Byproduct-based ettringite binder : a synergy between ladle slag and gypsum
Nguyen, Hoang; Adesanya, Elijah; Ohenoja, Katja; Kriskova, Lubica; Pontikes, Yiannis; Kinnunen, Paivo; Illikainen, Mirja (2018-11-28)
Hoang Nguyen, Elijah Adesanya, Katja Ohenoja, Lubica Kriskova, Yiannis Pontikes, Paivo Kinnunen, Mirja Illikainen, Byproduct-based ettringite binder – A synergy between ladle slag and gypsum, Construction and Building Materials, Volume 197, 2019, Pages 143-151, ISSN 0950-0618, https://doi.org/10.1016/j.conbuildmat.2018.11.165.
© 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Ladle slag (LS) is a byproduct from the steel industry that is usually reactive on its own and hydrates towards cementitious phases when mixed with water. However, these reaction products are often metastable, leading to micro-structural changes between 7 and 30 days after mixing. To address this issue, in this experimental investigation, a new binder was designed where LS was mixed with gypsum in order to deliver an ettringite-based binder (LSG). The experimental results revealed that the dominant crystalline phase of LSG was ettringite, which remained stable with no conversion at later stages. For better understanding of the ettringite-based binder, mortar characterization, mechanical properties, and durability of LSG were investigated. LSG showed good mechanical properties and excellent freeze-thaw resistance after 300 cycles, which is comparable to other calcium sulfoaluminate cements. Therefore, as a result, the byproduct-based ettringite binder synthesized herein could offer a solution to steelmaking byproducts with a low-CO2 binder, which could be used in a wide range of applications in the construction industry.
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