Entwicklung eines für die Herstellung mit dem Schleuderverfahren geeigneten Geopolymerbindemittels

The present work reports the development and properties of a geopolymer binder designed for the production of pipes using existing slinger devices. These pipes are used to transporting of low caloric gas, which can reach temperatures of up to 500°C. In the first step, a geopolymer binder was formulated according to the requirements with the help of production-specific properties and four key figures. The formulated geopolymer recipe, which met all requirements, was characterized in the next step. The study was divided into two points. First, the influence of curing time at ambient conditions on the durability of the resulting material was investigated. In the next step, the properties of the formulated geopolymer after thermal treatment, as well as depending on the temperature were characterized. The results indicates a chemical reaction (carbonation) when curing unsealed geopolymer samples under ambient conditions, between available alkali metals (K+) and atmospheric CO2. This reaction caused an expansion during the first 7 days of curing. Furthermore, an influence of temperature during hardening was examined. With the increase in temperature dehydration occurs, which is associated with an increase in porosity. Both, expansion as well as dehydration result in a decrease in strength. Initial applications tests with an existing slinger device were performed and the results show, that the designed geopolymer binder is suitable for pipe production. All application and shaping requirements were met. As an improvement potential further investigation of carbonation and dehydration is proposed.