Calculation of thermal conductivity coefficient of a binary mixture

Abstract

A correct consideration of the thermal factors during the design phase of civil engineering structures in the permafrost area determines their reliable and safe exploitation. Among the important indicators in selection of design solutions is the thermal conductivity coefficient of the construction materials used. The thermal conductivity coefficient is usually chosen from reference tables, but when using mixtures, the thermal conductivity coefficient is determined through a calculation. The aim of the present research was to compare the calculated values of thermal conductivity coefficient of binary mixtures (a mixture of a binding material and a filler) obtained using Lichtenecker and Schwerdtfeger formulas. The comparison was conducted in the range of properties of materials used for thermal accumulation and thermal insulation mixtures. It was determined that for thermal accumilation binary mixtures the calculation results are quite similar within a wide range of initial values. For thermal insulation binary mixtures, the calculation results are significantly different. The divergencies are by hundreds of percents. At the current stage of research it is impossible to make a conclusion about suitability of either calculation method to determine the thermal conductivity of a thermal insulation binary mixture.