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In this study, ground granulated blast-furnace slag (GGBFS) samples from Singapore, Korea, and the United Arab Emirates were hydrated with purified water to estimate the cementing capabilities without activators. Raw GGBFS samples and hardened pastes were characterized to provide rational explanations for the strengths and hydration products. The slag characteristics that influenced the best strength of raw GGBFS were identified. Although it is widely recognized that GGBFS alone generally shows little cementing capability when hydrated with water, the GGBFSs examined in this study demonstrated various strength developments and hydration behaviors; one of the GGBFS samples even produced a high strength comparable to that of alkali- or Ca(OH)2-activated GGBFS. In particular, as the GGBFS exhibited a greater number of favorable slag characteristics for hydraulic reactivity, it produced more C-S-H and ettringite. The results demonstrated a reasonable potential for commercial GGBFS with calcium sulfates to function as an independent cementitious binder without activators. [ABSTRACT FROM AUTHOR]

A technique for measuring the full field (x,y,z,u,v,w) velocity distribution of fluid flow at a micrometer scale spatial resolution has been developed. To investigate three-dimensional (3D) flow structures on a microscopic scale, a 3D scanning microparticle image velocimetry system was developed by combining a high-speed camera, an epifluorescent microscope, a cw laser, and a piezo actuator. Both numerical simulations and an experiment were carried out in order to validate the measurement accuracy of the system. Optimum measurement conditions were determined by numerical simulations using synthetic images under epifluorescent microscope observation. As a demonstration, the three-dimensional velocity distribution of water flow inside a microround tube having a diameter of 95 μm was measured at a spatial resolution of 5.4×2.7×4.2 μm. [ABSTRACT FROM AUTHOR]