Experimental study on the flexural behavior of engineering geopolymer composite and concrete composite beams combined with acoustic emission technology

Engineered geopolymer composite (EGC) is an emerging and environmentally friendly cementitious material that shows great potential for application. The purpose of this study is to reveal the effect mechanism of EGC on the bending performance of composite beams. This is achieved by comparing and analyzing the bending failure characteristics of EGC and OPC composite beams with different EGC layer thicknesses and reinforcement ratios. The acoustic emission (AE) technique was introduced to monitor the damage characteristics of the composite beams during flexural loading, and the influence of diverse parameters on the failure mode, cracking and yield strength, energy dissipation capacity, and AE characteristics was assessed comprehensively in this study. The results demonstrate that the EGC layer in the composite beam exhibits excellent crack control under bending load, presenting a multi-cracking characteristic. The capabilities for load-bearing and energy dissipation of the beam are enhanced as the thickness of the EGC layer and reinforcement ratio increase. In the damage process of EGC, the AE amplitude follows a power-law distribution, and the distribution of AE events in the EGC layer is denser than that in the OPC layer. The theoretical calculation model of the bearing capacity established in this study has extensive applicability and can accurately predict the cracking behavior. This study provides scientific evidence for improving the flexural performance of concrete structures using EGC and has promoting significance for broadening the application scope of composite materials.