Comparative Life Cycle Cost Analysis of Porous Asphalt Incorporating Nano-Silica and Conventional Porous Asphalt

Porous asphalt is widely applied for its drainage and environmental benefits; however, its relatively short service life increases long-term costs. The addition of nano-silica (NS) has potential to enhance the durability and cost-effectiveness. This study compares the technical performance and life cycle cost (LCC) of conventional porous asphalt and porous asphalt incorporating 6% nano-silica (NS6). A pavement section measuring 1,000 m × 3.5 m × 0.0762 m was analyzed. The overlay intervals were assumed to be 15 years for conventional porous asphalt and 20 years for porous asphalt NS6. The LCC evaluation applied a real-cost approach using Net Present Value (NPV) with a 5% discount rate, considering initial construction, routine maintenance, overlays, and salvage value. Porous asphalt NS6 showed higher initial construction costs (IDR 1.35 billion) than conventional porous asphalt (IDR 983 million, +37.15%). At a 15-year horizon, porous asphalt NS6 was more economical (-6.9%), whereas conventional mixtures were more cost-effective at 20 and 25 years (+10.5% and +15.5%, respectively). Despite the higher initial costs, porous asphalt NS6 offers an extended service life and improved rutting resistance, making it technically and strategically viable. Furthermore, large-scale implementation is expected to reduce the cost of nano-silica, thereby strengthening its economic feasibility.