Cement-based cementitious material and its formation method

Patent metadata

Field	Value
Publication number	US-11492297-B2
Application number	US-201916580710-A
Country	US
Kind code	B2
Filing date	Sep 24, 2019
Priority date	Jun 3, 2019
Publication date	Nov 8, 2022
Grant date	Nov 8, 2022

Abstract

A method for forming cement-based cementitious material includes: pouring a cement paste into a mold; applying an electrical current to the cement paste to perform an electro-osmotic reaction; and transferring the reacted cement paste into a water tank for curing, thereby obtaining a functionally graded cement-based cementitious material. A pair of electrodes is placed in the mold and connected to an external power source. The compressive strength of the functionally graded cement-based cementitious material in the middle is lower than that at either of both ends.

First claim

What is claimed is:

1. A method for forming cement-based cementitious material, comprising:
pouring a cement paste into a mold, wherein a pair of electrodes is disposed in the mold, and the pair of electrodes is connected to an external power source;
applying an electrical current to the cement paste between the pair of electrodes to perform an electro-osmotic reaction, wherein the electrical current is applied for 2 to 14 hours and wherein the electrical current is between 0.01 A and 0.2 A; and
transferring the reacted cement paste into a water tank for curing, thereby obtaining a functionally graded cement-based cementitious material,
wherein a compressive strength in a middle of the functionally graded cement-based cementitious material is lower than that at both ends, and
wherein the functionally graded cement-based cementitious material has a ratio of calcium hydroxide (Ca(OH) 2 ) to silica (SiO 2 ) at both ends being higher than that in the middle.

2. The method as claimed in claim 1 , wherein a water-to-cement ratio of the cement paste is between 0.6 and 0.8.

3. The method as claimed in claim 1 , wherein the cement paste further comprises an aggregate.

4. The method as claimed in claim 3 , wherein a size of the aggregate is between 150 μm and 75 mm.

5. The method as claimed in claim 1 , wherein the application of the electrical current to the cement paste is performed immediately after pouring the cement paste into the mold.

6. The method as claimed in claim 1 , wherein the application of the electrical current to the cement paste is performed after pouring the cement paste into the mold and resting for 1 minute or more.

7. The method as claimed in claim 1 , wherein the pair of the electrodes is metal or metal alloy.

8. The method as claimed in claim 7 , wherein the metal or metal alloy comprises titanium (Ti), or platinum (Pt).

9. The method as claimed in claim 1 , wherein the curing is performed for 3 to 28 days.

10. The method as claimed in claim 1 , wherein a length of the mold is between 250 and 550 mm.

11. The method as claimed in claim 1 , wherein the cement paste further comprises a pozzolanic material.

12. The method as claimed in claim 1 , wherein the pair of the electrodes is non-metal.

13. The method as claimed in claim 1 , wherein the functionally graded cement-based cementitious material has the compressive strength in its entirety is higher than 210 kgf/cm 2 .

14. The method as claimed in claim 1 , wherein the functionally graded cement-based cementitious material has a length between 200 and 500 mm.

15. The method as claimed in claim 1 , wherein the functionally graded cement-based cementitious material has a ratio of calcium hydroxide (Ca(OH) 2 ) to tricalcium silicate (3CaO.SiO 2 ) and dicalcium silicate (2CaO.SiO 2 ) at either of both ends being higher than that in the middle.

16. The method as claimed in claim 1 , wherein the functionally graded cement-based cementitious material has an amorphous ratio at either of both ends being higher than that in the middle.

17. The method as claimed in claim 1 , wherein the cement paste comprises a Portland cement.

18. The method as claimed in claim 1 , wherein the electrical current is a direct electrical current.

Assignees

• Univ Nat Taiwan Science & Technology

Inventors

• Chen Chun-Tao
• Wang yue-sheng

Classifications

• B28B11/242

  by passing an electric current through wires, rods or reinforcing members incorporated in the article · CPC title

• B28B11/246

  Underwater curing · CPC title

• C04B14/14

  Minerals of vulcanic origin {(granite C04B14/048)} · CPC title

• C04B40/0286

  Hardening under water · CPC title

• C04B2201/50

  for the mechanical strength · CPC title