G-UHPC slabs strengthened with high toughness and lightweight energy absorption materials under contact explosions

Abstract

This study investigates the dynamic characteristics of geopolymer-based ultra-high performance concrete (G-UHPC) slabs strengthened with high toughness and lightweight energy absorption materials under the 1 kg TNT contact explosions. A total of four slabs were tested, including plain G-UHPC slab (G-UHPC-P), 20-layer basalt textile reinforced G-UHPC slab (G-UHPC-BFM), 20-layer steel wire mesh reinforced G-UHPC slab (G-UHPC-SWM) and 1.5 vol-% steel fibre reinforced G-UHPC slab with polyurethane coating (G-UHPC–SF–PU). The test results revealed that the steel wire mesh reinforcement was more effective in resisting contact explosions than the basalt textile reinforcement for G-UHPC. The polyurethane coating on the rear face of the slab exhibited its high tensile strength and deformability to absorb the blast-induced energy so as to enhance the anti-explosion performance of the slab, and additionally prevented the splash of slab fragments upon contact explosions to minimise secondary hazards. Based on the multi-material arbitrary Lagrangian-Eulerian (ALE) algorithm, local damage of G-UHPC-SWM and G-UHPC–SF–PU induced by contact explosions was reproduced using the explicit finite element software LS-DYNA. Fair agreement between the numerical and test results demonstrated that the numerical model could simulate the response of G-UHPC-SWM and G-UHPC–SF–PU with reasonable accuracy. Extensive numerical studies by varying polyurethane strain rate, coating thickness and the bonding between the polyurethane coating and the slab were further performed to analyse their effect on the maximum bulge depth of the polyurethane coating subjected to contact explosions.