Mechanical Performance and Acoustic Emission Characteristics during Fracture of Strain-Hardening Cementitious Composites with High-Content Fly Ash | Journal of Materials in Civil Engineering | Vol 35, No 1

AbstractThe emergence of strain-hardening cementitious composites (SHCCs) improves brittle cracking of concrete materials. SHCC has the characteristics of strain hardening and multiple cracking under tensile load. In this study, 10 groups of SHCC were developed by incorporating polyvinyl alcohol (PVA) fiber into cement-based materials with high-content fly ash. Testing variables included water/binder ratio, sand/binder ratio, fly ash and cement content, and sand particle. The tensile test on the thin-plate specimen and compression test on cylindrical specimen were carried out. In addition, the double-edge notched plate specimens with relative notch lengths of 0.2, 0.4, and 0.6, respectively, were tested. The results showed that the average ultimate tensile strain of SHCC was 403 times that of ordinary concrete, and the peak compressive strain was about four times higher than ordinary concrete. The ultimate tensile strain of SHCC with high-volume fly ash ratio is generally higher than the low-volume fly ash ratio group. The failure mode of SHCC was ductile with good energy dissipation. Also, SHCC compressive strength is mainly adversely affected by the water/binder ratio and the ratio of cement to fly ash. With the increase of compressive strength, the angle of the failure face was reduced under compression. The acoustic emission (AE) activity captured the initiation and development of cracks at the three stages in the notched specimens under tension. With the increase of the notch length, the fracture energy calculated by the tensile stress–crack mouth opening displacement (CMOD) curve decreases.

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