Experimental Study on ReboundRatio of Wet Shotcrete with Elastomer Lowering Agent
In response to the challenge of high rebound rates in tunnel shotcrete applications,a micro-nano powder additive has been selected to enhance the performance of shotcrete.The fluidity,flexural and compressive strength of mortar samples containing 3%,6%,9%,12%and 15%of the additive by mass were tested.Additionally,an investigation into the rebound rate of C25 wet-mixed shotcrete was conducted,comparing formulations with single additions of fly ash and composite mixtures incorporating both fly ash and the additive at various proportions.The results showed that the fluidity of mortars decreases with the increase of the dosage of additive,the flexural and compressive strengths in 1 day and 3 days decrease gradually,and the flexural and compressive strengths of mortars in 28 days increase first and then decrease.The flexural and compressive strengths of mortar specimens in 28 days is the highest when adding 6%micro-nano additive,and the flexural and compressive strength ratio in 28 days are 1.049 and 1.014.The rebound rate of wet sprayed concrete mixed with fly ash and additive is significantly lower than that of wet sprayed concrete with fly ash,the total amount of cementitious material is 430 kg/m3,and the comprehensive rebound rate is the lowest when mixed with 14%fly ash and 6%additive,which is 8.09%.Adding 6%additive can promote the increase of compressive strength of shotcrete and reduce the amount of cementitious material.The research results can provide reference and inspiration for similar engineering projects.
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维普
