410BITUMINOUS SURFACE TREATMENT

New Hampshire Department of Transportation Standard Specifications – 2016 Description

1.1This work shall consist of preparing and applying one or more seal coats of bituminous material to a gravel or stone course.

This work shall also consist of a tack coat applied to a bituminous concrete surface or a Portland cement concrete surface. Materials

2.1Bituminous material shall be the type and grade specified or ordered and shall conform to the requirements of Section 702.

2.2Blotter material shall be natural sand composed of hard, durable particles, free from loam, showing uniform resistance to

abrasion. Gradation shall conform to Table 520-2. Construction Requirements

3.1Limitations. Bituminous material shall not be applied on a wet surface, or when weather conditions would prevent the proper

application and curing of the coat. The quantities, rate of application, temperatures, and areas to be treated shall be approved before application of bituminous material.

3.2Equipment.

Equipment required for this work shall be as follows:

applied uniformly on varia ble widths of surface up to 12 ft , at readily determined and controlled rates from 0.02 to 2.0 gal/yd2, with uniform pressure, and with an allowable variation from any specified rate not to exceed 0.02 gal. 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 with full circulation spray bars adjustable laterally and vertically. The spray bar shall contain spray nozzles providing a fan-shaped spray pattern adjusted so the vertical axis is perpendicular to the pavement surface. The spray pattern and spray bar height shall be adjusted to provide a uniform application of the tack coat without double coverage. The distributor shall be equipped with a mechanical device to adjust the spray height as material is discharged to keep a uniform height above the pavement for full coverage without overlapping. The distributors hall also be equipped with a hand-held spray attachment for applying the material to areas inaccessible to spray bars and to fill in irregular areas to provide full coverage. Approved sampling valves shall be installed in distributors and transport tank tr ucks to permit taking representative samples of the contents. The recommended location of the sampling valve is in the rear bulkhead of the tank roughly one-third of the height above the bottom. The inlet pipe shall project into the contained liquid as sho wn in AASHTO T 40. At least 1 qt of material shall be drained off through the sampling valve and discarded before the desired sample is taken. New sample containers will be furnished by the Engineer. To prevent the loss of solvents, containers shall be sealed with a tight fitting cover immediately after being filled.

bituminous material.

3.3Preparation of Surface to be Treated.

3.3.1 Tack coat. The existing surface shall be patched and shall be free of irregularities to provide a reasonably smooth and uniform surface to receive the treatment. Unstable corrugated areas shall be removed and replaced with suitable patching materials. The edges of existing pavements that are to be adjacent to new pavement shall be cleaned to permit the adhesion of bituminous materials.

3.4Application of Bituminous Material.

3.4.1 Tack coat. Bituminous material shall be uniformly applied with an approved applicator. When ordered, a pressure distributor shall be used. The tack coat shall be applied in such a manner as to offer the least inconvenience to traffic and to permit one-way traffic without pickup or tracking of the bituminous material. 3.4.1.1 A tack coat shall be applied immediately prior to placement of pavement. The rate of application of emulsified asphalt shall be between 0.02 and 0.08 gal/yd2, based on the application table below. The Engineer may further modify the rate depending on the relative absorbance and texture of the pavement surface.

New Hampshire Department of Transportation Standard Specifications – 2016

Existing Pavement Condition Application Rate in Gal/yd2 New HMA 0.02 – 0.04 Oxidized HMA 0.04 – 0.06 Milled HMA 0.04 – 0.08

3.5Seal Coat.

3.5.1 When directed, a seal coat shall be applied at the rate in gallons per square yard specified on the plans or as ordered. 3.5.1.1 Bituminous material shall be applied to the width of the section to be sealed by means of a pressure distributor in a uniform, continuous spread. When traffic is maintained, not more than one half of the width of the section shall be treated in one application. Care shall be taken that the application of bituminous material at junctions is not in excess of the specified amount. Excess material shall be squeegeed from the surface. Skipped areas or deficiencies shall be corrected. 3.5.1.2 When traffic is maintained, one-way traffic shall be permitted on the untreated portion of the roadbed. As soon as the bituminous material has been absorbed by the surface and no longer picks up, traffic shall be transferred to the treated portion, and the remaining width of the section shall be sealed. 3.5.2 Blotter material at the rate ordered shall be applied before the bitumen has set; the entire treated surface shall be dragged , rolled and maintained. The remaining blotter material shall be removed.

