Abstract: Recycled aggregate concrete(RAC) reinforced by different type of fibers was prepared for experimental specimens in order to measure the mechanical properties such as compressive strengths, splitting tensile strengths and elastic modulus. The mechanical properties were then compared with those of normal concrete. Meanwhile, the optimal amount of basalt fibers(BFs) to RAC was also investigated and the strength conversion formulas, as well as the calculation formulas for mechanical indices, were deducted based on the experimental measurements. Experimental results demonstrate that under an identical mixture ratio, the compressive strengths and splitting tensile strengths of RAC without fibers could be greater than those of normal concrete due to the fact that the water absorption of recycled aggregates induces a practically lower water-cement ratio. Meanwhile, non-optimal ratios and inhomogeneous distributions of fibers could decrease the compressive strengths of fiber-reinforced RAC. Additionally, BFs showed little contributions to the mechanical properties of RAC and in some cases reduction effect could happen. The optimal amount of BFs to the cubic compressive strengths was 0.1%. However, the optimal amounts to the other three mechanical indices were all 0.2%. Lastly, it was found that the proposed calculation formulas for the mechanical properties of BF-reinforced RAC presented satisfactory performance and thus could be used as a reference in practice.

Key words: fiber-reinforced recycled aggregate concrete, mechanical property experiments, strength conversion formulas, calculation formulas for mechanical indices