410.01 Micro Surfacing
E.Tack Coat Apply a tack coat in accordance with Section 407, “Fog Seal and Tack Coat” if required by the Contract . The Resident Engineer will approve the bituminous material type, grade, rate of application, and temperature. Do not use cutback asphalt or emulsified asphalt that contain petroleum distillate.
F.Pavement Overlay Place the pavement overlay immediately after placing the fabric, unless directed otherwise by the Resident Engineer. Ensure the pavement overlay temperature does not exceed 325 °F [163 °C] to prevent damage to the fabric. To avoid damaging the fabric, minimize turning movements. If necessary, turn pavers and vehicles gradually and broadcast clean, dry sand ahead of trucks and pav ers to prevent fabric damage. Remove excess sand ahead of paving operations. Repair damage to or debonding of the fabric reinforcement caused by traffic, wet weather conditions, improper installation, or equipment, at no additional cost to the Department.
409.05 Method of Measuremen T
The Resident Engineer will measure the area covered by Fabric Reinforcement after placement, not including overlaps.
409.06 Basis of Payment
The Department will pay for each pay item at the contract unit price per the specifie d pay unit as follows: Pay Item: Pay Unit:
A.FABRIC REINFORCEMENT Square Yard [Square Meter]
B.BITUMINOUS BINDER Gallon [Liter] Include the cost of the tack coat and sand used for blotting in the contract unit price for Fabric Reinforcement .
410.01 Description
This section covers the materials, equipment, construction and application procedures for placing Micro Surfacing material , filling ruts , and surfacing existing paved surfaces. The Micro Surfacing shall be a mixture of a polymer -modified asphalt emulsion, 100 percent crushed mineral aggregate, mineral filler, water and other additives for control of set time in the field. All ingredients shall be properly proportioned, mixed and spread on the paved surface in accord ance with this Specification and as directed by the Engineer. MICRO SURFACING 410.03
410.02 Materials
Provide materials in accordance with Section 707 “Thin Surface Courses.”
A.Aggregate Storage Handle mineral aggregate in such a manner as to prevent segregation, mixing of the various materials or sizes, and contamination with foreign materials. The grading of aggregates proposed for use and as supplied to the project shall be uniform. Suitable equipment of acceptable size shall be furnished by the Co ntractor to maintain the stockpiles and prevent segregation of aggregates. The aggregate shall be passed over a scalping screen immediately prior to transfer to the Micro Surfacing mixing machine to remove oversized material.
B.Storage of Bituminous Ma terial Provide bituminous storage capacity of adequate to meet the requirements of the production rate. Keep a ll equipment used in the storage and handling of bituminous material in a clean condition at all times and operate in such a manner that there is no contamination with foreign matter.
410.03 Equipment
Submit all equipment, tools, and machines used in the performance of this work to the engineer for approval . Do not attempt any work with equipment that is malfunctioning. The Engineer may order tha t the work be discontinued if sufficient equipment and tools are not in use to place the materials satisfactorily.
A.Mixing Equipment Blend paving mixture with a self -propelled, positive, non -slipping aggregate delivery system (belt over chain) Micro Su rfacing mixing machine . Ensure the machine has a continuous flow mixing unit able to accurately deliver and proportion the aggregate, polymer modified emulsion, mineral filler, field control additives and water to a revolving multi -blade, twin shafted mix er and discharge the mixed product on a continuous flow basis. Thoroughly blend the mixture so no uncoated aggregate is visible upon discharge from the mixing unit. Ensure t he machine has self-loading material devices to allow continuous Micro Surfacing, thereby minimizing construction joints. Use a machine equipped with opposite side driving stations to optimize longitudinal alignment. Use a machine equipped to allow the operator to have full hydrostatic control of the forward and reverse speed during the application of the Micro Surfacing material. Continuous -run equipment will be required to ensure continuity of mix and reduction of start -up joints. In some cases and with the Engineer’s approval, truck mounted units may be used for short narrow roadw ays, crossovers , and irregular areas. Ensure truck mounted units are equipped with a positive, non-slipping aggregate delivery system (belt over chain) and have the capability of applying a minimum of 10 tons of aggregate without recharging the aggregate bin.
1.Water Pressure System Use a mixing machine equipped with a water pressure system and nozzle type spray bar to provide a water spray ahead of and outside the spreader box when required
410.04 Micro Surfacing
2.Calibration & Proportioning Devices Use a machine eq uipped with individual volume or mass controls or other gauging devices for measuring and proportioning each material added to the mix. Calibrate, properly mark, and positively interlock each material control device . Equip t he aggregate feed to the mixer with a revolution counter or similar device so that the amount of asphalt emulsion, aggregate and mineral filler used may be determined at any time. Calibrate e ach mixing unit prior to commencement of the work. Perform calibrations and verif y in the presence of the Engineer or the Engineer’s representative. Once calibrated, any aggregate and emulsion flow change s require the approval of the Engineer. The water and additive may be adjusted in the field to control the mix properties to produce an acceptable mix. With the Engineers approval, previous calibration documentation covering the exact materials to be used may be acceptable provided they were made within the last three (3) months.
