Performance of Glass and Steel Slag Mixtures as a Partial Replacement for Fine Aggregate in Asphalt Concrete

Solid waste management is a significant challenge  particularly in developing countries for example Nigeria. The waste disposal technique is inadequate as negative effects from improper solid waste dumping can be easily visible in the environment. Recycling and reuse of wasteas aggregate in asphalt production may be an economic way to reduce these problems. This research evaluates the viability of crushed waste glass combined with steel slag (GSS) as fine aggregate in asphalt wearing courses. The Marshall mix method was used in production and evaluation of samples. GSS mixtures in the ratio 70:30 (steel slag: glass) were substituted for fine aggregate at varying percentages of 0 to 50 %. This mix ratio was adopted so that the glass content does not exceed 10%.Five samples of GSS content   (10%, 20%, 30%, 40%and 50%) were prepared and their Marsha lstability,Voids in Mineral Aggregates, Voids filled with Bitumen and bulk density were evaluated and compared to nominal asphalt mix. While a 10% GSS replacement in modified asphalt resulted in a greater peak stability value of 16.21 kN compared to the standard mix peak stability value of 12.68kN. The 20% GSS replacement resulted in a lower flow value and a significantly higher Marshall quotient of 5.11KN/MM was recorded at 20% replacement, making it preferable. As a result, a 20% replacement is advised for heavily trafficked highways, whereas up to 30% replacement is permissible on lightly traveled roads.