Maintaining a paved roadway surface is a fairly complicated process. Sure, it seems easy to some observers – just pave it! Well, it isn’t always that simple….in fact it rarely is. There are several steps we go through to keep the roadways in the best shape possible. A common misconception is that it only takes one trip out to the job site to fix the road – that is rarely the case.
For a good example of just how complicated and complex it can be at times, we will illustrate the work done to do a chip seal on a road. Chip sealing is the process of applying a good layer of liquid asphalt to the roadway to seal the surface, followed by covering it with crushed aggregate (chips). The end result is a well-sealed roadway surface with a new wearing-course on the top (the chips). This relatively inexpensive method of keeping a roadway surface in good shape is used by us on approximately 70 miles of county roads each summer. It is also much less expensive than paving the road with new asphalt – MUCH less expensive.
The steps involved in preparing a roadway to be chip sealed can include the following – each step usually requiring a separate crew of folks who are good at what they do. Also, we can’t efficiently do all the steps in one trip. One main reason is the ‘cure time’ of certain steps. In short, some steps require us to do the fix and then wait a while for the fix to age so we can then do the next step.
- Crack sealing – this crew fills in large cracks which sometime show up on our roads. The purpose of this step is to help keep moisture from getting under the asphalt. A special product is used to span the wider crack areas which standard chip sealing can’t accomplish.
- Grind/inlay patching – we will grind out failed sections of asphalt and put in new. The areas treated are very specific to the failure type. Grinding out just the failed piece saves us a lot of money. See the photo of how we mark a grind/inlay patch.
- Blade patching – for larger areas too big to grind we will sometimes apply new asphalt with a grader which will improve ride quality, etc. Another photo as part of this article shows our typical markings for where blade patches will occur.
- Fog sealing of patches - this step seals the brand new asphalt patches so when we chip seal later the new patch doesn't absorb too much oil.
- Sweeping – prior to chip sealing it is important we have a clean surface so the new liquid asphalt sticks well.
- Chip sealing – everyone notices this step because the loose gravel shows up for a time. We monitor the amount of rock applied to get just the right coverage of the oil – not too much, but not too little.
- Sweeping again – this removes the last bits of excess rock which don’t stick into the new road surface.
- Fog sealing – this step applies a light ‘fog’ of a different type of oil on top of the recent chip seal. It helps lock the aggregate in better.
- Striping – we restripe the roadway with fresh paint which may include yellow center-line stripes as well as white fog-line stripes.
Next time you see our road maintenance crews working on the road surface, see if you can identify what we might be up to doing. We can assure you we are always working to provide the best roads we can.
Please call our office if you have any further questions – 541.774.8184.