| 摘要: |
| 通过在900℃保温煅烧不同时间来制备活性不同的MgO,研究了MgO与硅灰(SF)所制备胶凝材料（MgO SF）的流动性、凝结时间、强度和pH值,采用X射线衍射（XRD）、同步热分析（DSC TG DTG）、傅里叶红外光谱（FTIR）等分析了MgO对MgO SF水化产物和水化硅酸镁(MgO SiO2 H2O,M S H)结构的影响.结果表明：随着保温时间的缩短,MgO衍射峰强度减弱,峰宽增大,晶粒尺寸减小,活性增强;高活性MgO制备的MgO SF净浆和砂浆流动性较差,初凝和终凝时间较短,强度较高;采用保温时间为20h的MgO所制备的MgO SF浆体流动性最好,凝结时间最长,力学性能最好;MgO SF净浆试样养护3d时M S H中Mg(OH)2的含量达到最高,随后降低,在28d时Mg(OH)2含量小幅度增加并出现强度倒缩现象;随着养护龄期的增长,M S H含量逐渐增加且其硅酸盐网络结构聚合程度增加. |
| 关键词: 水化硅酸镁 水化产物 MgO 硅灰 |
| DOI：103969/j.issn.1007 9629202004005 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（51974218）；西安建筑科技大学基础研究基金项目(JC1496)；先进耐火材料国家重点实验室开放基金项目（SKLAR201905） |
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| Effect of MgO Reactivity on MgO SiO2 H2O Cementitious System |
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WANG Qian, WU Zhihong, ZHANG Guoli, HU Yaru, ZHANG Luping
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College of Materials Science and Engineering, Xian University of Architecture and Technology, Xian 710055, China
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| Abstract: |
| The MgO with different reactivity was prepared by being calcinated at 900℃ for different time. The fluidity, setting time, mechanical strength, pH value of the cementitious materials prepared by mixing silica fume(SF) and activated MgO were investigated. The effects of MgO with different reactivity on the hydrated products of MgO SF paste and hydrated magnesium silicate（M S H）structure were characterized by an X ray diffraction（XRD）, simultaneous thermal analysis（DSC TG DTG） and Fourier transform infrared spectroscopy（FTIR）. The results show that with the decreasing of calcination time, the intensity of MgO diffraction peak is declined, the peak width is widened, the grain size is refined, and the activity is increased. The MgO SF prepared by the MgO with highly reactivity has poorer fluidity of paste and mortar, shorter initial and final setting time, and higher strength. MgO SF prepared by MgO calcined at 900℃ for 20h possess the longest setting time and the highest compressive strength. The content of Mg(OH)2 in M S H is increased gradually with the curing age increase from 0 to 3d, the content of Mg(OH)2 in M S H increased slightly and the strength collapsed at 28d. With the increase of curing age, the M S H content and the degree of polymerization degree of the silicate network structure in M S H are increased. |
| Key words: magnesium silicate hydrate(M S H) hydration product MgO silica fume(SF) |