3.Emulsion Pump Use a heated positive displacement type emulsion pump. Ensure the machine has a hydraulically adjustable (adjustable while applying mixture) type spreader box and positive screed adjustment for yield control. Attach a box to the mixer equipped with ribbon flights mounted on an adjustable s haft to continually agitate and distribute the material throughout the box. Provide a box equipped with curb bumpers and replaceable runners with a minimum of 5 -foot long end runners. Ensure t he box is equipped with a sufficient walkway to provide acces s to either side of the spreader box without walking through the freshly applied material. The box must be capable of laying mix to a width of 14 feet. The equipment must provide sufficient turbulence to prevent the mix from setting in the box or causing excessive build -up or lumps. To prevent the loss of mixture from the box, attach flexible seals, front and rear, in contact with the road. Use a full width application box equipped with a secondary strike -off located approximately 2 to 3 feet behind the primary strike -off to minimize transverse corrugations. Ensure t he secondary strike -off has elevation and width adjustments similar to the primary strike - off, and has a pivot point where it can be tilted for texturing or raised completely off the surface . The use of burlap drags or other drags necessary to obtain the desired surface texture, must be approv ed by the Engineer. Replace d rags that have excessive build -up. Keep drags in a completely flexible condition at all times.
B.Auxiliary Equipment Provide s uitable surface cleaning equipment, barricading equipment, hand tools and other support equipment as necessary to perform the work.
410.04 Construction Methods
Produce, transport , and place the specified materials in accordance with these specific ations and as approved by the Engineer. Provide a finished micro s urfacing with a uniform texture free from excessive scratch marks, tears , or other surface irregularities. Ensure t he cured mixture adhere s fully to the underlying surface. Based upon a visual examination or test results , the Engineer may reject any work due MICRO SURFACI NG 410.04 to poor workmanship, loss of texture, raveling or apparent instability. Repair a ny areas found to be deficient at the discretion of the Resident Engineer and at no additional cost to the Department.
A.SEASONAL AND WEATHER LIMITATIONS Do not apply Micro Surfacing when weather conditions prolong opening to traffic beyond a reasonable time. Spread t he Micro Surfacing mixture only when both the pavement surface and the ambient temperature is at least 50°F and rising , the weather is not foggy or rainy , and there is no forecast of temperatures below 32°F within 48 hours from the time of placement. Paving over ponded water is not allowed. Pond ed water may be broomed prior to placement.
B.SURFACE PREPARATION Thoroughly clean the area to be surfaced to remove vegetation, loose aggregate and soil. Protect manholes, valve boxes , and other service entrances from the surfacing material. Unless ot herwise directed by the Engineer, pre -wetting of the surface will be required. Spray water ahead of and outside of the spreader box at a n acceptable rate to dampen the surface without any free flowing water ahead of the spreader box.
C.TACK COAT Normally , tack coat is not required unless the surface to be covered is extremely dry and raveled or is concrete or brick. Apply tack coat at a rate of 0.05 -0.15 gal/yd2 [0.23 -0.68 L/m²] of diluted emulsion diluted at 3:1 water to original emulsion. Allow t he ta ck coat to set sufficiently before the application of Micro Surfacing. If a tack coat is to be required, it must be noted in the project plans.
D.APPLICATION
1.General Construct a minimum 500 ft. length test strip for approval by Resident Engineer. Fog spray the surface with water ahead of the spreader box when local conditions warrant . The rate of application of the fog spray may be adjusted as the temperature, surface texture, humidity, and dryness of the pavement change. The fogging operation shall b e used to dampen the existing pavement surface and no ponding of water is permitted. Screening aggregates at stockpile is required to eliminate oversize materials in the mix. Fill ruts, utility cuts, and depressions in th e existing surface with prelimina ry Micro surfacing material where indicated and before final surface course is place d. Ruts greater than ½ in. in depth must be filled independently with a rut filling spreader box , either 5 ft or 6 ft in width. For irregular or shallow rutting ½ in. or less in depth, a leveling course may be used as directed by the Engineer. Use the same spreader box for the leveling course as used for the surface course . However, use a steel or high density strike -off in lieu of a flexible rubber. Using a rut fill spr eader box, crown each individual rut fill to compensate for traffic compaction at a rate of 1/8 in. per 1 in. of rut depth. Place r ut filling and open to traffic a minimum of 24 hours prior to surfacing. All materials, mixture composition, equipment, and construction procedures and requirements must be as specified above.
