Studying the permeability and strength of concretes containing silica fume, zeolite and fly ash using “Cylindrical chamber” method and British standard

Concrete is a porous material. Water and other fluids can penetrate it and effect its durability. So permeability is one of the most effective parameters of concrete structures durability. Design and construction of concrete, which has a less permeability in addition of providing the desirable compressive strength is of great importance. In this paper, the permeability of 7-day concrete samples containing different pozzolans was investigated using cylindrical chamber method. The mass percentages of silica fume, zeolite and fly ash equal to 5, 10, 15 and 20 percentage that replace type II Portland cement and the existing method of British standard (BS EN 12390-8:2009) were used to compare the obtained results. The percentage of the permeable voids volume was also measured based on ASTM C642-06 standard and used as an index to evaluate permeability. Samples strength was also investigated using the results obtained from the twist-off method. The results of the permeability tests show that all of the pozzolans used in this investigation decrease the percentage of the permeable voids volume and consequently decrease the samples permeability, while silica fume increases the samples compressive strength and zeolite and fly ash decrease samples compressive strength. A very good correlation was also observed between the cylindrical chamber and British standard method results.