclaved aerated concrete item prepared by a method comprising: (A) casting the composition of claim 9 comprising the composition (C1), to obtain a casted composition, and (B) heating and pressurizing the casted composition, or a foamed concrete item prepared by a method comprising: (A) casting the composition of claim 9 comprising the composition (C2), to obtain a casted composition; and (B) drying the casted composition.

13 . An aggregate (A) suitable for preparing an aerated concrete composition or a lightweight concrete composition, comprising composition of claim 1 .

14 . A method for preparing the aggregate (A) of claim 13 , the method comprising:
grinding a silicon dioxide comprising material in the presence of the polymer (P), wherein the polymolecularity index (PI) is less than 3.

15 . A method for preparing an aqueous formulation of the composition (C) of claim 1 , the method comprising:
reducing an amount of the binder (B) compared to a similar composition wherein the aggregate (A) has not been ground in the presence of the polymer (P).

16 . The composition of claim 2 , wherein the aggregate (A) is slag, fly ash, sand, or a combination thereof.

17 . The composition of claim 1 , wherein the aggregate (A) is ground in the presence of at least one polymer (P), prior to its addition to the composition.

18 . The composition of claim 1 , wherein the aggregate (A) has an average particle size below 149 μm.

19 . The composition of claim 1 , wherein the aggregate (A) has less than 15 wt. % of particles having an average particle size above 74 μm.

Assignees

• Coatex Sas

Inventors

• Liu Haifeng
• Xiao Deyan

Classifications

• C04B7/02

  Portland cement · CPC title

• C04B2111/40

  Porous or lightweight materials · CPC title

• C04B14/06 Primary

  Quartz; Sand · CPC title

• C04B22/002

  Water · CPC title

• C04B20/1033

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title