A modified model considering the influence of porosity on thermal conductivity of iron sand cement mortar based on cubic three-phase model

Abstract

To improve calculation accuracy of cubic three-phase (CTP) model and figure out the influence of porosity on thermal conductivity, a thermal conductivity modified model for iron sand cement mortar (ICM) was proposed. Under the different water-cement (W/C) ratio, river sand-iron ore sand (R/I) ratio and sand-cement (S/C) ratio conditions, the experimental thermal conductivities of cement paste and ICM were measured by the laser flash method, and their theoretical thermal conductivities were calculated by CTP model. Moreover, the first functional relationship between ICM’s porosity and its experimental values of thermal conductivity, and the second functional relationship between ICM’s porosity and its theoretical values were both established using regression analysis. Afterwards, the difference between the first functional relationship and the second functional relationship was defined as the modified function in different conditions. Finally, the thermal conductivity modified model considering the porosity was proposed based on CTP model and modified function. The thermal conductivity modified model was compared with other theoretical models, and the results show that the modified values have a good agreement with experimental values, and it can enhance the calculation accuracy greatly. In this paper, a modified method between the experimental value and the theoretical value was proposed, which provides a practical basis and theoretical method for optimizing experimental value.