Feasible use of colliery spoils as subbase layer for low-traffic roads

Abstract

The aim of this paper is to characterise, both physically and chemically, the colliery spoils of Pozo San José, located in the Guadiato Valley (Córdoba, Spain), and evaluate their possible use as unbound materials or as materials bound with lime or cement in the construction of roads with low traffic intensity. The leaching of the material and its effect on the environment was also studied. The results obtained show that the main limiting property of the material is its high organic matter content. However, colliery spoils can be used unbound or bound with 2% of cement as a subbase, thus giving a second life to the colliery spoils of this mining region that currently have no purpose. The use of colliery spoils bound with lime is not recommended, since their mechanical properties are not improved. Finally, two sections are designed for roads with a traffic intensity of up to 24 heavy vehicles/day. This research contributes to the promotion of the new paradigm of the circular economy in the construction sector.