건설재료시공학연구실

Building material & construction lab.

Abstract
The performance of concrete mainly depend upon its water-cement ratio. If water percentage is excess in concrete, it may cause the degradation of performance. Because of these reasons, the change of water content is managed by using various evaluation method of unit water content. And criterion for the change of water content is regulated and used. However the criterion is set only considering production error and measurement error but criterion does not consider performance degradation of concrete.
 Therefore this study tries to investigate degradation of performance while adding extra water by artificial manipulation or management error in concrete. The contents of extra water for tests are set as 0, 20, 40, 60kg/m3, to examine the performance degradation of concrete, strength, shrinkage, cracks, carbonation are tested.
 This study conclude that, when extra water content is excess than 20kg/m3 in concrete, then performance level of concrete declined rapidly. So it is very important to maintain quality of concrete for its better performance.