Strength enhancer for concretes based on functionalized nanomaterials

Patent metadata

Field	Value
Publication number	US-2022220040-A1
Application number	US-202017607571-A
Country	US
Kind code	A1
Filing date	May 28, 2020
Priority date	May 28, 2019
Publication date	Jul 14, 2022
Grant date	—

Abstract

An admixture for cement based compositions, the admixture including a) an aqueous solution of polycarboxylate ether and b) at least one functionalized nanomaterial selected from carbon nanotubes functionalized by carboxyl groups and carbon nanofibers functionalized by carboxyl groups, wherein the at least one functionalized nanomaterial is dispersed in the aqueous solution. Low dosages of the admixture in cement based compositions result in significant enhancement of compressive strength.

First claim

1 . An admixture for cement based compositions, the admixture comprising
a) an aqueous solution of polycarboxylate ether and b) at least one functionalized nanomaterial selected from carbon nanotubes functionalized by carboxyl groups and/or carbon nanofibers functionalized by carboxyl groups, wherein the at least one functionalized nanomaterial is dispersed in the aqueous solution.

2 . The admixture according to claim 1 , wherein the carbon nanotubes functionalized by carboxyl groups have a diameter in the range of 10 to 90 nm and/or the carbon nanofibers functionalized by carboxyl groups have a diameter in the range of 50 to 200 nm.

3 . The admixture according to claim 1 , wherein the carbon nanotubes functionalized by carboxyl groups and/or the carbon nanofibers functionalized by carboxyl groups have an aspect ratio in the range of from 5 to 750.

4 . The admixture according to claim 1 , wherein the carbon nanotubes functionalized by carboxyl groups or the carbon nanofibers functionalized by carboxyl groups are obtained by oxidative treatment of the carbon nanotubes or the carbon nanofibers.

5 . The admixture according to claim 1 , wherein the proportion of functionalized nanomaterial is in the range of 0.04 to 0.4% by weight, based on the total weight of the admixture.

6 . The admixture according to claim 1 , wherein the proportion of polycarboxylate ether is in the range of 10 to 70% by weight, based on the total weight of the admixture.

7 . The admixture according to claim 1 , wherein the polycarboxylate ether comprises or consists of
a) a partial structural unit S1 of formula (I) in a mole fraction of a

b) a partial structural unit S2 of formula (II) in a mole fraction of b

wherein
M independent from each other is H + , an alkali metal ion, alkaline earth metal ion, a di- or trivalent metal ion, an ammonium ion or an organic ammonium group, wherein M is preferably H + or Na + ;
each R u independent from the others is hydrogen or a methyl group,
each R v is hydrogen;
m=1 or 2;
p=0 or 1;

R 1 is -[AO] n —H, wherein A=C 2 to C 4 -alkylene, and n is from 20 to 150, and
the molar ratio a/b of the mole fraction a of the partial structural unit S1 to the mole fraction b of the partial structural unit S2 is in the range from 6/1 to 2.5/1, provided that a+b=1.

8 . The admixture according to claim 1 , wherein the admixture essentially consists of the aqueous solution of polycarboxylate ether and the functionalized nanomaterial or wherein the admixture further comprises at least one additive selected from plasticizers or superplasticizers other than polycarboxylate ethers, strength enhancers, retarders, accelerators, air entrainers, defoamers, corrosion inhibitors, expansion producing agents, pigments, fibres, waterproofing additives, biocides, thickeners and alkali-aggregate reaction inhibitors.

9 . The admixture according to claim 1 , wherein the admixture is free of cement.

10 . A cement based composition, comprising cement and the admixture according to claim 1 .

11 . The cement based composition according to claim 10 , wherein the proportion of the admixture is in the range of 0.01 to 1.5% by weight, based on the weight of the cement.

12 . The cement based composition according to claim 10 , wherein the proportion of the functionalized nanomaterial is in the range of 0.00001 to 0.2% by weight, based on the weight of the cement.

13 . The cement based composition according to claim 10 , wherein the cement based composition is a concrete, a mortar or a grouting material.

14 . A method of forming a cement based composition, comprising
introducing an admixture according to claim 1 into a cement based composition as a compressive strength enhancer.

15 . A shaped body obtainable by curing a cement based composition according to claim 10 .

Assignees

• Sika Tech Ag

Inventors

• Guerrero Nayibe
• Gonzàlez Kimberly

Classifications

• C04B40/0039 Primary

  Premixtures of ingredients · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C04B28/04

  Portland cements · CPC title

• C04B14/386

  Carbon (carbon nanotubes C04B14/026) · CPC title

• C04B2111/70

  Grouts, e.g. injection mixtures for cables for prestressed concrete · CPC title