The city of Des Moines Department of Public Works has had an ongoing pavement maintenance program to fill cracks for the last 25 years. However, to improve the overall condition of the city’s street system, it was decided to increase street funding for hot-mix asphalt (HMA) resurfacing. At that time it also was determined that an investment was needed for a more effective crack-sealing program to protect the large HMA resurfacing investment.
In 2005, the Department of Public Works elected to purchase the new equipment and the materials necessary to rout and seal cracks that would eventually develop on the HMA resurfaced streets.
The purpose of the routing and crack-sealing program was to maintain pavement quality (ride) and extend the life of the pavement by preventing moisture from penetrating the pavement and deterring incompressible material from entering newly formed cracks. These sealed cracks reduced the eventual development of potholes.
The city of Des Moines crack routing and sealing crew consists of seven personnel. The goal of the operation is to rout and seal cracks on HMA resurfaced streets after three years and then again 10 years later to promote a full 15-year service life. The goal requires that approximately 854,000 lineal feet of routing and sealing be completed each year for an average of 5,000 lineal feet per day (April through November). The cracks are routed and then an air compressor is used to remove any debris before the cracks are sealed with the crack sealant. The crew has been able to maintain the 5,000 lineal feet per day average due to the dependability and efficiency of the equipment along with the excellent customer service provided by the equipment and material supplier, Logan Contractors Supply Inc.
The life expectancy that the city of Des Moines is experiencing with the routed cracks is 1:7, or on average, seven years to the previous non-routed one year life. A Crafco router, Model 200, and a Crafco model SS125 hot-sealant applicator were purchased for this effort. Crafco 221 sealant also was used.