Subsection 401.03 is supplemented as follows: (a) Liquid asphalts shall conform to subsection 702.02. (b) Emulsified asphalts shall conform to subsection 702.03. (c) Tars shall conform to subsection 702.08. The material for top dressing shall meet the requirements of subsection 703.10(b). Construction Requirements 404.03 General. The construction requirements shall be as prescribed in subsections 401.07 through 401.20, with the following modifications: (a) When combined with bituminous materials other than emulsified asphalt, the aggregate shall be at a temperature of not less than 60°F, nor more than 225°F. If not already surface dry, the aggregate shall be dried at a temperature of from 150°F to 300°F, then cooled before being mixed with the bituminous material. (b) When combined with emulsified asphalt, the aggregate shall be at a temperature of not less than 60°F nor more than 175°F. (c) The aggregate, prepared as prescribed above, shall be combined in the amounts required to meet the job-mix formula, introduced into the mixer and mixed dry for a period sufficient to distribute the various sizes uniformly throughout the batch. The bituminous material, in the proper proportion, shall then be introduced into the batch and mixed until the aggregates are thoroughly coated and the mass is a uniform color. The mixing time for each phase of the mixing operation shall be set by the Engineer as determined from the nature of the aggregates, the job-mix formula and the size of the batch, but in no case shall the mixing time, after the introduction of the bituminous material, be less than 2 minutes. (d) When a top dressing of aggregate is specified it shall be applied immediately after the rolling of the surface course. The top dressing shall be evenly applied at the rate specified and rolled as directed. 404.04 Method of Measurement. Cold bituminous pavement will be measured as prescribed in subsection 401.25. 404.05 Basis of Payment. The accepted quantities of cold bituminous pavement will be paid for at the contract price per ton for the bituminous paving mixture and the aggregate top dressing and per ton or gallon for the bituminous material complete in place. Payment will be made under: 404(6) Aggregate Top Dressing for Cold Bituminous Pavement.. 404(7) Cold Bituminous pavement Ton. 404(8) Tar, grade RT 404(9) Tar, grade RT Ton. Section 405.-ROAD MIX BITUMINOUS PAVEMENT Description 405.01 This work shall consist of constructing one or more courses of road mix bituminous pavement on a prepared base or road surface 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. Materials 405.02 Bituminous Material. The bituminous material shall be of the type and grade called for in the bid schedule and shall conform to the following subsections: Application temperatures of bituminous materials shall conform to subsection 702.05. 405.03 Aggregate. The aggregate will be tested for acceptance immediately preceding addition of bituminous material to the mix. This acceptance will be based on periodic samples of the windrow after all aggregates have been blended for each layer. (a) Case 1 (new aggregate).—New aggregate shall conform to subsection 703.09, for grading F of table 703-4. (b) Case 2 (aggregate salvaged from the existing surface).—Where aggregate required for the road mix surface course is already in place, the Contractor shall not be responsible for its grading or quality except for removal of oversize pieces. In general, salvaged aggregate to be used for road mix surface course will consist of material meeting the requirements given above for new aggregate or may consist of selected granular material for other gradings. Any particles of salvaged aggregate appearing in the surface at the time of lay-down and finishing that will not pass a 1/2-inch sieve shall be removed by the Contractor as directed by the Engineer. Construction Requirements 405.04 Weather Limitations. The construction of road mix bituminous pavement shall not be carried on when the surface on which the material is to be placed is wet or when the surface temperature is below 50°F. 405.05 Equipment. The equipment used by the Contractor shall include scarifying, mixing, spreading, finishing and compacting equipment; a bituminous distributor; and equipment for heating bituminous material. The distributor shall be so designed, equipped, maintained and operated that bituminous material at even heat may be applied uniformly on variable widths of surface up to 15 feet at readily determined and controlled rates from 0.05 to 2.0 gallons per square yard, with uniform pressure, and with an allowable variation from any specified rate not to exceed 0.02 gallons per square yard. Distributor equipment shall include a tachometer, pressure gauges, accurate volume measuring devices or a calibrated tank, and a thermometer for measuring temperatures of tank contents. Distributors shall be equipped with a power unit for the pump, and full circulation spray bars adjustable laterally and vertically. Traveling or stationary mixing plants or other equipment of proven performance may be used by the Contractor in lieu of the specified equipment if approved. Rollers shall be self-propelled steel-wheel tandem or 3-wheel rollers weighing not less than 8 tons each, and pneumatic-tire rollers having a total compacting width of not less than 60 inches and the gross weight adjustable within the range of 200 to 350 pounds per inch of compaction width. The operating weight shall be as directed. Contact pressure may be specified for penumatic-tire rollers. All tires on pneumatic rollers shall be equally inflated, exerting equal unit pressure, with a means of varying the contact pressure to suit project conditions. 