Rehabilitation and Impregnation of a Concrete Arch Bridge to Inhibit the Further Effects of Alkali-Aggregate Reaction and the Monitoring of the Effectiveness of the Coating System

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Title: Rehabilitation and Impregnation of a Concrete Arch Bridge to Inhibit the Further Effects of Alkali-Aggregate Reaction and the Monitoring of the Effectiveness of the Coating System

Author(s): G. E. Hoppe

Publication: Special Publication

Volume: 131

Issue:

Appears on pages(s): 357-380

Keywords: alkali-aggregate reactions; arch bridges; coatings; expansion; cracking (fracturing); impregnating; measurement; reinforced concrete; repairs; moisture; strengthening; Materials Research

Date: 3/1/1992

Abstract:
The 100 m reinforced concrete open spandrel arch bridge over the Storms River Gorge was constructed in the mid-1950s, and in 1982 surface cracking of the concrete was noticed. Cores were obtained from the various members and laboratory testing confirmed that the concrete was suffering from the effects of alkali-aggregate reaction (AAR). In 1986, the decision was made to rehabilitate this bridge, consisting of two distinct stages, of which the first was widening and strengthening the superstructure, as well as strengthening the concrete arch rib itself. The second stage consisted of treating the concrete surfaces with a hydrophobic coating to halt any further effects of AAR. To assess the long-term effectiveness of the hydrophobic coating, the bridge was instrumented and strain gage readings were taken at regular intervals. The analysis of the readings show that the concrete has been shrinking since the strain readings were started, confirming that, to date, the silane hydrophobic coating is still effective.