Theoretical model for thermal conductivity of rubber-sand mixtures based on similarity heat conduction principle

The aims of this study are to quantitatively assess the thermal conductivity of the artificial rubber particles-sand mixtures and to break through the limited applicability of the current empirical models. Based on the Wiener model and similarity principle, the thermal conductivity of each constitute in the mixtures is analyzed, and a theoretical model for calculating the thermal conductivity of the mixtures is developed. The meaning and the determination method of each parameter in the new model are investigated. The validity of this new model is verified throgh the thermal conductivity data derived from the existing literatures, and further lines of inquiry for the thermal conductivity model are discussed and suggested. The results indicate that the rubber particles process comparable thermal-transmission capacity to the pore water within the rubber-sand mixtures. Therefore, they can be categorized as similar thermal transfer medium when applied in either series or parallel Wiener models. The new model systematically consider the influences of rubber content, particle size ratio, saturation level and porosity on the structure and the thermal conduction capacity of the rubber-sand mixtures. It accurately describes the relationship between the thermal conductivity of the mixtures and either the rubber content or the particle size ratio, and shows high accuracy to the measured data results. Exploring the effects of complex stress state and the extreme climatic conditions on thermal conduction property of the rigid-soft granular particle mixtures is suggested important for further investigating and improving the proposed new model.