483POLYMER-MODIFIED EMULSIFIED ASPHALT PAVING SYSTEM (MICRO SURFACING)

(MICRO SURFACING)

483.1DESCRIPTION —This work is the construction of a polymer -modified emulsified asphalt paving

system, commonly known as micro-surfacing, to fill ruts and/or resurface existing pavements. Micro-surfacing material is classified into three mix types as follows:

course or surface seal. Use a double application, when specified, to meet total design pounds per square yard for surface courses.

course, a seal coat, or a surface treatment. Use a double application, when specified, to meet total design pounds per square yard for surface courses.

483.2MATERIAL—

approved producer and source listed in Bulletin 15 and provide quality control testing and certification as specified in Sections 106.03(b) and 702.1(b)1.

cures fast enough to allow traffic to be placed on the pavement within 1 hour, without damaging the surface.

Type B or better meeting the quality requirements of Table A, Section 703.1(c) and coarse aggregates meeting the quality requirements of Table B, S ection 703.2(a). The final gradation must meet the final gradation specified in Table A of this specification. For wearing courses, provide aggregate with at least the SRL designation specified. To achieve the specified SRL, the Contractor may provide a blend of two aggregates if the blend has an SRL designation equal to or better than that specified. Blends are 50% by weight of each aggregate. Blend the aggregates using an approved method.

sieve, as specified in Section 703.1(c)1 consisting of any approved, non- air entrained, Type 1, Portland cement free of lumps or hydrated lime as specified in Section 723.1.

ambient environmental conditions.

that the total aggregate and filler in the JMF conform to the composition by weight percentages specified in Table A. Perform the tests identified in Table B for each mix design and provide the test results to document each mix design's characteristics. Submit a certified mix design(s) using a Micro-Surfacing Mix Design and Materials Analysis Form TR-483 to the DME/DMM at least 2 weeks before its use in the work. Clearly show for each mix design the proportions of aggregate, filler, percent polymer-modified emulsified asphalt and asphalt residue, based on the dry weight of the aggregate, and the design cure time. Ensure all the materials used in the mix design represent the materials proposed for use on the project. If minor adjustments are required during construction, based on field conditions, provide the changes in writing to the Representative.

start of the project and at least annually thereafter. Include the number of applications and the mix design used with each application in the QC Plan. Do not start work until the QC Plan has been reviewed and the JMF has been submitted. When unsatisfactory results or other conditions make it necessary, a new JMF may be required. If a change in sources of materials is made, submit a revised JMF to the DME/DMM before using any new material.

TABLE A SIEVE SIZE COMPOSITION, TOTAL PERCENT BY MASS (WEIGHT PASSING) TYPE A TYPE B TYPE RF 12.5 mm (1/2 inch) 100 100 100 9.5 mm (3/8 inch) 100 95 - 100 90 - 100 4.75 mm (No. 4) 85 - 100 65 - 85 55 - 75 2.36 mm (No. 8) 50 - 75 46 - 65 40 - 55 1.18 mm (No. 16) 40 - 65 28 - 45 24 - 40 600 µm (No. 30) 25 - 45 19 - 34 19 - 34 300 µm (No. 50) 13 - 25 10 - 23 10 - 20 75 µm (No. 200) 5 - 15 5 - 15 5 - 15 Note: Material finer than the 75 µm (No. 200) sieve will be determined as per PTM No. 100.

TABLE B MICRO-SURFACING MIX DESIGN PROPERTIES Property Test Method Test Requirements Wet Cohesion: ISSA TB 139 30 Minutes ISSA TB 139 60 Minutes 12 kg-cm min 20 kg-cm min or near spin Wet Track Abrasion Loss: ISSA TB 100 1 Hour Soak ISSA TB 100 6 Day Soak 50 g/ft2 max 75 g/ft2 max Mix Time: ISSA TB 113 120 seconds min Classification of Compatibility: ISSA TB 144 11 grade points min Wet Stripping: ISSA TB 114 Pass (90% min) Loaded Wheel Test: ISSA TB 147 Vertical 10% max, Lateral 5% max Note: Provide aggregate with a minimum sand equivalency of 65 as determined by AASHTO T 176. If the sand equivalency is < 65, the aggregate may be approved as long as the Plasticity Index (PI) is zero. Test the PI as per AASHTO T 89 and AASHTO T 90 and meets the methyl blue test.

