Investigation of waste foundry sand as an eco-friendly fine aggregate replacement in asphalt concrete

Abstract

This study investigates the use of Waste Foundry Sand (WFS), a byproduct of the metal casting industry, as a partial replacement for fine mineral aggregates in asphalt concrete production. WFS is often discarded as waste, contributing to environmental concerns in landfills. However, its composition and gradation make it a promising alternative material for road construction, offering both cost and ecological benefits. It is noteworthy that Türkiye is an important metal casting producer in Europe and the world, yet there aren't many studies on this topic. The predominant domain of waste material utilization is the road sector, and the objective of this study was to examine the potential benefits and constraints of integrating WFS into asphalt mixtures. In this study, several asphalt mixes were prepared with varying percentages of WFS sourced from foundries in Türkiye, and tested using the Marshall Mix Design method. In levels not previously explored in the literature, 5 different WFS replacement ratios (0%, 3%, 6%, 9% and 12%) and 6 different bitumen contents (ranging between 3.5% to 6%) were tested, resulting in a total of 36 different mix ratios. The results indicated that as WFS content increased, the flow and elasticity values increased, while a reduction in Marshall stability and Marshall Quotient (MQ) values was observed. Mixes with 9% WFS content exhibited the best performance in terms of flow, while high WFS contents negatively impacted stability and MQ values. These findings suggest that WFS could be a viable material for asphalt concrete; however, careful optimization is necessary to balance performance, cost, and environmental impact. Furthermore, the variability of WFS quality and its long-term performance effects warrant further investigation.

Keywords

• Waste foundry sand
• Fine aggregate replacement
• Asphalt concrete
• Environmental sustainability

References

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