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Title |
An Influence of Unit-Water Content Distribution in Ready-Mixed Concrete on Strength and Durability of Concrete
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Keywords |
가수 ; 단위수량 ; 내구성 ; 동결융해 ; 염소이온 침투 extra water ; unit water content ; durability ; freezing and thawing ; chloride penetration |
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Abstract |
Various problems such as durability degradation may happen when extra water is added to concrete. Because of these reasons, the change of water content is managed by using rapid evaluation method of unit water content such as electric capacity method, heat drying method making use of micro wave, unit capacity mass method among various methods. Especially,in Japan, guidance for the change of water content (± 10, 15, 20 kg/m3 etc.) were regulated and used. However, it is the real situation that the guidance which were regulated in South Korea evaluate suitability only considering production and measurement error under the circumstances which are not considering the degree of durability degradation. Therefore, this study tries to investigate the influence of addition of extra water in the concrete on the durability degradation of concrete when it was added by artificial manipulation or by management error. From the test results, a guideline of the contents of extra water for the quality control is suggested with the consideration of the degree of durability degradation and the probable error resulted from the addition of extra water. The contents of extra water for tests are set as 0, 15, 25, 35 kg/m3. To examine the durability degradation of concrete, freezing and thawing, carbonation, chloride penetration and compressive strength are tested.
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