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Show Construction Aimed at Smoothing Travel The Utah Transportation fission opened bids last ' Jsday on a project which ; hopefully relieve the i ngs" of Mancos Shale 5 ly ng an 18.2 mile of 1-70 from White-r White-r e to Westwater near the JJmunity of Cisco in Grand CC L.A. Young Sons Construction Company of ichfield. Utah was the ' rent low bidder with a bid ($4 349,008. The official lineer's estimate was $,196,739. . a nemesis of road bilders in southern Utah, V,jncos Shale is a rock joimtion that softens and opands with moisture during J winter months, and hard-(js hard-(js and contracts during the to summer months-a process rtway engineers call "heav-1" "heav-1" For highways that are f hilt over the shale, the result can be a buckling of the pavement and the creation of ridges in the roadway, sometimes some-times up to a foot high. The Utah Department of Transportation has experimented experi-mented with many methods of dealing with the shale over the years, including placing a membrane under the pavement pave-ment to keep water from soaking into the shale and mixing lime into the shale to change its chemical structure. However, the most successful success-ful method to date, and the method which will be used by the contractor on this project, is to excavate the shale to a depth of about five feet and replace the shale material with granular back fill. According to the terms of the contract, this will be accomplished in about a dozen places along this section of 1-70 where the disruption from the shale is the worst. As a part of the contract, the contractor will also give the entire section of four-lane freeway its final layer of asphalt surfacing, which will range from three to five inches in thickness. |