Crystallization Characteristic of Periclase in Clinker and Effect of Mg2+ on Hydrate of Cement Pastes
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2019年第6期
论文作者：宋强 HU Yaru 陈延信
文章页码：1384 - 1395
摘 要：Crystallization characteristic of periclase in clinker and effect of Mg2+ on hydrate of cement pastes were investigated. Morphologies and relative content of periclase were characterized with scanning electron microscopy and X-ray diffraction. Derivative thermogravimetry analysis and backscattered electron imaging were used to characterize the effect of Mg2+ on hydrate of cement pastes. The experimental results show that in ample space, periclase forms octahedron structure, and subhedral or anhedral crystal is formed in limited space. Due to the accelerated burning temperature and prolonged holding time, coarse pericalase crystals are formed. Mg（OH）2 particle thickness increases due to faster crystal growth rate along c axis at later age. Mg2+can substitute Ca2+ in C-S-H or C-A-H to form magnesium silicate hydrate（M-S-H） or magnesium aluminate hydrate（M-A-H）, and the substitution extent for C-A-H is higher than that for C-S-H. Cured in 80 ℃ water, the decalcification rate of C-A-H in pastes is higher than that cured in 50 ℃ water. M-A-H with an atomic Mg/Al ratio of 2 is formed through substitution of Ca by Mg in C-A-H.
宋强，HU Yaru，陈延信
College of Materials Science and Engineering, Xi’an University of Architecture and Technology
摘 要：Crystallization characteristic of periclase in clinker and effect of Mg2+ on hydrate of cement pastes were investigated. Morphologies and relative content of periclase were characterized with scanning electron microscopy and X-ray diffraction. Derivative thermogravimetry analysis and backscattered electron imaging were used to characterize the effect of Mg2+ on hydrate of cement pastes. The experimental results show that in ample space, periclase forms octahedron structure, and subhedral or anhedral crystal is formed in limited space. Due to the accelerated burning temperature and prolonged holding time, coarse pericalase crystals are formed. Mg（OH）2 particle thickness increases due to faster crystal growth rate along c axis at later age. Mg2+can substitute Ca2+ in C-S-H or C-A-H to form magnesium silicate hydrate（M-S-H） or magnesium aluminate hydrate（M-A-H）, and the substitution extent for C-A-H is higher than that for C-S-H. Cured in 80 ℃ water, the decalcification rate of C-A-H in pastes is higher than that cured in 50 ℃ water. M-A-H with an atomic Mg/Al ratio of 2 is formed through substitution of Ca by Mg in C-A-H.
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