محمد مقصودی

This study examines the blast resistance of self-compacting concrete (SCC) slabs strengthened using two Fiber Reinforced Polymer (FRP) techniques: externally bonded reinforcement (EBR) and near-surface mounted (NSM). Four SCC slabs were tested: one non-strengthened control slab (NC), two slabs reinforced with polypropylene fibers (FC) and two slabs retrofitted with carbon fiber-reinforced polymer (CFRP) techniques (FC-EBR and FC-NSM). Blast loading was applied using Emulite explosives, with 1231 g used for the control slab and approximately 2070 g for the strengthened specimens. The adopted charge mass was determined by preliminary calibration tests and expressed in TNT equivalency using standard blast scaling laws to ensure the applied load represented a severe, realistic scenario. The experimental program was complemented by advanced finite element simulations performed in ABAQUS, incorporating the Concrete Damage Plasticity (CDP) and Conwep blast models. The FC slab demonstrated an 87.5% reduction in maximum displacement relative to the NC slab, despite being subjected to a higher explosive charge. In addition, the NSM-strengthened slabs exhibited superior performance, achieving a 12.3% reduction in central displacement compared to the EBR system, with maximum displacements of 2.93 mm (FC-EBR) and 2.57 mm (FC-NSM), respectively. This enhancement could be attributed to the improved bond characteristics and reduced debonding risk of the NSM method. Overall, both strengthening techniques effectively increased the slabs’ blast resistance. The close agreement between experimental and numerical results confirms the reliability of the ABAQUS model in predicting structural behavior under blast loading.