Development of a preloadable, temperature‐stable, geopolymer‐based gap compensation material

Consequences of climate change are becoming increasingly clear and while resources are dwindling, extreme climatic situations become more frequent. This leads to higher temperatures and thermal stress on the one hand and to the construction of more wind power plants and respectively an increasing demand for gap compensation materials on the other hand. These materials are commonly made of epoxy resins, which perform well under certain circumstances, but have some disadvantages such as heat instability, high costs, high resource claim, and hazards for the environment and health. This paper presents the latest results from the development of a low‐viscosity, high‐temperature stable geopolymer for gap compensation. In several newly developed test rigs, experiments were carried out to investigate injectability, flow behavior, mechanical properties, high‐temperature stability, and the possibility to induce preload. Through inorganic additives, the geopolymer expands or, if expansion is constrained, preloads itself during the hardening. This is essential to retain or enhance the preload of connection bolts and ensure force transmission as any volume reduction would create a new (smaller) gap.