Determination of Air Voids, Capillary, and Gel Porosity in Hardened Concrete using Mass-Based Saturation Techniques

The pore size distribution of concrete has a significant effect on its properties and durability. Three types of pores were investigated in this project: capillary pores, gel pores, and air voids. The percentage of each type of porosity in eight concrete mixtures was determined using various saturation/mass-based techniques. This involved vacuum, pressure, and solvent saturation. The effect of slag, silica fume, and w/cm ratio on each type of porosity was investigated. Results of porosity obtained by saturation techniques were compared to results of ASTM C642: Standard Test Method for Density, Absorption, and Voids in Hardened Concrete, and results of air content obtained by saturation techniques were compared with microscopic air void analysis results. The overall results indicate greater saturation obtained by the test protocol followed in this project as compared to the standard test. The results also indicated the significant effect of mixture design on the gel and capillary porosity.M.A.S