Utilization of Plastic Wastes in Asphalt Design for Road Construction

The use of synthetic polymers (Plastics) has become part of our everyday life since their introduction over 100 years ago. Every vital section of the economy ranging from clothing, agriculture, packaging, automobile, medicine, electrical and electronics have been virtually revolutionized by application of plastics. The challenge of the disposal of these plastics after use is what this study seeks to address in part. Low density polyethylene (LDPE) and polyethylene terephthalate (PET) plastic wastes were blended with bitumen as binder for road construction as an effective and valuable means of disposing these wastes, employing marshall hot-mix design. 15% and 30% w/w LDPE and PET wastes of total binder required for the asphalt design were incorporated at 6% optimum binder content. The polymer modified asphalts (PMA) were tested for marshall stability and flow. At 15% w/w LDPE, the stability and flow values are 819 kg and 3.6 mm, respectively, while at 30% w/w LDPE, the stability and flow values are 643 kg and 4.1 mm, respectively. Similarly, at 15% w/w PET, the stability and flow values are 737 kg and 3.3 mm, respectively, while at 30% w/w PET, the stability and flow values are 707 kg and 3.5 mm, respectively. These results are in agreement with the “general specification for roads and bridges, vol. II (1997)” of the federal government of Nigeria, which specifies a minimum of 350 kg and 2-4 mm for stability and flow, respectively. However, the 15% LDPE and PET plastic wastes incorporation gives better results than that of the 30% incorporation.