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: Symposium Paper
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
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.