Marshall performance evaluation of coarse stone matrix asphalt utilizing water-cooled nickel slag aggregate in sustainable development

This study investigates the potential use of water-cooled nickel slag as a partial replacement for coarse aggregates in Stone Matrix Asphalt (SMA) mixtures and evaluates its impact on mixture performance. The research varies asphalt content levels 6%, 6.25%, 6.5%, 6.75%, and 7% with 100% of the coarse aggregates replaced by nickel slag. Marshall mix design tests were conducted to assess the mixtures’ stability, flow, and volumetric properties, including Voids in the Mixture (VIM) and Voids in Mineral Aggregate (VMA). The results indicate that Marshall stability increases in a parabolic trend with asphalt content, peaking at 807.48 kg for 6.25% asphalt content. The Marshall flow values at all asphalt content levels 3.8 mm, 3.4 mm, 2.2 mm, 2.5 mm, and 2.9 mm, respectively comply with specification requirements. Volumetric analysis shows that as asphalt content increases, VIM decreases slightly 4.17%, 4.12%, 4.10%, 4.06%, and 4.03% but remains within the acceptable range of 3–5%. Conversely, VMA increases with asphalt content, yielding values of 17.15%, 17.44%, 17.05%, 18.04%, and 18.33%, all of which exceed the minimum requirement of 17%. This supports sustainable infrastructure development by reducing reliance on natural aggregates.