Good Repair, Bad Repair

If you have an asphalt parking lot, and have had to maintain it for any amount of time, then you probably know what we’re talking about when it comes to repairs. Sooner or later (one hopes for later) you’re going to have to address issues with your asphalt surface in the form of patching. The need to patch can arise from any number of issues—the most common being water and puddling issues, alligator cracking, and potholes.

The way to repair these issues varies as well—from just removing the oldasphalt and filling the area in, to a full depth removal which involves excavating the area down to the sub-base and installing fresh courses of stone and asphalt. Each contractor has a different method of how to repair a damaged area—some good, some bad. Typically, though, a general repair for a damaged area in your asphalt surface would go something like this:

1) The contractor will mark out the extents of the damaged area with paint

2) The area will be sawcut and all damaged asphalt will be removed from that area.

3) New asphalt will be placed in the area and compacted.

Pretty simple, right? Well, to a certain extent it is; but then there are the intricacies of asphalt repairs which most people don’t get to see, and not all contractors adhere to. Yes, the bottom line of asphalt repairs is to get the broken asphalt out and put the new asphalt in, but to make it look good, to get it to last, there is much more that your paving contractor should be doing.

What is a good repair? A good repair is fundamentally 3 things:

1. Structurally sound

2. Aesthetically pleasing

3. Either improves or maintains existing drainage patterns.

A good repair starts with the contractor’s quote. A good quote will tell you what exactly the contractor plans to do, for example:

“Saw cut perimeter of repairs as necessary. Excavate repair areas to a depth of 4” and haul offsite. Re-compact stone base and tack edges of repair. Install 4” of S9.5B asphalt in (2) lifts. Roll to a smooth even finish.”

By clearly specifying their intent a contractor obligates himself to the results and makes it easier for you to compare their quote with another contractor’s. Another important factor to look for and compare is the quantity of repairs to be performed. Some contractors will not divulge the square footage or yardage of asphalt they are repairing. It is important to make sure you get quantities out of the contractors so you can make sure you get what you pay for. It usually makes sense to try to get the bidders quoting on a apples to apples basis, but sometimes that may not be necessary because you have more confidence in one contractor as opposed to the other contractor.

Good repair work is work that meets the above 3 requirements. The final product should be something which is aesthetically pleasing, structurally sound and addresses the drainage needs of the area.

There is one last thing you must consider however and it is probably more important than any other issue. Does the contractor stand behind their work and are they committed to building long term relationships? Even the best contractors make mistakes from time to time. That is going to happen. Your parking lot is not going away. The older it gets the more maintenance it will need. You’re not going to want to chase several quotes every time you need minor repairs done. A contractor that is committed to quality should also be committed to building long term customer relationships by being always fair with their pricing and always fixing any problems in a timely manner. In the long term this is what will save the customer time and money and achieve the best results.

Case in point:

When it comes to repairing and maintaining our asphalt surfaces, especially in this down economy, people tend to go with whatever is the cheapest solution. This, however, doesn’t always cause the intended outcome of saving money—rather one’s money is wasted due to poor quality work by the lowest bidder.

After meeting in the field with a customer regarding structural and drainage repairs to a parking lot, we sent an estimate detailing our scope of work. The next day our salesman received an irate phone call from the customer who accused him of price gouging because our price was almost twice that of the other contractor. We were both dumbstruck and curious as a result of these comments. Our pricing is always competitive if not consistently lower than our competitors. Had the customer made any attempt to compare the two scopes of work?

Suffice it to say that our curiosity got the better of us. A few weeks later our salesman was in the area of the parking lot and decided to stop by. The axiom, “you get what you pay for” comes to mind. The repair areas were holding water, not cut around the perimeters, and no milling was done at the curb and gutter to ensure an even transition. It looked as if someone had just quickly dug out the broken asphalt, backed a dump truck up full of new asphalt and dumped it in with no care.

Check out the "Bad Repairs" section of photos below and you be the judge. It will not be long before these repairs will have to be done again .

Good Repairs:

Bad Repairs:

Dirt Coming Through Blacktop

When answering this question it is important to first understand exactly how the mud got there and it all comes back to proper preventative maintenance. Typically, if you see mud showing through in your blacktop it means that water usually by way of a surface crack has penetrated beyond the gravel base and into the underlying soil layer. If this happens, mud can then be pumped up into the grave acting as a lubricant and causing the overlaying asphalt to shift as cars and trucks drive across it. You see this a lot in areas which have a vast amount of cracks and in many cases inadequate drainage.

The solution is a full depth replacement. Simply putting a patch over such a repair will only cover the problem temporarily, causing it to worsen. With a full-depth replacement our crew will come in tear out the damaged blacktop and gravel layer and replace it with new stone and newly laid asphalt. Important to note here – this fix among several others in many cases could have been avoided with proper asphalt maintenance, like crack filling and sealer, which studies prove can add up to 30-50% more life span to your lot, eliminating costly repairs.

