Mechanical properties of mortars with waste plastic as replacement of natural aggregate

The use of waste plastic from waste electrical and electronic equipment as a substitute for natural aggregates in cementitious materials is an increasingly relevant issue. If proved to be suitable, this would allow the recycling of plastics destined for landfill and decrease the use of new natural resources. However, replacing sand with plastic tends to reduce the mechanical properties of mortars due to the different mechanical properties of natural aggregate and waste plastic and the poor interfacial compatibility between plastic and cement paste. Several strategies to improve the mechanical properties of mortars containing waste plastic were investigated in this study. The addition of 1% of superplasticiser coupled with a lower water/cement ratio was found to restore mechanical properties to values equal to a standard mortar prepared with natural aggregate, thus obtaining material that can be used in construction.