玄武岩纤维混凝土抗弯冲击的声发射特性研究

Research on Acoustic Emission Characteristics for Basalt Fiber Reinforced Concrete During Flexural Impact Tests

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。

Combining with flexural impact tests of basalt fiber reinforced concrete with different fiber admixing a- mounts and common non-fiber concrete, feature parameters and waveforms of acoustic emission（AE） signals were ac- quired using a full-digital acoustic emission system during the loading process. The damage and fracture mechanisms for BFRC were identified based on the acoustic emission parameters. The results show that initial cracking times is equal to 73 when fiber admixing amounts is 1.05 kg/ma , is improved by 108. 2 % compared to that of common non fiber concrete; fi- nal cracking times is equal to 81,is improved by 100. 5% compared to that of common non-fiber concrete. Acoustic emis sion characteristics of BFRC： 1）Average ring count and average energy of BFRC with different fiber admixing amounts is less than that of common non-fiber concrete, basalt fiber plays the role in inhibiting or restraining the creation and propa- gation of crack during flexural impact tests. 2）After the first crack, acoustic emission energy of common non-fiber con- crete is drastically reduced, each impact for BFRC alternately generates high amplitude signal after first peak, basalt fiber delays fracture of concrete and increases its impact toughness.