Fly Ash-Desulfurization Gypsum Mortar and Concrete Part I: Mix Proportions and Hydration

Abstract:

Fly ash (FA) and flue gas desulphurization gypsum (FGD) were blended in proportion into a new composite binder added with cement, lime and some modifiers. In the paper, the mix proportions of composite binder with low-quality FA and FGD were studied. FA-FGD more than 80% with FA:FGD 3:2 was suggested for mortar, plastering and slurry while FA:FGD 2:1 and FA-FGD 30~40% was recommended for middle-strength concrete. Hydration process of typical mixtures of FA-FGD paste was investigated through SEM and XRD tests. The conclusion could be made that FA showed much improved pozzolana activity especially at early ages due to the existence of FGD as an ideal sulfate activator, which also crystallized later to strengthen the hardened paste. The microstructure of hydrated FA-FGD paste was more excellent than that of neat cement stone or one blended with the same percentage of pure FA.

• Periodical: Advanced Materials Research (Volumes 250-253)
• Pages: 809-816
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.250-253.809
• Online since: May 2011
• Authors: Yu Chen, Ying Li Gao
• Keywords: Desulfurization Gypsum, Fly Ash (FA), Hydration, Mix Proportion, Sulfate Activation

References

[1] SHI Huisheng, YUAN Ling, ZHAO Yujing. Study of modification of composite using waste chemical gypsum and fly ash (in Chinese). Journal of Building Materials, No.2, 2002, 26~31

[2] YANG Yuanxia, ZHOU Shiqiong, LIU Baoju. Study on improving the early strength of fly ash-fluorogypsum cementitious binder (in Chinese). Journal of Railway Science and Engineering, No.1, 2005, 34~37

[3] YAN Peiyu, YANG Wenyan. Microstructure and properties of the binder of fly ash-fluorogypsum-Portland cement. Cement and Concrete Research, No.2, 1999, 349~354

DOI: 10.1016/s0008-8846(98)00214-2

[4] Manjit Singh, Mridul Garg. Cementitious binders from fly ash and other industrial wastes. Cement and Concrete Research, No.2, 1999, 309~314

DOI: 10.1016/s0008-8846(98)00210-5

[5] WU Shaopeng, SHEN Weiguo, ZHOU Mingkai. Study of phosphogypsum-fly ash-lime solidified material (in Chinese). China Journal of Highway and Transport, S1, 2001,15~17

DOI: 10.1016/b978-008044100-9/50117-0

[6] CHEN Deyu, YUAN Wei, TAN Kefeng. Research on the activating technique of wet fly ash (in Chinese), Concrete, No.10, 2008, 92~94

[7] Lin Fanghui, Peng Jiahui, Cong Gang. Study on hydration-hardening mechanism and water-resisting property of desulphogypsum-fly ash binder (in Chinese). Journal of the Chinese Ceramic Society, No.05, 1995, 219~223

[8] PELED A F, CYR M, SHAH S P. High content of fly ash (class F) in extruded cementitious composites. ACI Materials Journal, No.5, 2000, 509~517

DOI: 10.14359/9283

[9] ZHOU Wanliang, ZHAN Binggen, LONG Jinghua. Development of cement-based binder with large Content of fly ash and fluorogypsum (in Chinese). Bulletin of the Chinese Ceramic Society, No.5, 2007, 41~45

[10] Yan Peiyu, You Yi. Hydraulic properties of the binder consisting of fluorgupsum and fly ash under different curing conditions (in Chinese). Journal of the Chinese Ceramic Sociaty, No.6, 1999, 1~7