Condominium Pavements - Management Help Wanted
In capital reserve fund studies we usually assign a useful life of twenty years to a properly maintained pavement. With prudent management, that life can be extended. The sealing of pavement cracks and seal coating on a three to four year cycle is, in our opinion, an absolutely essential part of pavement management.
The seal coating replaces the asphaltic binder lost to evaporation. Without its binder, the aggregate begins to crumble, encouraging surface water to infiltrate down into the sub-grade. One way to spend money and get little for it is to patch only the part of the roadway width that has failed. That remedy may certainly seem intuitive, but if shoulder drainage pockets in the sub-grade up against the deep patch, you have a set up for frost heave problems. The better solution would be to spend a little more money and cut out the full width of pavement and then fill it with patch material.
The usual way to rehabilitate existing pavement is to overlay it with a minimum thickness of 1.5 inches of bituminous concrete. Here is where you can buy (literally) yourself some longevity. Make sure your paving contractor addresses some key points before overlaying. Number one, defects in the sub-grade should be cured. Next, make sure that the surface drains well. Some shimming may need to be done to get positive drainage. Cracks in the existing pavement need to be sealed. This is important for two reasons. You don’t want a rapid route to the sub-grade for any surface water. Plus any unsealed cracks in the underlying pavement can later move and cause what’s known as reflective cracking in the overlay. If the crack you want to seal is significant, lay down a synthetic fabric in a bed of hot asphalt to help bridge over it. A tack coat of emulsifier over the existing pavement will help the overlay to adhere better.
Make sure the contractor lifts to finish grade all curb boxes for utility shut-offs and manhole rims. You don’t want a series of pockets in the pavement or maybe worse, buried shut-offs. Then be prepared to invest in the future. When your overlay is about four years old start a program of seal coating. This application of a refined coal tar mix will inhibit degradation of the pavement surface by replacing the asphaltic binding “juices” on the surface of the pavement that are lost to ultraviolet exposure.
Continue this program of seal coating and crack filling at three to four year intervals. The pavements may look satisfactory to you at age twelve years and have good ride ability. For those reasons you may be tempted to skip maintenance to “save” money. But right here is where prudent management starts to pay off. For every dollar you spend now you will save four in the future trying to patch a pavement that suddenly starts to go downhill on you. Once water infiltrates into the sub-base through unsealed cracks the way is open to general pavement failure. Now an overlay may not be feasible. You may need to replace the entire roadbed. Smart investment in pro-active management now will pay dividends in extended service life.
