玄武岩纤维增韧混凝土冲击性能

Impact behavior of basalt fiber reinforced concrete

采用三点弯曲冲击试验装置,结合超声波测试技术,研究了玄武岩纤维质量分数为0%～0.60%时,玄武岩纤维增韧混凝土(Basalt Fiber Reinforced Concrete,BFRC)的冲击性能及其损伤演化规律,研究了混凝土冲击破坏过程中基于超声波波速的损伤演化过程,并应用体视显微镜观测了冲击过程中试件表面裂纹的发展,分析了玄武岩纤维提高混凝土冲击韧性的机制。结果表明:玄武岩纤维对混凝土的抗压强度无明显改善,但可以显著提高混凝土的冲击韧性,当纤维质量比为0.36%时冲击韧性提高了2.2倍。各玄武岩纤维掺量下混凝土的冲击破坏均表现出脆性特征,但玄武岩纤维的加入有效提高了混凝土对冲击能量的吸收,其临近破坏时损伤变量较素混凝土提高了40%～83%;玄武岩纤维混凝土冲击破坏过程表现出多缝开裂的特征,在最终破坏时主裂缝附近有明显的副裂缝出现。

The impacting behavior and damage evolution of basalt fiber reinforced concrete（BFRC） with different fiber mass fraction ranging from 0%～0.60% were tested using three-point bending impact equipment and ultrasonic testing technology.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 show that the basalt fiber has little effect on the compressive strength of BFRC,but it can significantly improve the impact toughness of BFRC.The flexural toughness of BFRC with basalt fiber of 0.36% is 2.2 times higher than that of plain concrete.The results also indicate that each specimen with various mass fraction reflects 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 after the final destruction.