Sustainable spot treatment for Sri Lanka's highway curves

Abstract

Sri Lanka records nearly 38,000 road crashes annually, causing over 3,000 deaths and 8,000 serious injuries, with losses equal to 3 to 5 percent of national gross domestic product (GDP). Roughly 45 percent of fatal and grievous crashes occur where excessive speed meets hazardous horizontal curves in the central highlands, yet existing safety measures rely mainly on driverbehaviour campaigns and civil works rather than pavement friction restoration. This study examines whether locally sourced aggregate can support High Friction Surface Treatment (HFST) as an affordable, low-carbon spot treatment for such curves, reducing dependence on imported bauxite and proprietary resins. Local quarry samples were tested against UK and AASHTO aggregate specifications, and three resurfacing options, hot-mix asphalt overlay, double bituminous surface treatment, and polymer-resin HFST, were compared using a tenyear Life-Cycle Assessment and Life-Cycle Cost Analysis. Quarry sources from Kandy and Anuradhapura met required friction and durability thresholds. HFST produced the lowest tenyear carbon footprint, despite a higher initial cost, and offered wet-weather crash reduction of 60–83% versus 15–25% for conventional treatment, with service life exceeding ten years. These results empirically indicate that domestically manufactured HFST, applied selectively at high-risk curves, offers a durable, economical, environmentally favourable safety solution for Sri Lanka's mountainous highway network, further warranting pilot-scale field trials on systemlevel performance.