Asphalt Pavement Distress Due To Bus Traffic
Asphalt Pavement Distress Due To Bus Traffic
(OP)
A project has landed in my lap as a result of some medical problems with the engineer that was doing the project. We are looking into pavement distress of asphalt pavement (rutting, cracking, shoving, etc.) at several high volume transit bus stop locations around a city in the northeast and need to make a recommendation on a solution to solve the problem. We have conducted several inspections of various bus stop locations to catalog the pavement distress and have researched a few options to correct the problem. These include complete reconstruction of the pavement section, addition of Superpave HMA or milling and placing of an Ultra-Thin Whitetopping on the existing asphalt. I have gotten extensive literature on both of these methods and understand the processes well. What I would like to know is if anyone has been faced with a similar problem, what solutions did you investigate, why was one selected and another discarded and what were the long term results of the implemented solutions. Other recommendations to correct the probelm would be helpfull as well.
Also, in general have you found that these types of pavement distresses are a result of an incorrect pavement design for the type and/or frequency of traffic that is using the road or is it more an issue of poor quality control during construction.
Thanks for your help.
Also, in general have you found that these types of pavement distresses are a result of an incorrect pavement design for the type and/or frequency of traffic that is using the road or is it more an issue of poor quality control during construction.
Thanks for your help.





RE: Asphalt Pavement Distress Due To Bus Traffic
Our solution was to cut out the broken areas about 6'square and patch with a 6" thick section of concrete paving. This worked in this instance because the buses had to turn in virtually the same spot all the time.
Just a thought, it worked in this situation.
RE: Asphalt Pavement Distress Due To Bus Traffic
RE: Asphalt Pavement Distress Due To Bus Traffic
RE: Asphalt Pavement Distress Due To Bus Traffic
Mike
RE: Asphalt Pavement Distress Due To Bus Traffic
RE: Asphalt Pavement Distress Due To Bus Traffic
RE: Asphalt Pavement Distress Due To Bus Traffic
Seems to be the prevailing solution...
TTFN
RE: Asphalt Pavement Distress Due To Bus Traffic
RE: Asphalt Pavement Distress Due To Bus Traffic
Rutting is usually a base, subbase, or subgrade stability problem, but could be exacerbated by poor asphalt mix characteristics.
Cracking, depending on the pattern, is a result of overstressing or weathering. Overstress in the bottom of the asphalt shows as longitudinal, then transverse, then alligator cracking. Weathering cracks result from drying shrinkage cracks (usually a long-term block cracking pattern), freeze-thaw fracture, or wet-dry cycle fracture.
Shoving is a mix stability problem relative to the imposed loads, or can be caused by slippage of one or more asphalt layers slipping on top of the base because of poor bonding between asphalt and base (improper tack coat).
Having said all that....portland cement concrete works well and is very durable for this application. Make sure you transition the concrete-to-asphalt interface to prevent failure as the bus moves from one type of pavement structure to the other. For heavy loads such as airfields, truck terminals, bus terminals and the like, I use a taper on the concrete vertical face of about 15 degrees. This "pushes" the asphalt against the concrete every time it's loaded, rather than "shearing the joint".
RE: Asphalt Pavement Distress Due To Bus Traffic
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