chapter
Strain Rate and Damage
Pages 41

The non-linear tensile stress-strain behaviour of concrete prior to peak stress depends upon the size of specimen and the stress distribution, and previous research has quantified these effects by the combined highly stessed volume/continuous damage model. The present investigation deals with the influence of the rate of stressing on the non-linear behaviour in direct tension and flexure. Direct tensile strength is more sensitive to rate of stressing than flexure, and the relative increase in strength is expressed as a function of the relative increase in stress rate and highly stressed volume. The combined model is also used to predict the stressrate influence on the ascending stress-strain curves of various tensile tests, using model input parameters from a direct tensile stress-strain curve obtained at a standard rate of stressing.