High-performance concrete engineered for protective barriers

This paper reviews the effects of high-performance concrete mix ingredients on its resistance to impact of non-deforming projectiles, and on the resistance of layered barriers, engineered based on these findings. First, the reported effects of the aggregate types and sizes and the application of steel fibres, which were observed experimentally, are presented, considering resistance parameters that include the impact energy at the ballistic limit, the extent of the damaged areas at the impacted (front) and rear faces and the overall damage. These findings indicate that a protective barrier may be engineered to have layers that utilize these effects to produce a better performance under impact. Results from reported experiments of doublelayered specimens, which examined the effects of the aggregate size and application of fibres, confirm this idea to a certain extent. They lead to conclusions regarding the importance of fibres in mitigating the damage, the use of large aggregates in a thicker front layer and their associated effect on increasing the damage at the front, impacted face. A 'resistance index' is proposed to quantify the resistance in a comprehensive way and the experimental results have been re-evaluated in view of this parameter.