doi:10.16186/j.cnki.1673-9787.2019120053

Received:2019/12/19

Revised:2020/06/10

Published:2021/05/15

Effect of pre-curing stress on strength and micro structure of sulphoaluminategrouting materials

DI Hongfeng1, ZHANG Haibo1,2, HOU Chengyan1, ZHENG Dongdong1, CHAI Hucheng1, LIU Lang1, GUAN Xuemao1,2

1.School of Materials Science and Engineering， Henan Polytechnic University ，Jiaozuo  454000 ， Henan， China;2.Henan Key Laboratory of Materials on Deep-Earth Engineering， fiao^^o  454000 ， Henan， China

Abstract:In the demonstration project of grouting reinforcement of coal mine roadways at 1 000 m deep and above， it was found that the strength of the grouting stone is higher than that under normal pressure. In order to solve this problem， a self-made pressure device was used to simulate the in-situ stress to pre-cure grouting material slurry. By testing the strength ， apparent density ， porosity ， hydration product type and microstructure of the sample， the mechanism of stress enhancement of the material was explained. The results showed the stress of 10 MPa could significantly increase the flexural and compressive strength of the grouting material stone body. The maximum flexural strength increased by 24. 3 % and the maximum compressive by 21.6% . Stress could promote the formation of early ettringite without changing the type of hydration products and increase the density of stones. The analysis suggested stress could increase the strength of the stone body by promoting the formation rate of ettringite， reducing the porosity of the stone body and the most pore size， that was， increasing the density of the stone body， and increasing the closeness of the ettringite overlap. Grouting reinforcement is a concealed project. Detecting the density of stones could evaluate the reinforcement effect of grouting reinforcement in a certain sense.

Key words:sulphoaluminate;grouting material;stress simulation device;microstructure;strength enhancement mechanism

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