Investigation of foam concrete's mechanical properties and multi-scale damage evolution characteristics under uniaxial loading

Abstract

The macroscopic mechanical behavior of foam concrete damages its mesoscopic pore structure. To study the macroscopic mechanical properties of foam concrete, a series of uniaxial compression tests were carried out. AE-DIC and SEM characterization were used to reveal the multi-dimensional damage evolution characteristics of foam concrete under load. Furthermore, the porosity response law of the foam concrete damage characteristics was analyzed using the finite element method. The results show a significant linear relationship between the residual and peak stress of foam concrete under uniaxial load (σr = kσp), and the coefficient k decreases with an increase in porosity. During uniaxial compression, tensile and shear damages were dominant on both sides of the yield point of foam concrete. The macroscopic load retention characteristics in the failure stage typically result from microscopic fracture structure reorganization and stress path optimization. The damage-dissipation energy during this period accounts for approximately 100% of absorbed energy. An increase in the porosity led to frequent adjustments in the stress path of the foam concrete, and the tensile damage tended to be significant and diffuse.