Thermal conductivity and shrinkage properties of modified waste polystyrene aggregate concretes

Using artificial aggregate in replacement of natural aggregate in production of concrete has a tendency to increase by the future in order to provide greater sustainability in construction industry. This study investigates the effectiveness of thermal modified waste expanded polystyrene (MEPS) on the workability, density, thermal conductivity and shrinkage of concrete. MEPS aggregate was used as lightweight aggregate in concrete by 25%, 50%, 75%, and 100% in replacement of natural aggregate. The thermal conductivity of samples decreased with increasing of MEPS aggregate and their values were 1.990, 1.518, 1.000, and 0.600 W/mK for 25%, 50%, 75%, and 100% MEPS aggregate in replacement of natural aggregate, respectively. Maximum reduction in the thermal conductivity was observed at the samples that made up of 100% MEPS aggregates and the reduction percentage was around 70%. The average drying shrinkage after 210-day of ambient curing condition was 2.59 × 10−3 for samples of 25% natural aggregate, while it was 5.08 × 10−3 for 100% MEPS aggregate samples.