A new technique of processing for waste-expanded polystyrene foams as aggregates

In daily life, expanded polystyrene foams (EPS) are widely used as packaging material, construction material, and in household appliances as well as many others. On the other hand, waste EPS has caused lots of environmental pollutions because it cannot be decomposed in nature. Utilization of waste EPS in concrete technology is more common. In this study, a new recycling process developed of the waste EPS foams by using heat treatment. Its characters and process are described in this paper, as well as its experimental system. This technique reduces the volume of waste EPS about 20 times of the original. Before the heat treatment, the average density, thermal conductivity and compressive strength of waste EPS foams were 10 kg/m3, 0.0368 W/mK, and 0.12 MPa, respectively. The best result of modification was determined at 130 °C and 15 min. After the modification, density, thermal conductivity and compressive strength of waste EPS, increased to 217 kg/m3, 0.0555 W/mK and 8.29 MPa, respectively. This new material, which is obtained after the heat treatment, is called modified waste EPS (MEPS).