摘要
利用冻融试验方法,测定了冻融循环对普通和高性能玻璃纤维增强氯氧镁水泥(glass fiber reinforced magnesium oxychloride cement,GRMC)弯曲性能的影响,并运用XRD和SEM-EDS分析了冻融前后GRMC水化产物的组成和微观结构的差异。结果表明,普通GRMC试件冻融前后的主要物相均为5Mg(OH)2·MgCl2·8H2O(5·1·8),浸水48 h后部分5·1·8分解为Mg(OH)2;冻融循环25次后Mg(OH)2被碳化为MgCO3,在孔隙中大量存在叶片状MgCO3。双掺15%复合抗水外加剂和20%矿渣的高性能GRMC试件,在浸水48 h、冻融25次条件下物相都未发生明显变化,水泥基体仍由5·1·8凝胶体和2MgO·SiO2·aq凝胶相互连生而成,5·1·8针棒状晶体在孔隙中大量存在,冻融循环对GRMC试件的水化产物的组成和微观结构没有影响,具有较好的抗冻性。
By freeze-thaw method, the bending mechanical properties of the common and high- performance glass fiber reinforce magnesium oxychloride cement （GRMC） were tested in this study. The differences of hydration product compositions and microstructures were observed by X-ray diffraction （XRD） and scanning electron microscopy-Energy dispersive X-ray spectroscopy （SEM-EDS）. The results indicated that the hydration product of 5Mg（OH）2 ·MgC12 · 8H2O （5 · 1 ·8） was the main phase after 25 times freeze-thaw cycle. After being wetted for 48 h, 5 · 1 ·8 was partly decomposed to Mg（OH）2 which was then carbonized to MgCO3 after 25 times freeze-thaw cycle. Foliated crystals of MgCO3 existed in the pore of gel phase in large masses. There was little effect on high-performance GRMC specimens with double-doped compound water-resistance additive and 20% slag with the following conditions of leaching for 48 h or 25 times freeze-thaw cycle. The gel phase 5 · 1 · 8 and 2MgO · SiO2 · aq stably existed in cement matrix. Needle stick crystals of 5 · 1 · 8 existed in the pore of gel phase in large masses. The freeze-thaw cycle had little effect on the hydration product compositions and microstructures of high-performance GRMC specimens, which indicated the freezing resistance of the GRMC was well.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2014年第3期459-464,469,共7页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金项目(21276264)
