The Effect of Heating Temperature of Asphalt Mixture on The Stability of LDPE Plastic Modified Asphalt: Microstructure and Elemental Composition Study using SEM and XRF

The use of LDPE plastic waste in asphalt mixtures is an innovation aimed at improving road pavement quality while reducing environmental pollution. The purpose of this study was to determine the effect of heating temperature on the stability value of conventional asphalt mixtures and modified LDPE plastic mixtures (AC-WC) through Marshall characteristic testing. It also examined changes in microscopic structure using SEM and changes in chemical composition using X-Ray Fluorescence. This study used a laboratory experimental method with varying LDPE content and asphalt heating temperatures (135°C for conventional asphalt, and 165°C, 170°C, 175°C, and 180°C for modified asphalt). The study was conducted at the Transportation and Highway Laboratory, Faculty of Engineering, Tadulako University, and the Integrated Laboratory of Tadulako University. The results showed that the addition of LDPE significantly increased the stability of the mixture, with the highest value of 2236.09 kg at a content of 1% and a temperature of 180°C, meeting the 2018 Bina Marga specifications. SEM analysis revealed the best microscopic structure at a 0.25% LDPE content (temperature 165°C), with a homogeneous distribution and reduced microcracks, while high content (>0.75%) caused agglomeration. XRF analysis showed an increase in light elements from LDPE, with fluctuations in SiO₂, Al₂O₃, and MgO, without disturbing the balance of the main minerals.