Axial Deformation Behavior and its Moisture Response of Adobe Materials

Abstract

Due to the unique absorption characteristics of sediment particles, the environmental relative humidity (RH) significantly affects the stability of adobe building during service. Based on an experimental study of adobe materials equilibrated at 50% RH, 60% RH, 70% RH, 80% RH, and 90% RH, the deformation behavior and damage process on a mesoscopic scale were exhibited through discrete element method (DEM) simulation. The stress-strain (σ-ε) constitutive models related to its own attributes were established by normalized dimensionless treatment. The results showed that the loading capacity and deformation properties of adobe materials were declined with the increasing equilibrium humidity. When adobe materials equilibrated at 90% RH, its compressive strength, elastic modulus, peak stress, peak strain, and strain energy were reduced by 24.3%, 12.3%, 17.1%, 10.6%, and 29.9%, respectively compared to those of specimens equilibrated at 50% RH. According to the mechanical properties of adobe materials equilibrated at different humidity settings, the mesoscopic parameters of DEM were determined. DEM simulation demonstrated the generation, growth, and lapping process of cracks in adobe materials through force chain transfer and bonding fracture among particles, and illustrated the impact of changes in equilibrated humidity on their deformation process. In accordance with test curves of adobe materials equilibrated at different humidity under axial compression, segmenting σ-ε constitutive models were constructed by normalization method, where the constants could be expressed by the elastic modulus or compressive strength of adobe materials.

Keywords: Adobe materials, relative humidity, Discrete element analysis, Stress-strain curve, Constitutive models, cement-based materials