Experimental Research on Flexural Properties of Chopped Basalt Fiber Reinforced Concrete Beams

Basalt fiber is added into the concrete substrate as a reinforcing material to form a cement composite which calls basalt fiber reinforced concrete (BFRC). Taking the aspect ratio of basalt fiber as the test variable, the four-point bending static loading test for BFRC beams was carried out to study its mechanical behavior and the reinforcement effect of basalt fiber; based on the collected mechanical property test data of fiber reinforced concrete, the relations between the tensile and compressive strength of fiber reinforced concrete and the compressive strength of matrix concrete, fiber content and fiber length diameter ratio was established, the prediction model of characteristic bearing capacity of BFRC beam was proposed based on RC beam model. The results showed that BFRC beams could meet the plane section assumption, and the addition of basalt fiber could improve the cracking and ultimate bearing capacity of BFRC beams, among which the characteristic bearing capacity of BFRC beams with length diameter ratio of 1200 was the most obvious; at the same time, the addition of basalt fiber could reduce the maximum crack width, increase the number of cracks and increase the bending stiffness of the beam; the calculation results of the improved characteristic bearing capacity prediction model of BFRC beams proposed in the paper could fit well with the test results, which could better predict the cracking and ultimate bearing capacity of BFRC beams, and reflect the gain effect of fiber in concrete beams.