A preliminary study on lightweight concrete made from Polystyrene waste

Abstract

Increasing importance of environmental awareness around the world has drawn a great attention on polymer recycling. The recycling processes are commonly meant to reproduce other polymeric material for domestic use or energy recovery from complete incineration. However, in Malaysia, only a small portion of discarded polymer was recycled while the rest was disposed at the landfill. Modifying polymer waste as an alternative construction material is seen as a highly potential step to overcome the severe increment of polymeric waste production. This paper discusses the experimental study on the substitution of conventional aggregate made of crushed stone with modified polystyrene waste aggregate to produce lightweight concrete. Waste polystyrene foam was modified by heat treatment to transform the soft material into a hard aggregate. The best temperature to produce aggregate with the highest compressive strength was 170oC. The aggregate was later used to substitute conventional aggregate in various mix design. Light weight concrete made of modified polystyrene aggregate with the highest compressive strength of 18.05MPa was produced by substituting 75% of the crushed stone. The density of this concrete was 1753 kg/m3, 29.51% lower than normal weight concrete. From the overall tests conducted, modified polystyrene can be successfully used to substitute conventional aggregate for lightweight concrete production with satisfactory properties and characteristics which are comparable with the normal weight concrete using crushed stone.