Influence of gibbsite and quartz in kaolin on the properties of metakaolin-based geopolymer cements

摘要: Abstract Three different kaolins (K1, K2, K3) from sources in Cameroon were applied for producing geopolymer cements. The differ significantly their gibbsite and quartz contents. Thermal transformation (700 °C, 4 h) into metakaolins MK1, MK2, MK3 shows the total loss of crystalline kaolinite reveal typically rather broad bump X-ray pattern. Gibbsite becomes dehydrated γ χ-Al 2 O 3 . Geopolymer cements (GP1, GP2, GP3) obtained using freshly prepared sodium silicate solutions (NWG) with a ratio NWG/MK = 0.87. It could be observed that initial (60/80/90 min) final (90/140/160 min) setting time increases 28 day compressive strength (49/39/30 MPa) decreases course GP1/GP2/GP3. is discussed higher content K1 (up to 22 wt.%), compared K2 (10 wt.%) K3 (8 wt.%) promotes values decreased times. was not present K1, but up 11 wt.% 28 wt.% K3, transformed its forms remains unreacted during geopolymerization. Therefore, related lower strength. reacted volumes compositions become almost same all three cases. A 30–50% metakaolin proved