Study Of Influencing Factors On Saturation Degree Of Concrete

In cold areas, concrete is always deteriorated by freezing and thawing cycle. The durability and the corrosion of concrete are directly affected by the water-saturated degree of concrete. By using the method of orthogonal table, the water binder ratio, air content and mineral admixtures which affect the saturation degree are analyzed in this paper. Meanwhile in freezing and thawing cycle circumstance including water environment and 3.5%NaCl liquor, the saturation degree and the saturation rate are also analyzed.Moisture content of the concrete is different by varying water pressure. This means the saturation degree of concrete is different. By means of analyzing the L9 (34) orthogonal table, the air content is the chief factor, the second factor is water binder ratio and the third is mineral admixture in both high water pressure and low water pressure. The water saturation degree of concrete in damaging point(E6 /E0=60%) can be found by measuring the dynamic modulus of elasticity after six freezing-thawing cycles. The test result shows that the water binder ratio is the chief factor in damaging point.The saturation of concrete and the higher degree of saturation in the surface layer of specimens can be used to explain the damage form of specimens in the freezing-thawing, which include change of relative dynamic modulus of elasticity and weight. The change of specimens scaling mass were measured, both the saturation degree of specimens and its changing rate within freezing-thawing are calculated. Under the different freezing-thawing cycle circumstance, three factors of water binder ratio, air content and mineral admixture are analyzed by using the method of orthogonal table. The test results show that the chief influencing factor is the water binder ratio in water freezing-thawing cycle circumstance, and in salt freezing-thawing cycle circumstance is the air content. This could illustrate that entraining air into concrete can improve the frost resistance of concrete effectively in salt freezing-thawing cycle.