A kind of preparation method and application of nano crystal seed for auxiliary gelling material system

Abstract

This application relates to the field of concrete admixtures, and specifically discloses a preparation method and application of nano-seeds for auxiliary cementitious material systems, including the following steps: in parts by weight, dispersing agent 30-40 parts, alcohol ether 90-100 parts, 10-15 parts of alcohol amine, 10-30 parts of inorganic thickener and 560-580 parts of water, the temperature is controlled at 30-35 °C, and 160-170 parts of 35-40wt% calcium source solution is added dropwise and 120-130 parts of 25-30 wt% silicon source solution, the addition time is controlled at 9-12h, after the dropwise addition is completed, it is rapidly cooled to below 5°C and aged for 1.5-2h to obtain nanocrystal seeds. The prepared nano-crystal seed product has high effective solid content, good product stability and long storage time, and can be applied to concrete with high admixture content to improve the utilization rate of solid waste resources and improve the performance of concrete.

Description

technical field [0001] The application relates to the field of concrete admixtures, more specifically, it relates to a preparation method and application of nano crystal seeds used in auxiliary cementitious material systems. Background technique [0002] With the urgent need for green buildings and the gradual improvement of environmental protection awareness, green and environmentally friendly solid waste resources are gradually developed and applied as concrete admixtures. [0003] In practical engineering applications, it has been found that after adding admixtures to concrete, the cement sets for a long time, the early strength of concrete develops slowly, and the strength in one day cannot meet the requirements of formwork removal. After adding admixtures to concrete, the alkalinity decreases and carbonation deepens. Reinforcement protection is not used; at the same time, the water retention of concrete decreases, and moisture easily forms penetrating channels inside th...

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Problems solved by technology

[0003] In practical engineering applications, it is found that after adding admixtures to concrete, the cement sets for a long time, the early strength of concrete develops slowly, and the strength in one day cannot meet the requirements of formwork removal. After adding admixtures to concrete, the alkalinity decreases and carbonation deepens. Reinforcement is not used for protection; at the same time, the water retention of concrete decreases, and moisture easily forms a penetrating channel inside the concrete, reducing the compactness of the concrete

If the content of the admixture is more than 30%, the surface dissolution rate of the admixture is low, and the gel formation is slow, resulting in large early shrinkage of the concrete. Although a better 90d strength can be obtained, the 28d strength is often low, so most In engineering applications, the replacement rate of admixtures is often controlled below 30% (except for hydraulic concrete that does not require early strength), and the utilization rate of solid waste resources is low

[0004] At present, some nano-crystal seeds have been developed on the market and applied to concrete with an admixture content of about 30%, but the inventors have found that the effective solid content of the commercially-available seed crystals is low (5-10%), and Nano-crystal seeds are very easy to agglomerate. After agglomeration, the size of the seed crystals increases, and problems such as sedimentation occur. The product has low stability and short storage time.

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