The impacts of contact explosions on ultra-high performance reinforced concrete slabs: experimental study and dimensional analysis

Ultra-high performance concrete (UHPC) is becoming a prevailing construction material in protective engineering. However, an insufficient research basis causes difficulty in the anti-explosion structural design of UHPC. To investigate the blast resistance of the UHPC slab (UHPCS), contact explosion tests were carried out. UHPCS exhibited superior blast resistance and a lower threshold range of failure modes than the normal reinforced concrete slab (NRCS). Compared with the NRCS, the UHPCS reached a lower damage level under the same scaled distance and had smaller craters and spalls, fewer cracks, and an absence of cross-shaped cracks. For NRCS, failure modes of medium spall, severe spall, and perforation were reached under charges of 1.0, 1.6, and 2.2 kg. In contrast, UHPCS reached medium spall, severe spall, and perforation under charges of 1.6, 3.3, and 5.0 kg. The scaled slab thicknesses (T/W 1/3 ) of the medium spall, severe spall, and perforation of the NRCSs were 1.17, 1.27, and 1.32 times larger than those of the UHPCSs, respectively. The formulae for predicting the spall and perforation thresholds of the UHPCSs were proposed. The reduction factors were used to evaluate the mitigation effect of the blast damage on the UHPC compared to that on the NRC. The reduction factors of the crater diameter ( ) and the spall diameter ( ) were determined to be 0.507 and 0.721, respectively. For quantitative analysis of the anti-explosion performance of UHPC, a simple estimation method for predicting the dimensions of the crater and spall of the UHPCS was proposed and verified based on the dimensional analysis method.