Experimental study and modeling on effective thermal conductivity of EPS lightweight concrete

The effect of expanded polystyrene (EPS) inclusions on thermal conductivity of lightweight concrete is studied. Various mixtures are produced by incorporating EPS aggregate at different volumes (0%, 10%, 20%, 30% and 40%) in concrete with three water/cement ratios (0.55, 0.50 and 0.45). The apparent density and thermal conductivity values of expanded polystyrene concrete decrease as the volume of EPS increases. The thermal conductivity increases with an exponential function of the apparent density whatever the water/cement ratios. The general thermal conductivity models can not well predict the present experimental results. Based on experimental results and composite approach, a new simplified model is proposed to evaluate the effective thermal conductivity with an equation of the plain concrete thermal conductivity, the EPS thermal conductivity, the density and the percentage of EPS particles. The model is applicable to the EPS lightweight concretes with different water and cement ratios.