Material properties of crushable concrete for use in vehicle antiram barriers

With raised national security awareness because of terroristic threats, more focus recently has been placed on barrier and safety systems that can prevent the loss of life and structural damage as a result of vehicular impact and blast loading. One potential method for dissipating some of a vehicle's high kinetic energy is to use crushable concrete in the barrier design. In this study, multiple crushable concrete mixtures containing partial and full replacement of aggregate by expanded polystyrene spheres were tested in unconfined and confined compression tests to evaluate their capacity of energy dissipation. Unconfined testing showed high ductility of polystyrene concrete, but the samples ultimately failed in shear. More efficient use of the crushable concrete was encapsulating the specimens. Confined compression tests showed much larger energy absorption capacity of all mixtures studied. Changes in the water-to-cement ratio (w/c) and loading rate had minimal effect on energy absorption and strength. However, increasing the amount of polystyrene replaced caused an increase in deformability and decreased the strength capacity. Additionally, dynamic compression tests were conducted on confined samples. Image analysis of the test samples showed that with an increase in strain values, the compression of the polystyrene increased. As a result, the relative volume of concrete increased with a decrease in the relative volume of voids.