Effects of accelerated carbonation on the microstructure of Portland cement pastes containing reactive MgO

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• 作者：Liwu Mo^a ; ^b ; Daman K. Panesar^a ; ^{d.panesar@utoronto.ca}
• 关键词：Microstructure (B) ; Carbonation (C) ; Acceleration (A) ; MgO (D) ; Characterization (B)
• 刊名：Cement and Concrete Research
• 出版年：2012
• 期刊代码：12_00088846
• 类别：ms
• 出版时间：June, 2012
• 卷：42
• 期：6
• 页码：769-777
• 文件大小：1452 K

摘要

Reactive MgO is produced at a lower kiln temperature compared to ordinary Portland cement (OPC) and gains its physical properties mainly as a result of carbonation processes. Use of reactive MgO as cement replacement has recently gained attention in context with precast concrete products subjected to carbonation curing. This study investigates pastes containing 0-40%reactive MgO and the effect of accelerated carbonation curing on the: formation of new carbonate phases, microstructural development, and microhardness. Outcomes from this study revealed that the primary Ca and Mg-bearing carbonates formed are calcite, aragonite, magnesium calcite, and nesquehonite. The combined effect of carbonation and reactive MgO resulted in: a reduction in pore size and total pore volume, increase in apparent density, and greater microhardness compared to OPC paste. The chemical processes, and physical properties revealed that the dense inter-connected network structure consisting of Ca and Mg carbonates is a significant factor that influences the microhardness.