Experimental Study on Deformation Properties of Basalt Fiber Reinforced Recycled Aggregate Concrete

In this paper, the effects of different substitution rates and basalt fiber (BF) contents on the deformation properties of recycled aggregate concrete (RAC) are studied, and the correlation degree of the changing parameters on the deformation properties of basalt fiber reinforced recycled aggregate concrete (BFRAC) is evaluated by gray correlation analysis. A total of 48 cylindrical test blocks are designed in this experiment, the failure modes of the test blocks are observed and analyzed, and performance indicators such as stress–strain curve, peak strain, and elastic modulus are obtained. The results show that the test block mainly suffers longitudinal splitting failure under uniaxial compression. The longitudinal cracks become denser and narrower with the increase in BF content. With the increase in BF content, the stress–strain curve decreases gradually, and the peak strain in the fully recycled aggregate concrete increases. There is no obvious change rule toward the peak strain with the increase in the substitution rate. The peak strain and elastic modulus of most test blocks show a trend of first decreasing and then increasing. At each substitution rate, when the BF dosage is 6 kg/m3, the elastic modulus of the test block is the minimum. Based on gray correlation analysis, the substitution rate has a greater impact on the deformation performance of BFRAC than fiber content. Therefore, an appropriate substitution rate has a better effect on improving the stiffness of test blocks and reducing the deflection of bending members.