Development of high-strength lightweight non-autoclaved aerated concrete

Six concrete mixes with different proportions of various pozzolanic materials were investigated for the development of high-strength non-autoclaved aerated concrete (NAAC). Fly ash and slag were used as partial cement replacements in order to perform comparative studies on the effects of fly ash and slag on NAAC. Aluminium powder was used as an expanding agent to produce gas in the mixes. The compressive strength of each mix after 7 and 28 d of curing was determined. The microstructure of the pozzolanic cellular concrete was also investigated using scanning electron microscopy. The influence of the pozzolanic materials on the microstructural and macrostructural characteristics of the cellular concrete was assessed. A cement-based concrete mix, with pozzolanic materials as partial replacements of cement and sand, was thus developed for lightweight cellular concrete with a 28 d compressive strength exceeding 17 MPa. The developed foam concrete with relatively high strength is ideal for several structural and non-structural applications.