Longtime road inspector weighs in on Killeen’s street repair problems
To the Editor:
As one who has served in the inspection of roadway construction for 40 years, I would like to offer my opinions on the failing streets in Killeen.
Any successful roadway construction must include: Good design, Good construction processes, Testing and Verification inspections.
1) Any citizen knows that a good roadway is only as good as the foundation it’s been built on. Failing and cracking often occur early in the life of a roadway due to the failure or inadequate supporting layers.
In my opinion, the roadway failures, as evidenced on Stagecoach Road, are most likely due to both these conditions and not the asphalt. The asphalt layer is an easy target to blame, until one remembers that the 2- to 3-inch asphalt layer is only as good as what it’s built on. The design guide referenced in the paper is a good tool if used properly.
In the design phase, the type of traffic, the anticipated vehicle loads and the number of anticipated passes must all be considered. I would respectfully submit that the failures observed in these roadways “suggests” that the “minimum” criteria for the design were used to avoid additional construction costs.
Sometimes an “over design” is the key to a roadway that will provide a longer service life. A roadway should NOT be failing early in its service life. I would suggest that an additional (or thicker) layer of the aggregate base course be used during the design phase for all heavily trafficked roadways.
I would also suggest that, when rehabilitating existing failing roadways, that they NOT build it back the “same” way. The usage of an additional layer of aggregate base layers will greatly enhance the service life of the roadways.
2) I often notice the construction of aggregate base course layers in city roadways, that those materials are not being processed correctly. There is a tendency to simply spread a layer of loose base materials across the roadway and then apply water on top and compact the base layer.
The correct construction of aggregate base materials must include thoroughly mixing and moistening the materials throughout the base layer to achieve an adequate supporting layer. Improper processing can be a contributor to roadway failures.
3) Any successful roadway program must include the testing of construction materials that are used in the roadways. Industry approved testing labs and industry certified technicians must be used for these testing services. Were approved labs used and sufficient testing performed? Were any tests taken in the failing areas?
4) A wise man once said “You get what you inspect, NOT what you expect”. Does the city provide quality assurance testing or inspections? Many failures can be detected during the construction. We should not have to wait until the roadway is turned over to the city and failing to start pointing fingers.
Thanks for allowing me to share my opinions. I’m hoping for safer and better built roads in 2022.
One last request ... please repair Old 440 from Kathy to Stan Schlueter. It’s a minefield.