Town Talk: Pavement surface reconstruction
New Ulm Street Department reconstructs 12 blocks of roadway each year in locations that have a stable sub-base, and the underground utility infrastructure is in good condition. Generally, the sub-base will be either sand or gravel and is not subject to frost heaves. Only then will the Street Department perform a “pavement surface reconstruction.”
The first step of this process is to replace any curb sections that impede storm water drainage, such as raised or sunken concrete sections. Then we perform cross-cuts with the pavement grinder at the ends of the construction limits and across the middle of the street to allow the wheel loader bucket and the compact track loader bucket to get below the existing pavement and begin removing it from the street. The old asphalt is hauled away to be recycled by running it through a crusher and mixing it with gravel to be used in other road construction projects.
As soon as the asphalt is removed, the open area is checked for any soil abnormalities such as pockets of clay or an overabundance of larger rocks, which must then be dug out and removed before grading. Manhole structures are removed, and a plate is installed over each open hole to keep out debris. Those plates are left in until paving.
The motor grader then begins reshaping the street section, and excess material is hauled away or more class 5 (gravel) is hauled in. A rubber tire roller is used to make the surface hard and ready to accept the new asphalt. The gravel and asphalt are purchased from local vendors.
When the street is set to grade, the paver and haul trucks begin laying a smooth, two-inch layer of 3/4-inch base asphalt on the street. When this is done, the crew finds any covered-up plates over sewer manholes and reinstalls the top castings of the manholes, leaving them two inches high so they will be flush with the next two-inch layer of 1/2-inch wear asphalt. The 3/4 inch and 1/2 inch are the rock sizes used in the asphalt mix. The larger the rock, the stronger the mix is, the smaller the rock, the smoother the ride will be.
After the asphalt sufficiently cools down (usually the next day), the last two-inch layer of asphalt is installed, leaving a new street with a full four inches of asphalt. This new street will be scheduled on the next year’s crack seal and seal coat list to keep it new for years to come.
This whole process takes about one week from start to finish. We understand the construction does disrupt the adjacent residents, and we try and work with them as much as we can, to get the project done as fast as we can. We will be starting the surface reconstruction project Monday 7/19/2021 weather permitting. If you have any questions or want to discuss the surface reconstruction project scheduled for your street, call Jeff Hoffmann, Public Works Superintendent at 359-8296.