Effects of Classified Fly Ash on Improving the Compactability of Roller Compacted Concrete for Pavements

Roller compacted concrete (RCC) pavements are expected to be an economic and rational concrete pvPmAnt system that will become increasingly popular in Japan. The maximum thickness of a RCC slab completed in one layer is limited to 25 cm because of limitations in the compactability of the concrete and the control of the pavement surface profile. Classified fly ash (CFA) is produced by grading fly ash and is expected to improve the consistency of fresh concrete and the durability of hardened concrete. The use of CFA as an admixture of cement provides the possibility to improve the compactability and to increase the slab thickness that can be executed at one time. In this paper, the improvement of the consistency of RCC mixed with CFA for pavements is studied. From a series of experiments, CFA has proved to have an excellent effect on the consistency of RCC for pavements.