Test And Analysis Of Mechanical Properties Of Silica Fume And Metakaolin Cement-based Grouting Materials

"Carbon peak and carbon neutrality" is one of the key tasks of ecological civilization construction.In the field of grouting engineering,the development of green grouting materials will become a trend.For the research of grouting materials,chemical grouting materials have good permeability and controllable setting time,but their durability and harmfulness make this kind of grouting materials can not be widely used.In order to improve the durability of grouting materials,it is necessary to study a new type of cement-based grouting materials,which can not only improve the working performance,mechanical properties and durability of grouting materials,but also reduce the cost of grouting technology.Paper based on the cement grouting material,the use of silicon ash and metakaolin as admixture,series through the orthogonal experiment and analysis method of poor performance and mechanical performance test,determine the right dosage,silicon ash and metakaolin in silicon ash and metakaolin,on the basis of appropriate dosage on the mechanical properties of grouting material under different salt erosion test and SEM analysis.The main contents are as follows:(1)The water evolution rate,stone evolution rate and viscosity test of the grouting material were carried out.The orthogonal test and range analysis method showed that with the increase of wollastonite and metakaolin content,the stone evolution rate of the grouting material increased and the water evolution rate decreased.The viscosity of the slurry decreases with the increase of water-cement ratio and the content of polycarboxylic acid superplasticizer.(2)Through the compressive and flexural strength tests of grouting materials grout stones at different curing ages(7d,14 d,28d),the effects of water-cement ratio,silica ash,metacolinite and polycarboxylate superplasticizer dosage on compressive and flexural strength and working performance of stones were studied.The results show that when the water-cement ratio of grouting materials is 0.75,the content of silica ash is 10%,the content of metakaolin is 10%,and the content of polycarboxylic acid water reducer is 0.15%,the compressive and flexural strength of the stone body is the maximum.(3)The natural erosion method was adopted to carry out chlorine salt and sulfate erosion on the cement base grouting materials with the optimal dosage of wollastonite and metakaolin in the test,and the erosion time was 60 d,120d and 180 d,respectively.The compressive and flexural strength of the eroded grout stone body was tested.It is found that with the increase of erosion solution concentration and erosion age,the compressive and flexural strength of grouting materials show a gradual decline trend.(4)Through microstructure analysis,the changes of the internal microstructure of grouting material grout stone body before and after 5% chlorine salt erosion,sulfate erosion and chloride salt-sulfate mixed erosion were observed.It is shown that the degree of internal hydration reaction,the change of hydration products and the appearance of internal space structure affect the strength of grouting stones.Figure [38] Table [29] Reference [82]...