PREDICTION MODEL OF BLEEDING CONTENT CONSIDERING FLOCK OF CEMENT AND RETAINING WATER OF FINE AGGREGATE

Abstract

 It is essential for the mix design of fresh concrete to provide adequate segregation resistance. The segregation resistance should be considered based on the amount of bleeding after placement of concrete. This paper discusses the mechanism of bleeding and proposes the prediction model of bleeding content under a given mix proportion of concrete. Since the bleeding content is an amount of extra water which is not retained by both cement particles and fine aggregate, the model consists of water retaining mechanism on both cement particles and fine aggregates. The characteristics of the model are as follows; (1) the influence of flock of cement particles is taken by water cement ratio, and (2) the amount of retained water by fine aggregates is estimated using the relationships between the relative flow area ratio and the water-cement volume ratio determined by a mortar-flow test. The effectiveness of the model is proved sufficient by experimental test results varying the mix proportion of 45 cases.