Investigation of Water Absorption in Recycled Aggregates for Application in Subbase Layer of Highway

Water absorption is a significant specification for aggregates which is used in highways. The performance of aggregates changes after absorbing water, then it effects in highways layers such as base, subase, capping. This is why these materials must comply requirements of codes and standards. With regard to the increasing trend of application of recycled aggregates in highways layers, this issue needs more investigation. This research is only a part of our large research programme on three different purposed mixes of unbound subbase mixture below: (1) 100% Recycled Concrete Aggregate (RCA); (2) 100% Lime stone (NA); (3) 50% Recycled Concrete Aggregate (RCA) + 50% Reclaimed Asphalt Pavement (RAP); Water absorption for each mix has been performed in different size fraction with pyknometer and wire basket methods. The relationship between density, grading and water absorption and its comparison for mixes would be indicating the changes in behavior of aggregates and future performance of layers. As further information this research is being performed at Kingston University and some complementary parts to compare are doing in Tehran Municipality.