The overlaying of concrete on asphalt, composite or old concrete pavements provides an environmentally friendly, long-lasting and cost-effective rehabilitation pavement solution.
There are two types of concrete overlays:
- Bonded — Relatively thin concrete placed directly on existing pavements that are in good to fair structural condition
- Unbonded — Usually thicker than bonded overlays, unbonded overlays restore structural capacity to existing pavements that are moderately to significantly deteriorated
The Figure below shows the various types of bonded and unbonded overlay systems.
This pavement solution is a cost-effective approach that can bring new life to streets and roads. Rather than removing and reconstructing the original pavement, the owner maintains and builds equity in it, realizing a return on its original investment as long as the original pavement remains part of the system. Overlays can be used for surfaces and rehabilitation of mainline highways; high volume streets and local roads; residential streets; heavy industrial/intermodal/military facilities; airport runways, taxiways and aprons; and parking lots.
Listed below are several key resources and documents on concrete overlays:
Useful websites and resources
- CP Tech Centre Concrete Overlays Landing Site
- Guide to Concrete Overlays: Sustainable Solutions for Resurfacing and Rehabilitating Existing Pavements
- ACI 325.13R-06: Concrete Overlays for Pavement Rehabilitation (Reapproved 2020)
- ACPA The National Concrete Overlay Explorer
- 11 years of Performance of Alberta Transportation’s First Bonded Concrete Overlay
- Guide to the Design of Concrete Overlays Using Existing Methodologies
- Development of Concrete Overlay Construction Documents
- Targeted Overlay Pavement Solutions (TOPS)
- Evaluating Unbonded Concrete Overlay for Usage on Ontario Residential Streets
- Ten Year Performance Evaluation of Unbonded Concrete Overlay and Jointed Plain Concrete Pavement: A Toronto Case Study