Bond Behavior of Recycled Concrete: Analysis and Prediction of Bond Stress–Slip Curve

Abstract

This paper studies the bond stress–slip curve of recycled concretes and the influence of recycled coarse aggregate, which leads to the determination of bond behavior at serviceability. In order to perform this analysis, a study of the compressive strength of the recycled aggregate concretes is required, due to the relationship between the bond strength and the mean compressive strength. Two series of concretes are designed with different water to cement ratios (0.50 and 0.65) and four different replacement percentages (0, 20, 50, and 100%). The experimental program tests cubic specimens through 144 compressive strength tests and 160 pull-out tests at different ages, from 3 to 365 days. The results show that replacement ratio significantly influences concrete properties related to the compressive strength and bond behavior. Two functions are developed to predict time-dependent compressive strength and bond stress–slip curve of recycled concrete, both based on the International Federation for Structural Concrete Model Code expressions for conventional concrete.