What makes excellent asphalt?
Here are the six steps to excellent asphalt paving for your driveway. Our Oregon home was recently awarded First Place for asphalt pavement construction on a residential project. Apparently paving contractor Knife River submitted our project to the Asphalt Pavement Association of Oregon for consideration. And it won!
I was not aware that there were awards given out for quality asphalt work. But then I was not even aware that paving companies had an association. It was refreshing to learn that these trades care enough about their work to actually compete over who can do the best job. Here is the criteria for judging the award explained to us by Executive Director John Hickey who personally inspected the work for the Association.
- Attention to detail—even seemingly minor flaws sometimes make the difference between placing and not.
- High-quality workmanship—criteria include:
- Uniform texture—make sure there is no segregation
- Smooth tight joints—both longitudinal and transverse
- Smooth tight matches—on all intersections, curbs, and/or appurtenances
- Ride! Smoothness is crucial for placing in the competition
- Overall appearance—layout and design will have an impact
- Degree of difficulty—some jobs are tougher than others to build
Scope of work
For our home, the key driveway concerns were durability and drainage. We need to drive heavy trucks with big horse trailers on the driveway. Because of this the paving and sub-structure had to be able to support these loads. The site is also on a slope so good drainage had to be designed into the driveway.
Contractor considerations
At nearly 50,000 square feet, our driveway was a large job (for us) so we wanted to get it right the first time. Knife River Corporation came strongly recommended by both friends and our general contractors. They are a substantial and capable company. Unfortunately, they were not the lowest bid. After some deliberation we decided to suck it up and pay the piper, and looking back now I am glad we did. We came out winners in the end because I believe Knife River delivered way more value than their higher initial cost.
Our project manager, Jill Hawkins took time to do much more than just measure the surface. She evaluated the existing underlying base material, and shot grades to make sure we had proper drain slopes. In order to get the driveway to properly shed water by gravity, Jill found and removed some rocky areas before starting the job. This required use of a large jackhammer to remove a high spot. She also made sure that existing finished areas of the home were protected from harm during the work. Along 130′ of the driveway, the asphalt abuts a nicely finished concrete parking area and a rough boulder retaining wall.
Installation
The installation team also worked hard to ensure a quality job. Joints were smooth and almost imperceptible. Edges were crisp and hand compacted. The paving machine operator never let the mix get cool or run out completely between loads. This made the transitions seamless and nearly invisible. Jill’s team actually invented a manual compaction method to get the paving tightly fit between the retaining wall boulders. It was a bit painstaking for guys used to working with road graders and steam rollers. But the result was amazing!
Even the batch plant participated in the quality by making sure every load delivered was uniform and perfect.
Summary
Just like other parts of the project, the paving took care, forethought and cooperation to produce a quality result. Our gratitude goes out to Knife River corporation, Jill, her team and everyone else who participated in this quality job.
Six steps for excellent quality asphalt paving
- Good foundation material-base. Appropriate for the projected use.
- Good drainage, no pooling or standing water.
- Smooth transitions, invisible and imperceptible when driven on.
- Appropriate excellent mix, uniform in texture and well compacted
- Good installation methods and practices
- Maintenance (check back for posts on maintaining asphalt paving)
