The Role of Water in Unbound Granular Pavement Layers: a Review

In many parts of the world, water is known to be a key factor in the performance of the structural elements of road pavements. The temporal and spatial distribution and the chemical composition of water within the unbound granular layers (UGLs) govern the durability characteristics of aggregates and control the possible physical and chemical interaction of geomaterials and water. This paper presents a thorough review of what is known about the effects of water on UGLs on both the micro- and macro scales and concludes that there are shortcomings in the current empirical standard tests used worldwide to predict the effect of water on the performance of unbound granular layers in pavements.