Abstract: Equal-amplitude cyclic (50 times) high stress loading test and uniaxial compression test were conducted on concrete specimen groups (with rubber dosages of 0%, 5%, 10%, 15%, 20%, respectively) to study the mechanical and deformation characteristics of rubber concrete (RC) under repeated loading. The change of uniaxial mechanical properties of concrete with varied rubber content before and after cyclic loading and the deformation during cyclic loading were analyzed. Results unveiled that with the growth of rubber content, the peak stress and modulus of elasticity of specimens decreased accordingly, while peak strain increased. During cyclic loading, the total strain, elastic strain and plastic strain curves of RC were significantly higher than those of normal concrete (NC); but the relative strain range was smaller than that of NC, displaying good ductility and stability. After cyclic loading, the degradation of NC’s peak stress and elastic modulus reached 11.0% and 36.8%, respectively, whereas the deterioration of RC’s corresponding index declined with the growth of rubber content. According to efficacy coefficient analysis, the mechanical properties of RC-1 (RC with 5% rubber content) was the optimum, followed by those of RC-2 (RC with 10% rubber content), RC-4 (RC with 20% rubber content), RC-3 (RC with 15% rubber content), and NC. The optimum rubber content was 5%-10%. The research results can provide a theoretical basis for the application of rubber concrete in engineering.

Key words: rubber concrete, equal-amplitude cyclic loading, deformation properties, degradation analysis, efficiency coefficient method