SECTION 410
SECTION 410 -- BITUMINOUS SURFACE TREATMENT
Description
Materials
Construction Requirements
3.2 Equipment.
3.3 Preparation of Surface to be Treated.
3.4 Application of Bituminous Material.
3.5 Seal Coat.
3.6 Finished Appearance.
Method of Measurement
Basis of Payment
Description
1.1 This 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
2.1 Bituminous material shall be the type and grade specified or ordered and shall conform to the requirements of Section 702.
2.2 Blotter 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
3.1 Limitations. 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.
3.2 Equipment.
Equipment required for this work shall be as follows:
(a) A distributor shall be so designed, equipped, maintained, and operated such that bituminous material at even heat may be
applied uniformly on variable widths of surface up to 12 ft, at readily determined and controlled rates from 0.02 to 2.0
gal/yd?, 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 distributor shall 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 trucks 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 shown
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.
(b) A rotary power broom for sweeping treated surface.
(c) A steel-wheeled roller.
(d) A self-propelled pneumatic-tired roller.
{e) A sand spreader capable of spreading blotter material in sufficient quantity to prevent traffic pickup of the applied
bituminous material.
(f) A steel-brush drag of an approved type.
3.3 Preparation 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.
2016 NHDOT
Go To=) TOC Division 100 Division 200 Division 300 Division 400 Standard
Division 500 = Division 600 = Division 700 Specifications
