Thermal behaviour of geopolymers prepared using class F fly ash and elevated temperature curing
Thermal behaviour of geopolymers prepared using class F fly ash and elevated temperature curing
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DOI：
10.1016/j.cemconres.2006.03.022
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发表时间：
2006-06-01
影响因子：
11.4
通讯作者：
Bakharev, T
中科院分区：
文献类型：
--
作者：
Bakharev, T
本文研究了用F类粉煤灰和Na、K碱性活化剂制备的地聚合物材料在800 ~ 1200℃烧制时性能的热稳定性。采用了抗压强度、收缩率、XRD、SEM （BEI）、TGA、MIP等测试手段。在水胶比为0.09-0.35，压实压力为10 MPa，固化温度为80和100℃的条件下制备的材料的热稳定性较低。在使用含钠活化剂制备的样品中，观察到在800℃时强度迅速恶化，这与平均孔径的急剧增加有关。最初的无定形结构被结晶的钠长石所取代。在用粉煤灰和硅酸钾制备的材料中，抗压强度在加热时显著提高，强度在1000℃时开始恶化。烧制后，这些材料保持无定形，平均孔径减小，抗压强度显著提高。在1- 10mpa的压实作用下，所有材料的烧制收缩都减少了。使用F类粉煤灰和碱性活化剂制备的地聚合物材料在800-1200℃范围内，随着烧结温度的升高，其收缩率高，抗压强度变化大，因此不适合耐火绝缘应用。(C) 2006 Elsevier Ltd版权所有。
This article reports a study of thermal stability of properties upon firing at 800-1200 degrees C of geopolymer materials prepared using class F fly ash and Na and K alkaline activators. Compressive strength and shrinkage measurements, XRD, SEM (BEI), TGA and MIP were utilised in these studies. The materials were prepared at water/binder ratios in a range of 0.09-0.35, using compaction pressures up to 10 MPa and curing temperatures 80 and 100 degrees C. Thermal stability of the studied geopolymer materials was rather low. In the samples prepared using sodium-containing activators rapid deterioration of strength at 800 degrees C was observed, which was connected to a dramatic increase of the average pore size. Initially amorphous structures were replaced by the crystalline Na-feldspars. In materials prepared using fly ash and potassium silicate compressive strength was significantly increased on heating, deterioration of strength started at 1000 degrees C. After firing these materials remained amorphous with reduced average pore size and significantly increased compressive strength. Compaction at 1-10 MPa reduced shrinkage on firing in all materials. Geopolymer materials prepared using class F fly ash and alkaline activators showed high shrinkage as well as large changes in compressive strength with increasing fired temperature in the range of 800-1200 degrees C. Thus the materials were found unsuitable for refractory insulation applications. (C) 2006 Elsevier Ltd. All rights reserved.