Sulphate Resistance of Metakaolin Mortar

Strength and chemical resistance of mortars containing brick manufacturing clays subjected to different treatments

“…It is considered that the moderate firing temperature of 800°C experienced by HTC has the effect of producing a material similar, in its physical state, to MK. It has also been shown [12] that MK reduces expansion as the level of PC replacement increases and that this is attributed to reduction of the CH content [10] thus reducing the amount available for ettringite formation and growth. In acting as an active pozzolan, HTC consumes CH early in the hydration process resulting in less CH being available for gypsum and ettringite formation on exposure to sodium sulphate solution.…”

Effect of metakaolin substitution on physical, mechanical and hydration process of White Portland cement

“…Positive effects of the use in metakaolin in the production of concrete and mortar such as its superior mechanical properties at early ages, reduction of the high hydration heat of cement, improvement of compressive, tensile and flexural strengths, reduction of shrinkage, increase in the freezing and thaw resistance, reduction of permeability, resistance against chemical effects, decrease of alkali silica reactivity and allowing for denser concretes were reported by several researchers [6][7][8][9][10][11][12]. Some researchers have also reported that metakaolin enhances workability, allows for obtaining a smoother surface and decreases efflorescence [9,11].…”

“…Samples that contain metakaolin at various rates up to 15%, pozzolanic reaction develops rather rapidly until 14 days, and therefore strength is increased and improvements in the porous structure of cement paste are observed. In curing periods longer than 14 days, on the other hand, it is reported by several researchers that the puzzolonic reaction rate decreases significantly and accordingly also the increase in compressive strength slows down [6,8,[13][14][15][16][17].…”

Comparison of surface properties between kaolin and metakaolin in concentrated lime solutions

“…Concretes containing metakaolin present behaviors similar to those containing some silica fume, that is, an improvement of the mechanical resistance and a significant reduction of the permeability and of the shrinkage of concrete [7][8][9]. Some authors note that an addition of the order of 15% by weight of metakaolin improves the resistance of concrete to aggressive environments, such as sea water or acid solutions [10][11][12]. Numerous studies on the thermal transformation of kaolin showed that the temperature and time of thermal treatment have a significant importance on the properties of concretes containing metakaolin as an addition [13,14].…”