Determination of Optimal Binder Range in Cold Asphalt Mixtures Containing Steel Slag Based on Concurrent Analysis of Strength-Flowability-Air Voids for Pothole Repair in Warm Climates

Document Type : Original Article

Authors
Mohammad Mehdi Khabiri 1
Mehdi Jokar 2
Fateme Karimi 3
1 Associate Professor, Department of Civil Engineering, Yazd University, Yazd, Iran.
2 Ph.D., Candidate, Department of Civil Engineering , Yazd University, Yazd, Iran.
3 M.Sc., Graduate, Faculty of Civil Engineering, Yazd University, Yazd, Iran.
10.22034/road.2026.600758.2551
Abstract
In the present study, the technical feasibility of utilizing induction furnace steel slag aggregates in cold repair asphalt mixtures was evaluated, with a particular emphasis on determining the optimum bitumen content range and analyzing volumetric-mechanical interactions. To this end, Marshall specimens were fabricated at five bitumen content levels (ranging from 5.5% to 9.5%). Following a 14-day curing period, the specimens were subjected to Marshall stability, flow, bulk specific gravity, and air void content tests. The results indicated that Marshall stability increased with rising bitumen content from 5.5% to 9%,. However, a further increase in bitumen content to 9.5%, despite reducing the air void content to 6.401%, led to a decline in stability to 241.7 kgf. A regression model with a coefficient of determination (R²) of 98.7% was successfully fitted to the data.Based on the findings, the optimal bitumen content range was established at 8.5% to 9%. This range simultaneously ensures maximum stability and adequate flow (3.8 to 4 mm), maintains air voids within the 7% to 8% range, and provides favorable conditions for thermal expansion and secondary compaction under the target climatic conditions. Flow analysis demonstrated a consistently increasing trend across the entire bitumen content spectrum, from 2.83 to 4.28 mm, which was predominantly governed by the thickness of the bitumen film. Furthermore, the presence of an upper threshold for maximum stability was confirmed within the density range of 2.462 to 2.485 g/cm³, indicating that increasing the density beyond this limit does not result in a significant improvement in stability.
Keywords
Cold asphalt mixture
Steel slag
Pothole repair
Response Surface Methodology
Warm and arid climate
-Amouzadeh Omrani,M . (2023). Laboratory comparison of mechanical properties of emulsified cold recycled asphalt containing cement kiln dust and steel slag with recycled asphalt containing cement. Journal of Transportation Infrastructure Engineering, 9(3), 57-79.
-Becerra-Duitama, J. A., & Rojas-Avellaneda, D. (2022). Pozzolans: A review. Engineering & Applied Science Research, 49(4), 495.
-Dovom, H. A., Kargari, A., Moghaddam, A. M., Kazemi, M., & Fini, E. H. (2024). Self-healing cold mix asphalt containing steel slag: A sustainable approach to cleaner production. Journal of Cleaner Production, 482, 144170.
-Jakati, S. S., & Kumar, G. S. (2024). Novel cold pothole patching mixtures utilizing EAF steel slag and pyro-oil from municipal plastic solid waste. Innovative Infrastructure Solutions, 9(3), 55.
-Hao, Y., Liu, W., Bai, M., Zhang, Z., Zhao, P., Li, H., & Zhao, Z. (2026). A Review of Interfacial Interaction Mechanisms of Steel Slag in Asphalt Concrete: Multi-Scale Characterization and Performance Implications. Case Studies in Construction Materials, e06242.
-Manjushree, B. C., & Lokeshwari, M. (2026). A Review on Sustainable Management of Potholes in Flexible Pavements Using Cold-Mix Asphalt Modified with Industrial Waste Materials. International Journal of Pavement Research and Technology, 1-19.
-Kumar, G. S., Jakati, S. S., & Ramaraju, H. K. (2023). Developing novel pothole patching mixtures utilizing iron ore waste as substitute to conventional aggregates with anti-stripping agent. Materials Today: Proceedings.
-Kumar, G. S., Nitin, G. C., Gurudeep, G., Ujwal, M. S., & Ramaraju, H. K. (2025). State of the art review of mix design parameters on the laboratory performance of cold patching mixtures. Journal of Building Pathology and Rehabilitation, 10(1), 51.
-Pasetto, M., Baliello, A., Giacomello, G., & Pasquini, E. (2023). The use of steel slags in asphalt pavements: a state-of-the-art review. Sustainability, 15(11), 8817.
-Sarkkinen, M., Kujala, K., & Gehör, S. (2019). Modification of Alkali Activated Blast Furnace Slag for Pothole Repairs. In MATEC Web of Conferences, EDP Sciences, Vol. 274, 04003.
-Tang, Y., Koting, S., Hung, M. K., Md Isa, M. H., & Zhang, H. (2026). Steel Slag in Asphalt Pavements: A Review on Performance, Multifunctional Applications, and Volume Expansion Mitigation Strategies. Journal of Material Cycles and Waste Management, 1-27.
-Yang, J., Ma, R., Dong, B., Ma, H., Wang, Y., Gao, M., & Jin, Y. (2025). Research progress and hotspots of steel slag application in road construction: a bibliometric perspective. Infrastructures, 10(3), 54.
-Wang, X., Huang, Y., Geng, L., Li, M., Han, H., Li, K., & Zhang, T. (2023). Multiscale performance of composite modified cold patch asphalt mixture for pothole repair. Construction and Building Materials, 371, 130729.
-Ziari, H., Ameri, M., & Khabiri, M. M. (2007). Resilient behaviour of hot mixed and crack sealed asphalt concrete under repeated loading. Technological and Economic Development of Economy, 13(1), 56–60.
-Zhang, Ran, Kailu Wang, Long Liang, Jie Ji, and Tansen Gao. (2026). Solvent-Based Cold-Mix Asphalt for Pavement Pothole Repair: Mechanisms, Performance, Challenges, and Future Perspectives. Journal of Transportation Engineering, Part B: Pavements 152, No. 4. 03126003.