Limestone powder mineral admixture special for concrete and preparation method thereof

Abstract

The invention relates to an admixture for concrete and a preparation method thereof. A limestone powder mineral admixture special for the concrete is characterized in that the admixture is prepared by mixing and grinding limestone powder, citric acid, oxalic acid and quartz powder; the admixture comprises the following raw materials in portion by weight: 10,000 portions of the limestone powder, 3to 10 portions of the citric acid, 40 to 60 portions of the oxalic acid and 400 to 600 portions of the quartz powder; and the content of calcium carbonate in the limestone powder is not lower than 85 percent, and the specific surface area is between 500 and 700 m<2> / kg. The admixture has better early strength function, has small influence on later strength, has good retarding effect, greatly improves the performance of the concrete, and can obtain better economic benefit.

Description

technical field [0001] The invention relates to a concrete admixture and a preparation method thereof. Background technique [0002] At present, my country is in a period of rapid development of infrastructure construction, and the amount of concrete is increasing rapidly. A large amount of limestone is mined every year as concrete coarse aggregate. According to relevant national standards, the particle size of concrete coarse aggregate is required to be above 4.75mm, which will inevitably produce a large amount of 4.75mm Long-term stacking of the following stone chips and stone powder will occupy a large amount of land, which is not conducive to the protection of the ecological environment. The current processing method is mainly to use it as artificial sand for concrete, or as a mixture of cement after grinding. Using these methods to process limestone powder, not only the economic benefits are not obvious, but also the performance of cement and concrete is not greatly impr...

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Problems solved by technology

[0002] At present, my country is in a period of rapid development of infrastructure construction, and the amount of concrete is increasing rapidly. A large amount of limestone is mined every year as concrete coarse aggregate. According to relevant national standards, the particle size of concrete coarse aggregate is required to be above 4.75mm, which will inevitably produce a large amount of 4.75mm The following stone chips and stone powder will occupy a large amount of land if they are piled up for a long time, which is not conducive to the protection of the ecological environment.

The current processing method is mainly to use it as artificial sand for concrete, or as a mixture of cement after grinding. Using these methods to process limestone powder, not only the economic benefits are not obvious, but also the performance of cement and concrete is not greatly improved.

[0003] Using limestone chips as artificial sand to replace part of the river sand has a great impact on the working performance of concrete. Due to the irregular shape and poor sphericity of the stone chips, the fluidity of concrete will be reduced.

Grinding stone chips and mixing them into cement as a mixture can improve the water retention performance of cement and increase the early strength of cement, but the amount is only about 5% of cement, and the amount is very limited. It is difficult to consume a large amount of limestone mines. stone chips

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