This section describes the construction of bonded concrete overlays (BCO) on both CRCP and CPCD pavements.

Many of the older concrete pavements in Texas were designed and constructed with insufficient thicknesses for today’s traffic demand. This insufficient thickness often results in pavement distresses such as punchouts for CRCP and mid-slab cracking or joint faulting in CPCD. However, if the Portland cement concrete (PCC) pavement is still structurally sound, does not show significant signs of distresses, but has insufficient thickness, BCO can provide cost-effective rehabilitation strategies to extend the pavement life.

When constructing a bonded concrete overlay, a new concrete layer is applied to the surface of the existing PCC pavement. This increases the total thickness of the concrete slab, thereby reducing the wheel load stresses and extending the pavement life. There are BCO projects in Texas that have provided an additional 20 yr. of service. At the same time, there are BCO projects that did not perform well for various reasons.

The most important factor for the success of a BCO is having a good bond between a new and old concrete layers. If a good bond is provided, the new composite slab, old and new concrete layers, will behave monolithically as a thicker slab. On the other hand, if the two layers are not properly bonded together, the two layers will behave as independent slabs, which will result in high wheel load stress within the new concrete layer, and the pavement performance will be compromised.