405.06 Preparation of Base. (a) Case 1 (new aggregate).—When new aggregate is to be used for the road mix surface course, the existing base shall be scarified lightly and bladed to uniform grade and to the cross section shown on the plans and shall then be rolled, or watered and rolled, as directed. If so ordered by the Engineer, depressions shall first be filled and weak portions of the base strengthened with new aggregate. (b) Case 2 (salvaged aggregate).—When material in the existing road surface is to be used for mixing, the surface shall first be scarified lightly and bladed to uniform grade and to the cross section shown on the plans. The reshaped surface shall then be scarified again to the depth ordered by the Engineer and in such manner as to leave a foundation of undisturbed material parallel, both in profile and cross section, to the proposed finished surface. The loosened materials shall be bladed aside into a windrow at the side of the road, and the undisturbed material rolled, or watered and rolled, as directed. 405.07 Placing Aggregates. New aggregates, where required, shall be uniformly spread on the prepared surface by the use of spreader boxes, or other approved mechanical spreading devices. When two or more sizes of aggregates are used, each size of aggregate shall be placed in the proper amount to provide for surfacing of the required width and thickness. The proper amounts of the separate sizes of aggregate for each course shall be blended and shaped into a windrow of uniform cross section. At least one day shall then be allowed for measuring, sampling, and testing for approval of quantity and gradation before the windrow is spread for application of bituminous material. If the surface moisture of the aggregate is more than 2 percent of the dry weight of the aggregate, except when the bituminous material is emulsified asphalt, the aggregate shall be turned by blades or disc harrows or otherwise aerated until the moisture content is reduced to 2 per cent or less. The aggregate shall then be spread smoothly and uniformly over half the road or other convenient width of the surface ready for the application of bituminous material, except that when a traveling mixing plant is used the aggregate shall be formed into a uniform cross section. In lieu of aerating and drying the aggregate, the Contractor may use an approved additive, except where emulsified asphalt is used, which shall be satisfactorily blended with the bituminous material. The additive shall permit suitable coating of the wet aggregate and shall prevent the bituminous coating from stripping in the presence of water. 405.08 Application of Bituminous Material. The bituminous material shall be uniformly distributed in successive applications, in such amounts and at such intervals as directed. The mixing equipment shall follow immediately behind the distributor, after each application of bituminous material, to partially mix the aggregate and the bituminous material. 405.09 Mixing. After the last application of bituminous material and partial mixing, the entire mass of bituminous material and aggregate shall be windrowed on the road surface and then mixed, by blading the mixture from side to side of the road, or by manipulations producing equivalent results, until all aggregate particles are coated with bituminous material and the whole mass has a uniform color and the mixture is free from fat or lean spots, balls or uncoated particles. During the mixing operations, care shall be taken to avoid cutting into the underlying course or contaminating the mixture with earth or other extraneous matter. When directed, the mixing process shall be confined to part of the width or area of the road so as to allow traffic to pass. Should the mixture show an excess, deficiency or uneven distribution of bituminous material, the condition shall be corrected by the addition of aggregate or bituminous material as required and re-mixing. If the mixture contains excessive amounts of moisture or volatile matter, it shall be bladed, aerated or otherwise manipulated until the moisture and volatile content are satisfactory. The spreading of the mix shall not be done when the surface to be covered is in an unsatisfactory condition. At the end of each day's work, or when the work is interrupted by weather conditions or otherwise, all loose material shall be bladed into a windrow, whether mixing is completed or not, and shall be retained in a windrow until operations are resumed. When the mixing operations have been satisfactorily completed, the mixture shall be formed into a windrow of uniform cross section. If the Contractor elects to use traveling or stationary mixing plants in lieu of the specified equipment, the same requirements regarding residual moisture and evaporation of volatiles given above shall apply. 