Rate effect on the stress–strain behavior of concrete under uniaxial tensile stress
Xiangling Gao, Laijun Zhou, Xiaodan Ren, Jie Li
Abstract
Abstract Concrete is a typical rate‐dependent material, and a direct tensile test is the most effective method by which to investigate its tensile performance. In this study, an additional loading device for direct uniaxial tensile tests was designed and fabricated to achieve central loading and determine the descending stage during direct tensile tests. Experimental results prove that the device is reliable and convenient for reuse; it is characterized by its ability to obtain complete stress–strain curves and to be used for many repetitive tests. Initially, 27 prismatic specimens were used to test the compressive strengths and elastic moduli of concrete specimens with designed compressive strengths of 25, 30, and 50 MPa. Next, a total of 256 uniaxial direct tensile tests were carried out, including 101 static tests at a loading strain rate of 10 −5 s −1 and 155 dynamic tests at loading strain rates of 10 −4 s −1 and 10 −2 s −1 . A total of 121 complete stress–strain curves were acquired for the 256 direct tensile tests. According to the test results, the SD s of the entire curves of the tensile stress of concrete are presented, and the energy absorption capacities of the specimens were also determined. The effects of the loading rate on the mean and variability of the peak stress, peak secant modulus, elastic modulus, and peak strain were analyzed. With the increase of the strain rate, the other indexes, excluding the peak strain, were found to notably increase.