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.
Key words
soda residue /
modification /
fly-ash-based geopolymer /
mechanical strength /
microstructure
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] 李 珍, 韩 炜, 邵晓妹. 地质聚合物在材料领域的应用及其发展方向[J].长江科学院院报,2008,25(4):93-96.
[2] KHALE D. Mechanism of Geopolymerization and Factors Influencing Its Development: A Review[J]. Journal of Materials Science, 2007, 42(3): 729-746.
[3] ALSHAAER M, SLATY F, KHOURY H, et al. Development of Low-cost Functional Geopolymeric Materials[J]. Ceramic Transactions, 2010, 222:159-167.
[4] CWIRZEN A, PROVIS J L, PENTTALA V, et al. The Effect of Limestone on Sodium Hydroxide-activated Metakaolin-based Geopolymers[J]. Construction and Building Materials, 2014, 66: 53-62.
[5] YIP C K, PROVIS J L, LUKEY G C, et al. Carbonate Mineral Addition to Metakaolin-based Geopolymers[J]. Cement Concrete Research, 2008, 30(10): 979-985.
[6] ROVNANIK P. Effect of Curing Temperature on the Development of Hard Structure of Metakaolin-based Geopolymer[J]. Concrete Building Material, 2010, 24(7): 1176-1183.
[7] YIP C K, LUKEY G C, VAN DEVENTER J S J, et al. The Coexistence of Geopolymeric Gel and Calcium Silicate Hydrate at the Early Stage of Alkaline Activation[J]. Cement Concrete Research, 2005, 35(9): 1688-1697.
[8] 朱国振. 粉煤灰/偏高岭土地质聚合物材料的制备及其性能研究[D].景德镇:景德镇陶瓷学院,2014.
[9] 刘春原,赵献辉,朱 楠,等. 粉煤灰基地质聚合物力学性能及碱渣改性机理[J].硅酸盐通报,2017,36(2):679-685, 691.
[10]黄 毅. 地质聚合物的制备、改性及应用于环境治理的研究[D].北京:中国矿业大学,2012.
[11]LEE W K W, VAN DEVENTER J S J. Structural Reorganisation of Class F Fly Ash in Alkaline Silicate Solutions[J]. Colloids and Surfaces A—Physicochemical and Engineering Aspects. 2002, 211(1): 49-66.
[12]MINARIKOVA M, SKVARA F. Fixation of Heavy Metals in Geopolymeric Materials Based on Brown Coal Fly Ash[J]. Ceramics-Silikaty, 2006, 50(4): 200-207.
PDF(2458 KB)
