Recycling foundry sand in road construction-field assessment

摘要

Foundry industry produces a huge quantity of foundry sand; its management has become an environmental, economic and social imperative since it is now considered as dangerous waste. Besides, non-renewable natural resources conservation drives investigations on potential recycling of industrial by-products. A source of 150,000 tons of foundry sand stock near a secondary road under rehabilitation led to an investigation on the feasibility recycling of this waste within sub-base layer. The new road material has to satisfy geotechnical functions and environmental prescriptions, avoiding any important leaching of polluting elements. This paper presents the chemical analysis of this by-product, the formulation of a sub-grade material and its leaching behavior assessed by experimental site monitoring. The results show that this foundry sand, treated by 5.5% of hydraulic binder, displays acceptable mechanical performances and do n't shows environmental impacts. This investigation demonstrates that this foundry sand can be used in road layers as road materials.