Thermal Stability of Lightweight Concrete with Incorporated Regranulated Polypropylene Aggregate

Plastic waste and its low recycling rate make a significant contribution towards the pollution of the environment. Therefore, it is essential that plastic waste is utilised in different applications, such as aggregates in concrete. Since the coefficient of thermal expansion of polypropylene (PP) is significantly higher than for the ordinary concrete, the resulting mismatch in thermal expansion behaviour of the lightweight concrete can cause many problems, especially when the external temperatures reach the higher values. In this paper, an investigation of a manufactured plastic aggregate as a partial replacement for natural silica aggregate in concrete is presented. For concrete manufacturing, regranulated polypropylene (R-PP) waste coming from PP pipes production was used for the partial replacement of silica sand in concrete mix composition by 10, 20 and 30 mass % respectively. The studied materials were heated up to 120 °C. The basic physical properties before and after thermal treatment were studied. To analyse the thermal strain and the coefficient of thermal expansion of the studied materials, the horizontal thermodilatometry was applied. (paper)