Effects of Mixture Proportions on Permeability and Pore Structure of High-Fluidity Concretes
M. Kakizaki, H. Edahiro, K. Fujii, and H. Nakase
Appears on pages(s):
fluidty; fly ash; permeability; porosity; water
High-fluidity concretes have been developed recently and are being more widely accepted in order to realize highly durable and easier-to-build concrete structures. However, very little research has been made so far on the permeability and pore structure of high-fluidity concretes. This paper discusses the influences of water-binder ratio, type of admixture and amount of fly ash upon the permeability and pore structure of high-fluidity concretes. Permeability of high-fluidity concrete decreased with a decrease in water-binder ratio regardless of the type of chemical admixture and addition of fly ash used. It also decreased with additions of fly ash and this tendency was noticeable at lower water-binder ratio and was affected by factors such as the applied pressure, type of concrete and water-binder ratio. Air permeability of all types of concrete decreased with an increase in applied pressure. Total pore volume (pore radius from 3.75 to 7500 nm) of high-fluidity concrete decreased with a decrease in water-binder ratio and the number of fine pores increased. This tendency was noticeable when fly ash was added to the mixtures.