Case study on premature cracking of an asphalt pavement with resin bonded coating

Abstract

Nowadays, apart from the mechanical performance demands for road pavements, other characteristics, such as road safety and landscape valorisation are also required. In order to improve those properties, microthin coatings can be applied to improve skid resistance and also to alert drivers to high risk areas. However, the conditions under which these solutions could be applied need to evaluated, in order to assure their durability and avoid consequent problems in the mechanical behaviour of the pavement. Thus, the aim of this case study is to evaluate the possible causes of premature and severe cracking observed in an asphalt pavement with microthin resin bonded surfacing, just a few months after the pavement construction, although it is not being subjected to traffic loads. In order to accomplish this goal, boreholes were initially excavated to define the pavement structure and collect undisturbed samples of pavement and subgrade materials. Then, all those materials were characterized and the possible causes of cracking were studied taking into account the results obtained. From this work, it can be concluded that the variable deformations of the pavement due to the subgrade expansion are compatible with the deformations and cracking observed in the pavement surface. In spite of its high antiskid characteristics, the resin bonded surface should not be used in asphalt pavements built over subgrades sensitive to water variations and/or with low bearing capacity.