Volume 40, Issue 7 (December 2012)
Performance Characterization of Bituminous Mixtures With Dolomite Sand Waste and BOF Steel Slag
The rapid growth of transport load in Latvia increases the demands for asphalt carrying capacity on large motorways. The limestone and sandstone that can be found in Latvia lack the mechanical strength and, for most of the large motorways, the aggregates are imported from other countries causing increase of the costs and growth of emissions from transportation. On the other hand, large amounts of basic oxygen furnace (BOF) steel slag aggregates with good qualities are being produced in Latvia and put to waste. During recent decades, the dolomite sand waste has been accumulating and its quantity has reached a million tons and is rapidly increasing. This huge quantity of technological waste needs to be recycled with maximum efficiency. The lack of experience on the use of steel slag and sand waste requires an accelerated evaluation of the asphalt performance-based characteristics. This paper presents the testing results of different combinations of steel slag, dolomite sand waste, and local limestone aggregates that were proportioned to develop a mixture that would satisfy the requirements of permanent deformation and fatigue. Analysis of the results showed that mixes with steel slag and local limestone in coarse portion and dolomite sand waste in sand and filler portions had high resistance to plastic deformations and good resistance to fatigue failure. These mixes can fully satisfy and, in some cases, significantly overcome the requirements of local asphalt specifications for highly loaded motorways.