Experimental and numerical study on local damage effect of ultra-early-strength reinforced concrete slabs (URCS) under contact explosion

UR50 ultra-early-strength cement-based self-compacting high-strength material has the advantage of short curing time and rapid development of early strength, which is an ideal material for rapid repair and construction of key facilities in wartime. In order to investigate the local damage characteristics of ultra-early-strength reinforced concrete slabs (URCS) under contact explosion thoroughly, 12 contact explosion tests were carried out on URCS cured for 28 days and 24 h with three reinforcement rates (0.23%, 0.41% and 0.79%) under 200 g, 400 g, 600 g and 800 g TNT mass by using TNT binding cube charge. The test results showed that the explosion resistance performance of URCS cured for 28 days under contact explosion was not much different from that cured for 24 h, and the variation of reinforcement rate within the conventional range had limited influence on the explosion resistance performance of URCS. Further, explicit dynamic finite element software LS-DYNA was used to simulate the local damage of URCS cured for 24 h under contact explosion, and the influence of slab thickness and TNT mass on local damage of 24-hour curing URCS was studied with validated numerical model, and the range of seismic collapse coefficients Kz for different failure modes of URCS under contact explosion was given.