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Impact of nesquehonite on hydration and strength of MgO-based cements
Cement and Concrete Research ( IF 10.9 ) Pub Date : 2024-12-20 , DOI: 10.1016/j.cemconres.2024.107772
Paula Montserrat-Torres, Frank Winnefeld, Barbara Lothenbach

Hydrated magnesium carbonate cements prepared from MgO and carbonates such as hydromagnesite (Mg5(CO3)4(OH)2·4H2O) or nesquehonite (MgCO3ˑ3H2O) have potential for carbon sequestration during hardening. This study investigates the hydration of MgO/nesquehonite blends with up to 50 wt% of nesquehonite. Nesquehonite is highly reactive in the presence of MgO and water. The replacement of 50 wt% MgO by nesquehonite causes a significant increase of compressive strength at higher nesquehonite contents with up to 43–44 MPa after 28 days. However nesquehonite delays early hydration and strength development. Progressive changes in XRD peak position and peak broadening with increasing amount of carbonate indicate the formation of hydrous carbonate-containing brucite, HCB, with variable content of gel-like water and CO2 as confirmed by FTIR and TGA. This research indicate a high potential of nesquehonite to permanently store CO2 in MgO-based cements, as up to 15 wt% of CO2 can be taken up in the hydrated solid phase.

中文翻译:


Nesquehonite 对 MgO 基水泥水化和强度的影响



由 MgO 和碳酸盐(如氢菱镁矿 (Mg5(CO3)4(OH)2·4H2O) 或油渣石 (MgCO3ˑ3H2O))制备的水合碳酸镁水泥在硬化过程中具有固碳的潜力。本研究调查了 MgO/nesquehonite 混合物与高达 50 wt% 的 nesquehonite 的水化。Nesquehonite 在 MgO 和水存在下具有高度反应性。用 nesquehonite 取代 50 wt% MgO 会导致 28 天后在较高 nesquehonite 含量下的抗压强度显着增加,最高可达 43-44 MPa。然而,nesquehonite 会延迟早期水化和强度发展。XRD 峰位置和峰展宽随着碳酸盐量的增加而逐渐变化,表明形成了含水碳酸盐的水镁石 HCB,其凝胶状水和 CO2 的含量各不相同,FTIR 和 TGA 证实了这一点。这项研究表明,Nesquehonite 在 MgO 基水泥中永久储存 CO2 的潜力很大,因为在水合固相中可以吸收高达 15 wt% 的 CO2。
更新日期:2024-12-20
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