Abstract: Uniaxial compression test was carried out on standard cube specimens under different strain rates (10^-5, 10^-4, 10^-3, 10^-2/s), and damage variable was defined with concrete elastic modulus as the parameter. Damage evolution rules and variation of critical point of damage with strain rate were analyzed under stress space. Results show that with the increase of strain rate, 1) the stress level at critical point of damage rises, and the first and second critical points move to the positions of higher stress level; 2) the interval length of first phase of damage increases and the interval length of third phase reduces, but the change of strain rate has little effect on the interval length of the second phase, which remains about 0.3.

Key words: concrete, dynamic damage, critical point, interval search, stress space