Evaluation of low-velocity impact response of layered concrete composites with viscoelastic interlayers

This study investigates the low-velocity response of composite-layered concrete with viscoelastic interlayers as an alternative to conventional reinforced concrete, aiming to improve energy absorption and reduce peak impact forces in structures such as railway catch walls. Cubic specimens were fabricated using Normal Concrete (NC) and Rubberised Concrete (RC) to evaluate mechanical properties. For impact testing, cylindrical samples were manufactured using the same mix design of NC and RC but with the inclusion of intermediate viscoelastic layers of Polyurethane (PU) or Silicone (SI). A total of 54 specimens were subjected to low-velocity impact testing (2.5 m/s, 5.0 m/s, and 7.5 m/s). Testing evaluated the strain-rate-dependent behaviour, including the peak force, the impulse, and the energy absorbed, enabling direct comparisons between investigated layering configurations. The study indicated that the integration of energy-absorbing interlayers enhanced the impact performance, with the best performing system reducing peak force by up to 85.7% under lower test velocities and increasing measured impulse by upwards of 75% at higher test velocities. SI-based systems achieved 26% greater impulse efficiency than their PU counterparts, while also maintaining structural integrity at higher impact energies. SI-based systems demonstrated consistent mechanical responses under increasing impact velocity, highlighting their potential for application in energy-absorbing structural protective systems. A predictive equation was developed through non-linear regression, enabling the design of layered concrete composites for civil damage-resistant protective structures.