Item mo-622 crack and joint sealing-bituminous pavement description 622 1




Yüklə 16.14 Kb.
tarix13.04.2016
ölçüsü16.14 Kb.
ITEM MO-622 CRACK AND JOINT SEALING-BITUMINOUS PAVEMENT
DESCRIPTION
622-1.1 This item shall consist of routing, heat lancing,, and sealing the existing transverse and longitudinal cracks and joints and random cracks in bituminous pavements in accordance with these specifications and in reasonably close conformity with the details shown on the plans.
The quantity shown is for bidding purposes and has been approximated. Actual payment for the work will be determined by field measurements of the work completed. The Engineer will determine the cracks and joints to be filled.

MATERIALS



622-2.1 SEALANT MATERIAL. The sealant material shall be a hot pour elastimeric type conforming to the requirements of ASTM D 6690 Type II, together with the following modifications:


Cone Penetration at 77oF (25oC), 150 g, 5 sec

50 – 90

Flow at 140oF (60oC), 75 degree angle, 5 hrs

5 mm

Bond at 0oF (-18oC), 100 percent extension, ½” (12.7mm) thick specimen

Pass 5 cycles

Resilience at 77oF (25oC)

25 - 60

Storage, heating instructions, and cautions shall be printed on each box of sealant. The sealant must be able to be reheated to application temperature at least once after the initial heat up without degradation of sealant specifications. Sealant shall have an application life at application temperature of approximately 12 to 15 hours.


622-2.2 MATERIAL ACCEPANCE. Prior to the use of the sealant material, the contractor shall submit to the Engineer, the appropriate material certification or laboratory test indicating that the material meets specification requirements. If the contractor applies the material prior to receipt of the test reports, payment for the material shall be withheld until they are received. If the material does not pass the specification it shall be replaced at the contractor’s expense.
The Engineer may request samples for testing, prior to and during production, to verify the quality of the materials and to ensure conformance with the applicable specifications.

CONSTRUCTION METHODS



622-3.1 WEATHER LIMITATIONS. The sealant material shall not be applied when the weather is foggy, rainy or when the ambient and pavement temperatures are below 40 F.
622-3.2 EQUIPMENT. All machines, tools and equipment used in the performance of work required by these specifications will be subject to the approval of the Engineer and maintained in a satisfactory working condition at all times.


  1. Router: The routing machine shall be an impact router equipped with carbide-tipped vertical-sided bits. It shall be portable and capable of routing existing asphalt surfaces along and adjacent to the crack and joint. The unit shall be capable of following random cracks and be designed to adjust the cutting widths. The unit shall be equipped with a cutter head clutch and shall have an adjustable depth control.




  1. Hot Compressed-Air Lance (HCA): The HCA shall be capable of producing air temperature up to 2500oF and constructed of suitable hardware. It shall be provided with separate valves to control propane, burner air, and lance air. The fuel and burner air shall be mixed only at the point of combustion before leaving the burner tube. A separate air lance tube shall pass inside the burner chamber and be orificed to a maximum 1/4”. At the fuel source, a high-pressure regulator to control fuel pressure from 5 PSI to 30 PSI and to prevent flashback shall be used. Burner BTU should range from 20,000 to 500,000 BTU. A wheel kit constructed to keep the unit at the proper height and angle from the pavement should be used. No external flame shall be allowed to touch the pavement.




  1. Hot-Applied Sealant Applicator (melter): The melter applicator unit shall be a self-contained double boiler device with the transmittal of heat through a heat transfer oil. It must be equipped with an onboard automatic heat-controlling device to permit the attainment of a predetermined temperature, then maintain that temperature as long as required. The unit shall have a means to vigorously and continuously agitate the sealant. The sealant shall be transferred from the unit to the crack by means of a direct-connected feed hose and wand. The equipment should be designed to allow the sealant to be circulated back into the unit when sealing is not being performed or equipped with a temperature controlled heated hose and wand that does not required circulation. The sealant should not be heated to a temperature in excess of that specified by the manufacturer.


622-3.3 PREPARATION OF CRACKS AND JOINTS. All open cracks and joints from 1/4” to 1-1/4” shall be routed to remove at least 1/8” from each sidewall. This will result in a minimum reservoir width of 1/2” to a maximum reservoir width of 1-1/2”. The depth of the routing shall be approximately a one to one ratio (width to depth), subject to the discretion of the Engineer. Cracks wider than 1-1/2” shall be repaired in accordance with the details shown on the plans or as directed by the Engineer.
No sealant shall be installed until all cracks and joints have be cleaned free of all deleterious materials, including any dust, old sealant, incompressibles, and organic material*, and are sufficiently dry. Following the initial routing and cleaning operation, all cracks and joints shall be HCA lanced within 10 minutes of application of the sealant. Equipment for the two operations should be kept in a compact configuration such that not more than 50 feet separates equipment required by the two operations. Extreme care shall be used to ensure the crack sidewalls do not become overheated and burned.
*When vegetation exists in the cracks and joints, it shall be removed and those cracks and joints shall be treated with a herbicide that sterilizes the soil subject to the approval of the Engineer.
622-3.4 APPLICATION OF CRACK AND JOINT SEALANT. No sealant material shall be installed until all cracks and joints to be sealed have been inspected and approved by the Engineer. The sealant shall be applied in the crack or joint reservoir uniformly from the bottom to the top and shall be filled without formation of entrapped air or voids. Pouring pots or gravity-fed sealant applicators shall not be used for sealing cracks and joints. Joints and cracks shall be filled flush with the surface and any overfill shall be squeegeed so that the overband cap does not exceed 1/16” above the surface and the width does not exceed 2” beyond the crack edges. All overbanding shall be kept to a minimum. After the sealant has cooled, settling shall not exceed 3/8” below the surface.
622-3.5 PAVEMENT CLEANING AND PROTECTION. The pavement surface and all work areas shall be left in a clean condition. Vehicular traffic shall not be permitted on the pavement in the areas of the treated cracks and joints during the curing period. The contractor shall supply all temporary traffic control devices (barricades, cones, signing, etc.) to protect the sealant, as required and approved by the Engineer. Any damage to uncured sealant shall be repaired at the contractor’s expense.

METHOD OF MEASUREMENT



622-4.1 The length of crack and joint sealing to be paid for shall be the number of lineal feet of crack and joint sealing completed in place and accepted.

BASIS OF PAYMENT



622-5.1 Payment shall be made at the contract unit price per lineal foot of crack and joint sealing. This price shall be full compensation for furnishing all materials, for all preparation, and placing of the material, and for all labor, equipment, tools, and incidentals necessary to complete this item.
Payment will be made under:
Item MO-622-5.1 Crack and Joint Sealing (MO-622)--per linear foot

Rev. 02/01/05


Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©azrefs.org 2016
rəhbərliyinə müraciət

    Ana səhifə