Performance and Toxic Leaching Evaluation of Dense-Graded Asphalt Concrete Using Steel Slag as Aggregate

Abstract

The comparative performance between steel slag (S) and limestone (L) as aggregates in dense-graded asphalt concretes were investigated in this research. The performance tests for fatigue cracking were undertaken using indirect tensile strength (ITS) tests, indirect tensile fatigue life (ITFL) tests, and indirect tensile resilient modulus (MR) tests. Dynamic creep tests and wheel tracking tests were also performed to assess the rutting behavior of these pavement materials. A heavy metal leaching test was also carried out to ensure that asphalt concrete with the usage of S, as a sustainable aggregate, was safe for the environment. The results indicated that asphalt concretes with S had better Marshall’s stability than the asphalt concretes with L, even though they had slightly less ITS values. The ITFL and MR of S asphalt concretes were higher than those of L asphalt concretes, indicating higher fatigue cracking resistance. The MR of S asphalt concretes were found to be higher than the required 3,100 MPa value recommended by AASHTO, while L asphalt concretes did not meet this requirement. In addition, the dynamic creep and wheel tracking test results showed that the S asphalt concretes had superior resistance to permanent deformation as compared to the L asphalt concretes. The usage of medium-sized S aggregate in developing asphalt concrete was evidently more sustainable in terms of engineering and economic perspectives than the usage of large-sized S aggregate. The research results indicated that the sustainable usage of S in asphalt concrete was suitable for the development of heavy traffic volume roads.