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Road Warriors

Road Warriors

Article written by Jack Carr, P.E., R.S., LEED AP, Criterium Engineers
Published in Condo Media, February 2012

Snow is falling and a hard freeze has set in, so why are we talking about paving? Because in New England our paving plants often close in November. If yon have a major paving job for your condo complex, it is best to not wait until the last minute. Now is the time to plan and get the best prices.

When it comes to paving projects, the board often needs an education on the issues and options available. There is a lot ofmisinformation out
there. There is no better way to have a meeting's agenda go astray than when no one knows the difference or benefits of sealcoating versus a binder top. So let's start with the basics.

Paving ABCs

Asphalt pavement is also called bituminous concrete. It is called "concrete" because, like cement-based concrete, bituminous concrete has a mineral aggregate of stone and sand. This aggregate is held together with a binder of petroleum derivative asphalt. Its advantage over concrete is that it is more flexible and less expensive than concrete pavement. It also handles deicing salt and sub-surface movement better than concrete. When it comes to the cost of materials versus volume, the cost issue is very important as 30 percent of the cost of asphalt paving is the aggregate, while 70 percent is the asphalt binder. This is particularly important when the price of oil spikes. It has a ripple effect on asphalt, hence, the need to lock in a paving project while the price of oil is at its lowest.
 
Different soil conditions (i.e. sandy subsurface versus clay) will warrant a different mix of asphalt paving, but this will be addressed by whoever creates your bid documents and specifications. For planning purposes, your board should assume paving will last about 20 years. Because it is a major cost for some condominium complexes, it should not just be a line item in your reserve fund budget, but should also have a separate Pavement Maintenance and Capital Improvement Plan with its own committee.
 
Typically roadways have a sub-base of four to eight inches of a well-drained, compacted soil and gravel mix. The first layer of paving is called the binder course and it is one and a half to two inches thick. This is covered by a topping coat of one and a half inches. If it were not for the sun and water, asphalt paving would last a long time, but paving begins to deteriorate as soon as water begins to penetrate into the binder course and UV rays remove asphalt from the topping coat. This can take less than five years and is why adding a sealing coat in the first two to five years is sometimes recommended. It is also an area of confusion.

Repair and Replacement

Sealing coat materials do not add back the asphalt that was lost to UV deterioration. It only protects the pavement for a period of time from further deterioration, such as shrinkage cracks and reveling (loss of surface aggregate). It does not bridge large cracks or fill in roadway depressions. Therefore, if the pavement is more than five years old and has never been sealcoated, it has lost its chance for physical benefit to the life of the pavement. At that point, it is only a cosmetic remedy.
 
When water begins to infiltrate the pavement here in New England, the freeze/thaw cycle takes its toll. Small cracks become larger in the binder course and eventually the sub-base begins to fail. At this point, surface cracks, settlement, alligatoring and other visible surface signs appear. Your Maintenance Plan should immediately address these problems by having crack filling as a yearly project. They should be filled with standard joint filler to within one-eighth to one-quarter inch of the top of the crack. Surface depressions and sink areas should be addressed annually as well. These problems are typically due to poor sub-surface soil conditions that need to be addressed or the settlement will continue. It is important to not allow ponding of water in the roadway or parking lot to minimize water infiltration, hydroplaning and eliminate slipping hazards.
 
After 15 years, major paving problems might arise. Sometimes resurfacing can be delayed by removing large areas of deterioration and repairing the sub-base. If the deterioration is widespread, options include a reclamation project where the top six to 12 inches of pavement and sub-base is ground into a recycled material that can be reused for a compacted and graded foundation for a new paving surface. This minimizes trucking, labor and materials costs. So if you are on the paving committee, it may be time to hit the road. 
 

 
© 2012 CRITERIUM ENGINEERS