Properties of high strength concrete using white and dune sands under normal and autoclaved curing

Dune sand generally has lower silica content compared to white sand. Effects of autoclave curing on concretes containing white and dune sands as a partial cement replacement on the strength and microstructural properties were investigated. It was found that the compressive strength of concretes containing white and dune sands increased by 38% and 36% respectively after autoclaving compared to those cured under normal curing. The final products obtained were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and the thermogravimetric analysis (TGA) to investigate the mechanism that causing increase in the compressive strength. Microstructure analysis revealed that the mixes containing 30% of white and dune sand as partial cement replacement subjected to autoclave curing produced lower Ca(OH)2 content compared to those cured under normal curing.