モルタル材の衝撃引張強度とひずみ速度依存性

抄録

Impact tensile strength of concrete at high strain rates is discussed by means of the experimental method of reflected tensile stress waves. The experiment is conducted by the Hopkinson bar technique using an air-gun arrangement and 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 test for mortar test specimen bars at wide strain rates was performed as well as static strength tests, and the experimental data for those strengths were analyzed statistically by a Weibull distribution. Strain rates were determined from the responses of both strain gages and crack gages pasted on the specimen bar. As a result, it was found that the effect of strain rates on impact tensile strength came out remarkably at strain rate 10⁰sec^-1 and the impact tensile strength was approximately proportional to strain rates throughout the range from 10⁰sec^-1 to 25sec^-1.