Construction Requirements 311.03 The stockpile sites, as staked by the Engineer, shal prepared by clearing and disposing of all trees, stumps, brush, debris as provided in Section 201. The floor for each stockpile shal comparatively uniform in cross section. The completed stockpiles & be neat and regular in form and shall be made to occupy the smal feasible areas. Only when ordered by the Engineer shall the heigh the piles or their average depth be less than 20 feet (6.10 m). The slopes shall not be flatter than 12:1. Stockpiling of aggregates shall be in accordance with subsec 106.06. Method of Measurement 311.04 The quantity of aggregate to be paid for will be the num of cubic yards or tons as ordered and placed in authorized stockpi When payment by the cubic yard is called for in the bid schedu completed stockpiles will be measured and computed by the aver end area method. No allowance will be made for settlement or shri age. When slag and stone (or gravel) are designated as alternative ma rials for pay items in the bid schedule and payment is by weight, estimated quantities will be based on assumed average bulk spec gravities of available alternative materials. No adjustment in contr unit price will be made for variation in quantity due to differences in specific gravity of the material actually used. Basis of Payment 311.05 The accepted quantities of stockpiled aggregate, det mined as provided above, will be paid for at the contract price per p unit complete in place, which price and payment will be full compens tion for the work of this section, except for clearing stockpile sit which will be paid for under Section 201. Payment will be made under: Pay item 311 (1) Stockpiled aggregate, section 311 (2) Stockpiled aggregate, section 401.01 These specifications include general requirements that are applicable to all types of bituminous pavement structures of the plant mix type irrespective of gradation of aggregate, kind and amount of bituminous material, or pavement use. Deviations from these general requirements will be indicated in the specific requirements for each type. This work shall consist of constructing one or more bituminous bound layers on the prepared foundation in accordance with these specifications and the specific requirements of the type under contract, and in reasonably close conformity with the lines, grades, thicknesses, and typical cross sections shown on the plans within the tolerances specified or established by the Engineer. All tables and figures referenced herein are included at the end of this section. Materials 401.02 Composition of Bituminous Mixtures (Job-Mix Formula). The bituminous mixtures shall be composed of a mixture of aggregate and bituminous material. Prior to producing bituminous mixtures, the Contractor shall submit in writing a job-mix formula for each mixture to the Engineer for his approval. Each job-mix formula submitted shall propose definite single values for: (1) The percentage of aggregate passing each specified sieve, based on the dry weight of aggregate. These percentages shall be within the ranges shown in Table 703-4. (2) The percentage of bituminous material to be added, based on the total weight of mixture. (3) The temperature of the mixture leaving the mixer. In addition, the job-mix formula as submitted by the Contractor shall conform to the following: *For aggregates having maximum sizes over 1-inch (25.4 mm), AASHTOT 1C5 will be mod to use 6-inch (152 mm) by 6-inch (152 mm) cylindrical specimens. The 6-inch (152 mm) cylin will be compacted by the procedures outlined in AASHTO T 167 modified to employ repetitions of a molding load of 1,400 pounds per square inch (9.653 MPa) with no appreci holding time after application of the full load. The mixture shall have a minimum dry retained strength of 200 (1.379 MPa). Should a change in source of material be proposed or should a job-r formula prove unsatisfactory, a new job-mix formula shall be est lished. The job-mix formula will be approved by the Engineer, in writi prior to production. 401.03 Bituminous Materials The type and grade of bitumin material will be specified in the contract. Asphalt cement shall conform to subsection 702.01, for the gra specified. Emulsified asphalts shall conform to subsection 702.03 for the gra specified. Tar shall conform to subsection 702.08 for the grade specified. 401.04 Coarse Aggregate. Coarse aggregate (retained on t No. 8 sieve) (2.36 mm) shall conform to the quality requirements Section 703.07, Aggregates. 401.05 Fine Aggregate. Fine aggregate (passing the No. 8 (2. mm) sieve) shall conform to the quality requirement of Section 703.0 Aggregates. The magnesium sulfate soundness test will not be use 401.06 Filler and Hydrated Lime. Filler and hydrated li shall conform to the requirements of subsection 703.15 and 712.03 applicable. CONSTRUCTION REQUIREMENTS 401.07 Bituminous Mixing Plant. Plants used for the prepar tion of bituminous mixtures shall conform to all requirements under (a In addition, all plants with Pugmill type mixers shall conform to th requirements under (b), batching plants to the requirements under (c continuous mixing plants to the requirements of (d), and dryer dru mixing plants to the requirements of (e). (a) Requirements for all plants. (1) Mixing plants shall be of suff cient capacity to adequately handle the proposed bituminous constru tion. (2) Equipment for Preparation of Bituminous Material: Tanks for storage of bituminous material shall be equipped for heat ing the material, under effective and positive control at all times, to th temperature required in the paving mixture specifications. Heating shall be by steam or oil coils, electricity, or other means such that no flame shall contact the heating tank. A circulating system for