Innovative use of industrially produced steel slag powders in asphalt mixture to replace mineral fillers

• Published in: Journal of cleaner production Vol. 344; p. 131124
• Main Authors: Chen, Zongwu, Leng, Zhen, Jiao, Yuyong, Xu, Fang, Lin, Juntao, Wang, Haopeng, Cai, Jun, Zhu, Linlu, Zhang, Yunlong, Feng, Namin, Dong, Yidan, Zhang, Yang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.04.2022
• Subjects: Asphalt mixture; Engineering performance; Filler; Material property; Steel slag powder; Material property; Asphalt mixture; Engineering performance; Steel slag powder; Filler
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2022.131124

Using steel slag to partially replace the natural aggregate in asphalt mixture to produce high-performance asphalt mixture has gained significant interest in recent years as a value-added option to recycle steel slag. However, the poor homogeneity of the material properties of steel slag aggregates remains a concern for this recycling approach. In this study, an innovative method of using industrially produced steel slag powder (SSP) to replace the mineral filler in asphalt mixture was proposed to address this concern. Five fillers, including four SSP fillers, obtained by grinding different steel slag aggregates with an industrialized production line, and one conventional limestone powder (LP) filler, were evaluated. The chemical compositions and micro-morphologies of the SSPs were first characterized to evaluate the material homogeneity and gain insights into the advantages of using SSPs as fillers. Then, asphalt mixtures with different fillers were designed and produced, and their moisture stability, rutting resistance, and low-temperature crack resistance, were characterized. It was found that the industrially produced SSPs possessed homogeneous properties, and improved the compatibility between filler particles and asphalt binder. Besides, the asphalt mixtures with SSP fillers showed better resistance to the moisture damage, permanent deformation, low-temperature crack in terms of fracture energy, than the asphalt mixture with LP filler. Therefore, it was concluded that using SSPs as a replacement of mineral fillers in asphalt mixture provided a reliable and value-added solution to recycle steel slag. •Steel slag powders (SSPs) were used to replace limestone powder (LP) filler.•The properties of SSPs were more homogeneous compared to steel slag aggregates.•SSPs showed some advantages when used as fillers in terms of material properties.•SSPs did better in improving engineering performances of asphalt mixture than LP.