Comparative Environmental Impact Assessment of Conventional Pavement Layers and Cement-Treated Recycled Base: Equipment Usage Analysis in Tropical Road Construction Projects

Abstract

This study investigates the fuel consumption, energy consumption, and carbon dioxide emissions associated with different pavement foundation structures in road construction projects in Palangka Raya, Indonesia. Using field data gathered at two study locations, the study contrasts the environmental impact of Cement-Treated Recycled Base (CTRB) with that of conventional Sub-Base and Base layers. Palangka Raya’s tropical climate offers difficulties for construction equipment operations, given its proximity to the equator and constant high temperatures. The study used a quantitative method to gather primary data on heavy equipment fuel consumption and verify it against theoretical calculations using known formulas and emission factors. Results show that CTRB works exhibit significantly higher fuel consumption (12.23 L/m³), energy consumption (440.13 MJ/m³), and carbon emissions (32.65 kgCO₂/m³) compared to conventional Sub-Base (1.47 L/m³, 52.73 MJ/m³, 3.91 kgCO₂/m³) and Base layers (1.53 L/m³, 54.96 MJ/m³, 4.08 kgCO₂/m³). With variations between field data and calculations ranging from−3.22% to 7.88%, the study revealed that Palangka Raya’s tropical climate equipment regularly consumed 0.48–0.49 L/h more fuel than model projections. This result emphasizes the trade-off between the long-term durability of CTRB and its higher environmental impact during construction, especially in hot tropical areas. Emphasizing the need for a thorough assessment of construction techniques, considering both immediate environmental effects and long-term sustainability elements, the study finds that choosing pavement foundation structures significantly affects energy efficiency and carbon emissions in road building. Particularly in tropical areas, the study offers insightful analysis of environmentally responsible building practices and promotes sustainable methods in civil engineering.