The San Joaquin County Supervisors are expected to call for bids today for the chip and sealing of 36 miles of existing roads.

The $1.9 million project will have a March 10 bid opening with work planned to start in June.

Roads that will be chipped and sealed in the Manteca, Lathrop, Ripon, and Escalon areas include:

*Roth Road from the Union Pacific Railroad tracks and Intermodal Way between Lathrop and Manteca.

*Louise Avenue between Austin Road and the eastern city limits of Manteca.

*Airport Way from just south of Woodward Avenue at the Manteca city limits to the San Joaquin River bridge where it turns into Durham Ferry Road with work ending at Kasson Road south of the San Joaquin River Club.

*North Ripon Road from the Ripon city limits just south of Clinton South Road to East Highway 120.

*River Road at a point east of McHenry Avenue heading east across Santa Fe Avenue to Henry Road.

*Lone Tree Road from Brennan Road to Escalon-Bellota Road.

The bulk of the remaining chip and seal work is to the east of Stockton. The longest segment is Alpine Road from Live Oak Road to Copperopolis Road.

The work is in addition to a $629,070 project awarded to United Pavement Maintenance to resurface Airport Way between Roth Road at Manteca’s northern city limits to French Camp Road.

The 1.3-mile project is expected to take place in April.

Chip and seal fills and seals cracks in older pavement. By doing so it minimizes the effects of aging and extends the life of the pavement by keeping water from penetrating the road structure on paved surfaces. The chip seal process cost is 15 to 20 percent of that of pavement overlays.

A synopsis of the chip and seal process follows:

*First, asphalt is mixed with about 30% water. This emulsified mixture is then applied to the road using a special spray truck. As soon as the liquid asphalt meets the road surface, the water starts to evaporate.

*Immediately after spraying this asphalt, a layer of crushed gravel is applied by a spreader. The gravel (or chips) has a maximum size of 3/8 inch.

*Next, the gravel is compacted and embedded into the asphalt by rubber-tired rollers. However, even with the high-pressure rolling, some gravel will not become embedded in the asphalt.

*The new chip-seal surface can require up to two days to cure properly. Hot, dry weather helps speed up this process in which all of the remaining water in the emulsion evaporates and the asphalt hardens. Traffic can pass over this surface at reduced speeds during the curing process.

*After curing, the loose gravel is swept off the surface. This may take several sweepings.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com