Performance of SMA Mix modified with waste plastic and fiber

Waste materials are harmful to the environment when incinerated, dumped in open water, or landfilled. Present-day society faces a serious challenge from the growing amount of waste materials and the need for a sustainable solution. Due to the limited amount of natural raw materials, there is a global need to minimize the amount of waste. Using suitable waste materials, such as waste plastic, as additives in asphalt mixtures is a viable strategy, offering an alternative to virgin materials like polymer-modified asphalt binders. This research studied the influence of waste fibers as a stabilizer and recycled Polyethylene waste as an asphalt modifier in the Stone Mastic Asphalt mix (SMA). Two categories of the SMA mixes were produced, base and modified mixes, with three different mixes under each category. The rheological properties of the Recycled Polyethylene Modified Asphalt (RPMA) have been assessed using different Recycled Polyethylene (RP) dosages at the upper-performance temperature. In addition, two Recycled Fibers (RF), cellulose and jute, were used as stabilizing materials for SMA mixes. The impact of RP and RF on the SMA mixes was investigated using three tests: Drain-down resistance, moisture sensitivity, and rutting performance. Statistical analysis was conducted to assess the effect of the additives on the measured SMA properties. The results showed that adding RP and RF improved the SMA mixes' ability to hold the asphalt and fine material inside the mix and solved the drain-down problem by 81.43%. In addition, adding RP as an asphalt modifier greatly enhanced the moisture and rutting resistance by 47.5% and 93%, respectively.