Utilizing plastic for pretreating recycled construction aggregate to eliminate binder absorption in asphalt mixture

The growing quantities of waste materials, lack of natural resources and shortage of landfill spaces represent the importance of finding innovative ways of reusing and recycling waste materials. Due to the large quantities of construction and demolition waste (CDW), recycling and utilization of Recycled Construction Aggregates (RCA) obtained from CDW in construction projects, including asphalt pavement construction, can be the most promising solution to this problem. Asphalt mixtures containing RCA have the problem of high bitumen absorption. Using plastic waste in RCA-contained asphalt mixtures reduces not only bitumen absorption but also the adverse environmental impacts associated with plastic waste disposal due to the nonbiodegradability of plastic waste. In addition, the demand reduction for virgin aggregates is another advantage resulting in subsequent economic advantages. This paper characterizes the effects of different types of plastic on the bitumen absorption and properties of asphalt mixtures containing RCA through laboratory investigation. Different types of plastic including High-Density Polyethylene (HDPE) and LowDensity Polyethylene (LDPE) were investigated in this research. The test results indicate that the plastic waste can be a viable material for improving the problem of high bitumen absorption of asphalt mixtures containing RCA.