Experimental and numerical investigation of normal reinforced concrete panel strengthened with polyurea under near-field explosion

In this paper, field blast tests and numerical simulations were conducted to investigate the strengthening effect of polyurea on the blast resistance of the normal reinforced concrete (NRC) panels under near-field explosion. Five specimens were fabricated and tested, including two NRC panels, and three NRC panels sprayed with polyurea at the rear side. The experimental results showed that polyurea could effectively improve the blast resistance of the NRC panel with less damage and smaller residual displacement. Furthermore, with the existence of the polyurea, the integrity of the specimen could be maintained, and the deadly fragments of the concrete panel were captured, thereby reducing the secondary damage to surrounding personnel and structures. The finite element (FE) model of NRC panels strengthened with polyurea under near-field explosion was established using the Arbitrary-Lagrangian-Eulerian (ALE) method, and validated with the experimental results. Thereafter, the validated FE models were used to investigate the effects of scaled distances and polyurea thickness on the blast resistance of the NRC panel. This research is of direct importance to both practitioners and researchers involved with strengthening design for NRC components against explosion.