Asphalt concrete performance with conventional and waste aggregates

Abstract

This paper investigates the use of dolomite sand waste and BOF steel slag for replacing conventional fine and coarse aggregates for design of high performance asphalt concrete. Annually 200 thousand tons of steel slag are being produced in Latvia making it the most available waste aggregate. Dolomite sand waste, which is co-product of crushed dolomite production, is the second widely available waste material in Latvia. At the same time local crushed dolomite and sandstone does not fulfill the requirements for mineral aggregate in high and medium intensity roads. This has raised great interest of highway engineers to find locally available and waste materials as substitute for natural mineral aggregates. This research has showed that physical and mechanical properties of steel slag aggregates and dolomite waste sand are comparable with the characteristics of natural aggregates. Sixteen different combinations of steel slag, dolomite sand waste and conventional aggregates were used to develop AC 11 asphalt mixtures with modified and unmodified bitumen. The mixture performance tests include resistance to permanent deformations (wheel tracking test, dynamic creep test) and fatigue resistance. Tests results showed that asphalt concrete mixture combinations containing 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.