Construction of an unpaved road using industrial by-products (bauxite residue)

Utilisation of bauxite residue, the secondary material of alumina production, has been the object of numerous research efforts striving to introduce the by-product in useful applications. In fact, bauxite residue is used today in fabrication of ceramics, in cement production as a colouring agent and in abandoned quarries as a filling material. On the contrary, rare are the research initiatives to date aiming to a potential application of the by-product in highway engineering, a sector capable of absorbing large quantities in earthwork contraction. The Highway Engineering Laboratory of the Aristotle University of Thessaloniki (AUTH) focused on the potential use of this by-product in road construction. This paper details the construction of a gravel road using bauxite residue in the vicinity of the "Aluminium of Greece" industrial plant. The aim of this pilot project was to construct a pavement made of the by-product, trafficable for trucks and other vehicles, resistant to heavy traffic loads and durable to variable climatic conditions and especially to erosion. The layer of bauxite residue applied was processed by fly-ash (3%) and reinforced by bauxite aggregates to provide additional bearing capacity. The success of the project, acknowledged three years after construction, unveils the right balance achieved between technically excellent result and environmentally beneficial solution. Key-Words: by-product; bauxite residue; gravel road; environment