Understanding the effects of stress on the coefficient of thermal expansion

Important coupled effects of stress and temperature change have long been recognised and taken into account in models assessing the performance of solid materials. However, due to incomplete understanding, existing models used for concrete are essentially empirical and lack rational basis. This limits their predictive capability and applicability range. In this paper, fundamental thermodynamics and continuum mechanics laws are used to obtain an expression that quantitatively predicts the effects of stress on the coefficient of thermal expansion. The newly-defined thermal expansion coefficient is then used to develop a rational model, which is shown to be capable of reliably quantifying the coupling effects of stress and temperature change. Good agreement between the model predictions, available data and observations is obtained. Equally important, all parameters of the developed model can be determined using simple tests. This enables a wide adoption of the model in practical engineering applications. While this paper uses data for concrete, the proposed model is developed from first principles and using fundamental physical laws. The model should thus be applicable to a wide range of solid materials.