Geopolymers from Jordanian Metakaolin: Influence of Chemical and Mineralogical Compositions on the Development of Mechanical Properties

Abstract

The present work selects four metakaolin materials; i.e., Jordanian MK, Metastar 501 MK, Fluka MK and mixed Fluka MK with quartz, to investigate the influence of chemical and mineralogical compositions on the compressive strength of geopolymers synthesized by alkali activation of metakaolin. The geopolymer cements were ageing at 25°C between 24 and 672 h. The influence of secondary phase (quartz) on the geopolymerization reaction of metakaolin has been investigated by comparing the above-mentioned four metakaolins. The bonding status and chemical environment of SiO4 and AlO4 tetrahedras of four different types of geopolymeric products were systematically investigated by infrared spectroscopy, and the phase changes were studied by X-ray diffraction analysis. The results show that quartz, at the concentration used in this work, does not prevent the geopolymerization reaction. On the other hand, in the case of Jordanian MK and mixed Fluka MK with quartz, the geopolymer products form a cohesive and relatively hard solid indicating that they have large and stable compressive strength compared with the other two metakaolins (Fluka and Metastar 501 MKs).