Mix Design And Performance Study Of Portland Cement-Sulphoaluminate Cement Composite Grouting Material

Cement-based grouting materials have been widely used in construction,road and water conservancy projects,but due to their early strength,uncontrollable coagulation time and poor volume stability,they affect their practical application.In view of the above problems,this paper uses fast hard sulphoaluminate cement combined with ordinary Portland cement,and obtains flow by screening suitable high-efficiency water reducing agent,expansion agent,and mixing mineral slag and other mineral admixtures.A new cement-based grouting material with large properties,controllable coagulation time,high early strength and good volume stability.The specific research results are as follows:1.Incorporating 30% sulphoaluminate cement into ordinary Portland cement shortens the setting time of the slurry,improves the strength of the grouting material,and reduces the fluidity of the cement slurry.When the amount exceeds 30%,the strength of the material is remarkably lowered.2.The water-cement ratio of the composite cement slurry is between 0.35 and 0.5,the fluidity of the grouting material increases with the increase of the water-cement ratio,and the strength decreases accordingly.When the water-cement ratio is 0.35,the strength meets the cement-based grouting.Standard of Materials(JC/T986-2005).3.In this paper,three kinds of water reducing agents were selected.By comparing the fluidity,strength and setting time,the compatibility of the slurry with HSC polycarboxylic acid type water reducing agent was the best,the naphthalene was the second,and the aliphatic was the worst.The optimum amount of HSC type polycarboxylic acid water reducing agent is 0.5%.4.The incorporation of 0.5% UEA type expansion agent can increase the vertical expansion rate and strength of the grouting material,but reduce the fluidity of the slurry.5.Select fly ash and slag powder to control the performance of composite cement.It is concluded that the two mineral admixtures have a strength of the grouting material and improve the fluidity of the grout when the blending amount is 10%.It is compounded with 10% fly ash and 20% slag powder,which further improves the fluidity and strength of the slurry than the single-mixed form.At the same time,reduce production costs and achieve better economic benefits.6.Based on the above admixture and admixture type,the optimum dosage is determined,that is,30% sulphoaluminate cement,water reducing agent and expansion agent content 0.5%,20% slag and 10% powder are added.The coal ash and water-cement ratio is 0.35.The new cement-based grouting material prepared is better than the ordinary Portland cement grouting material,which improves the fluidity and strength of the grouting material,and the setting time is controllable,the easy filling property is good,and the slurry is not.Segregation,bleeding,etc.,fully meet the "cement-based grouting material"(JC/T986-2005)standards.The results of this type of composite cement-based grouting material studied in this paper provide a certain reference value for the preparation and application of cement-based grouting materials in the future.