Acoustic emission characteristics of stainless steel reinforced geopolymer coral concrete beams under four-point bending

Abstract

The fabrication of geopolymer coral aggregate concrete beams (GCACB) can effectively address the challenges associated with constrained concrete raw materials and structural erosion in island construction. Acoustic emission technology (AE) presents an appealing solution for non-destructive evaluation and structural health monitoring. In this study, 6 specimens were conducted to examine the flexural behavior of GCACB accounting for variation in the reinforcement ratios under the four-point bending test, simultaneously recording the corresponding AE data. Then, the effect of the AE parameters on crack development was analyzed. By utilizing the GMM algorithm, the crack pattern classification was investigated. Finally, the GCACB damage was evaluated based on two different AE b-value analysis methods. The findings indicate that the cracks within GCACB predominantly occur along the coral coarse aggregate with low strength and high brittleness. The presence of reinforcement ratio has an enhancement on both the flexural capacity and deformation capacity of GCACB while impeding the crack width. It seems that a positive correlation between increasing crack damage and cumulative hits and AE energy occurs. Based on the enhanced GMM model, the cracks are categorized into tensile crack, shear crack, and mixed crack, with tensile crack predominating. A probabilistic division line is established for the RA-AF relationship that progressively leans towards the AF axis as the reinforcement ratio increases. In contrast to the b-value obtained from the GBR method, the Aki method demonstrates enhanced predictive capability for GCACB damage.