Bond behaviour of thin concrete overlays for maintenance of concrete pavements

Concrete pavements are exposed to a number of stresses during their service life, mostly resulting from traffic and climate conditions. In consideration of the continuously rising traffic volume, the durability requirements of concrete pavements become more and more significant. In this context, maintenance and repair become increasingly important. Small-scale repairs like spalling at edges up to the replacement of whole slabs are proven in several cases. In contrast, large-scale maintenance techniques for partial repairs of whole pavement sections are not available, yet. If the upper layer concrete is deteriorated, while the lower layer and the base course are still intact, the whole pavement needs to be replaced, due to a lack of alternatives. Therefore new maintenance techniques like the application of concrete overlays are needed for an economic rehabilitation and the prevention of an unnecessarily long traffic disruption by time-consuming maintenance of complete pavements. The relevant questions how a durable bond between old and new concrete can be ensured and which parameters affect this bond, were investigated in representative studies on large-scale concrete beams with a thin concrete overlay on existing concrete.