TABLE C MIX TYPE MINIMUM SURFACING APPLICATION THICKNESS (inch) ASPHALT RESIDUE (% by Weight of Aggregate) SINGLE APPLICATION RATE (Pounds per Square Yard) DOUBLE APPLICATION RATE (Pounds per Square Yard) A 1/4 6.0 - 8.5 25-30 35-40 B 3/8 5.5 - 7.5 35- 40 40- 55 RF N/A 5.5-7.5 22-38

Note A: Provide mix set additive for each mix type as required. Note B: Filler for each mix type to be from 1% to 2%± 0.5% by weight of dry aggregate depending on weather conditions. Note C: It is permissible to increase asphalt content for slag and other absorptive aggregates at the discretion of the DME/DMM.

design to be used within 60 days before its use on the project. Record mixing equipment meter readings of

material control devices on a Run Sheet, daily, for each mix design. Calculate the percent cement or hydrated lime, total emulsion, asphalt residue based on the dry weight of the aggregate, and the yield square yard. Certify the mixture composition and application rate based on quality control tests and Run Sheet calculations. Send certifications to the Inspector-In-Charge within 1 working day following any quality control testing. Certify mixtures and each shipment of material delivered to the job site as specified in Section 106.03(b)3.

Certify each shipment of material delivered to the job site.

483.3CONSTRUCTION—

the Representative with both C ontractor and PennDOT personnel present before placing any material on the project. Identify any areas of concern in the pavement that may show any signs of fatigue or excessive rutting at the pre-placement meeting. Also review the Specification, QC Plan, source of supply list, and the Aggregate Delivery Plan. It may be necessary to hold more than one pre placement meeting on larger projects with multiple State Routes.

and adhesion and the atmospheric temperature is 50F minimum during the entire placement. Under no circumstances will the 50F minimum temperature requirement to be waived even for night work. Do not apply mixture if rain is imminent or if freezing temperatures are expected within 24 hours after application. Remove and replace rained on mixture before it sets. Do not apply from September 16 to April 30 in Districts 1-0, 2-0, 3-0, 4-0, 10-0, and 5- 0 (Monroe, Carbon, and Schuylkill Counties only) and from October 1 to April 30 in Districts 6-0, 8-0, 9-0, 11-0, 12-0, and 5-0 (Berks, Lehigh, and Northampton Counties only). No exceptions to weather limitations will be allowed, unless directed in writing by the District Executive.

DME/DMM for approval. Include in the plan the number of trucks that will be used to haul aggregates to the micro-surfacing machine to keep it moving continuously to limit starting and stopping. All aggregates being delivered to the micro-surfacing machine must be screened directly into the truck. All screening plants must be equipped with a scalping screen with a 3/8- inch maximum square opening for Type A and with a 1/2-inch maximum square opening for Type B and Type RF.

machine equipped with a chain- dragged conveyor belt aggregate delivery system interconnected with a positive displacement, water-jacketed gear pump to accurately proportion ingredients. Truck mounted units may be allowed on projects less than 20,000 square yards except for limited access highways and for all municipal projects. Locate filler feed so that the proper amount of cement is coating the aggregate before charging into the mixer. Provide a spray bar to completely wet the aggregate dropping down into the pug mill with additive and water. Provide a continuous-flow, twin shafted, multi-bladed pug mill at least 50 inches long. Introduce polymer- modified emulsified asphalt beyond the first quarter point of the mixer to ensure thorough mixing of aggregate, cement, additive, and water before polymer -modified emulsified asphalt is added. Meet manufacturer's recommendations for blade size and side clearance. Provide readily accessible material control devices, placed so that the Inspector is able to determine the amount of each material being used at any time. Calibrate each material control device before production of each mix type. Equip the machine with a water pressure system and nozzle spray bar to provide a water spray ahead of and outside the spreader box, when required.

