2021 Volume 77 Issue 2 Pages 65-77
In order to ensure the durability of cast-in-situ prestressed concrete road bridge deck in an environment where deicing salt is sprayed, we examined the workability of fly ash concrete on the premise of local production for local consumption and implemented it on highway road bridge. As the evaluation procedure of fly ash concrete, 1) laboratory test, 2) workability confirmation test using site mock up deck, 3) laboratory test for problem solving from the workability confirmation of site mock up deck, 4) actual concrete mixing plant test for final confirmation were conducted. And the mix proportion of fly ash concrete that satisfies the required performance for construction on site was decided from the evaluation procedure. As a result, it was found that the loss of slump and air content during transporting from ready-mixed concrete factory to site was remarkable in the fly ash concrete using both early-high-strength Portland cement and fly ash. Therefore, at the time of mixing fly ash concrete at the ready-mixed concrete factory, it is decided that properly setting the amount of increase in slump and in air content in anticipation of the slump and air content of arrival time at the site is needed. In addition, since the fresh properties such as slump and air content after pumping fly ash concrete in the implementation work were good, it was clarified that fly ash concrete can be applied to cast-in-situ prestressed concrete road bridge deck.
