High-strain rate compressive behavior of concrete made with substituted coarse aggregates: Recycled crushed concrete and clay bricks

The high-strain rate compressive behavior of concrete made with different levels of substitution and types of coarse aggregate is addressed in the present work. The compressive behavior was investigated by performing standard quasi-static tests and Split-Hopkinson Pressure Bar tests with a large bar diameter of 155mm. Two different types of concrete with different substituted coarse aggregates are studied, namely Recycled Aggregate Concrete (RAC) and Recycled clay Bricks Concrete (RBC). Specimens were divided into 9 groups with different levels of substitution and types of coarse aggregate ranging from 0% (Natural Aggregate Concrete, NAC) up to 100% (full substitution with recycled crushed concrete or clay bricks). Tests were executed up to a strain rate of around 100s-1. Data-driven predictive equations were proposed for the compressive strength Dynamic Increase Factor (DIF). Results indicate that RAC and RBC are more strain-rate sensitive than NAC. In particular, DIF markedly depends on the level of substitution in RAC, while this dependency is less marked for RBC.