Concrete composition and making method

Patent metadata

Field	Value
Publication number	US-10035728-B2
Application number	US-201715799531-A
Country	US
Kind code	B2
Filing date	Oct 31, 2017
Priority date	Nov 1, 2016
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

A concrete composition is obtained by dry mixing cement and an aggregate, adding thereto a water dispersion which is preformed by dispersing a low substituted hydroxypropyl cellulose having a hydroxypropoxy substitution of 5-16 wt % in the form of fibrous particles having an aspect ratio of 4-7 in water, and mixing the ingredients. Because of reduced drying shrinkage, only a little drop of fluidity, and proper flow, the concrete composition is useful to form concrete buildings having frost damage resistance.

First claim

The invention claimed is:

1. A concrete composition comprising, in admixture, a water dispersion of a low substituted hydroxypropyl cellulose having a hydroxypropoxy substitution of 5 to 16% by weight in the form of fibrous particles having an aspect ratio of 4 to 7, cement, and an aggregate.

2. The composition of claim 1 wherein the low substituted hydroxypropyl cellulose has an average particle size of 40 to 100 μm and a 90% cumulative particle size of 130 to 250 μm as measured by laser diffractometry.

3. The composition of claim 1 wherein the water dispersion contains the low substituted hydroxypropyl cellulose in a concentration of 0.01 to 20% by weight.

4. The composition of claim 1 wherein the low substituted hydroxypropyl cellulose is added in an amount of 0.01 to 10% by weight based on the unit cement content.

5. The composition of claim 1 , further comprising at least one water-reducing agent selected from lignin, polycarboxylate, and melamine-based water-reducing agents.

6. The composition of claim 1 , further comprising a surfactant containing at least a higher alcohol and a fatty acid ester.

7. The composition of claim 1 , further comprising an air-entraining agent.

8. A method for preparing a concrete composition, comprising the steps of dry mixing cement and an aggregate, adding a water dispersion to the dry mix, the water dispersion being preformed by dispersing a low substituted hydroxypropyl cellulose having a hydroxypropoxy substitution of 5 to 16% by weight in the form of fibrous particles having an aspect ratio of 4 to 7 in water, and mixing the contents.

9. The method of claim 8 , further comprising the step of adding at least one water-reducing agent selected from lignin, polycarboxylate, and melamine-based water-reducing agents to the dry mix together with the water dispersion of the low substituted hydroxypropyl cellulose.

10. The method of claim 8 , further comprising the step of adding a surfactant containing at least a higher alcohol and a fatty acid ester to the cement and the aggregate.

11. The method of claim 8 , further comprising the step of adding an air-entraining agent to the dry mix together with the water dispersion of the low substituted hydroxypropyl cellulose.

Assignees

• Shinetsu Chemical Co

Inventors

• Konishi Hidekazu
• Yamakawa Tsutomu

Classifications

• C04B14/04

  Silica-rich materials; Silicates · CPC title

• C04B40/0028

  Aspects relating to the mixing step of the mortar preparation · CPC title

• C04B18/24 Primary

  Vegetable refuse, e.g. rice husks, maize-ear refuse; Cellulosic materials, e.g. paper {, cork} · CPC title

• C04B14/06

  Quartz; Sand · CPC title

• C04B2103/304

  Air-entrainers · CPC title