Performance of Asphalt Concrete With Dolomite Sand Waste and Bof Steel Slag Aggregate

Abstract

The rapid growth of traffic loads in Latvia increases the demands for asphalt carrying capacity on large motorways. The dolomite and sandstone that can be found in Latvia lacks the mechanical strength and for most of the large motorways the aggregates are imported from other countries causing increase of 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 the recent decades, the dolomite sand waste has also been accumulated and its quantity has reached a million of tons and is rapidly increasing. This huge quantity of technological waste needs to be recycled with max efficiency. The lack of experience in the use of steel slag and dolomite sand waste requires an accelerated evaluation of the asphalt performance-based characteristics. This paper presents the testing results of dense graded asphalt concrete AC 11 mixtures made of four types of aggregate: steel slag, dolomite sand waste, conventional imported dolomite aggregates and conventional local crushed quartz sand that were proportioned to develop a mixture that would satisfy the requirements of permanent deformation and stiffness. Analysis of the results showed that the mixes with steel slag and dolomite waste sand or unconventional aggregate combination with dolomite in coarse portion, crushed quartz sand in sand portion plus dolomite waste sand in sand and filler portions had high resistance to plastic deformations and fatigue failure. These mixes can fully satisfy and in some cases significantly overcome the requirements of local asphalt specifications for highly loaded motorways.