Effect of waste electronic plastic and silica fume on mechanical properties and thermal performance of concrete

Abstract

Production of plastic and the resulting plastic waste is on the rise due to the rapid increase in population and urbanization. In this context, studies investigating the recycling and reuse of plastic waste in construction industry provides an avenue to reduce adverse environmental impacts of waste plastic and to save natural resources. This research work investigates the use of plastic fine aggregate (PFA) manufactured from electronic waste as a replacement of natural fine aggregate in concrete. Concrete mixes with 10%, 15%, and 20% replacement of natural sand with PFA are prepared and tested. Fresh properties are studied based on workability and density while mechanical properties are studied based on compressive strength, split tensile strength, stress–strain behavior, Poisson’s ratio, and lateral-to-axial strain ratio. The results revealed that manufactured PFA improves the workability of concrete but as expected, the compressive and tensile strength was reduced significantly. To improve the strength properties, silica fume (SF) is incorporated in the concrete mix as a replacement of cement with same replacement percentage as for PFA. Addition of silica fume minimized the effects of plastic aggregate on strength properties with compressive and tensile strength of concrete showing a reduction of only 4.7% and 1.1%, respectively, for maximum replacement of plastic aggregate and silica fume. Indoor and outdoor thermal performance tests showed that concrete with 20% replacement percentage of PFA and silica fume exhibits better thermal performance with an average reduction of 8% in the thermal conductivity. Results from thermogravimetric analysis showed an increased loss of mass at around 300 °C to 480 °C in addition to the usual weight loss that concrete exhibits from 600 to 800 °C. Overall results suggest that plastic aggregate can be utilized as a natural fine aggregate replacement to produce eco-friendly concrete with comparable strength properties and improved thermal properties.