Fracture Properties of Basalt Fiber Reinforced Concrete after Freeze-Thaw Cycles

The full-field deformations of notched concrete prisms were observed inrealtime in three-point bending test by using the digital image correlation(DIC) technology. The horizontal strain and displacement nephogram based on DIC technology were used to determine the initial cracking load and the crack mouth opening displacement. The effects of freeze-thaw cycles and basalt fiber dosage on the fracture energy, ductility index and equivalent fracture toughness of basalt fiber reinforced concrete(BFRC) were investigated. The results show that the fracture energy of BFRC can be improved by adding basalt fiber under freeze-thaw cycle condition, but the degree of improvement is smaller than that of the decline caused by freeze-thaw cycles. The ductility index of BFRC increases first and then decreases with the increase of basalt fiber dosage, and increases with number freeze-thaw cycles. The flexural toughness of BFRC reduces significantly with number freeze-thaw cycles at micro and small deformation stages, followed in the middle deformation stage, and that is not significant in the large deformation stage. The toughening effect of the basalt fiber is significant in all deformation stages and the effect from low to high is in the order as follows: the micro deformation stage, the small deformation stage, the middle deformation stage, and the large deformation stage. © 2019, Editorial Department of Journal of Building Materials. All right reserved.