405.10 Spreading, Compacting, and Finishing. The material shall be spread by a selfpropelled, pneumatic-tire blade grader or a mechanical spreader of approved type. In spreading from the windrow, care shall be taken to avoid cutting into the underlying base. After the material is spread, the surface shall be rolled. Rolling shall be parallel to the road center line and shall commence at the outer edges of the road, overlapping the shoulders and progress toward the center, overlapping on successive passes by at least one-half the width of the roller, except that on superelevated curves rolling shall progress from the lower to the upper edge. Each pass shall terminate at least 3 feet in advance or to the rear of the end of the preceding pass. During the compaction the surface shall be dragged or bladed as necessary to fill ruts and to remove incipient corrugations or other irregularities. Rolling shall continue until the surfacing is of uniform texture and satisfactory compaction is obtained. Initial rolling shall be performed with a pneumatic-tire roller and final rolling with a 3-wheel or tandem-type steel wheel roller. Rolling shall be discontinued whenever it begins to produce excessive pulverizing of the aggregate or displacement of the mixture. Where the compacted thickness of the road mix surface is to be more than 2 inches the mixture shall be spread from the windrow and compacted in 2 layers, the first layer to be bladed and rolled before the second layer is spread. While the surface is being compacted and finished the Contractor shall trim the edges neatly to line. 405.11 Surface Requirements. Surface requirements shall be as specified in subsection 401.23 except that the permissible surface variance will be 3⁄4-inch in 10 feet. Method of Measurement 405.12 Aggregate and bituminous material furnished for road mix bituminous pavement will be measured by units shown in the bid schedule. The quantity of road mix acceptably completed will be measured by the mile or square yard, as shown in the bid schedule. 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 difference in the specific gravity of the material actually used. Basis of Payment 405.13 The accepted quantities of road mix bituminous pavement determined as provided above will be paid for at the contract price per specified unit for all construction, aggregates, and bituminous material complete in place which price and payment will be full compensation for the work of this section. Section 406, 407, 408, 409-RESERVED Section 410.—BITUMINOUS TREATMENTS Description 410.01 This work shall consist of the construction of a single or multiple course bituminous treatment in accordance with these specifications and in reasonably close conformity with the lines shown on the plans or established by the Engineer. The bituminous treatment may consist of the application of one or more seal coats, a prime coat followed by one or more seal coats, a prime coat or tack coat. The approximate quantities of materials and the sequence of applications and spreadings shall meet the requirements set forth in the subsection applicable to the designated or type of work called for in the bid schedule. Materials 410.02 Bituminous Material. The bituminous material shall be of the type and grade called for in the bid schedule and shall conform to the following subsections: Application temperatures of bituminous materials shall conform to Subsection 702.05. 410.03 Aggregates. Aggregates and blotter material shall meet the requirements of Subsections 703.13 and 703.14 for the sizes specified. The material may be accepted in stockpile at the source. When a specific grading is listed in the bid schedule, that grading shall be furnished. When a designation is listed in the bid schedule, more than a single grading may be required. Materials will be accepted on a lot by lot basis. Unless otherwise provided, the entire quantity of each grading of aggregate or of blotter material shall constitute a lot for the purpose of sampling, testing, and acceptance. Normally, five samples shall be taken for each lot, and the selection of the samples will be by a statistical procedure such that all units of production have a chance of being sampled. The Engineer will select one of the samples and test it for acceptance. If the tested sample meets the gradation requirements of the specification the material will be assigned a pay factor of 1.00 and further testing will not be required. If the sample tested fails to meet the gradation specification in any regard the remaining samples will be tested. If the average of all samples tested is within the specification limits a pay factor of 1.00 will be assigned. Material that is not assigned a pay factor of 1.00 will be considered to be in substantial compliance provided the average of each specified sieve fraction does not exceed the specification by more than 2%, and no single value is more than 5% beyond the specification. Materials that are in substantial compliance may be accepted at an adjusted unit price based on a pay factor of 0.85. Materials that fail the above tolerances will be rejected. |