Composite cement expanding agent and preparation method thereof

A technology of compound cement and expansion agent, applied in the field of compound cement expansion agent, can solve the problems of long process and harmful expansion, and achieve the effects of improving expansion performance, increasing effective expansion, and improving the limited expansion rate and plastic expansion rate.

Inactive Publication Date: 2015-03-25
CHINA UNIV OF GEOSCIENCES (WUHAN)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Metal aluminum powder and iron oxide can also cause volume expansion of cement, but the expansion mainly occurs in the plastic stage of concrete; alkali-aggregate reaction can also cause volume expansion of concrete, but the expansion is harmful and the process is very long

Method used

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  • Composite cement expanding agent and preparation method thereof
  • Composite cement expanding agent and preparation method thereof
  • Composite cement expanding agent and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Weigh 8g of aluminum-containing clinker, 32g of metakaolin clinker, 35.2g of anhydrite, 80g of quicklime, 3.2g of quartz powder, and 1.6g of polyethylene glycol, mix them evenly in a mixer, and then grind until the specific surface area is 250m 2 / kg, made into composite cement expansion agent.

[0029] The aluminum-containing clinker is prepared from high-alumina bauxite (with an aluminum content of 86wt%) by high-temperature calcination at 1350°C; the metakaolin clinker is prepared from 200-mesh kaolin by high-temperature calcination at 700°C.

[0030] According to the national standard, the composite cement expansion agent is added to 2000g of cement at a dosage of 8%, and the limited expansion rate of 21 days in the air is 0.024%; the plastic expansion rate is 0.15%. At the same time, the flexural strength of 7d is 8.8MPa, the flexural strength of 28d is 10.7MPa, the compressive strength of 7d is 54.7MPa, and the compressive strength of 28d is 64.1Mpa, all of which ...

Embodiment 2

[0033] Weigh 64g of aluminum-containing clinker, 8g of metakaolin clinker, 55.84g of anhydrite, 8g of quicklime, 24g of quartz powder, and 0.16g of naphtha, mix them evenly in a mixer, and then grind until the specific surface area is 270m 2 / kg, made of composite cement expansion agent.

[0034] Among them, the aluminum-containing clinker is prepared from high-alumina bauxite (with an aluminum content of 88wt%) by high-temperature calcination at 1400°C; the metakaolin clinker is prepared from 200-mesh kaolin by high-temperature calcination at 850°C.

[0035] According to the national standard, the composite cement expansion agent is added to 2000g of cement at a dosage of 8%. The limiting expansion rate of 21 days of curing in air is 0.012%, and the plastic expansion rate is 0.02%. At the same time, the flexural strength of 7d is 9.3MPa, the flexural strength of 28d is 11.3MPa, the compressive strength of 7d is 57.9MPa, and the compressive strength of 28d is 83.5Mpa, all of ...

Embodiment 3

[0037] Weigh 37g of aluminum-containing clinker, 8g of metakaolin clinker, 80g of anhydrite, 30g of quicklime, 4g of quartz powder, and 1g of sodium lauryl sulfate, mix them evenly in a mixer, and then grind until the specific surface area is 260m 2 / kg, made into composite cement expansion agent.

[0038] The aluminum-containing clinker is prepared from high-alumina bauxite (86wt% aluminum content) by high-temperature calcination at 1400°C; the metakaolin clinker is prepared from 200-mesh kaolin by 800°C high-temperature calcination.

[0039] According to the national standard, the composite cement expansion agent is added to 2000g of cement at a dosage of 8%. Cured in air for 21 days, the limit expansion rate is 0.029%, and the plastic expansion rate is 0.15%. At the same time, the flexural strength of 7d is 10.1MPa, the flexural strength of 28d is 13.2MPa, the compressive strength of 7d is 59.3MPa, and the compressive strength of 28d is 92.1Mpa, all of which meet the requi...

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Abstract

The invention relates to a composite cement expanding agent and a preparation method thereof. The composite cement expanding agent comprises 5-50mass% of quicklime, 20-50mass% of anhydrite, 5-40mass% of an aluminum-containing clinker, 5-20mass% of a metakaolin clinker, 2-15mass% of quartz powder and 0.1-1mass% of an organic additive. The expanding agent utilizes different aluminate mineral clinkers to adjust the expansion rate and increase the effective expansion; and the expanding agent also utilizes the organic additive to improve the expanding performance in a cement plasticity phase and well compensate the contraction in the cement hydration plasticity phase and the contraction after the later-stage hardening of cement. The alkali content of the expanding agent is lower than 0.5%, so the alkali aggregate reaction can be effectively avoided; and when the doping amount is 8%, results of detection according to JC476-2001 standard of the expanding agent show that the restrained expansion rate under the maintenance in air for 21d is greater than the standard, and especially the plastic phase expansion rate is 0.02-0.15%.

Description

technical field [0001] The invention relates to a composite cement expansion agent, which is used in bridge prestressed pipeline grouting, large-area concrete, and water conservancy facilities and other engineering fields, and can effectively solve the shrinkage and cracking problems of cement or concrete in the plastic stage and after setting and hardening . Background technique [0002] Expansion agent is an admixture with huge market capacity and development prospects. Ordinary cement or concrete often leads to cracking and deterioration due to drying shrinkage and dry cooling. People hope to have such a material that makes cement or concrete expand in a certain amount during the plastic stage and setting and hardening, so as to resist various disadvantages caused by its shrinkage. [0003] In 1936, Losey of France was the first scholar to realize that ettringite could eliminate cement shrinkage and generate prestress, and he invented expansive cement. The expansion ag...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B24/32C04B24/16C04B24/12C04B24/00
Inventor 靳洪允侯书恩黄丹汤小文
Owner CHINA UNIV OF GEOSCIENCES (WUHAN)
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