Comparison of Various Permeability Methods Applied upon Clay Concretes–Statistical Evaluation

In this article, comparison of different permeability test methods was conducted using data obtained from measurements done on clay concretes. Two raw clay types were used as partial cement replacements for up to 40 % clay and employed to prepare 150-mm cubes of clay concretes at 0.70–0.85 water/cementitious ratios. Cylindrical specimens were cored from the cubes and used to conduct permeability measurements. The different permeability methods conducted include triaxial water permeability, air permeability, oxygen permeability, and water penetration. The tests were conducted using various fluid types consisting of air, gas, or water. Statistical analysis techniques were used to evaluate the permeability test methods. In addition, a leaching study was also conducted. It was found that the use of clay in concrete enhanced leaching of calcium, which, in turn, adversely influenced pore parameters and concrete permeability. Of the various tests used, the triaxial water permeability method was the most sensitive technique towards the influence of clay content in concretes, while the water penetration method was least sensitive and perhaps most suited for permeability testing of clay concretes. Of the methods evaluated, only the water penetration method and triaxial water permeability under a non-steady-state condition of testing were found to be interchangeable.