Experimental Study On The Influence Of Silica Fume To Static And Dynamic Mechanical Properties Of EPS Concrete

Expanded polystyrene (EPS) particles are light, and also have a large number of closed pores. EPS concrete with different apparent densities are obtained by partial replacing coarse and fine aggregate with EPS particles. As a new type of building material, the mechanical properties and cushioning absorption properties of EPS concrete have been widely concerned by researchers.Through static compression test, splitting tensile test and SHPB test, static compressive strength, splitting tensile strength, dynamic compressive strength and cushioning absorption properties of EPS concrete have been investigated in various EPS particle volume contents,10%,20%,30% and 40%. When volume content of EPS particle is 30%, static compressive strength, splitting tensile strength, dynamic compressive strength and cushioning absorption properties of EPS concrete have been investigated in various silica fume contents,5%,10%,15% and 20%. When volume content of EPS particle is 30% and silica fume content is 15%, dynamic compressive strength and cushioning absorption properties of composite material made by EPS concrete and ordinary concrete have also been studied in different structure forms with EPS concrete as core layer, cushion layer or shock resistance layer.Test results show that both static compressive strength and splitting tensile strength of EPS concrete decrease with volume content of EPS particle increasing. When volume content of EPS particle is 10%,20%,30% and 40%, corresponding static compressive strength is 54.3MPa,41.0MPa,31.7MPa and 19.4MPa, and corresponding static splitting tensile strength is 4.9MPa,4.2MPa,3.9MPa and 3.5MPa. Dynamic compressive strength of EPS concrete presents a decrease tendency with volume content of EPS particle increasing, and it presents a increase tendency with strain rate increasing, which indicates an obvious strain rate effect. Energy absorption of EPS concrete increase with strain rate increasing. When volume content of EPS particle is 30%, energy absorption of EPS concrete in critical failure mode is 101.4J, which is about 3.37 times of ordinary concrete. Therefore, an obvious cushioning absorption property present.Bonding performance between EPS particles and cement paste and dispersing performance of EPS particle in cement paste can be improved by adding silica fume. Hence, strength properties of EPS concrete is improved. When silica fume content is 15%, compressive strength of EPS concrete is improved by 20%, and splitting tensile strength is improved by 13%. Both dynamic compressive strength and energy absorption of EPS concrete in various silica fume contents increase with strain rate increasing. Under certain strain rate, dynamic compressive strength of EPS concrete with silica fume content of 15% increases greatly. When strain rate in the range of 38.9s"1 to 60.5s-1, EPS concrete specimens crack rather than broken. When in critical failure mode, energy absorption of EPS concrete is about 105.0J under various silica fume contents.SHPB test results of different structure forms with EPS concrete as core layer, cushion layer or shock resistance layer indicates that under certain strain rate, dynamic compressive strength reaches its minimum value when EPS concrete is core layer and reaches its maximum value when EPS concrete is cushion layer. Failure mode is severe when EPS concrete is core layer, while good integrity present when EPS concrete is cushion layer or shock resistance layer.