Experimental Study on TGA, XRD and SEM Analysis of Concrete with Ultra-fine Slag (TECHNICAL NOTE)

The performances of cementitious materials as well as the efficiency of construction are adversely affected at high temperatures. Previous studies have already demonstrated that ultra-fine (alccofine) material accelerates the hydration of cement particles and subsequently improves the mechanical and durability properties of the concrete at normal temperature. Moreover, at higher temperatures the performance of the concrete with the addition of alccofine is still unknown. This paper presents the effect of analytical properties of concrete with alccofine (25%) as a replacement of cement for various W/B ratios (i.e. 0.38, 0.4 and 0.45). The effect of addition of alccofine dosage on the thermogravimetric analysis was carried out in which not only mass loss and decomposition of hydration products from concrete with respect to temperature was found but also bound water (%) and calcium hydroxide (%) present in the concrete were determined. From X-ray diffraction it was observed that alccofine improved the formation of calcium silicate hydrate and calcium silicate aluminum hydrate in concrete and scanning electron microscope (SEM) analysis showed the formation of ettringite needles and calcium silicate hydrate in voids which made concrete denser. Therefore, it was concluded from this study that alccofine can be used as a viable substitute to cement in normal concrete considering its positive effects on property enhancement and an eco-friendly product.