Method of Measurement 401.21 Plant mix bituminous pavement including bituminous material will be measured by the ton in accordance with Section 109-Measurement and Payment. Batch weights will not be permitted as a method of measurement, unless the alternative provisions of subsection 401.08(a) (1) are met, in which case the cumulative weight of all the batches will be used for payment. The tonnage will be the weight used in the accepted pavement and no deduction will be made for the weight of bituminous material in the mixture. When slag and stone (or gravel) are designated as alternative materials for pay items in the bid schedule and payment is by weight, the estimated quantities will be based on assumed average bulk specific gravities of available alternative materials. No adjustment in contract unit price will be made for variation in quantity due to differences in the specific gravity of the material actually used. When specified in the contract as a pay item, the quantity of bituminous material will be the number of tons or gallons used in the accepted work. Basis of Payment 401.22 All work performed and measured as prescribed above will be paid for as provided in the respective sections for each type specified. Work prescribed in subsection 401.12 will be paid for at the contract unit prices for the material used. Section 402.-RESERVED Section 403.-HOT BITUMINOUS PAVEMENT Description 403.01 This work shall consist of constructing one or more courses of bituminous pavement on a prepared base in accordance with these specifications, and in reasonably close conformity with the lines, grades, thicknesses and typical cross sections shown on the plans or established by the Engineer. The bituminous pavement shall be composed of a mixture of aggregate, filler if required, and bituminous material of the type shown in the bid schedule. Materials 403.02 General. The materials and their use shall conform to the requirements of subsections 401.02 through 401.06. The percentage range by weight of bituminous material to be added will be shown in the special provisions. Aggregate shall meet the requirements of subsection 703.09 for the grading called for in the bid schedule. Construction Requirements 403.03 General. The construction requirements shall be as prescribed in subsections 401.07 through 401.20. Method of Measurement 403.04 Hot bituminous pavement will be measured as prescribed in subsection 401.21. Basis of Payment 403.05 The accepted quantities of hot bituminous pavement determined as provided above will be paid for at the contract price per ton for the bituminous mixture and per ton or per gallon for the bituminous material, when specified, complete in place, which price and payment will be full compensation for the work of this section. Payment will be made under: Letter suffixes will be added to the pay item number 403 (1) to designate alternative types of materials to be bid on. Section 404.-COLD BITUMINOUS PAVEMENT Description 404.01 This work shall consist of constructing one or more courses of cold bituminous mixture on a prepared base in accordance with these specifications and in reasonably close conformity with the established lines, grades, thicknesses and typical cross section shown on the plans or established by the Engineer. The bituminous pavement shall be composed of mixtures of aggregate, liquid bituminous material, liquefier, hydrated lime, and a top dressing of sand, stone screening, or slag screenings. Materials 404.02 General. The materials and their use shall conform to the requirements of subsections 401.02 through 401.06, supplemented as shown. Subsection 401.02 is supplemented as follows: (a) The job-mix formulas will include percentages in accordance with the following: (b) liquefier shall conform to the job mix formula within a tolerance of 0.2 percent. Subsection 401.03 is supplemented as follows: Aggregates and top dressing material shall meet the requirements of subsections 703.10 (a) and (b) respectively. Subsection 401.06 is supplemented as follows: (a) Bituminous material.-Bituminous material shall be asphalt cement of penetration grade 85-100. (b) Liquefier.-Liquefier shall conform to the requirements of AASHO M 83. The grade to be used will be designated by the Engineer. Construction Requirements 404.03 General. The construction requirements shall be as prescribed in subsections 401.07 through 401.20, with the following modifications: (a) Drier.-The requirement for mechanical cooling of the aggregate while it is being stored may be waived in the case of material entering the storage space at atmospheric temperatures. (b) Liquefier control unit.-There shall be an accurate calibrated device installed for the measurement of liquefier. The discharge pipes from such device shall be installed to spray liquefier into the mixer in such manner as to insure uniform distribution of the material. (c) Mixer. The mixer shall be a batch mixer of the pugmill type. The use of dual mixers will be permitted if the type of equipment furnished and the total mixing time are satisfactory to the Engineer. (d) Preparation of asphalt cement.—The asphalt cement shall be heated to a temperature between 200° F. and 300° F. in the melting kettles or tanks. (e) Preparation of aggregates. All aggregate shall be dried until it has no surface moisture and not more than 0.4 percent of contained moisture. Mixing temperatures of the aggregate shall at no time be less than 45° F. nor more than 110° F. (f) Preparation of mixture. The separated fractions of dried mineral aggregate, prepared as prescribed above, shall be combined into uniform batches by weighing and conveying into the mixer the amount of each fraction required to meet the appropriate job-mix formula. After these fractions have been thoroughly mixed, liquefier shall be sprayed over the aggregate and mixing shall be continued until all the aggregate is coated. The quantity and grade of the liquefier used shall be varied within the limits prescribed in subsection 404.02 and will depend on the weather and the distance the material is to be transported. The liquefier shall be used in such manner as will insure the desired consistency of the mixture when it is delivered and deposited on the road. The asphalt cement and hydrated lime shall then be successively introduced and the mixing continued until the mixture is uniform and homogeneous. The dry mixing period will be set by the Engineer after he has considered the nature of the aggregate used. The total mixing time shall be varied according to the nature of the aggregates and the capacity of the mixer but in no case shall the mixing time, after the introduction of the asphalt, be less than 2 minutes. The mixture shall be so prepared that it may be unloaded and placed at the prevailing air temperatures without application of heat. The details of plant operation shall be arranged to meet the requirements above and at the same time produce the workability of mix and thickness of film coating found most advantageous. Each batch shall be kept separate throughout the mixing operations. The mixture shall be uniform in composition, free from lumps or balls of material containing an excess quantity of asphalt, and free from pockets containing less than the required amount of asphalt. Mixtures for the bottom course and for the wearing course shall be mixed and handled separately. (g) Transportation and delivery of materials.-Shipments found to contain a surplus amount of bituminous material in the bottom of the car or truck will be rejected. (h) Spreading and finishing.-Wearing course material shall not be spread on the bottom course until the latter has cured for at least 12 hours, unless otherwise directed by the Engineer. (i) Application of top dressing.-After the wearing course has been rolled and finished satisfactorily, and as soon as the condition of the pavement will permit, top dressing shall be applied, by means of an approved mechanical spreader, at a rate of from 3 to 6 pounds per square yard as directed by the Engineer. Only sufficient top dressing shall be spread to permit filling the voids in the surface of the wearing course. The application shall be spread uniformly and screeded or broomed. Any unavoidable excess shall be removed. It shall then be rolled as directed by the Engineer, and shall be rebroomed and re-rolled the next day if required. Method of Measurement 404.04 Cold bituminous pavement will be measured as prescribed in subsection 401.21. When slag and stone (or gravel) are designated as alternative materials for pay items in the bid schedule and payment is by weight, the estimated quantities will be based on assumed average bulk specific gravities of available alternative materials. No adjustment in contract unit price will be made for variation in quantity due to differences in the specific gravity of the material actually used. Basis of Payment 404.05 The quantities determined as provided above will be paid for at the contract price per pay unit for each of the pay items from the list below that is shown in the bid schedule, which price and payment will be full compensation for the work of this section. |