碱-偏高岭土基胶凝材料的热稳定性研究

High-temperature Stability of Cementitious Materials Based on Metakaolin

将粉煤灰漂珠、G碱-偏高岭土基胶凝材料Geopolymer(普通水泥为对比样)和水按比例混合,成型为3cm×3cm×3cm的试块并养护28d;将试块在规定的温度和时间内煅烧,并用其剩余抗压强度来判断其热稳定性.试验结果表明:Geopolymer的剩余抗压强度随煅烧温度升高而提高,并从800℃到1000℃呈现大幅度提高的趋势,而相应的普通水泥的剩余抗压强度随煅烧温度升高而下降.对Geopoly mer和水泥的水化产物进行了差热分析和热失重分析,发现Geopolymer具有优良的热稳定性能,这可能是由Geopolymer特殊的水化产物而引起的.

The aim of this research is to clarify that alkali-activated metakaolin cementitious materials (Geopolymer) is a new type of cementitious material against ordinary cement by researching high-temperature stability of Geopolymer. The research methods include floated bead in fly ash and Geopolymer (ordinary cement as the control sample ) and water are blended according to a given mix proportion, then, the mixture is cast into 3 cm×3 cm×3 cm metal model and cured for 28 days. Finally, the specimens are calcined in a given temperature and time retention, and the remnant compressive strengths of specimens are used to estimated the high-temperature stability of Geopolymer. The results show that the remnant compressive strengths of Geopolymer after high-temperature function are increased with increasing calcination temperature and increased by a big margin when the calcinations temperature is raised from 800 ℃ to 1 000 ℃. While the corresponding remnant compressive strengths of ordinary cement after high-temperature function are decreased with increasing calcination temperature. Furthermore, the comparative study of hydration products of Geopolymer and Portland cement are also carried out by differential thermal analysis(DTA) and thermo-gravimetric analysis(TGA) in this paper. The conclusion in this paper is that Geopolymer have excellent high-temperature stability, this may be resulted from the unique hydration products of Geopolymer.