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结合不同纤维掺量的玄武岩纤维混凝土(简称BFRC)与无纤维的普通混凝土抗弯冲击试验,采用全数字化声发射系统采集对BFRC从加载至最终破坏的声发射特征参数,识别BFRC以声发射特征参数为基础的损伤断裂机制。结果表明,在较合理的纤维掺量为1.05kg/m3时,BFRC初裂次数达到73次,与素混凝土梁相比提高108.2%,终裂次数达到81次,与素混凝土梁相比提高100.5%。BFRC具有以下声发射特征:1)不同掺量的BFRC在初裂前平均振铃计数和平均能量都比素混凝土小,玄武岩纤维能够有效阻止冲弯作用下裂纹的产生和发展;2)初裂后,素混凝土采集的声发射能量和振铃计数急剧降低,而BFRC每次冲击产生的高幅值信号在第一峰值后交替产生,玄武岩纤维能够延迟混凝土的断裂并提高其冲击延性。
Combined with different fiber content of basalt fiber reinforced concrete (BFRC) and non-fiber ordinary concrete flexural impact test, using all-digital acoustic emission system to collect the characteristic parameters of acoustic emission of BFRC from loading to final destruction, to identify the characteristics of BFRC Parameter-based damage fracture mechanism. The results showed that the primary cracking frequency of BFRC reached 73 times when the reasonable fiber content was 1.05kg / m3, increased 108.2% compared with the plain concrete beam, the number of the final cracking reached 81 times and increased 100.5 compared with the plain concrete beam %. BFRC has the following characteristics of acoustic emission: 1) The average ringing counts and average energy of BFRC with different dosages are lower than that of the plain concrete before the initial cracking, and the basalt fiber can effectively prevent the generation and development of cracks under the bending. 2) Acoustic emission energies and ring counts decreased sharply after the acquisition of plain concrete. However, high-amplitude signals produced by each impact of BFRC alternated after the first peak. Basalt fibers delayed the fracture of concrete and increased its impact ductility.