Effect of ground granulated blast furnace slag on the properties of calcium sulfoaluminate cement. (10th December 2019)

• Record Type: Journal Article
• Authors: Gao, Danying; Meng, Yang; Yang, Lin; Tang, Jiyu; Lv, Mingyan
• Is Part Of: Construction & building materials. Volume 227(2019)
• Publication Date: 2019-12-10
• Subjects: C CaO -- A Al2O3 -- S SiO2 -- S¯ SO3 -- H H2O; Calcium sulfoaluminate cement -- Low carbon emission -- Mechanical strength -- Microstructure; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2019.08.046
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Effect of GGBFS on the hydration process of CSAC was investigated. Effect of GGBFS on the setting time and mechanical strength of CSAC was studied. Isothermal calorimeter, MIP, XRD, SEM and thermal analysis were used together. An addition of GGBFS reduces the number of micro-cracks in the hardened cement paste. Abstract: In order to make a good understanding of the properties of calcium sulfoaluminate cement (CSAC) blended with ground granulated blast furnace slag (GGBFS), the effect of GGBFS on the hydration heat, setting time, mechanical strength, pore structure and hydration process of CSAC was investigated using isothermal calorimeter, MIP, XRD, SEM, thermal analysis and so on. Results show that the hydration rate and total hydration heat are reduced with the addition of GGBFS, meanwhile, the initial and final setting time has obvious increase. The compressive strength of mortars with GGBFS ≤ 10% is close to that without GGBFS when they are cured for 28d, 56d and 120d, however, it decreases obviously when the GGBFS content is more than 10%. The pore size of hardened cement paste shifts to larger diameter with the GGBFS content increasing from 0% to 30% and the total porosity increases from 26.1% to 35.4%. The addition of GGBFS has no obvious effect on the formation of hydration products, while the total amount of hydration products is reduced. Besides, the number of micro-cracks in the hardened cement paste reduces with the GGBFS content increasing.