Impact of Mg substitution on the structure and pozzolanic reactivity of calcium aluminosilicate (CaO-Al2O3-SiO2) glasses

被引:34
作者
Nie, Shuai [1 ,2 ,3 ]
Thomsen, Rene M. [1 ,2 ]
Skibsted, Jorgen [1 ,2 ]
机构
[1] Aarhus Univ, Dept Chem, Langelandsgade 140, DK-8000 Aarhus C, Denmark
[2] Aarhus Univ, Interdisciplinary Nanosci Ctr iNANO, Langelandsgade 140, DK-8000 Aarhus C, Denmark
[3] Wuhan Univ Technol, State Key Lab Silicate Mat Architectures, Wuhan 430070, Peoples R China
关键词
Glass; Al-27; NMR; Si-29; Pozzolanic reactivity; Hydration products; Supplementary cementitious materials; SI-29 MAS NMR; C-S-H; BLAST-FURNACE SLAG; HYDRATED PORTLAND CEMENTS; HIGH-RESOLUTION SI-29; BRIDGING O ATOMS; SILICATE-GLASSES; HIGH-FIELD; AL-27; NMR; 3QMAS NMR;
D O I
10.1016/j.cemconres.2020.106231
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
Calcium aluminosilicate (CAS) glasses are the main reactive component in supplementary cementitious materials such as fly ashes and slags, which may also include significant amounts of magnesium. Eighteen CAS glasses have been synthesized in six series with 0, 25, and 50 mol% of Ca substituted by Mg. Their structure, pozzolanic reactivity and impact on Portland cement hydration are investigated by Si-29 and Al-27 NMR spectroscopy and TGA analysis. The aluminosilicate network is only slightly affected by the Mg for Ca substitution, although an increased distortion of the network is observed, which is ascribed to a lowering of the Mg coordination state relative to Ca. The glass reactivity is mainly governed by the network depolymerization, which increases with the MgO + CaO content, with Mg substitution only having a minor impact. Increasing Mg contents in the glasses lead to OH-hydrotalcite formation and a smaller fraction of Al incorporated in the C-A-S-H phase.
引用
收藏
页数:16
相关论文
共 66 条