Comparative life cycle assessment of asphalt modified with mineral-based and biomass-derived nano silica

Abstract

Asphalt pavements are prone to issues such as permanent deformation and cracking, which reduce pavement lifespan and increase maintenance costs. As a result, there is a growing demand for asphalt mixtures that offer higher durability and improved performance over time. To meet this need, researchers have explored various modifiers, with nano silica emerging as a promising material due to its ability to enhance the mechanical and structural properties of asphalt binders. Nano silica (SiO2) is one of the most commonly used nano additives due to its ability to improve the mechanical properties of asphalt mixtures. However, nano silica is produced from non-renewable sources, raising concerns about its environmental sustainability. This study compares the environmental impacts of nano silica and rice husk, a renewable agricultural by-product, as asphalt modifiers using Life Cycle Assessment (LCA). The system boundary includes the cradle-to-gate phase, covering raw material production, transport, and asphalt mixing. The results show that rice husk produces lower impacts in several categories, including global warming potential, fossil resource scarcity, and cumulative energy demand. These findings suggest that rice husk can be a more sustainable alternative to nano silica in asphalt modification while maintaining environmental performance.