Mechanical and microstructural properties of alkali-activated lightweight mortars exposed to high temperatures

The influence of the curing conditions (ambient curing or heat-curing), and concentration of the activating agent (8, 10, 12, 14, 16, 18 and 20 Molar sodium hydroxide solution) on the properties of alkali-activated lightweight mortars (AALWMs) containing ground granulated blast furnace slag (GGBFS) as sole binder is reported in this study. AALWMs are exposed to elevated temperatures (150, 250 and 500 degrees C) at the age of 28 days. The investigated properties of AALWMs at ambient and high temperatures are the unit weight (U-w), ultrasonic pulse velocity (U-pv), flexural strength (f(s)), compressive strength (f(c)) and the analyses of X-ray powder diffraction (XRD) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). The best strength results have been achieved on the ambient-cured AALWMs activated with 8 M NaOH solution.