Thermal Exchange and Skid Resistance of Chip Seal with Various Aggregate Types and Morphologies

Abstract

Steel slag, the by-product of steelmaking, is a desirable alternative material for natural aggregate. However, there are few studies applying steel slag in the preventive maintenance of asphalt pavements, especially chip seal. The main objective of this study is to explore the feasibility of applying steel slag in chip seal and the effect of steel slag on the thermal exchange and aggregate retention properties. Furthermore, the surface features, including texture depth and skid resistance. of chip seal were also evaluated. The results show that the thermal exchange performances of chip seal vary with aggregate types. The ranking of the chip seal samples according to the cooling rate places ferrochromium (FER) slag as the fastest and basic oxygen furnace (BOF) slag as the slowest, with the basalt (BS) falling in between. The use of FER slag can make the chip seal resume traffic about ten minutes earlier than original samples. The skid resistance and texture depth of FER slag meet the requirements of the specification, although they are less than those of ordinary aggregates. Moreover, FER slag has a better aggregate retention performance than BOF slag and BS due to its spherical particles and alkaline surface. The application of steel slag in chip seal can recycle industrial waste, reduce the consumption of natural resources and promote economic pavement maintenance technology.