the bituminous material shall be of adequate capacity to provide proper and continuous circulation between storage tank and proportioning units during the entire operating period. The discharge end of the bituminous binder circulating pipe shall be kept below the surface of the bituminous material in the storge tank to prevent discharging the hot bituminous material into the open air. All pipe lines and fittings shall be steam or oil-jacketed or otherwise properly insulated to prevent heat loss. Storage tank capacity shall be such as to ensure continuous operation of the plant and uniform temperature of the bituminous material when it is introduced into the pugmill. Tanks shall be accurately calibrated to 100-gal (0.379 m3) intervals and shall be accessible for measuring the volume of bituminous material at any time. The contractor shall provide a sampling outlet in the bituminous material feed lines connecting the plant storage tanks to the bituminous material weighing system or spray bar. The outlet shall consist of a valve installed in such a manner that samples may be withdrawn from the line slowly at any time during plant operation. The sampling outlet shall be installed between the pump and the return line discharge in a location that is readily accessible and free from obstruction. A drainage receptacle shall be provided for flushing the outlet prior to sampling. (3) Truck scales.-The bituminous mixture shall be weighed on approved scales furnished by the Contractor or on public scales at the Contractor's expense. Such scales shall be inspected and sealed as often as the Engineer deems necessary to assure their accuracy. Scales shall conform to the requirements of Section 109.01, and shall be sensitive to one half their minimum graduation, which shall not be greater than 10 lbs (4.54 kg). (4) Safety requirements.-Adequate and safe stairways to the mixer platform and sampling points shall be provided and guarded ladders to other plant units shall be placed at all points where accessibility to plant operations is required. Accessibility to the top of truck bodies shall be provided by a platform or other suitable device to enable the Engineer to obtain sampling and mixture temperature data. Overhead protection will be provided where necessary a hoist or pulley system shall be provided to raise scale calibration equipment, sampling equipment and other similar equipment from the ground to the mixer platform and return. All gears, pulleys, chains, sprockets, and other dangerous moving parts shall be thoroughly guarded and protected. Ample and unobstructed space shall be provided on the mixing platform. A clear and unobstructed passage shall be maintained at all times in and around the truck loading area. This area shall be kept free from drippings from the mixing platform. (5) Field laboratory.-The Contractor shall furnish a field laboratory in accordance with subsection 106.05. This laboratory shall be maintained for the exclusive use of the Engineer, and shall b located that details of the Contractor's plant are plainly visible from window thereof. If conditions permit, this laboratory shall be adja to the weigh house. (b) Requirements for all plants with pugmill type mixers. (1) Feeder for drier.—The plant shall be provided with accu mechanical means for uniformly feeding the aggregates into the d so that uniform production and uniform temperature will be obtain (2) Drier.-The plant shall include a drier or driers which cont ously agitate the aggregate during the heating and drying process. drier shall be capable of drying and heating the aggregate to moisture and temperature requirements set forth in subsection 401 or 401.14, without leaving any visible unburned oil or carbon residue the aggregate when discharged from the drier. (3) Screens.-Plant screens, capable of screening all aggregate the specified sizes and proportions and having normal capacities excess of the full capacity of the mixer, shall be provided. To prevent discharge of dust into the atmosphere, dustproof cov will be required over the screens. (4) Bins.-The plant shall include hot aggregate storage bins sufficient capacity to assure uniform and continuous operation. Bins shall be divided into at least 3 compartments and shall arranged to assure separate and adequate storage of appropriate fr tions of the mineral aggregates. Separate dry storage shall be provid for filler or hydrated lime when used and the plant shall be equipped feed such material into the mixer or weighing hopper. Each compa ment shall be provided with overflow pipes, of such size and at su location as to prevent backing up of material into other compartme or bins or into contact with the screens. Each compartment shall provided with its individual outlet gate, constructed so that wh closed there shall be no leakage. The gates shall cut off quickly a completely. Bins shall be so constructed that samples can be read obtained. Bins shall be equipped with adequate tell-tale devices indicate the position of the aggregates in the bins at the lower quart points. An automatic plant shutoff shall be provided to operate when a aggregate bin becomes empty. (5) Bituminous control unit.-Satisfactory means, either weighing or metering, shall be provided to obtain the proper amount bituminous material in the mix within the tolerance specified. Mea shall be provided for checking the quantity or rate of flow of bitumino material into the mixer. Metering devices shall prove accurate to within ±1.0% when test for accuracy. (6) Thermometric equipment.-An armored thermometer of ad quate range in temperature reading shall be fixed in the bitumino feed line at a suitable location near the charging valve at the mixer uni The plant shall also be equipped with either an approved recordin |