Impact and Blast Resistance Enhancement of Reinforced Concrete Slabs Strengthened with CFRP and GFRP Systems: Experimental and Numerical Investigation

Articles in Press

Document Type : Research Article

Authors

1 PhD in structural engineering, A' Lecturer in Islamic University Al-Najaf, College of Engineering Technology, Department of Building and Constriction Technology,

2 Civil Eng , Tikrit University

Abstract

Reinforced concrete (RC) slabs are widely used in critical infrastructure, yet they are vulnerable to sudden high strain-rate loads such as low-velocity impact and blast. These hazards can induce brittle punching, large residual deformation, and loss of load-carrying capacity. This study evaluates the effectiveness of externally bonded fiber-reinforced polymers (FRP) for strengthening RC slabs against such actions. Nine slabs (1800 × 600 × 100 mm) were tested: three control (unstrengthened), three strengthened with GFRP, and three strengthened with CFRP. Drop-weight impact tests were performed at energy levels ranging from 400–900 J. Results showed that CFRP strengthening reduced peak displacement by up to 28–35% and increased absorbed energy capacity by approximately 20–26% compared with control slabs. GFRP strengthening provided smaller improvement, reducing displacement by only 10–14%. In addition, peak force resistance increased from an average of 48 kN (control) to 62 kN for CFRP-strengthened slabs. A calibrated nonlinear numerical model was developed to simulate both impact and idealized blast loading. The model predicted peak force and displacement values within ±8% of experimental results and confirmed the superior performance of CFRP layouts. The findings demonstrate that externally bonded CFRP is an effective retrofitting strategy for increasing the impact and blast resistance of RC slabs and improving structural resilience.

Keywords

Main Subjects

Mechanics of Advanced Composite Structures

Articles in Press, Accepted Manuscript
Available Online from 20 June 2026

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