Influence of slag content and water-binder ratio on leaching behavior of cement pastes. (30th December 2016)

• Record Type: Journal Article
• Authors: Tang, Yu-Juan; Zuo, Xiao-Bao; He, Shao-Li; Ayinde, Olawale; Yin, Guang-Ji
• Is Part Of: Construction & building materials. Volume 129(2016)
• Page Start: 61
• Page End: 69
• Publication Date: 2016-12-30
• Subjects: Slag-cement pastes -- Slag content -- Water-binder ratio -- Calcium leaching -- Porosity -- XRD -- SEM; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2016.11.003
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Slice specimens with slag-cement paste were designed to carry out the calcium leaching experiment. Influences of slag content and water-binder ratio on the leaching resistance of cement pastes were investigated. The slag-cement pastes with the optimum leaching resistance were obtained. Abstract: In order to obtain quickly the influences of blast furnace slag and water-binder ratio on the leaching behavior of cement-based material and its corrosion resistance in water environments, an accelerated calcium leaching experiment on a slice specimen with slag-cement pastes in 6 M NH4 Cl solution was carried out. Using the saturation-drying weighing method, X-ray diffraction (XRD) and the scanning electron microscope (SEM/EDS) measurement, the influences of water-binder ratio and slag content on the porosity, phase composition, microstructure morphology and Calcium-Silicon ratio of slag-cement pastes in the process of calcium leaching were analyzed. Results show that, compared to cement pastes without slag, the slag-cement paste with the appropriate slag content has a low rate of microstructure deterioration and a good leaching resistance. The optimum slag contents in slag-cement pastes are respectively 40% and 50% corresponding to the low and high water-binder ratio. The porosity, Calcium-Silicon ratio and microstructure morphology of slag-cement pastes exhibit small change in the process of accelerating leaching, and this indicates that the slag-cement pastes with the optimum slag content can provide the best performance of calcium leaching resistance in the soft-water environment.