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Northlake Wood-CS 980413April 13, 1998 TO: Ken Griffi~ Director of Engineering and Public Services FROM: Curtis Snow, Interim Assistant Director of Public Servic~ ~ Larry Morton, Crew Leader, Streets Division, Public RE: Crack Sealant Complaint on Arbor Brook Drive The City received a complaint from a citizen on Arbor Brook Drive, Thursday April 9, concerning the crack sealing performed on her street. The Asphalt Crew f~m the Streets Division crack sealed Arbor Brook this date. The citizen first complained to the crew leader that she thought the sealant significantly detracted from the appearance of the sueet in front of her house. After not receiving answers from the crew leader that were ~ati~factory to her, she asked for the supervisor to come to her address and see what the crew had done to the sueet. I responded to the call and saw the lines of sealant in front of her house. I explained that it is not an atUactive process but ve~ necessary to the life of her street. Again, my answers were not satisfactory, and she said that she would do something about this. Apparently that is when she called your office, and I expect she will contact the Council. If you will allow me, I would like to explain in this memo why we crack seal so that you can use this memo as a resource in the event Council calls for an explanation. Also, I will give you some history of what we have been doing in the North Lake Woodlands Addition. Asphalt streets have a life expectancy of approximately seven to ten years with no maintenance. With proper maintenance, an asphalt street can last another five to seven years without an overlay and can last substantially longer with overlays before the street needs to be recoustmcted. The key to keeping an asphalt street in excellent shape is good maintenance. Good maintenance means keeping moisture from getting underneath the asphalt to weaken the base it sits on. It also means rejuvenating the asphalt periodically to maintain its flex~ility. All asphalt surfaces will crack. It is an inherent characteristic that is a reflection of its flexible characteristic. Because it will crack, there is always a poss~ility of getting moisture below the asphalt surface. This water in the base material, more often than not, is the cause of potholes and major street failures. If we know that asphalt will inevitable crack and, thus, allow moisture in to the subgrade, it is the Street Maintenance Division's primary responsibility to ensure the streets are sealed from water. There are three ways to seal a street. First, sim~le and least expensive: chase after the cracks with a sealant. Second, more expensive but more effective: periodically seal the entire width of the street ("chip and seal" or "slurry seal"). This is usually done when two things happen, when there are too many cracks, and/or when the asphalt starts losing its elasticity (when causes the cracks). A street sealer will cover all the cracks and rejuvenate or restore elasticity to the asphalt. The third type of maintenance is overlay; literally, placing a new road surface over the old one. This is the most expensive and the most effective, but it can only be applied to streets that have received proper care with crack sealing and a street seal. You cannot use an overlay on a street that has major failures in it. For instance, you could not overlay Bethel Road because of the base failures in the street. Having some underslanding of proper maintenance, attached are photos that are examples of what the Street Division is trying to accomplish. Pictures "A" and "B" are examples where reflection cracks were not attended to in time and the road base got wet and allowed the asphalt to cave in and push out. The large black stripe running through the picture is an attei~t to seal off the major crack that caused the problem, but the failure itself needs to be dug out and recoustmcted. When we find these cracks, we drip a hot asphaltic material into them to seal out water. You can see examples of this in pictures "D", "E" and "F", Cottonwood Lane and Carter Drive. These are three good examples of asphalt streets that are being preserved. Pictures "G" and "H" are of two of the streets we have completed in the North Lake Woodlands Addition. Pictures 'T' and "l" are shots of Arbor Brook where the citizen complained. These pictures are taken to show these streets are not much different from the other well-maintained asphalt streets. After the citizen complained, the Asphalt Crew worked diligently to improve the appearance of their crack sealing effort. Picture "K" is a picture of Briar Cove where the crew sealed the right half of the street much like they did the other streets and the left haft in a more controlled fashion, trying to minirrfize the mess. There is some difference in appearance, but the right half took a little better than a half hour, while the left side took nearly two hours. Lastly, the remaining pictures are of surrounding communities and results of their crack sealing program. Crack sealing may not be atlractive, but it is essential. In sum, the Sireets Division will make every effort to improve the application process. We hope the Council appreciates how necessary this messy process is to preserve the life of our streets.