AAC building components for modular construction using recycled materials

The article presents the results of a study of the use of aggregates from the processing of wastewater treatment plant waste for the manufacture of large‐scale prefabricated building components means large‐scale autoclaved aerated concrete. This aggregate, applied to hydration‐bonded materials, makes it possible to obtain lightweight concretes (density 1400–1600 kg/m³) with increased thermal resistance. In addition, the addition of an aluminosilicate phase to the concrete mix can favorably affect mechanical characteristics and durability. The lightweight aggregate obtained using sewage sludge is characterized by high porosity, resulting from the complete combustion of the organic parts contained in the sludge (more than 90% d.m.), which act as a porophore in the ceramization process. This feature predestines this type of aggregate for use in hydration‐bonded materials that exhibit improved thermal insulation properties. The combination of sludge‐based lightweight aggregate technology with AAC production technology, therefore, implies a synergistic action to obtain a material with improved thermal insulation parameters combined with the mechanical strength expected for structural materials. An important environmental aspect of the proposed approach is the use of waste materials including municipal sewage sludge, which is particularly difficult to manage and dispose of, and the reduction of natural resource exploitation.