The Effect of Curing Temperature on the Properties of Kaolin Geopolymer Paste

Abstract

This research paper focuses on the effect of curing temperature on the properties of kaolin geopolymer paste. Alternatively, kaolin was used as binders in making concrete paste in order to reduce the emissions of carbon dioxide (CO2) to the environment. Kaolin geopolymer paste was made by mixture of kaolin and alkaline activators with 0.8 :1 of solid to liquid ratio. The alkaline activator solutions were prepared with 0.2:1 ratio of Na2SiO3/NaOH. The mixture were placed in cube moulds (50 mm × 50 mm × 50 mm) and left for 24 hours until it hardened. Then, the samples were cured at 60, 70 and 80°C for 24 hours in the oven. The samples were then tested based on compressive strength, porosity, water absorption and morphology after days 28. Kaolin geopolymer paste with 70°C curing temperature is proved to have the highest compressive strength (1.04 N/mm2), lowest percentage of water absorption (1.71%) and lowest percentage of porosity (0.15%) compared to 60°C and 80°C curing temperature. The microstructure of 70°C curing temperature also shows that the geopolimerization was fully occurred with no pore.