Title: Deterioration and Rehabilitation of the Elevated Roadway Bridge at Baltimore/Washington International Airport

Author(s): Alexander M. Vaysburd

Publication: Symposium Paper

Volume: 122

Issue:

Appears on pages(s): 401-426

Keywords: alkali-aggregate reactions; bridges (structures); carbonation; chlorides; concrete cores; concrete durability; control joints; corrosion; cracking (fracturing); deterioration; epoxy resins; maintenance; petrography; reinforced concrete; repairs; Construct

DOI: 10.14359/3412

Date: 6/1/1990

Abstract:
During the 12 years since construction of the bridge, cracking and spalling have developed in the concrete superstructure, predominantly on the underside of the bridge deck in the area of expansion and construction joints. The evidence indicates the deterioration was initiated by leakage of expansion and construction joints, and that poor performance should be attributed to design and construction practices whose effectiveness falls short of the environmental demands. Moisture, deicing salts, and debris that spill through the joints had deteriorated concrete at an accelerated rate and penetrated to the reinforcing steel. The concrete breakdown caused by corrosion of reinforcing steel, as well as from freezing and thawing action, and the expansion resulting from alkali-aggregate reaction damaged the bearing areas of cantilever spans and adjacent parts of suspended slabs, and was a cause for concern for the bridge's structural integrity. The paper addresses the main factors involved in the initiation phase of the corrosion mechanism: carbonation, chloride diffusion, and water penetration into concrete. The selected materials and methods are discussed, as well as importance of compatibility of materials for durable repairs. The paper outlines a need to integrate knowledge and understanding of the mechanism of deterioration with concrete design, materials, and methods of repairs.