610 - DOUBLE ASPHALT SURFACE TREATMENT
600-58 e. Preparation of Road Su rfaces for First Seal Coat. After the prime coat has thoroughly penetrated the
subgrade, and before applying asphalt mate rial, clean the surface to be treated of all foreign material and broom it as necessary to remove dust.
f.Application of Asphalt Material for First Seal Coat. Using a distributor, uniformly apply asphalt material at the rate shown in the Contr act Documents. Equip and operate th e distributor to prevent asphalt material from dripping on the pavement. At the beginning of each spread, use a strip of building paper, approximately 3 feet in width and 1 foot longer than the spray bar. If the spray cut-off is not positive, use paper at the end of each spread. Remove the paper and dispose of it in a satisfactory manner. Open the spray bar when the distributor is moving forward at proper speed, unless it is equipped to apply the specified rate from a standing start. Co rrect any skipped areas or deficiencies. Carefully make junctions of spreads to obtain a smooth riding surface. Do not spread more asphalt material than can be immediately covered. Do not allow the asphalt material to remain uncovered long enough to impair retention of the cover material. Do not exceed the spread width of the cover material with the spread width of asphalt material by more than 6 inches. Regulate the distribution of the asphalt material to obtain a uniform application. Do not allow the distributor to "blow". Check and adjust the angle of the spray nozzles and th e height of the spray bar frequently to obtain uniform distribution. If the rise of the spray bar as the load is removed is excessive and contributes to drilling and streaking, modify the distributor to maintain a constant spray bar height. Should any nozzle malfunction, immediately stop distribution. Correct any deficiency before distribution is resumed.
g.Application of Aggregate for First Seal Coat. Immediately following the ap plication of the asphalt material, spread cover material with a self-propelled aggregate spreader in quantities designated in the Contract Documents. The tires of the trucks or aggregate spreaders shall not come in contact with the fresh asphalt material at any time. Do not allow the asphalt material to remain uncovered long enough to impair retention of the cover material. Do not apply the spread width of the cover materi al greater than 6 inches wide r than the spread width of asphalt material. Uniformly cover the asphalt before rolling. Equip an d operate spreading equipment to provide complete coverage. Brooming, dragging or blading of the cover ma terial is prohibited before initial rolling. Perform any rearrangement of the cover material by hand methods. Avoid overlapping applications of cover material and remove all spillage from the surface. At the time of delivery to the roadway, the moisture content of the cover material shall not exceed 3% by weight plus ½ the water absorption of the aggregate. Do not let free moisture drain from the truck. The moisture limitations do not apply if lightweight aggregate is used. When directed by the Engineer, moisten the cover material with water to eliminate or reduce the dust coating of the aggregate. Pe rform the moistening the day be fore the aggregate is used. Any operation of equipment that resu lts in displacement of the cover materi al or damage to the seal course is prohibited.
h.Rates of Application of Cov er Material for First Seal Coat. When alternate types of cover material are shown in the Contract Documents, the quantities of aggregate and asphalt material are for the purpose of estimating and bidding only. Once the Contractor designates the alternate type of aggregate to be supplied, the total quantities to be used and paid for are determined by using the application rates in TABLE 608-1 . No change in the contract unit price will be made. The application rate shown in TABLE 608-1 may be changed with written approval from the Engineer. If the quantity of cover material computed from TABLE 608-1 exceeds the amount used on the roadway, the Engineer will designate a stockpile location for this excess quantity. Locate the stockpile along the project, or at locations requiring a haul distance no longer than the most distant end of the project. The maximum quantity of cover material to be stockpiled is as follows: The amount shown on the Contract Documents minus the amount used on the road when one type of cover material is shown in the Contract Documents. The amount determined by using the application rates in TABLE 608-1 minus the amount used on the road when alternate types of cover materi al are shown in the Contract Documents. 610 - DOUBLE ASPHALT SURFACE TREATMENT
600-59 The amount specified by the Engineer minus the amount used on the road when the Engineer changes
the application rates in TABLE 608-1 . Payment for the stockpiled material will be at the co ntract unit price per cubic yard of cover material.
i.Manipulation. Immediately following the application of cover material, embed using pneumatic rolling. Provide a sufficient number of pneumatic rollers to complete the initial roller coverage within 15 minutes after the application of cover material. Continue pneumatic rolling until a total of 7 complete coverages are obtained. Keep the speed of rollers such that aggreg ate displacement is minimized. Vary th e weight of the rollers to embed the cover material as shown in the Contract Documents. If emulsified asphalt is used, cure the asphalt material a minimum of 4 hours before opening the roadway to unrestricted traffic. If polymer modi fied emulsified asphalt is used, the cu re time shall be a minimum of 1 ½ hours before the traveled way is opened to unre stricted traffic. If traffic causes ex cessive chip loss, increase the cure time until excessive chip loss is eliminated. On seals using CM-A, B or E, the Engineer may require the use of a steel roller for one of the coverages, provided excessive crushing of th e cover material does not occur. Control the rolling sequence so it shall be unnecessary for one roller to turn out to permit another roller to pass. Do not turn rollers on the sealed surface. When required, apply additional cover material and roll it with the pneumatic rollers as directed by the Engineer. Provide self-propelled rollers. Broom the loose cover material from the surface of the traveled way as soon as the asphalt material has cured enough to prevent damage by brooming or vehicular traffic. Continue periodic brooming until all loose aggregate has been removed. Perform a minimum of 1 light brooming of the cover material before opening to traffic. Additional broomings may be required before opening to traffic to prevent the cover material from being picked up by moving vehicles. Broom excess cover material from the shoulder. The Contractor may seal in 1 lane for the entire day. When CM-B and cutback asphalt are specified in the Contract Documents, begin a second period of manipulation on the day following the first rolling, or as soon thereafter as weather conditions permit. This manipulation consists of spreading the loose cover material uniformly over the surface and rolling with the type of rollers specified by the Engineer. The rolling operation consists of 2 complete coverages of the previous day’s work. Following the second day’s rolling, broom excess cover material off the traveled way and shoulders, as directed by the Engineer.
