The effect of basic oxygen furnace steel slag and recycled concrete aggregate on the mechanical properties of asphalt concrete

As a result of the extensive road infrastructure development projects that have been occurring in India for the past 30 years, traditional stone aggregates are getting more and more expensive and difficult to find. In India, the usage of unconventional aggregate materials in flexible pavement is still at the experimental stage. Basic Oxygen Furnace Steel slag(BOFS), a byproduct from the steelmaking process, can be used to substitute natural aggregates. On the other hand, Recycled Concrete Aggregate (RCA) is generated by crushing demolished concrete. Utilizing waste materials as aggregates in the pavement industry has the potential to mitigate waste accumulation and lower primary production costs. In developing countries like India, limited to no studies have been conducted to understand the combined effect of RCA and steel slag in the Asphalt concrete mix. Therefore, this novel study analyzed the feasibility of using BOF steel slag and RCA to replace natural aggregate in asphalt mixture. Five different types of bituminous mixes were prepared along with a polymer-modified binder. The chemical composition of different aggregates was evaluated through XRF technology. The combined influence of Steel Slag and RCA on asphalt mixture performance has been evaluated through fatigue, cracking, raveling, and water resistance. The findings demonstrated that the Steel Slag as coarse aggregates and natural aggregate as the fine aggregates outperformed all other mixtures.