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<br />4278 <br /> <br />Par. 273 <br /> <br />surfacing will not be permitted. <br /> <br />The slopes of embankments, excavations, and <br />borrow pits shall be trimmed and finished to the <br />prescribed lines and grades. Ditches and channels <br />shall- be- cleared of debris and obstructions and ~he <br />slopes and beds of side ditches shall be trimmed <br />smooth and true to line and grade. Excess earth, <br />debris, or other waste material adjacent to culvert <br />ends. bridge ends, poles, posts, trees, or other <br />objects shall be removed or shaped and trimmed as <br />directed. The entire roadway and right-at-way shall <br />be left in a neat and pre::;entable condition. <br /> <br />b. Cost.- The cost of performing all work necessary <br />to finish the roadway as specified herein, including <br />road connections either inside or outside of the <br />right-ot-wav, shall be included in the unit price per <br />cubic yard bid in the schedule tor excavation, all <br />classes, for roadway. <br /> <br />274. DISTRIBUTOR FOR APPLYING <br />L10UID ASPHALT <br /> <br />The distributor used in applying all liquid asphalt shall <br />be of the self-propelled type, of sufficient power and <br />capacity to apply the asphalt under pressure uniformly <br />and at the proper rate with not more than 10 percent <br />variation therefrom. The distributor shall be equipped <br />with tachometer and charts, pressure gage, <br />thermometer well, and thermometer and shall have <br />adjustable length spray bars of sufficient length to <br />cover one-half of the roadbed at one time. The spray <br />bars shall be adjustable vertically to permit application <br />of the asphalt at the height above the surface approved <br />by the contracting officer and shall be of the <br />full-circulating type with satisfactory cutoff device at <br />each nozzle. The use of trailer-type distributors will <br />not be permitted. There shall be a trough under the <br />sprays, properly arranged to be swung out of the way <br />after the sprays are operating in a uniform manner at <br />the desired pressure or, in lieu thereof, building paper <br />shall be spread over the treated sur1ace for a sufficient <br />length back so that the sprays are operating properly <br />t when the uncovered surface is reached. If the cutoff is t <br />not sufficiently positive, the similar use of paper may <br />be required at the end of the aree being covered. The <br />distributor shall be operated in such a manner that <br />liquid asphalt will not be splashed on adjacent <br />guardrails or structures. Any asphalt so splashed shall <br />be removed at the expense of and by the contractor. <br /> <br />275. L10UID ASPHALT PRIME COAT <br /> <br />a. Description.- The prime coat shall Consist of <br /> <br />SPECIFICATIONS NO. DC'6945 <br />(SUPPLEMENTAL NOTICE NO. 31 <br /> <br />liquid asphalt applied to the compacted base course <br />in advance of placing the bituminous surfacing. <br /> <br />b. Material.-Liquid asphalt, Grade MC.70, shall be <br />furnished in accordance with Interim Federal <br />Specification SS.A.OO671b or the Asphalt <br />Handbook of the Asphalt Institute. <br /> <br />c. Applying.-Liquid asphalt shall be applied to the <br />full width of the area to be surfaced at a <br />temperature and in the amounts determined by the <br />contracting officer. The prime coat shall be allowed <br />to dry prior to plaCing of bituminous surfacing. The <br />prime coat shall not be applied during rainy weather <br />or when the atmotpheric temperature is less than <br />400 F. <br /> <br />d. Measurement.- The quantity of material for <br />liquid asphalt prime coat MC-70 for which payment <br />will be made will be determined as provided in <br />Paragraph 268. <br /> <br />e. Paymcnt.-Payment far liquid asphalt prime coat <br />MC.70 will be made al the unit price per ton bid <br />therefor in the schedule, which unit price shall <br />include the CO$t of furnishing and applying the <br />liquid asphalt. <br /> <br />276. PLANT-MIX BITUMINOUS <br />SURFACING <br /> <br />a. Oescription.-Plant-mix bituminous surfacing <br />shall conlist of penetration grade asphalt cement <br />and graded mineral aggregate, mixed at a central <br />mixing plant and placad on the roadbed to the lines, <br />grades, and dimension5 shown on the drawings. <br />Application of the plent-mix material will not be <br />permitted during unsuitable weather conditions or <br />when the atm05pheric temperature is below 400 F. <br /> <br />b. Asphalt cement.-A5phalt cement, Grade 85.100, <br />shall be furnished in accordance with Federal <br />Specification SS-A-706b or the Asphalt Handbook <br />of the Asphalt Institute. <br /> <br />c. Mineral aggregate.-Mineral aggregate shall be <br />crushed from rock or gravel, shall be uniform in <br />quality and grading, and shall be free from highly <br />plastic clays, vegetable matter, and other deleterious <br />substances. <br /> <br />(1) Grading.- Tha mineral aggregate when tested <br />by means of standard screens (Designation 4) <br />shall conform to the following limits of <br />gradation: <br /> <br />260 <br /> <br />'. <br /> <br />.', <br /> <br />. <br /> <br />. <br /> <br />. <br />