Initial damage effect on dynamic compressive behaviors of roller compacted concrete (RCC) under impact loadings

Abstract

Roller compacted concrete (RCC) usually remains in the damage state due to improper vibrating compaction control, and suffers from the attenuation of mechanical behaviors, leading to a limitation of the original concrete design. The aim of this paper is to promote a greater knowledge and understanding of the initial damage effect on dynamic compressive behaviors of RCC, taking the initial material damage into consideration in the context of original engineering design. In this paper, the actual construction technology was simulated in the laboratory and three damage measurements (i.e., density, ultrasonic pulse velocity (UPV) and elasticity modulus) were conducted to quantify the initial damage of RCC. Then, the dynamic compressive behaviors of RCC were tested by split Hopkinson pressure bar (SHPB) after initial damage measurement. The experimental results show that the initial damage of RCC shows a great influence on dynamic compressive strength and toughness. More remarkable attenuation of dynamic compressive strength (or toughness) occurs at higher strain rates. Furthermore, the dynamic compressive strength of RCC can be predicted with nondestructive testing (NDT) methods based on their tight correlation. An initial damage evaluation method under impact loadings, illustrated as damage graph accompanied with strength assurance rate, is proposed to determine a more reasonable damage grade, which can be used in practical engineering design.