Strain rate effect on compressive stress–strain curves of recycled aggregate concrete with seawater and sea sand

Abstract

Recycled aggregate concrete with seawater and sea sand (SSRAC) was tested under uniaxial compressive loading with five strain rates (from 10−5 to 10−1 /s). The peak stress, elastic modulus, peak strain (strain at the peak stress) and ultimate strain of tested stress–strain curves as well as the failure patterns were analyzed. The test results indicate that strain rates have significant effects on the peak stress and elastic modulus of SSRAC. Compared with quasi-static state, the peak stress and the elastic modulus was increased by 26.29% and 64.69% for M-SSRAC (SSRAC with medium shell particle contents), and 34.23% and 74.98% for H-SSRAC (SSRAC with high shell particle contents) at a strain rate of 10−1/s, respectively. Furthermore, the dynamic increase factors (DIFs) of SSRAC were evaluated based on a comparison analysis with those of the recycled aggregate concrete (RAC) and ordinary concrete reported in the literature. When the strain rate is 10−1/s, the DIFs of peak stress for M-SSRAC and H-SSRAC are 1.26 and 1.34, and the DIFs of elastic modulus are 1.65 and 1.75, respectively. Finally, based on an analysis of the pore structures by computed technology (CT) scanning, the shell particles decrease the porosity and contribute to the compressive strength and elastic modulus of H-SSRAC specimens, which therefore leads to the lower peak strain and ultimate strain.