Estimation of Impact Tensile Strength of Mortar Using Reflected Tensile Stress Waves

摘要

Impact tensile strength of concrete (mortar) and its measuring method is discussed. The experiment is conducted by means of a Hopkinson bar technique using an air-gun arrangement. The measuring method is based on the superposition and concentration of tensile stress waves reflected both from the free ends of a striking bar and a specimen bar. The impact tensile experiment of mortar specimen bars was performed as well as static strength tests. The experimental data in relation to those strengths were analyzed statistically by a Weibull distribution. The impact tensile strength was significantly influenced by loading rates, and it was found to be about 1.5 times of the static value. For examining the adequacy of the present measuring method, numerical simulations on the stress waves propagated in the specimen bars were carried out under the condition of two-dimensional axisymmetric model using the FEM code and some reasonable results were found.