Katsuya Mita, Masanori Tsuji
Improvement of defect caused by bleeding of water plays an important role to construct durable concrete structure. Distribution of chloride ion diffused in concrete is very complex, because path of bleeding of water remains as the path of diffusion of chloride ion in hardened concrete. To make the path smaller by decreasing bleeding water or revibration must be an effective way for the chloride diffusion to be uniform and smaller. On the other hand, chloride will diffuse easily from crack
more » ... n compared with cut section by concrete saw, because the aggregate near the crack section must be loosened. And the degree of the loosing will be depending on the bleeding water movement. In this study, the effects of bleeding of water in concrete on chloride diffusion into concrete were investigated. Following 1), 2) and 3) were concluded in this study. 1) It is very difficult to make chloride diffusion in concrete isotropic and uniform, because complex path formed under bleeding of water must remain in hardened concrete. To achieve more isotropic concrete, the remixing to reduce the bleeding and the revibration to distribute the path of bleeding are very effective ways, and proportioning to reduce the bleeding is also effective. 2) Chloride diffuses faster at the part where the bleeding water tends to remained, corner of T section and bottom surface of flange for example. This influence can be improved by the revibration and/or the decrease of bleeding by mix proportion and/or mixing technique i.e. SEC mixing method. 3) Chloride diffusion from the cracked surface was much faster than that from the cut surface by concrete saw. This tendency was remarkable when the water-cement ratio was higher and also when the remix and the recompaction were not done. The reason is considered that the interface between aggregate and cement paste loosened easier under cracking when the more bleeding water remains around the aggregate.