ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The reaction between Ca²⁺ from steel slag and granulated blast-furnace slag system: a unique perspective

Mengqi Wang, Binbin Qian, Jun Jiang, Huachen Liu, Qiang Cai, Bing Ma, Yueyang Hu, and Luming Wang

College of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng, China

E-mail: huyueyang1989@163.com

Received: 19 March 2020  Accepted: 7 June 2020

Abstract:

This paper proposes that Ca²⁺ in steel slag (SS) has a weak early hydration activity when SS and granulated blast-furnace slag (GBFS) are used as alkali-activated cementitious materials. Herein, alkaline activators and Ca(OH)₂ are used as indicators of Ca²⁺ reaction in the SS and GBFS system. It is found that the 28-day compressive strength of the cementitious material with 2 wt% Ca(OH)₂ addition increased by 25.9% compared with the blank. Hydration products and microstructures were characterized by XRD, SEM/EDS, FTIR and TG/DTA. Results show that the addition of Ca(OH)₂ increased the content of active calcium ions in the reaction system, which promotes the reaction and the formation of C–S–H gel, resulting in an enhanced compressive strength ultimately. It can be also concluded that SS is not suitable as a sole precursor for the production of building materials on a large scale due to the weak early activity of Ca²⁺ in SS.

Keywords: Ca(OH)2; Steel slag; C–S–H gel; Activity

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-020-01248-5

Chemical Papers 74 (12) 4401–4410 (2020)