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Advances in Materials Science and Engineering
Volume 2018, Article ID 5893254, 9 pages
https://doi.org/10.1155/2018/5893254
Research Article

Hydration Properties of STS-Refining Slag-Blended Blast Furnace Slag Cement

1Environment and Resources Research Group, Research Institute of Industrial Science and Technology, 67 Chengnam-ro, Nam-gu, Pohang, Republic of Korea
2Department of Civil and Environmental Engineering, Gachon University, 1342 Seongnamdaero, Sujeong-gu, Seongnam-si, Gyeonggi-do 13120, Republic of Korea

Correspondence should be addressed to Young Cheol Choi; rk.ca.nohcag@eforez

Received 24 February 2018; Revised 22 April 2018; Accepted 30 April 2018; Published 17 May 2018

Academic Editor: Fernando Rubio-Marcos

Copyright © 2018 Bong Suk Cho and Young Cheol Choi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The refining process using an aluminum deoxidizer for fabricating stainless steel generated steel slag (STS-refining slag (SRS)) that contains a large amount of Al2O3 and is a compound of mainly 12CaO·7Al2O3 and 3CaO·Al2O3. When SRS was mixed with slag cement, rapid exothermic reaction occurred in the initial phase of hydration. During the hydration of slag cement and SRS, a large quantity of xCaO-yAl2O3-zH2O hydrate was observed. Until 10% weight replacement ratio of SRS to slag cement, the compressive strength was in the same level as in the existing slag cement. However, 20% replacement was accompanied by much strength degradation and high drying shrinkage. When a mixture of SRS and gypsum was added to slag cement, ettringite (3CaO·Al2O3·3CaSO4·32H2O) was actively created in the initial hydration phase. The compressive strength of the OPC-BFS-SRS-gypsum binder at 91 days was 91% of that of slag cement (B50) and was similar to that of OPC (O100). Besides, drying shrinkage was almost half that of slag cement, which indicates excellent performance for shrinkage. In case SRS is adequately used, which is an industrial by-product of the steel-making process, high shrinkage, a basic problem of slag cement, will be mitigated.