Investigation on reinforcement of aligned steel fiber on flexural behavior of cement-based composites using acoustic emission signal analysis

• Published in: Construction & building materials 2019-03, Vol.201, p.42-50
• Main Authors: Mu, Ru, Xing, Peng, Yu, Junchao, Wei, Luansu, Zhao, Quanming, Qing, Longbang, Zhou, Jian, Tian, Wenling, Gao, Shuling, Zhao, Xiaoyan, Wang, Xiaowei
• Format: Article
• Language: English
• Subjects: Acoustic emission; Acoustic emission testing; Acoustic properties; Aligned steel fiber; Analysis; Cements (Building materials); Flexural strength; Mechanical properties; Steel fiber reinforced cement-based composite
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.12.084

•The cracking of ASFRC under three-point bending was monitored by Acoustic Emission.•The effect of fiber orientation was identified by AE signal analysis.•AE analysis proved that ASFRC has more fibers pulled out and less matrix crush.•The mechanism of the reinforcement of aligned steel fibers is suggested. This study is aimed at exploring the mechanism of the reinforcement of aligned steel fibers on the mechanical properties of cement-based composite by acoustic emission (AE) signal analysis. Flexural tests were carried out and the results shown that the flexural strength of aligned steel fiber reinforced cement-based composite (ASFRC) increases by around 50% over that of conventional steel fiber reinforced cement-based composite (SFRC) with randomly distributed steel fibers inside. In the flexural tests, the interior deterioration of the specimens was monitored by AE. AE signal analysis results show that, compared to the conventional SFRC, the ASFRC specimens with aligned steel fibers have larger number of signals originated by the steel fiber pullout on the fracture sections, which indicates that there are more steel fibers working. It is also found that in the specimens with aligned steel fibers the local damage of matrix around the fibers in the fracture section caused by the pullout of steel fibers is less than that in the specimens with randomly distributed steel fibers. The difference in the local crushing of matrix and the number of steel fibers (AE signals) in fractured sections between the ASFRC and SFRC specimens may be the main reasons that ASFRC is superior to SFRC in mechanical performance.