Nanostructured high insulating autoclaved aerated concrete / Nanostrukturierter, hochwärmedämmender Porenbeton

Efficient insulation for residential buildings is one of the keys for implementing an energy transition. The technology used for exterior walls is usually made by combining load-bearing and difficult to recycle insulating components. For this reason, Celitement GmbH, Karlsruhe Institute of Technology and Xella Technology and Research have joined their forces to develop a high insulating AAC, which is also resource efficient using the main components quick lime, sand, and water. The thermal conductivity of the AAC was reduced. Macropores formed in the conventional production process by hydrogen gas, diameter of approximately 1 mm, could be partially replaced by lightweight aggregates, with an average pore diameter of 50 nm. A process for producing lightweight aggregate, which is based on optimized, hydraulically active calcium hydro silicate binders (Celitement), was developed. The aggregate quantity in AAC could be raised to 40% by weight through optimizing formulation and mixing. This project, sponsored by the German Federal Ministry of Education and Research, ended in 2017. Based on the results so far, it is worth pursuing this approach in the future, whereby the material properties of the CSH granules could be further improved to obtain the sought final AAC product.