Derivation of the True Strain Rate Effect of Roller Compacted Concrete (RCC) from Impact-Induced Fragmentation

Abstract

The true strain-rate effect for roller compacted concrete (RCC) removing the structural effect is a primary concern to achieve a reliable response prediction of RCC structures. In this study, a series of laboratory tests were carried out to study the dynamic compressive strength of RCC specimens with three different sizes subjected to various high-rate loadings. Based on the traditional decoupling method, the strength enhancements due to the inertial and end friction confinements were numerically evaluated and removed from the experimental DIF data. However, the mean values of material properties are generally employed in numerical simulation, which cannot reflect the high variability due to fast-successive constriction and mix proportion. This brings subjectivity and may result in incorrect evaluation of the structural effect and high variability in corrected DIF data. To solve this problem, the fractal dimension was introduced to quantify the fracture degree of impact-induced concrete fragments and describe the strain rate effect without significant variability. At last, a fragmentation-based approach was proposed to derive the true strain-rate effect of RCC and verified by comparison with the numerical and semi-theoretical methods.