Abstract: The freeze-thaw damage of concrete is a severe problem for hydraulic structure in cold and arid regions in Northwest China. In this research, we investigated the mechanical properties, freeze-thaw resistance and impermeability of fly ash concrete with uniform strength and water-cement ratio at different ages. The strength of high volume fly ash concrete in the early stage was lower than common ones, but the strength grew rapidly in the mid-late ages. The freeze-thaw resistance, self-healing ability and the impermeability of fly ash concrete with uniform strength were not significantly weakened when fly ash content was increased. When the water-cement ratio and the fly ash content were 0.35 and 50% respectively, the mechanical properties, freeze-thaw resistance and impermeability of the concrete were prominent and able to meet the requirements of water project construction in the northwest cold and arid regions.

Key words: cold and arid regions, fly ash content, curing time, concrete