The technology of aerated concrete

The technology of aerated concrete is a topic that is permanently studied and developed because of the incessant demand for a building material which ensures relatively high strength at low volume weight. This bachelor’s thesis examines the influence of replacing a part of sand with another silica material – microsilica. The increase of mechanical strength is expected at the same volume weight. Microsilica contents around 98 % of amorphous silicon dioxide with a high specific surface area that is substantially higher than a specific surface area of a ground sand. The reactivity of silicon dioxide increases with a higher specific surface area and also with the creation of a mineral tobermorite, which is the keeper of the strength in autoclaved aerated concrete. Three types of microsilica were chosen to examine the influence of replacing a part of sand with microsilica according to their availability for manufacture: microsilica Sikron and Elkem 971 U, microsilica Grace Davison was tested only marginally. Tests were carried out to determine volume weight, compressive strength, phase composition (by X-Ray diffraction method), and the content of tobermorit (by TG-DTA method)