Mechanical properties of fully recycled coarse aggregate concrete with manufactured sand

To investigate the influence of aggregate type, water-cement ratio, and stone powder content on the mechanical properties of concrete with manufactured sand and fully recycled coarse aggregate, we prepared specimens of fully recycled aggregate concrete with different stone powder mass fractions (5%, 10% and 15%) and various water-cement ratios (0.50, 0.37 and 0.32). A total of 72 cubic specimens were used for compressive strength tests, and 72 cylindrical specimens for elastic modulus tests. The results indicate that an appropriate stone powder content can effectively enhance the mechanical properties of recycled aggregate concrete, but the optimal stone powder content varies under different water-cement ratios. When the water-cement ratio and stone powder content interact, the mechanical properties of recycled concrete are optimal at a water-cement ratio of 0.32 and a stone powder mass fraction of 15%. Moreover, a relationship model between the compressive strength and elastic modulus of concrete with manufactured sand and fully recycled coarse aggregate and the water-cement ratio & stone powder content was established. The standard deviation and dispersion coefficient of the calculated results do not exceed 5%, indicating good model accuracy. The research results can provide a theoretical basis for enhancing the mechanical properties of recycled aggregate concrete and its engineering application.