How do we stretch the budget? That is a difficult question to answer. At the August 11 meeting of the Tennessee Chaper of the American Public Works Association (TCAPWA) Upper East Tennessee Branch, Shawn Lindsey, Public Works Director from the City of Athens, presented a proven alternative. The following is a synopsis of that presentation.
Athens is using a specific slurry seal product to extend the life of asphalt pavement in selected areas freeing up monies to be used in more expensive paving projects. The slurry seal is a blend of polymers, aggregate and reinforced asphalt emulsion, being comparable to a micro surface. Micro surfacing can cost up to 75% of the cost of doing a thin overlay while this slurry seal product can be done in house by municipal crews at about 1/3 the cost of paving. The product is applied to moderately traveled asphalt roadways that are 10 to 20 years old and are in moderate condition. The city of Athens has completed its application on several low volume streets between 11 years of age and over 30 years of age.
The advantages are:
These and other recommendations may be found at http://www.fhwa.dot.gov/pavement/preservation/ppcl13.cfm.
Steps in preparing a road for the specific slurry seal product:
The product will dry in about one to two hours on a sunny day. Athens tries to leave the roadway closed from 8:00 a.m. after most leave for work until about 3:00 p.m. when school is letting out. The crew performs a "door to door" reminder before starting the process to give residents the opportunity to move vehicles. It is best to avoid traffic on the uncured surface. Crews can put down up to 2,000 gallons between 8:00 a.m. and 1:00 p.m. even allowing for several breaks. The city uses six to eight workers when the street has a curb and gutter cross section as it requires more handwork. A crew of five employees can easily handle a non-curbed street. When working a curbed street, Athens combines the street maintenance crew and street construction crew to expand the work force. The Street Maintenance Crew handles noncurbed streets with minimal help.
It cost approximately $50,000 to purchase a spray/squeegee machine capable or spreading and keeping the slurry of aggregate and asphalt properly mixed. This amount can be saved in the first year of paving avoidance. A small 250 gallon tack tank is necessary to apply cold tacks. To speed up production, crews prefer that the aggregate be already mixed. Adding aggregate causes the crew to spend more time mixing and loading the tank than applying product. If the aggregate is already in the tank, the crew spends 5 to 10 minutes loading a tank and has more time for application.
Athens' current plan is to apply the product two to threee days per week in the hottest and driest months of August and September. May-July are possibilities, but crews that apply the product also do all of the other street, sidewalk, and storm water work. It helps to set aside months for various parts of the operation to concentrate on. Mr. Lindsey estimates that most municipal operations that have at least six to eight people in their street departments can work with this new product. Others may consider contracting it out.
For more information, contact Shawn Lindsey, City of Athens Public Works Director, email@example.com.
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