Additive for cementitious materials

Patent metadata

Field	Value
Publication number	US-2016257614-A1
Application number	US-201414915664-A
Country	US
Kind code	A1
Filing date	Aug 28, 2014
Priority date	Sep 6, 2013
Publication date	Sep 8, 2016
Grant date	—

Abstract

The invention relates to use of nano-fibrillar cellulose as an gas-entrainment stabilizer, which when used in cementitious materials, provides improved gas pore structure quality and/or stability and/or robustness with regard to water content variation. The invention further relates to a method for stabilizing gasentrainment of cementitious materials and to a method for providing cementitious material with improved air pore structure quality and/or stability and/or robustness with regard to water content variation.

First claim

1 . Use of nanofibrillar cellulose (NFC) as a gas-entrainment stabilizer.

2 . The use as claimed claim 1 , wherein NFC is used in a cementitious composition, paste, or material.

3 . The use as claimed in claim 1 , wherein the diameter of the NFC or NFC bundles is less than 1 μm, preferably less than 200 nm, more preferably less than 100 nm.

4 . The use as claimed in claim 1 , wherein the used amount of dry NFC is 0.01% or more by weight based on dry weight of binder in the cementitious composition, preferably from 0.01% to 0.3%, more preferably from 0.02% to 0.2% , most preferably from 0.05% to 0.11%.

5 . The use as claimed in claim 1 , wherein the NFC is native NFC.

6 . The use as claimed in claim 1 , wherein the NFC is chemically and physically modified NFC, preferably anionically charged NFC, more preferably particular oxidized NFC or carboxymethylated NFC, most preferably mechanically disintegrated TEMPO oxidized NFC.

7 . The use as claimed in claim 1 , wherein NFC is used together with at least one gas-entraining agent or admixture.

8 . The use of NFC as claimed in claim 1 for providing gas-entrained cementitious material with improved gas pore structure quality and/or stability and/or robustness with regard to water content variation.

9 . The use as claimed in claim 8 , wherein the gas-entrained cementitious material is air-entrained cementitious material, such as concrete, in particular foamed concrete or self-compacting concrete (SCC).

10 . The use as claimed in claim 8 , wherein the gas-entrained cementitious material is hydrogen-entrained cementitious material, such as autoclaved aerated concrete (ACC).

11 . A method for stabilizing gas-entrainment of cementitious materials, comprising the steps of:
providing nanofibrillar cellulose (NFC); mixing said NFC and with a cementitious composition and water to obtain a cementitious paste; and allowing the thus obtained cementitious paste to harden to obtain gas-entrained cementitious material.

12 . A method for the preparation of gas-entrained concrete, comprising the steps of:
providing nanofibrillar cellulose (NFC); providing at least one gas-entraining agent mixing said NFC and the at least one gas-entraining agent with a cementitious composition, comprising at least binder, and water to obtain a cementitious paste; and allowing the thus obtained cementitious paste to harden to obtain gas-entrained cementitious material.

13 . The method as claimed in claim 11 , wherein the amount of NFC is 0.01% or more by based on dry weight of binder in the cementitious composition, preferably from 0.01% to 0.3%, more preferably from 0.02% to 0.2%, most preferably from 0.05% to 0.11%.

14 . The method as claimed in claim 11 , wherein the water/cement ratio of the cementitious paste is from 0.25 to 1.50, preferably from 0.35 to 0.8, more preferably from 0.40 to 0.65.

15 . The method as claimed in claim 11 , wherein the hardened gas-entrained cementitious normal weight material and cement paste fraction included in it, or normal weight cement paste fraction included in any lightweight material have air pore spacing factor less than 0.4 mm, preferably from 0.2 to 0.35 mm, more preferably from 0.22 to 0.3 mm.

16 . The method as claimed in claim 11 , wherein the gas pores in the hardened normal weight material and cement paste fraction included in it, or normal weight cement paste fraction included in any lightweight material, have air pore specific surface greater than 20 mm 2 /mm 3 , preferably greater than 25 mm 2 /mm 3 .

17 . A hardened gas-entrained cementitious material comprising nanofibrillar cellulose (NFC).

18 . The hardened gas-entrained cementitious material as claimed in claim 17 , which is foamed concrete, self-compacting concrete (SCC) or autoclaved aerated concrete (ACC), in particular foamed concrete or SCC.

19 . The hardened gas-entrained cementitious material as claimed in claim 17 , wherein the amount of dry NFC is 0.01% or more by weight based on the dry weight of binder in cementitious composition, preferably from 0.01% to 0.3%, more preferably from 0.02% to 0.2%, most preferably from 0.05% to 0.11%.

20 . The hardened gas-entrained cementitious material as claimed in claim 17 , having spacing factor less than 0.4 mm, preferably less than 0.30, more preferably less than 0.20.

21 . The hardened gas-entrained cementitious material as claimed in claim 17 , having specific surface greater than 20 mm 2 /mm 3 , preferably greater than 25 mm 2 /mm 3 .

22 . The hardened gas-entrained cementitious material as claimed in claim 17 , obtained by the process defined in claim 12 .

Assignees

• Upm Kymmene Corp

Inventors

• Kuosa Hannele
• Suurnakki Anna
• Laukkanen Antti
• Teirfolk Jan-Erik
• Leivo Markku

Classifications

• C04B38/02

  by adding chemical blowing agents · CPC title

• C04B28/02 Primary

  containing hydraulic cements other than calcium sulfates · CPC title

• C04B20/006

  Microfibres; Nanofibres · CPC title

• C04B2111/00103

  Self-compacting mixtures · CPC title

• C04B2103/48

  Foam stabilisers · CPC title