CCP 01-22-2006 Work Session - Laserfiche WebLink

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2006 PMP Update . 1/1812007 Page 2 hecoming brittle and cracking, and also helps keep the \\ater li'om seeping through the pavement and causing problems to the hase material. .Milt and Overlav There are several maintcIJ<lJlce practices that in\oln:: milling. An {'(Ip.t' mill typically consists of grinding the old bituminous sur1llce along the lIuter X fed lIfthe street. This helps estahlish a uniflm11 cross-section, especially in instances whLTC the cnl\m in the street is relatively Hat. A fid/wid/II mill. or resurfacing, is necessary when the UppLT surbce layer of a pavement has deteriorated considerably. Significant surlllCe IXI\l'ment distresses and more extensive ..thenlla\'" cracking need to he removed and/or repaired with a full \\'idth and unitlJrlll depth milling process. Both edge mills and full-\vidth mills arc typically 1.5 t01 inches thick. hut can vary on a project by project basis. Milling creates an even surt~lce to ensure a unil(JrI11 oH.:rall thickness to the new overlay. An asphalt overlay of J.5 to 2 inches over the entire pan:mcnt width forms a smooth crown, renews the street surface. restores structural capacity and propLT drainage. and e.xtends the life cycle of the original pavement. A/ill/ depth mill can he used on a stred that has aln.:ady been reconstructed \vith a good hase . section, hut the pavement has deteriorated to a point where seal coating or a standard mill and overlay is not effective. A pavement section with signi1icant cracking will end up rdlecting through the new pavement. The full depth of the pavement is ground up and rcmoved. This process may also involve some subgrade soil cOiTecil\ins and S\HIK rem(ival of aggregate base, if it has been contaminated or is suh-standard. The sIred is pil\"C<1 with the same thickness of new asphalt. Pav'cment can also he reclaimed, where approximately S to J 0 inches of the existing asphalt and hase are ground up in place. This 1<1rI11S a new more stable base without adding new material. 'fhe road is then paved with new asphalt. This is ullly rl'commended wherc there is no curb and gutter on the road. since the existing materials stay in place and a hi~her road elevation is created once the new pavement thickness is added. Ryconstruction \Vhen a strcet is fully reconstructed. the cxisting asphalt and hase are C(llllpktcly removed and replaced. Reconstruction may also involve suheradc soil corrections. For streets that do not mcet . . ,,-. current design standards for width, curb and gutll-I". and drainage. an upgrade may also he incorporated. .