부산대학교 도서관

In this study, the change in surface quality of concrete with aging was studied using concretes with different mix designs, curing conditions and exposure conditions. We used three sets of specimens. The first set was composed of rectangular blocks. The second set was specimens that simulate a part of box culvert. The third set was column specimens of a middle-scale bridge model with RC rigid frame. These specimens were prepared with various mix designs and curing conditions in the Kanto area, Japan. The surface quality of concrete was evaluated by the coefficient of air permeability measured using the surface air permeability test proposed by Torrent Robert. Results showed that the difference in the air permeability owing to curing conditions decreased with age. About one year later, the coefficient of air permeability of specimens exposed to rainfall was approximately the same regardless of the curing method. The effect of curing was present even after one year for specimens under the roof-not exposed to rain, but the difference in the coefficient of air permeability continued to decrease. On the other hand, the difference in surface air permeability between concretes with different water to cement ratios remained even at the age of five years.