Experimental investigation of basalt fiber-reinforced polymer (BFRP) bar reinforced concrete slabs under contact explosions

Abstract

This study evaluates the effectiveness of basalt fiber-reinforced polymer (BFRP) bar reinforcement on the blast-resistant performance of concrete slabs. Contact explosion tests of 30-cm-thick concrete slabs with three layers of reinforcement were conducted. Eight slabs were tested and four were reinforced with steel and four were reinforced with BFRP bars. Four charges of TNT, 0.8, 1.0, 1.6, and 1.9 kg, were set for each type of slab. Damage modes of the crater, medium spall, and severe spall of the normal reinforced concrete slab (NRCS) and BFRP bar reinforced concrete slab (BRCS) were reached under contact explosions of TNT charges of 0.8, 1.0, and 1.6 kg, respectively. The BRCS exhibited severe spall while the NRCS experienced breaching under explosions induced by 1.9 kg TNT. The threshold ranges of spall and breaching of the NRCS and BRCS were obtained. Compared with the NRCS, the BRCS exhibited better blast-resistance based on the smaller crater and spall sizes, the absence of a cross-shaped crack, and the presence of fewer cracks. Existing formulae were applied to predict the damage modes obtained in the tests. McVay's formula caused an overestimation in which the crater modes of all eight slabs were predicted. Although the formulae proposed by Morishita et al. provided better predictions, the thresholds of spall and breaching were inaccurate.