Development of Expressway Asphalt Pavement Using Steel Slag Aggregate

by Siah Keng Boon, Hong Yiying, Er Chin Lu, Than Than Nyunt, Fwa Tien Fang, See Soo Loi, Yoong Chin Chong

Publisher - NSL Chemicals Ltd, Land Transport Authority, National University of Singapore, Singapore

Category - General Novel

In Singapore, steel slag has been used for dense wearing course construction for areas with challenging traffic conditions such as slip roads and intersections. Recently, new collaborative research was conducted to develop new steel slag asphalt mixes for expressway. The new mixes are designed with 15% air void for enhanced durability with good skid resistance and adequate permeability for expressways. Two mixes were developed, each with 16 mm and 13.2 mm maximum aggregate size respectively. Testing showed that the steel slag aggregates possessed superior physical and geometrical properties compared with granite aggregate and the mix specimens showed satisfactory Marshall stabilities in lab. Field trials were conducted with two control pavements, namely, drainage mix (20-26% air voids) and OGW (7-9% air void). Field tests showed comparable skid resistance of the four pavements four months into the service life. The two steel slag pavements delivered better noise reduction. The 13.2 mm mix generated tire-pavement noise 2-3 dBA lower than the control pavements at 80 km/h. IRI of all pavements were lower than 2 mm/m.

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