SECTION 409 - GEOTEXTILE FABRIC FOR UNDERSEAL
409.01 Description . This work consists of furnishing and placing fabric underseal in
accordance with the details shown on the plans and the requirements of these specifications. An underseal shall consist of an application of asphalt cement covered with a layer of fabric.
409.02 Materials .
409.02.1 Geotextile Fabric . The fabric shall meet the specific requirements for
geotextile fabric underseal contained in Subsection 714.13.4 and the applicable requirements of Subsection 714.13.
409.02.2 Bituminous Material . Unless otherwise designated, the asphalt sealant shall
be asphalt cement Grade PG 67 -22 meeting the applicable re quirements of Section 702.
409.03 Construction Requirements .
409.03.1 Equipment . The Contractor shall provide equipment for heating and applying
bituminous material and for laying the pavement fabric. Heating equipment and distributors shall meet the requirements of Subsection 410.03.3. The mechanical fabric laydown equipment shall be capable of handling full rolls of fabric and shall be capable of laying the fabric smoothly without excessive wrinkles and/or folds. When manual laydown is required, a length of standard one inch pipe and suitable roll tension devices shall be used for proper roll handling. The fabric manufacturer or distributor shall furnish a technician to supervise installation of the fabric and training of Contractor's personnel.
409.03.2 Surface Preparation . The surface to be treated, and at least one additional
foot on each side, shall be cleaned by sweeping, blowing, or other methods until all dust, dirt, mud, vegetation, and foreign materials are removed entirely from the pavement before the asphalt sealant is applied. Care shall be exercised to prevent material so removed from becoming mixed with subsequent courses.
409.03.3 Application of the Asphalt Sealant . The application of the asphalt sealant
shall conform to the applicable requirements of Section 410. The sealant shall be uniformly sprayed over the area to be covered by fabric at a rate recommended by the fabric manufacturer or distributor's technician and/or ordered by the Engineer. The rate of application is usually between 0.20 and 0.40 gallon per square yard. Varying surface conditions such as the degree of porosity of the existing pavement will cause varying application rates. The quantity applied shall be sufficient to bond and saturate the fabric, and to bond the subsequent overlay course to the fabric. Within intersections or other zones where vehicle braking is frequent, the application rate should be reduced. The sealant shall be applied to an area two to six inches wider than the width of fabric being placed, but restricted to the area of immediat e fabric laydown. Application shall be by distributor spray bar with hand hose spraying allowed only where the distributor spray bar cannot be used. Asphalt leakage from the distributor and any spillage shall be cleaned from the road surface to avoid flus hing and possible fabric movement at these asphalt rich areas. The asphalt cement used as a sealant shall have distributor tank temperature between 300°F and 350°F, except when applying a tack coat to the fabric, the temperature shall not exceed 320°F to avoid damaging the fabric.
409.03.4 Fabric Placement . The fabric shall be placed on the asphaltic sealant as soon
as practical and before the adhesion properties of the sealant is lost. The fabric shall be placed as smoothly as possible to avoid wrinkles. Wrinkles severe enough to cause "folds" shall be slit and laid flat. Small wrinkles which flatten under compaction are not detrimental to performance. The fabric shall be broomed or squeegeed to remove air bubbles and make complete contact with the road surface as recommended by the fabric manufactur er or distributor. The fabric shall be laid straight, however moderate curves can be negotiated by stretching the fabric on the outside of the curve. Longitudinal and transverse joints shall be made by overlapping the fabric at least six inches. Additional sealant shall be applied to the joints as required and may be applied by hand hose spraying or with mop and bucket if extreme care is taken to not over apply. Transverse joints should be "shingled" in the direction of construction traffic and paving to prevent pick-up. In circumstances where this method is impractical, asphalt pavement or sand spread over the joint will aid in prevention of pick-up. When recommended by the manufacturer or distributor's technician and/or ordered by the Engineer, the fabric shall be rolled with a pneumatic roller to improve bonding and reduce slippage.
409.03.5 Treatment of Fabric Prior to Overlay . Normally it is not necessary to tack
coat the fabric unless there are circumstances such as delay in placement of subsequent course, dust accumulation or insufficient ini tial application of sealant which would make tack coating desirable. If a tack coat is re quired by the Engineer, emulsified asphalt shall be applied at a rate of 0.02 to 0.05 gallon of residual asphalt per square yard. Placement of the subsequent course shall closely follow fabric laydown. In the event that the sealant bleeds through the fabric, it may be necessary to blot the sealant with sand to prevent construction equipment from picking up the fabric. Turning of the paver and other vehicles must be gradual to avoid strippage or damage to the fabric. If traffic must be maintained on the fabric prior to placement of the subsequent course, it is advisable to spread a small quantity of sand over the fabric and roll with a pneumatic roller to prevent tires from picking up the fabric. If rain should cause a blistered appearance and bond loss, it shall be corrected by rolling with a pneumatic roller.
409.03.6 Asphalt Pavement Overlay . The overlay shall conform to Sections 401 and
403 except that the mixture shall be delivered to the paver at a temperature of 275°F to 300°F. Temperature of the mix shall in no case exceed 325°F.
409.04 Method of Measurement . Geotextile fabric for underseal, placed in accordance
with these specifications and as directed by the Engineer, will be measured by the square yard of surface area. Any overwidth of material installed and additional material required for laps will not be measured. Asphalt cement for fabric underseal, applied in accordance with these specifications and as directed by the Engineer, will be meas ured by the gallon in accordance with Subsections 109.01 and 410.04. Any blotting with sand, rolling to restore bond and application of a tack coat will not be measured for payment and is considered incidental to completion of the work.
409.05 Basis of Payment . Geotextile fabric for underseal will be paid for at the
contract unit price per square yard. Asphalt cement for fabric underseal of the kind and grade specified, measured as provided above, will be paid for at the contract unit price per gallon. These prices shall be full compensation for satisfactorily completing the work. Payment will be made under: 409-A: Geotextile Fabric for Underseal, Type * - per square yard 409-B: Asphalt Cement for Fabric Underseal - per gallon * When not designated, see Subsection 714.13. SECTION 410 - BITUMINO US SURFACE TREATMENT
410.01 Description . This work consists of the construction of a single layer bituminous
surface treatment (chip seal) in accordance w ith these specifications and in reasonably close conformity with the lines shown on the plans or established by the Engineer. 410.02--Materials .
410.02.1 Bituminous Material . The type and grade of bituminous materials will be
specified in the contract and shall conform to the applicable requirements of Section 702. 410.02.2--Cover Material . Cover material shall meet th e applicable requirements of Subsection 703.14, and the kind and type will be specified in the contract. Only one type of aggregate or combination of aggregates shall be used on a particular project except with written permission of the Engineer. Sites for stockpiles of materials shall be grubbed and cleaned prior to storing the aggregates, and the ground shall be firm, smooth, and well drained.
410.03 Construction Requirements .
410.03.1 General . Prime coats, when specified, sha ll meet the requirements of Section
408. After the application of a prime coat, the primed surface shall be kept in continuous repair. All holes, raveled areas, and areas deficient in prime shall be patched and repaired with approved materials.