Review Steel slag and its applications in cement and concrete technology: A review Osman Gencel a,⇑ , Omer Karadag b , Osman Hulusi Oren c , Turhan Bilir d a Bartin University, Faculty of Engineering, Department of Civil Engineering, Bartin, Turkey b Özyeg ˘in University, Faculty of Architecture and Design, Department of Architecture, Istanbul, Turkey c Sirnak University, S ßırnak Vocational School, Construction Technology Program, Sirnak, Turkey d Istanbul University-Cerrahpasa, Faculty of Engineering, Department of Civil Engineering, Istanbul, Turkey highlights  Current applications of steel slag in concrete were presented.  Its chemical composition and durability properties of steel slag in literature were compared.  Use of steel Slag as coarse and fine aggregate in concrete was presented.  Effect of curing temperature and time on concrete containing steel slag was presented.  Different usage areas of steel slag were recommended for future studies. article info Article history: Received 29 November 2020 Received in revised form 17 February 2021 Accepted 18 February 2021 Available online 5 March 2021 Keywords: Steel slag Coarse aggregate Fine aggregate Sustainability Recycling abstract In this review, steel slag usage in the cement and concrete industry and its environmental effects were examined. Also, its physical and chemical structure, its effect on the characteristics of concrete, and its applications in different usage areas were specified. Within the scope of the study, literature was exam- ined by reviewing investigations of steel slag usage in the cement and concrete industry. The content and results of these studies were assessed, and the intended effects of these by-products were presented. These factory by-products, whose storage and release into nature are quite inconvenient, are assessed at different sites around the world and regained to the sector. Thus the benefits of both economic and ecological balance were examined. As a result, opinions and recommendations were presented. Ó 2021 Elsevier Ltd. All rights reserved. Contents 1. Introduction ........................................................................................................... 2 2. The relationship between concrete and environment .......................................................................... 3 3. Steel slag from iron and steel plants........................................................................................ 4 3.1. Physico-chemical characteristics of steel slag ........................................................................... 5 3.2. Usage areas of steel slag ............................................................................................ 6 3.2.1. Using steel slag as asphalt pavement on highways ............................................................... 6 3.2.2. Advantages of asphalt production by using steel slag ............................................................. 8 3.2.3. Disadvantages of asphalt production by using steel slag ........................................................... 9 3.2.4. Steel slag usage as ballast for railways ......................................................................... 9 3.2.5. Steel slag usage as aggregate in concrete ...................................................................... 10 4. Conclusion and recommendations ........................................................................................ 15 Declaration of Competing Interest ........................................................................................ 16 References ........................................................................................................... 16 https://doi.org/10.1016/j.conbuildmat.2021.122783 0950-0618/Ó 2021 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Civil Engineering Department, Faculty of Engineering, Bartin University, 74100 Bartin, Turkey. E-mail addresses: osmangencel@gmail.com, ogencel@bartin.edu.tr (O. Gencel). Construction and Building Materials 283 (2021) 122783 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat