EFFECT OF GROUND BLAST FURNACE SLAG ON TSA RESISTANCE OF CEMENT-BASED MATERIAL

Thaumasite form of sulfate attack (TSA) is recognized to be detrimental to durability of cement-based material because its formation consumes the binder phase, C-S-H gel. To discuss TSA prevention, effect of ground blast furnace slag on TSA resistance of Portland cement-based material were investigated by means of mechanical property of specimens and erosion phases identification using micro-analytical techniques like fourier transform infrared spectroscopy (MR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrum (EDS) as well as Raman spectra. When exposed to aggressive environment with 33800 ppm mass concentration Of SO42- in magnesium sulfate solution at low temperature (5 degrees C +/- 2 degrees C) for 15 weeks, ratios of compressive strength loss decrease with increase of slag contents in binder. Furthermore, When thaumasite came into being in erosion phases of specimens with 0, 15% slag content, only ettringite and gypsum appeared in those with 30%, 45%, 60% slag, which indicate that definite amount of slag can restrain or retard formation of thaumasite and improve TSA resistance of Portland cement-based material sufficiently.