Influence of Water-binder Ratio on the Microstructure of Air-entrained Concrete

Abstract

The concrete’s microstructure affects its macroscopic properties such as the strength and the frost resistance. This research is to study the influences of different water-binder ratio on the microstructure characteristics of air-entrained concrete, which will be done by using both the mercury intrusion test and the optical lead test. The research aims to find out the influences of the change of water-binder ratio on the pore size distribution and pore structure of the air-entraining concrete and non air-entraining concrete. The research results showed that the water-binder ratio mainly influenced the pore gel pore volume in the non-entrained concrete, and the pore volume of capillary pores as well as excessive pores in air-entraining concrete increased along with the increasing of water-binder ratio. The most probable aperture and porosity also gradually increased, while the fractal dimension decreased, when the water-binder ratio increased. It was the increasing of entraining agent content in the air-entraining concrete that increased the pore fractal dimension. The lower average pore spacing factor was to get in the air-entraining, the higher water-binder ratio required more air content.