It is important for transportation agencies to have a variety of pavement maintenance, rehabilitation and reconstruction techniques to deal with the ever deteriorating roadway infrastructure. Concrete overlays are one option to providing a sustainable solution for resurfacing and rehabilitating existing pavements. This paper explains the various types of bonded and unbonded concrete overlays available to transportation agencies when analyzing pavement preservation options for their deteriorated sections of roadway. It also looks at the steps in evaluating existing pavement condition, as well as, identifying the appropriate overlay system to use for the pavement being evaluated. A discussion on design, construction and other general details of overlays is also provided. In additional the many sustainable attributes of concrete overlays such as utilizing the existing pavement structure as pavement base, truck fuel savings, light reflective surface, decreased energy use and use of industrial by-products will also be discussed. The paper will also identify four concrete overlay projects (two bonded overlays and two unbonded overlays) constructed in Canada and provide design details. Comments will also be provided on the performance of these projects.