j.Maintenance of First Seal Coat. When directed by the Engineer, add asphalt material and aggregate to completed portions of the project. All additional asphalt ma terial and aggregate so ordered will be included in the pay quantities. Spreading and rolling of additional aggregate will not be paid for separately but is considered as subsidiary to the item of "Manipulation (D.A.S.T.)". If the shoulder vegetation is not sufficient to define the edge of the traveled way, broom and blade the excess cover material off the shoulder to provide delineation.
k.Treatment of Adjacent Areas. When shown in the Contract Documents, seal the existing intersections and entrances, mailbox turnouts, etc. having asphalt surfaces. Seal all widened areas. Asphalt and cover material for this work is included in the contract quantities and will be paid for at the contract unit price.
l.Second Seal Coat. If the asphalt material consists of cutback asphalt, do not apply the second seal coat until 60 days after the application of the first seal co at, unless shown otherwise in the Contract Documents. Immediately prior to the second seal coat applicatio n, clean the surface of all foreign material, and broom to remove dust and excess cover material . Exercise care not to dislodge any cover material which is embedded in the asphalt material. Apply the sec ond seal coat according to the provi sions for the First Seal Coat in subsections 610.3f. thru i. Do not use brooms to shift the cover material until the initial rolling is complete, and until the asphalt material has sufficiently cured to hold the cover material. Perform any rearrangement of the cover material during the initial rolling by hand methods. Continue rolling until the en tire surface has been covered a minimum of 7 times with a pneumatic roller. Operate rollers at speeds which shall not displace the aggregate. 610 - DOUBLE ASPHALT SURFACE TREATMENT
600-60 m. Maintenance of Completed Work. Maintain the completed surface for a period of 5 days after the
project or portions of the project are open to traffic. If fo r reasons beyond the Contractor’s control, traffic can not be routed over the work upon completion of the project, maintain the surface for a period of 5 days after completion of the second seal coat. Maintenance consists of the following:
1.Make one, complete coverage each day of the 5 days after the project or porti ons of the project are open to traffic with a light blade equipped with broom drag followed by a pneumatic roller. If weather and roadbed conditions are such that the dragging and rolling would not be beneficial to the surface the daily dragging and rolling may be omitted with approval of the Engineer.
2.The application of additional asphalt material, aggreg ate, dragging and rolling or all of these operations may be required. Asphalt material and aggregate ordered by the Engineer used in the maintenance work will be included in the quantities of these materials for which payment is to be made. Additional manipulation required for the maintenance work will not be paid for separately, but will be considered as subsidiary work to the item of "Manipulation (D.A.S.T.)" included in the Contract Documents.
n.Treatment of Adjacent Areas. When shown in the Contract Documents, perform the second seal on the same areas as the first seal, including existing inters ections and entrances, mailbox turnouts, all widened areas etc. Asphalt and cover material for this work is incl uded in the contract quantities and will be paid for at the contract unit.
o.Maintenance of Traffic. Maintain traffic according to DIVISION 800 and the following. Coordinate all construction operations to result in the least practicable delay of traffic. Maintain one-way traffic and restrict traffic speeds to 30 MPH on bare pavement and 20 MPH on freshly applied seal. Use pilot cars to lead one-way traffic through the areas of distribution and curing. Coordinate the work so the pilot car completes a round trip in 15 minutes or less. Do not delay traffic at more than 2 separate locations of work on a project. Station one flagger immediately ahead of the ap plication of the asphalt material and one flagger immediately behind the section being cured. Move the signs and flaggers forward as the work progresses. Complete all brooming activities before opening the traveled way to unrestricted traffic. On projects where asphalt sealing is constructed in connection with other work from which traffic is detoured, the provisions of this subsection do not apply. Restrict the speed of all equipment traveling on the freshly applied seal to 20 MPH for 24 hours.
p.Seasonal and Weather Limitations.
1.Construct asphalt sealing using cutback asphalt between May 1 and October 15, when the ambient air temperature is 60ºF and rising.
2.Construct asphalt sealing using emulsified asphalt between June 1 and September 15, when the ambient air temperature is 60ºF and rising, and the pavement temperature is a minimum of 70ºF.
3.Construct asphalt sealing using asphalt cement between June 1 and September 1, when the ambient air temperature is 70ºF and rising, and the pavement temperature is a minimum of 80ºF. When aggregate retention is unsatisfactory, suspend sea ling. Do not seal when the surface is wet, or the weather is foggy or rainy. These limitations may be modified with written approval from the Engineer. If the seal is damaged or lost, due to rain or we t pavement, repair or re-seal the damaged pavement.
q.Pavement Smoothness. Double asphalt surface treatment is excl uded from profilograph testing, and not eligible for pay adjustments. 610.4 MEASUREMENT AND PAYMENT The Engineer will measure cover material by the cubic yard. The material will be measured in the vehicle at the time and place of unloading. No deductions will be made for moisture in the cover material. The Engineer will measure asphalt material by the ton. Deductions will be made for the number of tons that are not placed on the road surface. The Engineer will measure manipulation by the Station, along the centerline. On divided highways, the Engineer will measure manipulation by th e Station, along the centerline of each divided direction. This includes all widened and irregular areas and irregular variations in depth. The Engineer will measure ordered water by the M Gallo n by means of calibrated tanks or water meters.
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 295–297 of 978.