Evaluation of Benefits of Open-Graded Friction Courses with Basic Oxygen Furnace Steel-Slag Aggregates for Hilly and High-Rainfall Regions in India
Santanu Pathak, Rajan Choudhary, Abhinay Kumar, Sanjay Kumar Shukla
Abstract
In hilly and high-rainfall regions, very sharp curves, lack of skid resistance, and poor visibility form a major cause for road-traffic accidents in India and other similar parts of the world. The construction of pavements with open-graded friction course (OGFC) wearing surfaces in such regions will help enhance road safety due to increased skid resistance, reduced hydroplaning, reduced splash and spray, and better visibility. OGFC mixes demand a high percentage (>90%) of good quality coarse aggregates for adequate stability and load transfer. India is the second-largest producer of steel, and about 12 million t of steel slag (as a byproduct) is generated every year and mainly lies unutilized in open areas, leading to environmental concerns. This study aimed to investigate the design and performance characteristics of OGFC mixes with basic oxygen furnace (BOF) steel slag as the coarse aggregate. Properties of OGFC mixes were evaluated by replacing 0%, 25%, 50%, 75%, and 100% of coarse natural aggregates by BOF steel slag. OGFC mixes were first evaluated for design parameters, including air void content, stone-on-stone contact, Cantabro abrasion loss (unaged and aged), and binder draindown. OGFC mixes with the different percentages of BOF slag were then evaluated for performance through the determination of indirect tensile strength, moisture damage resistance, porosity, and permeability. In addition, the benefits of OGFC mixes in terms of improved skid resistance were found under both dry and wet conditions at different contents of BOF slag. Results showed that steel slag used as coarse aggregate improved the frictional resistance of OGFC mixes. Steel slag-OGFC mixes also showed improved design and moisture resistance parameters compared to the values of these parameters for the control mixes (without slag). A replacement of coarse aggregate with BOF steel slag by 50% on a weight basis is recommended in OGFC mixes for enhanced safety in hilly and high-rainfall regions.