Compound high-performance expanding agent for cement-based material

A technology of cement-based material and expansion agent, applied in the field of cement-based material admixture, can solve the problems of high alkali content of expansion agent, rapid loss of concrete slump, incomplete cement slurry, etc., and achieve excellent expansion performance and excellent flow performance. , the effect of saving engineering costs

Active Publication Date: 2012-05-23
中冶武汉冶金建筑研究院有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, studies have shown that the hydrogen molecules introduced by the aluminum powder expansion agent will cause "hydrogen embrittlement" in the steel bar, resulting in the formation of tiny cracks inside the steel bar, which will endanger the durability of the concrete structure. It has been banned from being used in the concrete structure.
Other commonly used calcium sulfoaluminate expansion agents, calcium oxide expansion agents, calcium sulfoaluminate-calcium oxide expansion agents, etc., are generally produced within 24h-14 days when they are added to cement or concrete. A certain amount of expansion can not avoid the plastic settlement shrinkage of concrete (or cement paste) in the plastic stage (within 4h), which cannot meet the requirements of prestressed tunnel grouting
At present, in the grouting construction of pr

Method used

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  • Compound high-performance expanding agent for cement-based material
  • Compound high-performance expanding agent for cement-based material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Taking 100KG composite high-performance expansion agent as an example, its formula is:

[0031] Weigh 35KG of lipid film lime powder, 45KG of anhydrite powder, and 19.3KG of limestone powder, mix and grind until the specific surface area reaches 300m 2 / kg~600m 2 / kg, then add 0.4KG of azodicarbonamide and 0.3KG of sodium tripolyphosphate, and mix for 15 minutes. Made into cement concrete composite high-performance expansion agent. The experimental materials used Huaxin 42.5 grade ordinary Portland cement and polycarboxylate high-efficiency water reducer. The experimental ratio was: cement 2760g, expansion agent 240g, water reducer 6g, water-cement ratio 0.27, tested according to national standards, and tested performance indicators as follows:

[0032] Table 1 The detection data of the present invention compares with the technical performance of the construction specification

[0033]

[0034] Table 2 The detection data of the present invention is compared with ...

Embodiment 2

[0038] Taking 100KG composite high-performance expansion agent as an example, its formula is:

[0039] Weigh 30KG of lipid film lime, 50KG of anhydrite, and 19.4KG of limestone powder, mix and grind until the specific surface area reaches 300m 2 / kg~600m 2 / kg; add 0.4KG of a mixture of azodicarbonamide and azobisisobutyronitrile in a weight ratio of 1:1, and 0.2KG of sodium hexametaphosphate. Mix for 15 min. Made into cement concrete composite high-performance expansion agent. According to the national standard test, when the dosage accounts for 9% of the total mass of cement-based materials, the limit expansion rate of 7 days in water curing is 0.061%, the limit expansion rate of 21 days in air curing is 0.022%, and the compressive strength of 7 days is 36.2MPa. The 28-day compressive strength is 59.7MPa, the 7-day flexural strength is 6.3MPa, and the 28-day flexural strength is 10.1MPa, which meets the requirements of the "Concrete Expansive Agent" GB23439-2009 standard;...

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Abstract

The invention discloses a compound high-performance expanding agent for a cement-based material and belongs to the technical field of cement-based material additives. A plurality of materials such as panniculus adiposus lime, natural anhydrite, limestone, an azo compound and the like are selected as expanding components. The compound high-performance expanding agent provided by the invention is prepared by the following steps of: grinding panniculus adiposus lime, natural anhydrite and limestone according to a certain proportion to a certain fineness by a grinding machine, adding the azo compound and a dispersant in a certain proportion, and uniformly mixing. The expanding agent can be used to produce appropriate expansion of the cement-based material during plasticity and hardening phases, greatly raise dispersibility and fluidity of the prepared pulp and enhance rupture and compressive strength of the material. In addition, low alkali and microamount chlorine can raise endurance of the cement concrete construction.

Description

technical field [0001] The invention belongs to the technical field of admixtures for cement-based materials, and in particular relates to a high-performance composite expansion agent for cement-based materials. Background technique [0002] During the pouring and hardening process of cement-based materials, volume shrinkage will occur due to chemical shrinkage, cold shrinkage and dry shrinkage, and even lead to cracking of the material in severe cases. Concrete expansion agent is an admixture that can make cement-based materials produce a certain volume expansion after hydration reaction after mixing with cement and water, and is used to compensate for the shrinkage of cement concrete. For some special projects, especially for some special parts such as post-tensioned prestressed channel grouting, expansion agents must be used in the grouting materials to ensure that the material fills the gap between the embedded channels and prestressed tendons to protect the steel bars f...

Claims

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Application Information

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IPC IPC(8): C04B24/12
Inventor 曾明周紫晨张建武陈晶张冰李君
Owner 中冶武汉冶金建筑研究院有限公司
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