Paper ICMPA160 8th International Conference on Managing Pavement Assets INVESTIGATING THE PERFORMANCE OF SURFACE SEAL TECHNIQUES AND PAVEMENT MATERIALS UNDER WET CONDITIONS USING ACCELERATED PAVEMENT TESTING

Low volume roads are normally the backbone of a countries ’ rural road infrastructure. In New Zealand most of these roads consist of unbound flexible pavements with a wearing course that varies between unsealed, chipseal (surface dressing) and thin asphalt surfacing. Chipseals are used on the majority of these roads with the primary role of keeping the unbound pavement layers water tight along with various other functions (ie, reducing maintenance and vehicle operating costs, dust and increasing safety). The construction and maintenance of chipseals varies between countries and regions depending on climatic conditions and accepted construction techniques. For example, some countries like South Africa use a penetration membrane (prime coat) prior to placing seal chips on the road surface. This practice was used previously in NZ however because of safety reasons is now not that common and likewise in other countries. This paper documents research on the ability of different surface techniques to keep surfaces water tight. It investigates the behaviour of different base course materials under these varying moisture conditions and specifically the aggregates susceptibility to moisture. The experiment was conducted at the Canterbury Accelerated Pavement Testing Indoor Facilit