Alunite concrete expanding agent

Abstract

The invention discloses an alunite concrete expanding agent, and belongs to the technical field of concrete admixtures. The invention aims to provide the alunite concrete expanding agent capable of fully utilizing local resources and meeting the standard requirements of conventional Chinese expanding agents. The alunite concrete expanding agent comprises the following components in percentage by weight: 8 to 15 percent of ammonium alum, 10 to 15 percent of natural alunite, and 75 to 79 percent of natural anhydrous gypsum or gypsum dihydrate; and the alunite concrete expanding agent is prepared by pulverizing the natural alunite and the natural gypsum uniformly and mixing the powder and ammonium alum powder uniformly. The alkali content of the alunite concrete expanding agent is reduced, the limited expanding rate is produced in advance, the expanding performance is enhanced, the compressive strength is improved, the physical and chemical properties of the alunite concrete expanding agent reach and exceed the standard requirements of the conventional expanding agents, and the alunite concrete expanding agent has high economic benefit and social benefit.

Description

technical field [0001] The invention relates to an alum stone concrete expansion agent mixed with an activator in a calcium sulfoaluminate concrete expansion agent, specifically an alum stone concrete expansion agent improved on the basis of an old formula, belonging to the technical field of concrete admixtures . Background technique [0002] As we all know, ordinary concrete often leaks due to shrinkage and cracking, which reduces its use function and durability. Add calcium sulfoaluminate concrete expansion agent that does not contain sodium salt and is not easy to cause concrete alkali-aggregate reaction into the cement, mix it into shrinkage-compensating concrete, make the concrete structure self-waterproof, extend the distance between the post-casting joints, and prevent large volume The emergence of concrete and high-strength concrete temperature difference cracks greatly improves the crack resistance and waterproof ability of concrete structures. [0003] In the 19...

AI Technical Summary

Problems solved by technology

Chinese patent ZL98126823.4 discloses the low-alkali and low-volume concrete expansion agent, and its alkali content is less than 0.6%, but the raw material that it uses is the more expensive aluminum powder and calcium oxide or calcium carbide and alum mud, does not utilize and does not need Calcined Natural Alunite Resources

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