Research On Impact Behavior Of Basalt Fiber Reinforced Concrete

Among the current trends in the field of the high-performance concrete are the cement-based composites, the core of which is fiber reinforced concrete. In the future, the high-performance fiber reinforced concrete will make significant changes in the concrete structures. Basalt fiber, as a new type of engineering fibers, has attracted great attentions in the materials and engineering areas.In this paper, by combining the research results at home and abroad, the research status of fiber reinforced concrete and the latest research achievements of basalt fiber reinforced concrete were introduced. Current researches mainly focused on the quasi-static mechanical properties of basalt fiber reinforced concrete, but its dynamic properties and toughening mechanism were seldom reported. The experiments based on the theoretical analysis were tested using three-point bending impact equipment and ultrasonic testing technology. The damage variable D was defined to characterize the damage evolution of basalt fiber reinforced concrete under cyclic loading. In order to analyze the toughening mechanism, the crack propagation theory based on fracture mechanics was used to reveal the damage evolution process and the stereomicroscope was applied to observe the surface cracks.The impact behavior and damage evolution of basalt fiber reinforced concrete (BFRC) with different fiber dosages ranging from 0~2.5 kg/m3 were tested using impact equipment. The results show that the basalt fiber has little effect on the compressive strength of BFRC, but it can improve the impact toughness of BFRC significantly. The flexural toughness of BFRC with fiber dosage of 1.5 kg/m3 was 2.14 times higher than that of plain concrete. In order to analyze the mechanical properties, the continued damage detection based on ultrasonic testing was used to reveal the damage evolution process, and the stereomicroscope was applied to observe the surface cracks. The results indicate that each specimen with various mass fractions reflected the brittle fracture behavior, but the energy absorption capacity of concrete can be effectively enhanced by basalt fibers. Contrasted with the controlled concrete, the damage variable of BFRC near destruction increases by 40%～83%. BFRC specimens show'multi-cracking'characteristics in the failure process, and the vice crack near the main crack is clearly observed while the final destruction.