Study on the interfacial bond slip constitutive relation of I-section steel and fully recycled aggregate concrete

17 standard push-out specimens which are designed to study the interfacial bond-slip behavior of I-section steel and reinforced recycled concrete with 100% replacement ratio of coarse aggregate (SRRC). The parameters of test are strength of recycled aggregate concrete, thickness of I-section steel protective layer, embedded length of I-section steel and ratio of stirrups. The test results show that the strain and stress of the I-section steel at the interface of SRRC distribute exponentially, and the four test parameters have a certain influence on the interfacial bond strength of SRRC. Based on the analysis of the test data, the calculation formulas of the interfacial bond strength of SRRC are established. The constitutive relations of the bond-slip at the loading end are established, and the multistage linear results are more satisfied with the test results than power-type. Finally, the position function of the bond-slip F (x) and the bond stress G(x) are introduced, and the bond-slip constitutive relation with changes of position are established, which provides a reference for related specification design and engineering construction. (C) 2019 Elsevier Ltd. All rights reserved.