The permeability of concrete to air. The effect of ageing of concrete on its permeability

Abstract

The results obtained describe the change in permeability to air of six slabs of concrete during a period of 23 years. The measurements were taken at four intervals of pressure: 0.40, 0.95, 1.35 and 1.90 kp/cm² and the concrete slabs, measuring 1 x 1 x 0.20 m, were kept in a test shed. The results in the permeability which are put forward have a qualitative value; therefore the effect to the edges has been discounted. In the bibliography quoted, the publication (1) includes quantitive results of eight differently composed concretes. This is to emphasize the differences obtained in the slabs despite having the same preparation and having been conserved in the same way. After 23 years of producing concrete, and under normal conditions of conservation in the test shed, it is noted that the point of permeability tends to stabilize specially at the lowest pressure of 0.40 kp/cm².