We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Tensile Strength of AC-BC (Asphalt Concrete – Binder Course) Asphalt Mixture Using Low-Density Polyethylene (LDPE) Plastic as an Additive: A Marshall and SEM Microstructural Study
Summary
Researchers found that mixing recycled plastic bag waste (LDPE) into road pavement, up to about 4%, actually makes roads stronger and more crack-resistant, offering a promising way to reuse plastic trash instead of sending it to landfills or letting it pollute the environment. This matters for human health because reducing plastic waste in the environment means less of it breaking down into microplastics that can end up in our water, food, and air; however, this study focused on pavement durability, not on whether plastic-infused roads themselves shed microplastics over time, so that question still needs research.
Flexible pavement, particularly the Asphalt Concrete–Binder Course (AC-BC) layer, plays an important role in distributing traffic loads and therefore requires an asphalt mixture with good tensile strength. Meanwhile, Low-Density Polyethylene (LDPE) plastic waste remains a significant environmental problem in Indonesia. This study analyzes the effect of adding LDPE plastic as an additive on the Indirect Tensile Strength (ITS) of AC-BC asphalt mixtures and observes the resulting microstructural changes through Scanning Electron Microscope (SEM) testing. LDPE was added using the dry process at variations of 0%, 2%, 3%, 4%, and 5% of the coarse aggregate weight, at the optimum bitumen content (5.80%) obtained from Marshall testing. Specimens were evaluated through Marshall and indirect tensile strength testing. Results show that the ITS value increased with increasing LDPE content up to 4%, reaching a maximum of 0.108 kg/mm², before decreasing at 5% content. A quadratic regression analysis (y = −0.0038x² + 0.0261x + 0.637; R² = 0.9957) produced a theoretical optimum point at 3.434% LDPE content with a maximum ITS value of 0.107 kg/mm², closely matching the experimental result. SEM observations supported these findings: the 4% LDPE content produced the most homogeneous surface morphology, with better interfacial bonding among aggregate, bitumen, and LDPE, and fewer voids and microcracks, whereas the 5% content exhibited LDPE particle agglomeration that reduced mixture compatibility. Based on the combined results of Marshall, ITS, and SEM testing, an LDPE content of 4% is recommended as the optimum level for improving the resistance of AC-BC mixtures to cracking under indirect tensile loading.