Strength Characteristics of Concrete with Plastic Granules as Partial Replacement for Sand

Abstract

The rising cost of concrete materials, as well increase in waste plastic junks, at the backyards or around buildings in cities in Nigeria necessitate research into the possibility of a more productive use of plastic waste in concrete production or for other purposes. This work presents the results of experimental investigation on the effect of partial replacement of fine aggregate with plastic granules on the workability and compaction characteristics of concrete. Granulated plastic, obtained from waste plastic water tank, was used as partial replacement of sand by 5%, 10%, 15% and 20%. Zero percent replacement was adopted as reference concrete mixture. Nominal mix ratio of 1:2:4 was used for this study and mix compositions were calculated by absolute volume method. Test result show that partial replacement of sand with granulated plastic led to increase in workability and slump of fresh concrete. Increase in partial replacement of sand with granulated waste plastic from 5 – 15% led to increase in compacting factor of fresh concrete. Above this replacement, the compacting factor reduced. Water absorption of fresh concrete also decreased after 10% replacement. The average compressive strength developed by concrete cubes with 0%, 5%, 10%, 15%, and 20% replacement of sand with plastic granules after twenty-eight days curing is 27.50 N/mm2, 24.70 N/mm2, 26.22 N/mm2, 19.19 N/mm2 and 21.82 N/mm2 respectively. The higher the percent replacement of sand with plastic granules, the lower the strength. Concrete with partial replacement of sand with granulated plastic has average dry density of 1752 kg/m3, which is within the range stipulated for structural lightweight concrete (1440 – 1840 kg/m3). Therefore, concrete with granulated plastic may be used as partial replacement for sand where lightweight or low density concrete is required.