Quality control of autoclaved aerated concrete by means of X‐ray diffraction

Abstract X‐ray diffraction is a very powerful tool for the characterization of crystalline phases in multi‐phase materials. In recent years, this method has been established in numerous industrial branches for quality control in processes where materials consisting of crystalline phases are produced. For instance, cementitious materials exhibit up to 20 different phases of which each is responsible for certain physical and chemical properties of the product. Knowing and understanding the phase assemblage of a material and the effects on its behavior allows the optimization of a product with respect to properties, quality, and production costs. The cement industry is using this knowledge by characterizing the materials along the production chain from raw materials to the final products by means of X‐ray diffraction. Autoclaved aerated concretes (AACs) consist mainly of crystalline and non‐crystalline solids, and for that reason, they have been subject to many crystallographic studies using X‐ray diffraction. Although the phase assemblage is regularly investigated, only little knowledge gained from these studies is transferred to production sites in order to monitor the manufacturing process. The crystallographic phase assemblage of autoclaved aerated concrete could be examined by X‐ray diffraction on a routine basis in order to maintain constant product quality and, thus, even material properties. Another beneficial aspect of this method is that it enables choosing more economic raw materials and optimizing process parameters.