Additive for cementitious materials

Patent metadata

Field	Value
Publication number	US-9809496-B2
Application number	US-201414915664-A
Country	US
Kind code	B2
Filing date	Aug 28, 2014
Priority date	Sep 6, 2013
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

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

The invention claimed is:

1. A method for stabilizing gas-entrainment of cementitious materials, 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;
wherein the gas-entrained cementitious material has an air pore spacing factor less than 0.4 mm.

2. The method as claimed in claim 1 , wherein the amount of NFC is 0.01% or more by based on dry weight of binder in the cementitious composition.

3. The method as claimed in claim 1 , wherein the water/cement ratio of the cementitious paste is from 0.25 to 1.50.

4. The method as claimed in claim 1 , wherein the NFC has a fiber or fiber bundle diameter less than 1 micrometer.

5. The method as claimed in claim 1 , wherein the NFC has a number average diameter of 2 to 200 nanometers.

6. The method as claimed in claim 1 , wherein the NFC is native NFC.

7. The method as claimed in claim 1 , wherein the NFC is chemically and physically modified NFC.

8. The method as claimed in claim 1 , wherein the gas-entraining agent is an air-entraining agent.

9. The method as claimed in claim 1 , wherein the gas-entraining agent is a hydrogen-producing agent.

10. The method as claimed in claim 1 , wherein the amount of NFC is from 0.01% to 0.3% based on dry weight of binder in the cementitious composition.

11. The method as claim in claim 1 , wherein the gas-entrained cementitious material comprises a normal weight cementitious composition and a lightweight cementitious paste fraction, wherein the normal weight cementitious composition fraction included in the lightweight cementitious paste fraction has a gas pore spacing factor from 0.2 to 0.35 mm.

12. A method for stabilizing gas-entrainment of cementitious materials, 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, the gas-entrained cementitious material having gas pores;
wherein the gas pores have an air pore specific surface greater than 20 mm 2 /mm 3 .

13. The method as claimed in claim 12 , wherein the amount of NFC is 0.01% or more by based on dry weight of binder in the cementitious composition.

14. The method as claimed in claim 12 , wherein the water/cement ratio of the cementitious paste is from 0.25 to 1.50.

15. The method as claimed in claim 12 , wherein the NFC has a fiber or fiber bundle diameter of less than 1 micrometer.

16. The method as claimed in claim 12 , wherein the NFC has a number average diameter of 2 to 200 nanometers.

17. The method as claimed in claim 12 , wherein the NFC is native NFC.

18. The method as claimed in claim 12 , wherein the NFC is chemically and physically modified NFC.

19. The method as claimed in claim 12 , wherein the gas-entraining agent is an air-entraining agent.

20. The method as claimed in claim 12 , wherein the gas-entraining agent is a hydrogen-producing agent.

21. The method as claimed in claim 12 , wherein the amount of NFC is from 0.01% to 0.3% based on the dry weight of binder in the cementitious composition.

22. The method as claim in claim 12 , wherein the gas-entrained cementitious material comprises a normal weight cementitious composition and a lightweight cementitious paste fraction, wherein the normal weight cementitious composition fraction included in the lightweight cementitious paste fraction has a gas pore spacing factor from 0.2 to 0.35 mm.

23. A hardened gas-entrained cementitious material comprising nanofibrillar cellulose (NFC), having a void spacing factor less than 0.4 mm, wherein void spacing factor is a maximum distance from any point in a capillary system to a surface of a nearest air bubble.

24. The hardened gas-entrained cementitious material as claimed in claim 23 , which is foamed concrete, self-compacting concrete (SCC) or autoclaved aerated concrete (ACC).

25. The hardened gas-entrained cementitious material as claimed in claim 23 , obtained by a method 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.

26. The hardened gas-entrained cementitious material as claimed in claim 23 , wherein the gas-entrained cementitious material is air-entrained cementitious material.

27. The hardened gas-entrained cementitious material as claimed in claim 23 , wherein the gas-entrained cementitious material is hydrogen-entrained cementitious material.

28. A hardened gas-entrained cementitious material comprising nanofibrillar cellulose (NFC), having specific surface greater than 20 mm 2 /mm 3 .

29. The hardened gas-entrained cementitious material as claimed in claim 28 , which is foamed concrete, self-compacting concrete (SCC) or autoclaved aerated concrete (ACC).

30. The hardened gas-entrained cementitious material as claimed in claim 28 , obtained by a method 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.

31. The hardened gas-entrained cementitious material as claimed in claim 28 , wherein the gas-entrained cementitious material is air-entrained cementitious material.

32. The hardened gas-entrained cementitious material as claimed in claim 28 , wherein the gas-entrained cementitious material is hydrogen-entrained cementitious material.

Assignees

• Upm Kymmene Corp

Inventors

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

Classifications

• C04B2103/48

  Foam stabilisers · CPC title

• C04B20/006

  Microfibres; Nanofibres · CPC title

• C04B2111/00103

  Self-compacting mixtures · CPC title

• C04B28/02 Primary

  containing hydraulic cements other than calcium sulfates · CPC title

• C04B38/10

  by using foaming agents (C04B38/02 takes precedence){or by using mechanical means, e.g. adding preformed foam} · CPC title