SYNERGISTIC EFFECT OF PLASTIC WASTE AND SILICA FUME ON PROPERTIES OF RECYCLED AGGREGATE CONCRETE AT AMBIENT AND AFTER ELEVATED TEMPERATURES

The recycling and utilization of waste materials are among the most difficult challenges faced by governments throughout the world. Previous researches have pointed towards wa...aste consumption in the production of concrete, the second largest material consumed globally. This study is intended to assess the synergistic effect of plastic waste and silica fume on the properties of recycled aggregate concrete at ambient and after elevated temperatures. The fine natural aggregates in recycled aggregate concrete will be replaced by plastic wastes in proportions of 15%, 30%, 45%, and 60%. Furthermore, silica fume will be used as a replacement for cement to recover the properties of concrete containing waste plastic and recycled aggregates. Workability, density, water absorption, porosity, abrasion resistance, drying shrinkage, thermal conductivity, compressive strength, splitting tensile strength, flexural strength, and ultrasonic pulse velocities will be measured for different concrete mixtures. Fire resistance of the concrete mixtures will be evaluated in terms of weight loss, crack growth, spalled area, and residual strength after exposure to elevated temperatures. The optimized concrete mixture in terms of maximum waste utilization, reasonable strength, and fire resistance will be used to cast concrete-filled steel tubes. The concrete-filled steel tubes will be tested in uniaxial compression to explore the possibility of using recycled aggregate concrete containing a high percentage of plastic waste modified by silica fume for structural purposes.