Credit: Propex

Unbonded concrete overlays must be, well, unbonded. The overlay must be able to act as an independent structure or else the stresses can build up between the overlay and the existing pavement (see Problem Clinic, page 28). During construction, most geotextile bondbreakers are black (often just a layer of asphalt) and can therefore absorb the sun’s heat before the overlay is placed. That heat can lead to cracking stresses in the overlay. Propex Reflectex reflects the sun’s heat, keeping existing pavement cool while providing a 100% bond break between existing pavement and the overlay. Visit