EFFECT OF SURFACE-PENETRANTS FOR CONCRETE UNDER FREEZE-THAW CYCLES

Reinforced concrete (RC) structures are generally deteriorated by penetration of water and gases that induce corrosion of reinforcements. Surface-penetrants, which increase gas-penetration resistance of concrete, can improve the long-term durability of RC members. A kind of surface-treatment, such as silane penetrants, gives a high water-repellant effect to concrete. It is well known that concrete in cold regions is occasionally damaged by freezing and thawing (F-T) cycles. In a microscopic viewpoint, water-pressure in pore structures of concrete increases due to freezing. The increase of internal water pressure may be a cause of the F-T damage of concrete. It is possibly hard to ease the water-pressure in saturated concrete incorporating the water-repellant penetrant. That is, the surface-treated concrete under the F-T cycles may deteriorate seriously. To examine the effect of surface-treatment, the study conducted the F-T test (JIS A 1148) by using concrete that was painted with surface-penetrants. The foci of this investigation are to examine the F-T durability of surface-treated concretes and to compare the effect of the surface-penetrants. This paper reports the effects of the water-repellant penetrant on the F-T durability.