Differences Between Patching, Peel & Pave, and Mill & Pave

Asphalt Patching
Patching is a common asphalt repair in areas where the asphalt has cracked, but the base is still stable, or in areas where potholes have occurred. This process begins by cleaning the repair area and applying a tack coat to help the new asphalt adhere to the existing surface. A layer of asphalt is then installed upon the existing surface; the depth will vary from 1”-2.5” depending on the severity of the existing damage. Patching is a cheap solution to asphalt defects; however it will not last as long as removal and replacement. Eventually cracking will reflect through the new patch, or spread beyond the patch.
Asphalt Removal & Replacement
Asphalt removal and replacement or as we call it “peel & pave” is another common repair. The repair is often prescribed for areas with cracking and or base/failure. This process begins by saw cutting the perimeter of the repair area in order to achieve a clean edge. After the edges are saw cut, the existing asphalt is removed to the depth specified. Typically the new asphalt is installed in 2 lifts; a binder course usually at 3” is followed by a 1” top course. The depth of repair will vary dependent upon the extent of existing damage, and/or the load requirements needed to be met. By adding up to 10 times more life span than patch work, asphalt removal & replacement is often a very cost effective fix for your surface’s distressed areas.
Mill & Pave
Milling, or grinding, takes a much different approach than either patching or peel & pave in that it removes built-up layers of deteriorated asphalt down to a specific depth, making room for a new surface, by actually grinding up the existing asphalt into a tiny like gravel. The millings, as they are often referred to are then hauled off site and can easily be recycled. The newly grinded surfaced is then layered with tack and set to receive a fresh smooth coat of asphalt. In many cases this type of fix is done on much larger areas where a peel and pave or patch is just not sufficient.

Cracks in Asphalt

The next 5 questions (13-17) from the top 50 paving maintenance questions are on the subject of cracking:

13. My lot has cracking can you repair the cracks?

14. What is the difference between normal cracking and alligator cracking?

15. What are my options for fixing the alligator areas?

16. You said there is reflective cracking in my lot, what is reflective cracking?

17. What are the advantages of repairing the cracks.

Although these are the common questions that we get, they really do not cover all the questions associated with cracking. This is a really big topic and from the perspective of someone who has spent over 30 years in the asphalt industry its an interesting one. This article is not intended to be definitive. I am trying to be informative to the typical property manager who is trying to deal with degrading conditions in their asphalt.

After spending some time on google, going through various journals and researching this subject in all the publication I have at my disposal, its clear to me that there is alot of information that covers this topic but not alot that pulls the whole topic together. Actually I didn't find any articles that did this. Even in the Asphalt Handbook you would have to pull alot of sections together to try to cover all the reasons for cracking. As a result there do not appear to be any ready reference guides to help property managers figure out what their problem is.

This article will attempt to give some insight into the issue. Lets start with the broad sweep and say cracking is a symptom of some sort of pavement failure. The question is why does pavement fail and does it always result in cracking? Not always but for the most part yes there is always some sort of cracking that occurs at some point with a pavement failure. Its worth repeating though that its not the problem. Its a symptom of the problem.

Pavement failures for three main reasons:

1. Surface Failures

2. Bonding Failures

3. Structural Failures

This provides a nice umbrella but it needs to be said that every crack or failure cannot be neatly classified into one of these categories. They often fall in between or in both.

Surface failures have to do with problems that occur in the surface layer of the asphalt. A common example of this is a crack that forms along a seam. Another example is cracking that water causes through erosion or deterioration of the asphalt. Oxidation or the effects from the sun would fall into this category.

Bonding failures are problems that occur between layers. Asphalt unraveling from layers not being tacked well together. Shoving or sliding that occurs at intersections where trucks always stop. Reflective cracking in my mind would fall into this group.

Structural failures are usually associated with the underlying stone base. Causes include weak or deficient base, excessive moisture, and lack of proof rolling procedures before placing the stone base.

Determing the cause of the crack usually will dictate the remedy. Normally crackfilling techniques can be used for surface failures and, on the other hand, would not be an acceptable remedy for structural failures. In the case of structural failures, it would be better to address the fundamental underlying problem by doing some sort of full depth repair.

Bonding failures could require either crackfilling or full depth repair but also might have other remedies that may be more appropriate. For example if asphalt is sliding or shoving the right remedy has to be determined by finding out what is the root cause. Asphalt might shove because the new surface was not properly tacked to the old, or its on a steep incline and the weight of the vehicles is pushing the asphalt, or there is something inherently wrong with the asphalt. Only someone with reasonable experience in these situations would be able to determine the cause. Generally an experienced geotech with roadtech experience would be able to determine the cause. There is no substitute for experience. A contractor who has dealt with these situations before would almost always have a good grasp of the problem and reasonably come up with a remedy that will work.

Be careful to consult a contractor that has the knowledge and technical skill to come up with the right remedies to problems. Our field estimators have alot of experience to draw from and if they don't know the answer they will get someone out there that does.