410.04 Micro Surfacing
Ensure the Micro Surfacing is the appropriate consistency upon leaving the mixer. Carry a sufficient amount of material in all parts of the spreader at all times to obtain complete cov erage. Avoid overloading the spreader box. Lumpy or unmixed aggregate will not be permitted. Do not use aggregate either spilled from the lay -down machine or existing on the road. Do not leave streaks in the finished surfaces, and do not allow excess bu ildup, uncovered areas, or unsightly appearance on longitudinal or transverse joints. Provide suitable width spreading equipment to produce minimum number of longitudinal joints throughout project. Place longitudinal joints on lane lines. Use partial w idth passes only when necessary. Do not use partial width passes as the last pass of any paved areas. Provide a maximum overlap of 3.0 in for longitudinal joints. Provide maximum difference in joint elevation of 0.25in [6.4mm] when measured by placing a 10ft [3m] straight edge over the joint and measuring the elevation difference.
2.Mixture Use Micro Surfacing of sufficient stability so that premature breaking of the material in the spreader box does not occur. Provide a homogeneous mixture during and following mixing and spreading , that is free of excess liquids . Do not spray additional water into the spreader box.
3.Handwork For s urface a reas which cannot be accessed by the mixing machine , use hand squeegees to provide complete and uniform coverage . Lightly dampen the area to be hand worked , if necessary , prior to mix placement. For handwork , exhibit the same finish as that applied by the spreader box as much as possible . Complete a ll handwork prior to final surfacing.
4.Lines Provide straight l ines at intersections, curbs, and shoulders to yield a good appearance. Mask off the end of streets , if necessary , to provide a straight line. Longitudinal edge lines shall not vary by more than ± 2 in. [± 51 mm] horizontal variance in any 96 ft [29 m] of length.
5.Cleanup Remove micro surfacing in a ll utility access areas, gutters and intersections as specified by the Resident Engineer. Remove all debris associated with the performance of the work on a daily basis.
E.AGGREGATE APPLICATION RATE Control the spread rate for all full width Micro Surfacing , not intended as a leveling course , to within plus or minus two pounds per square yard of spread rate based on the weight of dry aggregate . Provide a f ull width spread rate of 18 pounds (for Type I) and 2 5 pounds (for Type II) per square yard , unless otherwise approved by the Resident Engineer . A five -percent (5%) reduction in unit price will be applied for each pound of aggregate per square yard outside the spread rate tolerances established above for ea ch day’s placement of material. In lieu of pay reduction, the Contractor may elect to overlay the deficient area at no additional cost to the Department. Do not c ontinue operation and placement of materials outside the spread rate tolerances. Make adjus tments as necessary in the placement operation to maintain production within the tolerances given. HOT MIX ASPHALT / WARM MIX ASPHALT 411.02
410.05 Method of Measuremen T
The Resident Engineer will measure completed Micro Surfacing as the relevant mineral aggregate pay item, by the dry weight (including mineral filler) , and as Polymer -Modified Emulsified Asphalt by the volume or weight of the original emulsion. When payment for Micro Surfacing is to be by the ton of aggregate, including mineral filler, and gallon of asphalt emulsion, provide certified scales capable of providing an automated ticket printout for each truck load of material delivered to the Micro Surfacing machine. Include the project number, ticket number, truck number, date and batch weight of material loaded on each ticket . Subtract the unused portion of emulsion from the total of the bill of ladings to determine total emulsion to be paid.
410.06 Basis of Payment
The Department will pay for each pay item at the contract unit price per the specified pay unit as follows: Pay I tem: Pay Unit:
A.POLYMER -MODIFIED EMULSIFIED ASPHALT Gallon [Liter] or Ton [Metric Ton]
B.TYPE I MINERAL AGGREGATE Ton [Metric Ton]
C.TYPE II MINERAL AGGREGATE Ton [Metric Ton]
D.TYPE III MINERAL AGGREGATE Ton [Metric Ton] SECTION 411 HOT MIX ASPHALT / WARM MIX ASPHALT
411.01 Description
This work consists of constructing one or more courses of bituminous mixture on the prepared foundation (roadbed or base). Asphalt mixture includes Hot Mix Asphalt and Warm Mix Asphalt. Hot Mix Asphalt (HMA) includes Superpave, Stone Matrix Asphalt (SMA), and Rich Bottom Layer. Warm Mix Asphalt (WMA) is defined as an asphalt binder and aggregate mixture which, by additive or process, can be produced and placed at a reduced temperature from normal HMA temperatures. WMA requirements are the same as for HMA except where noted.
411.02 Materials
Provide asphalt materials in accordance with Section 708, “Plant Mix Bituminous Bases and Surfaces.”
Source: Oklahoma Standard Specifications for Highway Construction, 2019 Edition. Pages 246–250 of 935.