Effect of organic alkali on hydration of GGBS-FA blended cementitious material activated by sodium carbonate. Issue 2 (15th January 2022)

• Record Type: Journal Article
• Authors: Deng, Xiufeng; Guo, Huiyong; Tan, Hongbo; Nie, Kangjun; He, Xingyang; Yang, Jin; Wang, Yingbin; Zhang, Junjie
• Is Part Of: Ceramics international. Volume 48:Issue 2(2022)
• Page Start: 1611
• Page End: 1621
• Publication Date: 2022-01-15
• Subjects: Alkali-activated cement (AAC) -- Ions dissolution -- Hydration -- Organic alkali -- Sodium carbonate; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.09.240
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Sodium carbonate (SC) activated ground granulated blast-furnace slag (GGBS) and fly ash (FA) is a potential substitute of traditional cement with ultra-low carbon footprint. However, its hydration rate and strength growth are limited, owing to the slow leaching of ions during the activation of weak base. In this work, 60% wet-grinded GGBS and 40% FA were blended as the binder, and two organic alkalis, i.e. triethanolamine (TEA) and triisopropanolamine (TIPA), were adopted to facilitate the ions dissolution and pozzolanic reaction of SC activated GGBS-FA blended cementitious material (SCSF). The compressive strength was tested and the hydration kinetics was studied by hydration heat and chemical shrinkage. Besides, ions leaching behavior was characterized by ICP; hydrates and microstructure were also detected by XRD, TG-DTG and SEM. Results indicated that the addition of TEA or TIPA significantly promoted the ions dissolution. 0.05% TEA increased the concentration of leached Ca 2+, Al 3+ and Fe 3+ by 36%, 33% and 1545%, respectively. This solubilizing effect was also found in TIPA. Moreover, these two chemicals could promote the formation of hydrates, such as C-S(A)-H gel, hydrotalcite, calcite and aragonite, especially at the early period; these also activated the hydration process of SCSF effectively, and the compressive strength of the mortar reached above 40.0 MPa at 7 d and 48.0 MPa at 28 d. The carbon emission of the designed system is 85.9% and 55.9% lower than that of PC and strong base activated GGBS system, respectively.