Characterization of Pore Structure for Permeability Prediction of Cement Based Materials under Frost Attack - the Fractal Approach

The main aim of the paper is to investigate the influence of cyclical temperature changes on the microstructure, mechanical and transport properties of cement-based materials prepared without air-entraining admixtures. The experimental study is performed on cement mortar samples, which are exposed to the freeze-thaw cycles. In order to assess how the frost damage affects the material properties, the gas permeability and mercury intrusion porosimetry tests are performed. Moreover the fractal analysis is conducted for cement mortar microstructure. The fractal dimension values are estimated according to the box counting method. Additionally, the relation between fractal dimension and number of freeze-thaw cycles is proposed. Finally, the values of gas permeability coefficient for particular samples are predicted on the basis of fractal dimension.