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X-Ray computed tomography (X-CT) three-dimensional imaging microscopy was used to scan the test specimens made with hardening alkali-activated slag cementing material, and the distribution and morphology characteristics of internal micron pores were obtained accurately; meanwhile the test specimens at the age of 1 day, 7 days, 14 days and 28 days were also scanned, and the data collected by X-CT were processed accordingly by use of images and data processing software Avizo for three-dimensional reconstruction study and comparison on the change conditions of internal pores. The experimental results showed that the proportion of micron pores firstly increased and then decreased, the pore volume was basically stable over the age of 14 days, and the diameter of most pores was 200µm or less. more...

In this paper, with water glass as alkali activator, slag and class F fly-ash based cementing material is mixed to prepare alkali-activated concrete. The dynamic mechanical property and surface micro-topography under different temperature of −50°C−140°C was evaluated by using dynamic mechanical analyzer (DMA+1000) and ESEM technology. DMA results show that when the ambient temperature changes from 28°C to 140°C, the rigidity of alkali-activated concrete increases, but the elastic deformation ability decreases; the temperature increment stimulates surface cracks of concrete to become wider and more, and increases the dissipation factor. When the ambient temperature changes from 28°C to −50°C, the storage modulus and rigidity of alkali-activated concrete increase first, and then decrease. ESEM test results show that the storage modulus will increase, and the dissipation factor will decrease at ordinary temperature. When the temperature increases, the surface cracks become larger, and the strength of materia... more...