New experimental method for evaluating the water permeability of concrete by a lateral flow procedure on a hollow cylindrical test piece

The durability of concrete depends to a large extent on the difficulty of external aggressive agents in penetrating the porous network of concrete. The ability of this material to withstand the intrusion of these aggressive agents is mainly characterized by permeability. The latter is influenced by the interconnected capillary pores which depend on the water/cement ratio (WIC). The objective of this study is: first, to review and discuss the main existing methods used to measure the water permeability of cementitious materials. Secondly, to propose a new experimental method which provides an increase in the area of contact of the water with the sample. The hollow cylindrical shape of the sample thus permits a transverse flow of the liquid from the inside to the outside. This method provides a high volumetric flow of water and ensures a good seal between the sample and the cell Of the apparatus. The accuracy is much higher and the measurements are more representative. In order to validate the proposed experimental procedure, the study comprises 12 types of concrete with variable W/C ratio. The latter constitutes a means for characterizing the porous structure and the transfer properties in concrete. The results obtained show that the proposed method treats the disadvantages commonly encountered in current permeability apparatus. These results are reliable and explain the considerable influence of the W/C ratio on the water permeability of concrete. (C) 2017 Elsevier Ltd. All rights reserved.