A coupled thermo-mechanical damage model for fired clay bricks based on the unified strength theory

On the rise request for long-lasting materials, clay materials are in between the well-nigh minerals exploited by production and ecological fields in the making of fired bricks. Clay incessantly expounded to high temperature reacts differently at ambient temperature which critically touches its longevity. In present study, a coupled thermo-mechanical damage model of clay is established. In this model, the Unified Strength Theory (UST) criterion is used as the failure criterion based on the Weibull distribution and the continuous damage theory. The proposed model is validated by uniaxial compression experiment of high-temperature clay. The variation of the two distribution factors (m and W0) in the combined TM damage relationship with temperature is analysed. The results show that the damage evolvement speed of the clay shows a curving form getting closed to one as the temperature rises, indicating that the temperature can delay the development of cumulative damage. The damage fundamental modelling discussed is in accord with the testings curves at the various phases of yielding and pre-apex force. This study leads to an enhanced understanding of high temperature clay mechanics and affords the fundament to heighten clay bricks resourcefulness lastingness.