摘要
研究了硅酸盐水泥(OPC)对陶瓷模具石膏凝结时间、机械强度及工作性能(吸水性、耐水性、耐溶蚀及耐磨性)的影响,采用XRD,DSC-TG和SEM-EDS测试技术对其作用机理进行深入分析.结果表明:OPC的掺入减少了相同流动度下拌合水量,促进了半水石膏的凝结硬化并使半水石膏硬化体后期强度显著增加,且耐水、耐溶蚀及耐磨性能大幅提高.XRD和SEM-EDS分析表明半水石膏-硅酸盐水泥复合体系主要水化产物有针棒状二水石膏(DH)晶体,细针尖状钙矾石(AFt)晶体及无定形C-S-H凝胶.DH与AFt晶体相互交织生长形成网状结构,C-S-H凝胶填充在晶间孔隙内并覆盖于DH晶体表面使晶胶结构更趋密实,结晶接触点减少,硬化体孔隙率降低、孔径细化,强度、耐水、耐溶蚀性能显著提高;DSC-TG分析得出石膏脱水温度由140℃升至150℃,表明密实的晶胶结构增强了石膏硬化体热稳定性能.
The effects of ordinary Portland cement （OPC） on setting time,mechanical behaviors and working performances,including water absorption,softness efficiency,corrosion-resistance and arasionresistance of ceramic gypsum model,were investigated.The mechanisms were characterized with the measurements of X-ray diffraction,scanning electron microscopy （SEM） and DSC/TG.The results showed that the amount of water demand was reduced and the setting time was shortened by adding OPC.Besides,the strength at the later stage of hydration was significantly increased by the amount of OPC rising which remarkably enhanced the performances of corrosion-resistance,softness efficiency and arasionresistance.The mechanisms indicated that CaSO4 · 2H2O（DH）,AFt and C-S-H gel were the main hydration production.The interconnection between needle,clavuligerus DH and acicular AFt crystals together with the filling of C-S-H into pore space led to a more compacted crystal-gel microstructure,which enhanced the macro-performances of gypsum hardened paste.In addition,DTA-TG results indicated that the dehydration temperature of DH was also improved from 140 ℃ to 150 ℃ due to the more compact microstructure of gypsum hardened paste.What＇s more,the morphology of gypsume was modified to be grainy,noodles-shape and stumpy.
出处
《湖南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2014年第12期46-52,共7页
Journal of Hunan University:Natural Sciences
基金
国家自然科学基金资助项目(50872160)
关键词
模具石膏
普通硅酸盐水泥
工作性能
增强机理
model-gypsum
ordinary Portland cement
mechanical performances
mechanisms
