Minimally Invasive Technologies For Measurement Of Water in Pavement Systems

In recent years, there has been increasing interest worldwide in the potential pavement life cycle cost and environmental impacts of the interaction of asphalt pavements with water. Trapped water in the aggregate may result in debonding of the bitumen from the stone over time and subsequent deterioration. Intrusion of water into the asphalt (such as into longitudinal joints or cracks) may lead to accelerated deterioration and failure due to freeze/thaw cycles. On the environmental side, water movement through the pavement and subgrade has raised issues of salts and pollutants leaching from the pavement into the ground water. International conferences and workshops (such as Water in Pavements 20052007) underscore the increasing awareness and concern over the effects of the interaction of water with pavements and the environment. Recent research resulting from initiatives, such as COST351, has dramatically increased the awareness and understanding of these important issues (Dawson 2007). Recent research has also shown that knowledge of the water content of the asphalt itself is important in the design and curing of recycled pavement systems, such as Cold in Place Recycling (CIPR) and the emerging emulsion based binders such as Warm Mix Aphalt (WMA). Lagging behind the theoretical research is the development of instrumentation that can validate the research and determine the conditions in the field as related to the presence of water on, in, below, and around pavement systems.