Effect of steel slag on compaction times of asphalt mixtures based on prediction of cooling curves

This study investigates the thermal properties of asphalt mixtures incorporating steel slag as a potential substitute of natural aggregates in hot mix asphalt, precisely the BBTM11B type. The thermal properties were analysed using the QuickLine equipment following the ASTM D5930 standard. Experimental tests were conducted to measure the cooling curves of different mixtures at different compaction levels, while numerical simulations using the finite element method (FEM) were employed to predict the cooling curves. The experimental observations indicate that as the substitution levels of steel aggregates increase, the samples exhibit lower thermal conductivity and specific heat. It was also shown that the numerical simulation successfully estimated the temperature evolution of the mixtures, enabling the prediction of their thermal behaviour. The study suggests that mixtures containing steel slag, although they need a longer cooling time, exhibit a wider compaction window, allowing for better compaction and improved mechanical performance compared to mixtures without this material.