Pavement Maintenance - Cornell Local Roads Program - Cornell ...

Pavement Maintenance
Materials
Using the wrong material in the right place or the right material in the wrong place can lead to
premature failure. Sometimes the problems are obvious. Sometimes the problem does not appear
to be related to the material choice. Backfilling an underdrain trench with large stone is actually
a materials problem. The stones will retain silt particles brought in by the drained water and will
lead to premature plugging of the pipe. Be sure to select the correct material for the job.
Wrong material
The wrong material will lead to premature failure. Using a dirty gravel base is a classic
example. The use of the less expensive material can lead to much larger expenses in the
future. Understand what the limitations of a particular product are before you use it. Ask
the vendor, other highway departments, or the New York State Department of
Transportation. Get a clear picture of the best material for the job.
Material does not meet specifications
Once you select the material, make sure it meets specifications. By some estimates, 1/4 of
the wire in the main cables of the Brooklyn Bridge did not meet the specifications. When
the contractor was caught, the extra expense of more cable was paid out of their contract.
Some failures are due to a material not meeting specifications. One recommendation is to
always sample the materials on site. It is not always possible to go back and get a sample
after the construction is complete.
Material installed incorrectly
If material is put in incorrectly, there can be premature failure. Is this a construction issue
or a material issue? It could be both. It should be neither. Sometimes the problem is
failure to install the item using a newer technique. For instance, Superpave asphalt
concrete needs to be rolled differently than older Marshall Mix design asphalt concretes.
Incompatibility with other materials
Aggregate charge incompatibility is cited almost every time a chip seal fails. In reality, it
almost never occurs. Much more common is using a dusty stone that does not adhere to
the asphalt emulsion. When this problem occurs, the consequences can be dramatic.
Examples of failures in materials
• Chip sealing over a good quality surface gravel (a good surface gravel has too
many fines to be a base gravel)
• Using an asphalt emulsion to seal cracks
• Using a cheaper cold patch that may last only a few hours
• Using a dusty or wet aggregate in surface treatment operations
10 Cornell Local Roads Program