Experimental study on mechanical behavior of steel fiber recycled concrete under cyclic compression

In order to study the mechanics behavior of steel fiber recycled concrete under seismic load, 52 cylindri-cal specimens were designed for uniaxial cyclic compression test, three variation parameters including recycled coarse aggregate replacement rate, steel fiber volume fraction and loading rate were considered in the test. The failure modes of steel fiber recycled concrete were observed, and the stress-strain curve, peak stress, peak strain and plastic strain and other important indexes were obtained. The influence of different parameters on mechanical properties was deeply analyzed. The experimental results show that the steel fiber recycled concrete mainly occurs oblique splitting failure under cyclic loading. With the increase of steel fiber volume fraction, the width of main cracks on the specimens surface decreases obviously. The addition of steel fiber can enhance the specimens' peak strain and the residual strength while reduce the specimens' peak stress. When the volume fraction of steel fiber is 1.0vol%, the peak stress of recycled concrete decreases by 5.9% and the peak strain increases by 15.9%, the modified effect is the best. The relationship of the standardized plastic strain and the unloading point strain was fitted using the power function. Finally, the calculation of the stress-strain constitutive relationship of the steel fiber recycled concrete under the uniaxial cyclic compression was proposed. © 2022, Editorial Office of Acta Materiae Compositae Sinica. All right reserved.