Abstract: Through uniaxial compression tests under different strain rates(10^-5,10^-4,10^-3 and 10^-2/s), the mechanical properties of concrete are analyzed to obtain the material properties of concrete during operation. Results show that as strain rates increase, the peak stress and initial elastic modulus tend to increase, but the regularity of peak strain’s variation is not obvious. With strain rate sensitivity into consideration, a rate-dependent segmented constitutive model of concrete is established based on Lemaitre’s strain equivalent principle and the statistical distribution theories of Weibull and Lognormal. On the basis of test data, the model parameter is determined under different strain rates, and the curve of uniaxial compression stress-strain and the curve of damage variation are obtained. The results indicate that the rate-dependent constitutive model could reflect the whole process of the concrete’s damage of uniaxial compression under different strain rates.

Key words: statistical distribution theory of Weibull, rate-dependent constitutive model, stress-strain full curve, the law of damage variation