Water Permeability of High Slag Content Concrete

The purpose of this study was to determine the water permeability of high slag content concrete (HSCC) incorporating large amounts of ground granulated blast-furnace slag (GGBS) of high fineness. The main variables are the replacement level of slag, the fineness of slag and the type of chemical admixtures. The slag content in cement ranged from 0 to 95% by weight of total cementitious materials and the fineness of slag ranged from 404 to 1200 m squared/kg. Within the range of this study, the following results were obtained: 1. The coefficient of water permeability of high slag content (HSC) concrete increased as the content of ground granulated blast-furnace slag (GGBS) was increased. However the water tightness of HSC concretes could be improved by utilizing high fineness slag within the range of 122 m squared/kg, and was further improved by utilizing an air entraining and high range water reducing (AEHW) admixture. 2. Both the total porosity and mean diameter of pores increased by raising the slag content, but decreased as the fineness of slag increased. The water permeability of HSC concretes was closely related to the porosity, with the diameter over the certain threshold value, rather than to the mean diameter of pores.