Investigation of the effect of the used cement and mineral admixture type on concrete permeability using “Cylindrical chamber” method

Since a portion of concrete is made of the cement paste, its impact on the concrete permeability can be considerable. For this reason, in this paper, permeability of the concretes containing different types of cements (type 1-425, type 2, type 5, pozzolanic and white cements) and mineral admixtures (microsilica, fly ash, zeolite and limestone powder) was studied, using the results obtained from “Cylindrical chamber” method. Cement replacement levels with mineral admixtures were 5%, 10%, 15 and 20%. Considering the durability problems of the concrete structures located in Iran’s seashores, in addition to the tap water, seawater was used for the permeability assessment of the concrete specimens containing different types of cements. The results tend to show that, except the concrete specimen containing limestone powder with a replacement level of 20%, other concrete specimens have lower permeability than the concrete specimen without any mineral admixtures. Microstructural properties of the concretes containing the mentioned mineral admixtures with replacement levels of 0% and 5%, obtained from analyzing scanning electron microscope images were also consistent with the results obtained. Furthermore, it was observed that water type has great impact on concrete permeability. In this regard, concrete specimens containing type 1-425 and pozzolanic cements had the lowest permeability when exposed to potable water and seawater, respectively. On the contrary, concrete specimens containing pozzolanic and white cements showed the highest permeability against potable water and sea water, respectively. Weak correlation was also seen to exist between permeability and compressive strength of the studied concrete specimens.