Experimental investigation of a new sustainable approach for recycling waste styrofoam food containers in lightweight concrete

The disposal and treatment of non-biodegradable styrofoam food containers are excessively expensive for any government. So, finding a technical economic solution to reuse and utilize these waste products in a sustainable environmentally friendly approach is a big challenge. This study represents a novel preliminary investigation of utilizing waste styrofoam food containers to partially replace the natural aggregate in lightweight concrete mixes. Six types of concrete mixes were prepared with different aggregates substitution percentages of 0%, 2.5%, 5%, 7.5%, 10%, and 12.5% by volume. The results indicated that the replacement of aggregate by appropriate WSFC content produced a workable concrete with a maximum density reduction of approximately 21.8% when the percentage replacement of the natural aggregate by waste styrofoam was 12.5%. The results revealed that compressive and flexural strength decreased with increasing the waste styrofoam content at different curing ages of 7, 14, 21, and 28 days. The maximum decrement ratio was 81.5% and 57% for compressive and flexural strength, respectively, for WSFC5 at 28-day curing, while, by increasing the temperature to 600 °C for one hour, the maximum decrement ratio of compressive strength was 10.18% compared to the plain concrete mix. Also, the results demonstrated that about 46% was the maximum decrement ratio of thermal conductivity for WSFC5 at 28-day curing compared to the plain concrete.