Relationship Between Timber Bridge Characteristics and Asphalt Pavement Wear Surface Performance: Summary

Abstract

This summary offers an overview of on a research study that assessed the magnitude of premature asphalt deterioration on timber bridges; identified the primary mechanisms responsible for wear surface deterioration; and suggested methods for improving asphalt pavement performance on timber bridges. The study revealed that approximately 50 percent of counties experience some problems with premature reduced serviceability of the asphalt pavement wear surfaces that cover their timber bridges. The summary looks at possible pavement failure mechanisms and presents the following proposed solutions for controlling timber bridge asphalt pavement cracking: asphalt pavement saw & seal, asphalt pavement fabric or material underlay, removal of extruded oil-type preservative before surfacing, conditioning of bridge timbers to the expected equilibrium moisture content before bridge installation, and tightening of timber decks through maintenance practices.