Finite element analysis and experimental validation of soil-covered CFRC slabs subjected to blast loading

This study conducted finite element simulations of soil-covered carbon fiber-reinforced concrete (CFRC) slabs subjected to blast loading. The dynamic behavior of CFRC was simulated using the Johnson–Holmquist Concrete (JHC) constitutive model, while the soil response under blast conditions was modeled using the framework developed by the U.S. Federal Highway Administration (FHWA). The material parameters for the JHC model were derived from quasi-static compression tests and Split Hopkinson Pressure Bar (SHPB) tests. Parameters for the FHWA soil model were obtained through consolidated undrained triaxial test. In the experimental setup, both a benchmark concrete slab and a CFRC slab—reinforced with 1% carbon fiber by cement weight and using 24 mm fibers—were covered with a 7.5 cm thick soil layer. A 200 g charge of C4 explosive was placed on top of the soil. The results from the soil-covered blast tests confirmed that the soil layer effectively reduced front-face damage and minimized crater formation. Finite element simulations were performed using LS-DYNA software, incorporating the JHC and FHWA constitutive models to replicate the mechanical response and damage patterns of the slab specimens. The deformation depth trends predicted by the simulations closely matched the experimental results, validating that the JHC model calibrated through SHPB testing can reliably simulate the blast response of concrete slabs.