Experimental research on mechanical and impact properties of lightweight aggregate fiber shotcrete

Abstract

Shotcrete is formed by the construction method of spraying and pouring fine stone concrete under a pressure spray gun. With the development of urban green and low-carbon construction, Lightweight Aggregate Fiber Shotcrete (LAFS) has been widely used in roadway mining and railway tunnels. In order to explore the effects of ceramsite, pottery sand, polypropylene fiber and basalt fiber on the static and dynamic mechanical properties of LAFS, the compressive strength, splitting tensile strength, flexural strength, thermal conductivity, water seepage height test under four dosage levels of LAFS were carried out. The grey relational analysis method was used to determine the proportioning range that satisfied the good static performance of LAFS. The macro-mechanisms and micro-mechanisms of the impact resistance of LAFS were revealed through the split Hopkinson pressure bar test and SEM scanning electron microscope test. The results show that the content of ceramsite is the most important factor affecting the proportion of the range of each evaluation index of LAFS. The proportion of the range of LAFS's compression resistance, splitting tensile strength, flexural strength, thermal conductivity, and water penetration height range are 38.77%, 43.50%, 51.55%, 44.31%, and 59.04%, respectively. The basalt fiber and polypropylene fiber with different physical properties show good rigidity and ductility during the impact test. While the peak stress of the hybrid fiber LAFS is increases, the impact plasticity becomes obvious.