CORROSION OF REBARS IN BLENDED CEMENT CONCRETES

摘要

Concrete industry is growing in India with adoption of the latest construction practices. One of the advances is the use of fly ash in structural concrete. This by-product of power plants is being used by ready mix concrete suppliers for all concrete for economy and durability. In the areas where ready mix concrete is not available, fly ash is used in the form of blended cements. Though the use of fly ash in either of these forms has been growing, a section of engineers have doubt about the durability of the reinforced concrete structures with respect to corrosion of embedded rebars in these concrete, specially in cracked elements. It has been observed that with fly ash content in the range of 25% in cement, initiation of corrosion is delayed by almost four times. The alkalinity of concrete around rebars is not changed significantly and is well above the threshold level of corrosion initiation requirements. Concrete resistivity has been significantly higher as compared to those observed with normal Portland cement concrete.