TOPS News: September 2023

Concrete Overlay—
Is it the right tool for my project?

Concrete overlays can help extend pavement life, improve safety, and  meet drivers’ expectations for a reliable, comfortable system, all without requiring reconstruction. But how do you select the right treatment for the situation? A recent FHWA webinar outlined possible feasibility considerations and next steps.

Knowing what questions to ask and what to do with the answers are keys to selecting the right solution.

Possible Feasibility Considerations

When determining the feasibility of a concrete overlay, gathering information is important:

1. Can the existing pavement provide a uniform subbase to overlay?
2. If not, what pre-overlay repairs may be necessary to obtain uniformity?
3. If targeting a concrete on asphalt (COA) bonded or concrete on concrete (COC) bonded overlay solution, will enough structure remain after repairing and milling?
4. What interlayer treatment is needed to bond or separate the overlay?
5. Can a COA unbonded or COC unbonded work within constraints such as vertical clearances, shoulders, etc.?

Concrete overlay. (Source: Jerry Voigt)

Possible Evaluation Steps

Once the feasibility is determined, evaluation steps could include:

1. Identify the existing pavement type and general condition. Know what you’re dealing with.
2. Make a preliminary determination of typical section layers or thickness.
3. Perform an on-site review and evaluation.
4. Assess any profile grade adjustment and vertical constraint issues.
5. Validate existing pavement conditions by coring and material testing.
6. Select the overlay option.

Watch the FHWA concrete overlay feasibility strategies webinar to learn more.

For more information, visit the TOPS website or contact TOPS co-team lead Robert Conway (concrete) or Tim Aschenbrener (asphalt).

Additional Concrete Overlay Webinars: Concrete Over Concrete Unbonded Concrete Over Asphalt Bonded Value Proposition

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