Abstract: The relationship among strength, impermeability, and micro-pore structure of concrete bridge pier cured with four different methods at three different curing ages (7d, 14 d, 28d) is examined in extremely dry area with large temperature difference. The strength, impermeability and pore structure of concrete pier are tested and analyzed on the 28^th day of curing. Results demonstrate that the most probable pore and the harmful pore in natural curing condition are the largest, followed by those under geotextile curing, new material curing, and standard maintenance in sequence, indicating an improvement of impermeability. With the increase of curing age, the impermeability, strength, and harmful pore of concrete gradually decline; when curing age exceeds 14 days, the concrete pier performs well, hence we suggest curing for 14 days. New material is superior to geotextile in maintenance. Better moisturizing effect of curing method could result in higher strength and impermeability.

Key words: extremely dry with large temperature difference, concrete bridge pier, impermeability, micro-pore structure, curing method