Freeze-thaw resistance assessment of cement-bound steel slag aggregate for pavement structures

This paper investigates the durability of cement-bound layers with steel slag as a partial aggregate replacement. Mixtures with various amounts of slag and cement are investigated for their durability after freeze-thaw cycles and exposure to de-icing agent. Optical microscopy analysis is conducted as a method for assessing the behaviour of low-strength material in order to determine why the application of slag resulted in greater compressive strength and durability properties. It was shown that this method is suitable for providing more details and insights into the material's internal structure. All the mixtures show a loss in compressive strength after exposure to freeze-thaw cycles and de-icers, but this loss is more pronounced in mixtures with gravel-only aggregates. A strong linear correlation is obtained between 28-day compressive strength and retained compressive strength after 10 freeze-thaw cycles. The main conclusion of the research presented here is that steel slag aggregate presents good potential for use in adverse climates, and it is possible to predict the freeze-thaw resistance of cement-bound aggregate on the basis of compressive strength.