Hydration of potassium citrate-activated BOF slag

Journal Article · Mon Feb 15 04:00:00 EST 2021 · Cement and Concrete Research

DOI:https://doi.org/10.1016/J.CEMCONRES.2020.106291· OSTI ID:23206173

Kaja, A. M. ^[1]; Schollbach, K. ^[1]; Melzer, S. ^[2]; Laan, S.R. van der ^[1]; Brouwers, H. J.H. ^[1]; Yu, Qingliang ^[1]

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1. Department of the Built Environment, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands)
2. Tata Steel, R&D, Microstructure & Surface Characterization (MSC), P.O. Box 10.000, 1970 CA, IJmuiden (Netherlands)

Basic Oxygen Furnace (BOF) slag is currently utilized with low-grade applications or landfilled. Here, we investigate a novel route to upgrade BOF slag to a high-performance binder by chemical activation with tri-potassium citrate. The impact of tri-potassium citrate on hydration and phase assemblage of BOF slag is analyzed with a multi-technique approach. Results reveal that the addition of tri-potassium citrate considerably enhances the reactivity of brownmillerite and accelerates the hydration of belite at early ages. The majority of brownmillerite hydrates within 24 h, and the reaction kinetics is controlled by the activator dosage. The main products of BOF slag hydration are siliceous hydrogarnet and C-S-H gel. Acting as a strong water reducer, tri-potassium citrate enables the manufacture of slag pastes with high compressive strength (up to 75 MPa at 28 days) and low porosity. Leaching of heavy metals from the slag pastes fulfills the Dutch Soil Quality Decree limits.

• OSTI ID: 23206173
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Vol. 140; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BINDERS
CHEMICAL ACTIVATION
CITRATES
COMPRESSION STRENGTH
GELS
HEAVY METALS
HYDRATES
HYDRATION
MICROSTRUCTURE
OXYGEN
POROSITY
REACTION KINETICS
SANITARY LANDFILLS
SLAGS
SOILS
WATER