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BCOA (Bonded Concrete Overlay)

– Whitetopping 2.0

Whitetopping, the process of a concrete overlay to resurface distressed asphalt pavement, has a long history of use and is a well-established process.  However, recent advances in whitetopping techniques that rely on a bond between the concrete overlay and the existing asphalt pavement have rejuvenated the topic.

Known as BCOA (Bonded Concrete Overlay Asphalt), these bonded overlays incorporate thinner concrete resurfacing (typically 3”-to-6”) and shorter joint spacing (typically 4’-to-6’).  These thinner overlays have reduced or eliminated the amount of shoulder and inlet rework typically required to bring all surfaces to the same grade and the shorter joint spacing has reduced the bending and curling stresses inherent to concrete.

In addition, likely the most exciting news being validated is the durability and life cycle of these thinner, bonded overlays and in turn, the life cycle costs.  Initial results of which are all favorable (and exciting!)

The process for BCOA begins with preparation of the existing asphalt surface including milling to remove rutting and restore the profile.  A minimum 2.6” (6.5cm) thickness must remain after milling – which is why BCOA is better suited to asphalt surfaces in the early stages of decay and not in complete failure or deterioration.  The milled surface is then cleaned via either waterblasting or sweeping (with waterblasting being the most effective/preferred)

Once cleaned the concrete overlay is placed with traditional placing equipment including roller pavers and slip-form pavers.  The resulting bond formed between the new concrete overlay and the prepared asphalt base has proven to be stronger and more durable than unbonded overlays (traditional whitetopping) and the original asphalt pavement.

HEM is excited about this advancement in whitetopping technology and working with our customers on providing the right equipment solution for your BCOA/Whitetopping needs.  For more information or questions on this exciting opportunity contact Darren Huinker, VP of Sales at darren@hempaving.com or 319.824.3011.

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