Surface Treatments: Bonded Wearing Course
Bonded Wearing Course (BWC) is an award-winning technology that seals the existing road surface and provides a new, skid-resistant, ultrathin (5/8" to 3/4") wearing course in one simultaneous operation. The process consists of polymer modified asphalt emulsion spray applied (at a rate of approximately 0.2 gallons per yd2) immediately ahead of an overlay of gap-graded hot mix asphalt (HMA). The thick polymer asphalt membrane seals and protects the surface and provides superior bonding of the ultrathin mix to the pavement. The high quality gap-graded aggregate is designed for a durable, skid resistant surface. The ultrathin mat optimizes the use of the high quality aggregates, while maintaining overhead clearances and curb reveal. The one-pass construction process moves quickly, allowing quick construction and traffic return. With crack sealing, the surface can last up to ten years or longer.
Benefits of Bonded Wearing Course
- Seals and waterproofs existing surface
- Resists raveling and delamination with superior bonding of the open, ultrathin overlay
- Restores durable skid resistance while conserving high quality aggregates
- Reduces user delays with quick, one-pass construction, immediate traffic return and possible night construction
- Retains curbs and clearances under bridges and overpasses
- Reduces tire noise, especially on concrete pavements
- Reduces back spray, preventing hydroplaning and improving visibility in wet weather
- Long lasting, effective preventive maintenance treatment that preserves the value of your pavement
The Sealing Process
All States Materials Group’s polymer emulsion is formulated to break immediately when covered with the hot mix. We use aggregates that have been tested for proper shape, hardness, gradation and cleanliness. A laboratory design determines the job mix formula for a special, high quality gap-graded hot mix. The hot mix binder may be conventional asphalt, or crumb rubber modified (CRM) asphalt. A laboratory design with the project materials determines the correct asphalt emulsion and hot mix application rates. There should be enough asphalt in the membrane to seal the existing pavement and migrate up into the hot mix. The hot mix is placed at a depth approximately 1½ times the stone size (typically 75 to 85 pounds per yd2). After any repairs are made and the pavement is cleaned of any loose debris, our trained and experienced crews use a specially designed paving machine that both sprays the emulsion and applies the hot mix. We roll the mat to properly orient and seat the aggregate. Traffic can be returned to normal speed immediately after rolling.
Where and When to Use Bonded Wearing Course
Bonded Wearing Course provides a durable, open-graded, drainable wearing surface on existing pavements. It is a high performance surface suitable for all types of asphalt and concrete roads, and has given outstanding performance for almost twenty years as preventive maintenance on major urban highways as well as residential streets. It is ideal for places where construction delays, overpass clearance, curb reveal, wet weather visibility and skid resistance are concerns. The polymer modified hot mix overlay system should be placed on structurally sound pavements with uniform crown and good drainage. There should be no sign of sub-base movements, and only low severity surface distresses. Any large cracks should be filled prior to construction. The surface should be swept of any stones, sand, mud or other loose debris. It is not designed to bridge weak spots or to cover underlying pavement deficiencies. It can also be used as the final wearing course on reconstruction, rehabilitation, or resurfacing projects. Bonded Wearing Course is the ideal treatment for preserving the value of your aging and new pavements.
All States Materials Group wants to make sure your paving job is a success. We can help with determining the right treatment at the right time for your pavement, and where Bonded Wearing Course will be the best fit in your overall road system. Contact our professionals for more information about how to preserve the quality and value of your pavements.