Study on Energy Absorption Characteristics of BF-SP-EPS Concrete Under Dynamic/Static Load
YU Zeming1,2, CHEN Yan3, MA Rongping1,2, HU Xiaochen1,2, LYU Xiangfeng1,2
1 School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China 2 Beijing Key Laboratory of Urban Underground Space Engineering, University of Science and Technology Beijing, Beijing 100083, China 3 Beijing Guodian Jingwei Engineering Technology Co., Ltd., Beijing 100192, China
Abstract: Underground space engineering often suffers from deformation and failure after dynamic load, and the damage degree can be reduced by absorbing dynamic energy by protective structure. However, the energy-absorbing concrete material which can effectively absorb impact energy and its mechanical properties are still unclear. Based on the central optimal combination principle of response surface method, the dyna-mic/static load combined synchronous acoustic emission (AE) monitoring test method was adopted, and the deformation energy encroachment process of concrete affected by key factors of expanded polystyrene foam (EPS), slag powder (SP) and basalt fiber (BF) and cement matrix was studied by means of high-precision scanning electron microscope(SEM). The results show that EPS particles change the distribution of pore structure of concrete, and the failure mode of BF-SP-EPS concrete under dynamic and static load changes from brittle failure to ductile failure, showing the characteristics of crushing compaction and energy dissipation, greatly improving the deformation toughness and providing effective deformation space for absorbed energy; the bridge effect of BF-SP-EPS and cement matrix can significantly improve the energy absorption performance of concrete. Compared with the same kind of concrete without admixture, the absorbed energy reaches 71J, and the impact energy absorption increases by 50%; the craving function optimization model is established, and the optimal BF-SP-EPS ratios with the compression resis-tance and absorbed energy as the response target are 33.7vol%, 17wt% and 0.13vol%. The correctness of the optimal ratio is verified by the same condition test method. The research results provide a strong theoretical basis for the energy absorption protection safety of underground space engineering structures.
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2021, Vol. 35 
