常温常压下NaOH溶液激发F级粉煤灰凝胶材料由于强度发展慢而固化不理想。利用碱渣来改性碱激发粉煤灰基地质聚合物材料的性能,通过抗折抗压强度及XRD、SEM-EDS和FTIR试验对材料的早期力学性能和微观结构进行研究。结果表明:碱渣掺量27%时,60 d胶砂抗压强度增加了1.4倍;碱渣降低了粉煤灰基地质聚合物中沸石晶体的结晶度;可溶性Ca2+使得改性材料凝胶趋于形成粘结性更强的粒状含钙类沸石相地质聚合物;碱渣能促进Si-O-Al链聚合以及Ca2+、Na+吸附。碱渣对粉煤灰-NaOH溶液材料的早期力学性能和微观结构改性效果显著,为固废碱渣的综合利用提供了新思路。
Abstract
Alkali-activated class F fly-ash-based polymer materials (FA-GEO) by NaOH solution has not ideally solidified at room temperature and atmospheric pressure. In this research, the properties of fly-ash-based geopolymer materials are improved by soda residue. The early mechanical properties, microstructure and thermal stability of the modified materials are researched through flexural strength test, compressive strength test, XRD, SEM-EDS, FTIR and TG-DSC test. Results show that the early mechanical properties and microstructure of FA-GEO are significantly improved by soda residue. When soda residue content is 27%, the 60 d compressive strength of mortar increases by 1.4 times. Soda residue reduces the crystallinity of zeolite crystals of FA-GEO. Soluble Ca2+ makes the modified gels tend to form a more cohesive calcium-containing zeolite-like phase geopolymer which is particle-shaped. Soda residue promotes the polymerization of Si-O-Al chain and the absorption of Ca2+ and Na+. The research result could be regarded as a new idea in optimizing FA-GEO.
关键词
碱渣 /
改性 /
粉煤灰基地质聚合物 /
力学强度 /
微观结构
Key words
soda residue /
modification /
fly-ash-based geopolymer /
mechanical strength /
microstructure
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参考文献
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基金
河北省科技计划项目(15273802D,16273809)
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