Rapid water content measurement for processed asphalt planings

A rapid field technique for evaluating water content of processed asphalt planings has been developed. The need for developing a rapid water content measurement technique has arisen from a technology programme (partly sponsored by the UK Government), in which a commercially viable novel process for road asphalt planings has been established. Integral to the process is the addition of water and the ability to rapidly and reliably determine the water content during production, stockpiling and transportation of the processed asphalt planings. Various techniques exist for measuring water content, but these are generally applicable for aggregates and soil. This paper appraises the various techniques for measuring water content and proposes techniques that would be most suited for asphalt planings. The standard methods of measuring moisture content can be time consuming and are not suitable for routine field production, sampling, stockpiles and transportation. Experimental work has been undertaken for those techniques that are deemed most suited for processed asphalt planings and the results are presented. A fast and reliable method of measuring water content for processed asphalt planings was determined to be a portable probe that is simple to use by operators, is reliable and is safe.