Citation

Kar A. Indian Highw. 2000; 28(7): 5-13.

Copyright

(Copyright © 2000, Indian Roads Congress)

DOI

unavailable

PMID

unavailable

Abstract

In India, road bridges are usually constructed with reinforced concrete, which is normally either given no protection or only a wash coat with water-proofing cement. The same is true for the prestressed concrete road bridges. This absence of surface protection has led to early distress in many recent concrete bridges, usually as cracking or spalling of concrete and exposure of rusted steel elements. To reduce the problem of corrosion in Indian coastal areas, some bridges have recently been built with epoxy-coated reinforcing bars, but this has not led to any notable improvement in the durability of concrete structures. Concrete bridges are liable to decay and distress caused by moisture, carbon dioxide, and oxygen. Such damage can be caused, for example, as a result of carbonation, or in relation to slag cement, high-strength torsteel, concrete cover, water-cement ratio, curing, or higher carbon dioxide concentrations in today's environment. Early damage to concrete structures can be prevented by using Slag Portland Cement (SPC) for underground construction but Ordinary Portland Cement (OPC) for above-ground construction, limiting stresses in steel to low levels or using mild steel, adequate cover to reinforcing bars, and prolonged curing. Alternatively, surface protection can be provided by waterproofing.