Size effect on compressive behaviors of waste fiber-reinforced recycled aggregate concrete

The compressive size effect of conventional concrete is well known, but there is limited knowledge of the fiber-reinforced recycled concrete. A total of 270 specimens with the different cube and prism sizes, water-cement ratios, compressive strength grades, the replacement rates of recycled aggregates, and volume fractions of waste fibers were tested until failure to study the size effect behaviors of waste fiber-reinforced recycled concrete subjected to axial compression. The results showed that as the replacement rate of recycled aggregates increases, the size effect degree of the cube and axial compressive strength increases. With the increase of the volume fraction of waste fibers, the size effect degree of compressive strength decreases first and then increases, with the optimum volume incorporation of 0.12%. The higher the strength grade of concrete is, the more obvious the size effect of strength is. For large-scale components, no incision correction of Bazant and Carpineri's fractal size effect theory is more suitable for the analysis of the size effect of waste fiber recycled concrete. It is essential to understand the compression size effect of waste fiber-reinforced recycled concrete so that the laboratory investigation results can be applied to real full-scale structures subjected to compressive loading.