Abstract
The fly ash (coal ash) discharged from a thermal power plant as an industrial by-product can serve for a constitutive material of geopolymer. However, geopolymers which have been produced from some kinds of fly ash do not solidify and the strengths are weak. The strengths were improved remarkably by addition of ground granulated blast furnace slag, generated as a by-product in an iron mill, into the fly ash (Matsuura JIS ash). The maximum compressive strength was obtained in M8S2 geopolymer which was produced by using Matsuura JIS ash and ground granulated blast-furnace slag in a weight ratio of 8:2. The compressive strength of M8S2 geopolymer produced in winter season did not exceed the strength of the M8S2 geopolymer which produced in summer season. Then the improvement of the strength of M8S2 geopolymer was found out remarkably in cases of temperatures higher than approximately 20°C. Moreover, the investigations of the improvement of strength were examined by the results of compressive, tensile and bending strengths, chemical constitution of the materials, and SEM observation.
