Modified "Single Seal" Surface Treatment
This program was first begun during the calendar year 1998 paving season in order to minimize residential complaints due to surface treatment, reduce sweeping requirements, increase the competitive nature of the bid, and to obtain a lower unit price per square yard, resulting in the maintenance of additional road mileage. The application uses #8 / #9 stone (Type I) and #8 stone (Type II) which are smaller sized stones than that previously used in regular surface treatment applications. A sand filler/binder designed to help reduce the loosening of stones from the surface is also included in the mix. Performance is not sacrificed and some added strength may be realized. We have also changed the emulsion from an oil base to a latex base for easier clean-up and faster set-up time. This particular maintenance effort can cover an average of one (1) to two (2) miles of roadways per day. It is estimated that this particular treatment extends the service life of a roadway between five (5) to eight (8) years depending on the volume of traffic.
The contractor is required to sweep any loose material/stones from the roadway for a period of two (2) weeks, once the pavement has cured, via the use of broom trucks. In the interim, “loose stone” signage may be placed along the roadway to advise motorists, as needed. Overlay operations are typically completed by mid June. Residents may also experience a loose sandy grit residue and slight “raveling” of small stones for up to four (4) weeks following the overlay during which time the Department may request the contractor perform additional roadway sweeping. Motorists are requested to exercise caution and reduce their traveling speed during this time. This application also “turns” darker with age, similar to an asphalt overlay, and is cosmetically more pleasing. $840,000.00 is budgeted annually for this program, which treats 30 to 40 miles of roadway, including preparatory work, and crack sealing for approximately 2 to 4 miles of roadway. Please refer to our Modified Seal Program Listing for additional information."
It is often that a surface treatment is subsequently slurried (cape sealed) or overlaid with asphalt the following year(s). Cape Seals are used where a chip seal is too rough and requires a smooth finish, for example in residential streets. In instances where cracking is a problem a chip seal can alleviate cracking and the slurry can provide the smooth and hard wearing surface. The addition of a slurry capping not only makes the surface smooth but locks the aggregate of the chip seal in place eliminating stone loss. A cape seal can last longer, can treat cracks, is smoother than a chip seal, more durable than a slurry and could last as long as ten (10) years depending on traffic volumes.
Each year a paving contractor for this program is selected. Once the listing of roadways to be treated is finalized, the Department will provide a public informational message, similar to the one below, for posting on the County website to advise residents that may live along the affected roadways: St. Mary’s County has awarded a new contract to resurface your County roads with Surface Treatment. Surface Treatment consists of liquid asphalt, material, stone, and sand. The liquid asphalt is sprayed on the road and immediately covered with stone. We should begin work in May or early June. The contractor generally starts work each day between 7 a.m. and 8 a.m. and works until about 6 p.m. You can expect some minor delays in traffic when the contractor is resurfacing our roadway, especially the narrower roadways within the County. You may drive on surface treatment after the stone is placed on the road. There will be some loose stone on the road so please reduce your speed on newly treated roads. This will allow the Surface Treatment time to cure, which may take 2 to 3 weeks. Your patience and cooperation on this matter is greatly appreciated. In working together we can improve your roads and keep the inconvenience to a minimum. Should you have any questions please to not hesitate to contact our Construction and Inspections Division at (301) 863-8400 extension 3531.
Proper notice to local utility companies is required. Unexpected utilities can cause delays, impact the scope of work, potentially creating greater traffic hazards, especially if work needs to be performed under emergency conditions. Utility Coordination Meetings are held at the Department of Public Works & Transportation during the first week of April each year to discuss the prior year’s construction, resolve conflicts, improve communication and provide a project overview of the Departments construction schedule.