Low Viscosity, High Temperature Stable Geopolymer for Crack Injection and Cavity Filling with Optional Increase of Volume and Preload

Abstract

Consequences of climate change are becoming increasingly obvious and while resources are dwindling, buildings tend to be operated longer than originally expected and have to be maintained according to prolonged service life and more intense environmental impacts. Cracks and cavities are crucial for the durability of reinforced concrete structures and need to be filled, to ensure usability. Often, this is done with epoxy resins. While these polymers perform well under certain circumstances, they have many disadvantages such as heat-instability, high costs, high resource claim and hazards for environment and health. Thus, the Institute for Building Materials Research (IBAC) at RWTH Aachen University (Germany) is researching an eco-friendly and durable alternative binder based on geopolymers in collaboration with Diamant Polymer GmbH (Germany).

This paper presents the latest results from the collaborative project and the development of a low-viscosity, high temperature stable geopolymer for crack injection and cavity filling. In several test rigs, experiments were carried out to investigate injectability, flow behaviour, mechanical properties, high temperature stability and the possibility to increase volume and induce preload. Through inorganic additives, the geopolymer expands or, if expansion is constrained, preloads itself during the hardening, which IS essential to create a durable backfilling as any volume reduction would create a new (smaller) cavity or crack. As further advantages, the high alkalinity of the geopolymer supports remaining the alkaline milieu in concrete and the geopolymer can be recycled similarly to concrete.