Abstract
The durability of concrete in temperate and tropical climates where there is no exposure to cycles of freezing and thawing depends to a great extent on corrosion of reinforcing steel. Steel protected by concrete does not rust because of the alkalinity of concrete, but the concrete is gradually carbonated from the surface by carbon dioxide existing in the atmosphere and after many years the ability of the concrete to protect steel becomes lost. In other words steel does not rust in a basic salt solution, but begins to when the basic salt is lost. This paper takes notice of the fact that corrosion of steel accompanying earbonation of concrete governs the durability of reinforced concrete structures and attempts to make clear the various factors of concrete and the rate of carbonation and maintaining that the fundamental principle for improving durability of reinforced concrete is to use concrete with a slow rate of carbonation, reports on an investigation of actual means of attaining this object.
