Estimation Of Thermal Conductivity Of Fine Concrete With Recycled Pet Flakes By Two-Scale Homogenization Method

The present work aims to estimate the macroscopic thermal conductivity of fine concretes with recycled PET (Polyethylene terephthalate) flakes (Concrete with Waste Recycled Plastic - CWRP). To achieve this objective, the PET flakes are first assumed to exhibit a penny-shaped inclusion form whose aspect thickness/width (t/w) ratio is given as t/w = 1/33.33. These PET flakes are then supposed to be randomly distributed and oriented in a mortar phase consistuting of a cement paste (matrix) and silicious sand (inclusions). Next, a simple analytical two-scale homogenization method based both on different homogenization schemes and on the Eshelby's solution is proposed to determine first at the mesoscopic scale the conductivity of the mortar and compute then at the macroscopic scale the effective conductivity of the fine concrete with recycled PET flakes. Finally, by varying the volume percentage of sand including 5, 10, 15, 30, 50 and 100 % of PET flakes, we show that the analytical results obtained for the effective thermal conductivity of CWRP by using the analytical homogenization method are in good agreement with experimental values.