3.6Finished Appearance.

3.6.1 Any bituminous material splashed or sprayed onto exposed surfaces of curbs, sidewalks, or other masonry structures shall be removed by sandblasting at the Contractor's expense. Method of Measurement

4.1Bituminous surface treatment will be measured by the ton, in accordance with 109.01, to the nearest 0.1 ton.

4.1.1 Blotter material furnished will be subsidiary.

4.2Asphalt emulsion for tack coat will be measured by the gallon, in accordance with 109.01, to the nearest gallon.

4.2.1 The measurement will be based on a calibrated meter mounted on the distribution vehicle or calibrated tank chart. The meter shall be calibrated at least twice per year. Measurement will be at the delivered temperature (no adjustment). Basis of Payment

5.1The accepted quantities of bituminous surface treatment will be paid for at the Item Bid Price per ton for bituminous material,

complete in place.

5.2The accepted quantities of asphalt emulsion for tack coat will be paid at the Item Bid price per gallon, complete in place.

5.2.1 Emulsified asphalt for tack coat required under 401.3.10.10 will not be subject to price adjustment.

5.3Payment for patching existing pavements under 3.3.1 will be made at the contract unit price for Item 403.11 or 411.1, as

ordered. Pay items and units:

410.22Asphalt Emulsion for Tack Coat Gallon

410.31Asphalt Surface Treatment Including Blotter Material Ton

410.41Emulsified Surface Treatment Including Blotter Material Ton

New Hampshire Department of Transportation Standard Specifications – 2016

Description

This work shall consist of a leveling course when ordered and one or more courses of bituminous mixture constructed on an

existing pavement.

1.2This work when specified shall consist of a dual purpose single course bituminous mixture which acts as a shim course and

a wearing course constructed on an existing pavement. Materials

Materials and their use shall conform to the requirements of 401.2 as amended below:

2.1.1 Asphalt binder PG grade to be used for a particular project will be specified in a Special Provision contained in the Proposal. 2.1.2 Unless a volumetric mix design has been p erformed by the Contractor, the composition of the mixtures shall conform to historical gradation and binder content. Leveling course, AC Paver Shim, Paver Spot Drag Shim, and 3/4” PMST shall be Type H unless otherwise noted.

Table 411-1 - Composition of Mixtures - Master Ranges Plant Mixed Surface Treatment Type H 3/8” Sieve Size Percentage by Weight Passing Min Desired Max 3/8” 95.0 100 100 No. 4 70.0 77 84.0 No. 8 54.0 59 65.0 No. 16 35.0 43 51.0 No. 30 20.0 28 36.0 No. 50 10.0 15 20.0 No. 100 5.0 8 11.0 No. 200 2.0 4 6.0 Percentage of Total Mix Asphalt Cement 6.25 6.7 7.25

2.1.3 Blotter materials shall be sand conforming to the requirements of Table 411-2. Table 411-2 -- Blotter Material Sieve Size Percent by Weight Passing No. 4 100 No. 10 70 - 92 No. 200 0 - 6 Construction Requirements

Mixing plants shall be as prescribed in 401.3.1.

Mixing and storage shall conform to 401.3.1.6.11, 401.3.6, and 401.3.7 with the following modifications:

3.2.1 If the aggregate contains sufficient moisture to cause foaming in the mixture, it shall be re moved from the bins. The quantity of cold aggregate fed to the dryer shall be governed by the ability of the dryer to remove the moisture completely f rom the aggregate, as determined by the Engineer.

Weighing and hauling shall conform to 401.3.8.

Placing shall conform to 401.3.10 with the following modifications: