【作者】 冯竟竟；

【导师】 陈忠辉；

【作者基本信息】 中国矿业大学（北京） ， 结构工程， 2009， 博士

【摘要】 以多种配比的水泥基材料为研究对象,运用试验量测和理论分析相结合的方法对水泥基材料高温微细观劣化与损伤过程进行了研究。根据持续温升条件下水泥基材料表面微细观结构的演化规律与力学性能的劣化规律,得出了水泥基材料高温微细观结构的劣化规律,并从水泥基材料微细观形貌、孔隙结构、孔隙分形特征等三个方面对温度影响下水泥基材料微细观结构的劣化规律进行了系统研究,揭示了水泥基材料高温微细观劣化的机理和粉煤灰抗高温的作用机理,得出了不同配比材料抗高温性能的优劣。研究表明,水泥基材料表面微细观结构的劣化在50℃左右开始,100℃是水泥砂浆微细观结构劣化加剧的起始温度,300℃是水泥净浆微细观结构劣化加剧的转折温度,水泥砂浆的劣化程度比水泥净浆严重；温度影响下水泥基材料所发生的一系列物理化学变化是导致材料微细观结构劣化的本质原因,其中水化硅酸钙凝胶的劣化是关键因素；粉煤灰抗高温的有效温度范围在100-400℃之间,在300℃左右抗高温效果最明显。更多还原

【Abstract】 Microstructure and damage process of cement-based materials exposed to high temperatures are investigated with test measurement and theoretical analysis. Based on the evolution of microstructure on the surface of cement-based materials and the degradation of mechanical properties under the continuous temperature rising, the microstructure deterioration of cement-based materials is derived. And a detailed research is carried out about the deterioration of cement-based materials under high temperatures from the three aspects of the micro-morphology, pore structure and pore fractal characteristics. The deterioration mechanisms of cement-based materials and the mechanism of fly ash resistance to high temperatures are revealed. The performance resisting high temperatures of different ratio materials are discussing. Studies have shown that deterioration of microstructure on the surface of the cement-based materials starts at 50℃around, and 100℃is the starting temperature of mortar increased deterioration, and the threshold temperature of deterioration of microstructure of cement paste is 300℃. Effects of high temperatures on the deterioration of microstructure of mortar were more serious than that of cement paste. A series of physical and chemical changes which happened because of high temperatures in the cement-based materials leads to the deterioration of microstructure. And C-S-H gel is the key factor of the deterioration. The effective temperature range of fly ash resistance to high temperatures is 100-400℃, which works best at 300℃.更多还原