attached to the mixer and equipped with paddles mounted on adjustable shafts to continually agitate and distribute the material throughout the box. Provide sufficient turbulence to prevent the mix from setting up in the box, forming excessive side build-up, or forming lumps. Attach flexible front and rear seals, in contact with the road, to prevent loss of mixture from the box. Furnish rut filling equipment with movable steel strike- off

bar. Operate spreading equipment to prevent loss of the mixture on super elevated curves and to leave a uniform, skid-resistant application of aggregate and asphalt on the surface. Operate spreading equipment to achieve a uniform consistency without skips, lumps, or tears in the finished surface.

Immediately before placing mixture, clean the surface of vegetation, loose materials, dirt, mud, and other objectionable items. Ensure all pavement markings and legends are completely removed before placing any mixture. Before placing mixture on existing concrete surfaces, apply tack coat over the entire area as specified in Section 460. Do not apply tack coat on existing asphalt surfaces. Apply water to dampen entire surface immediately before placing mixture.

Spread the mixture to seal cracks, fill voids, and to leave a uniform surface. When filling ruts, take care to restore the designed profile of the pavement cross section. Avoid excess crowning (over filling) of rutted areas. Use squeegees and lutes in areas inaccessible to the spreader box. Carry a sufficient amount of material at all times, in all parts of the spreader box, to obtain complete coverage. Water may be sprayed into the spreader box, to facilitate spreading, without harming the mix. Lumps, balls, or unmixed aggregate in the finished surface is not allowed. Adjustments to the additive may be required to slow mixture set time where hand spreading is needed. When hand spreading, pour mixture in a small windrow along one edge of the surface to be covered and spread uniformly by hand squeegee or lute. Make a neat seam where two passes join. Immediately remove excess material from the ends of each run.

takes longer than one hour to properly set, the Representative will give the Contractor a warning and an opportunity to immediately correct mixture application and set time. If the mixture takes longer than one hour and twenty minutes to properly set, stop placement operations immediately.

hour and twenty minutes.

108.05(c)3.f, except having tire pressures of 40 pounds per square inch to 60 pounds per square inch. Roll

the entire surface area of the placed mixture. On a double application, roll the entire surface area of the placed mixture for each application.

of the Representative, obtain samples of the aggregates from stockpiles designated and constructed for each mixture type and each project. Obtain a minimum sample size of 3 pounds using guidelines for stockpile sampling specified in PTM No. 607. Immediately deliver the samples to the Representative for testing. Passing aggregate acceptance test results are required before placement of the mixture. All acceptance samples will be obtained and all acceptance tests will be performed by the Representative according to PTM No. 616 and PTM No. 100 using the following frequency:

• When the projected quantity of aggregate for the specified mixture type is less than 500 tons. The entire quantity will be designated as one lot and divided into three equal sublots for sampling. Under the direction and supervision of the Representative obtain a sample from each sublot and immediately deliver the samples to the Representative for testing. One of the three sublot samples will be randomly selected and tested according to PTM No. 1 by the Representative and tested for compliance with Table A. If the sample tested meets the specification, the entire lot will be considered acceptable for delivery to the designed project. If the sample fails, the remaining two samples will be tested, and the Representative will determine the percent within limits (PWL) according to Section

106.03(a)3. If results indicate a PWL for the material less than 90, the Representative will reject the

stockpile. After the entire rejected lot has been blended, screened, or replaced, retesting for acceptance

of the aggregate will be performed. If retesting is performed, all sublot samples will be tested as specified in Section 703.5(b)2. All acceptance testing will be performed by the Representative. All test results will be recorded on a TR-4126A aggregate report form.

• When the projected quantity of aggregate for the specified mixture type is 500 tons or greater. The aggregates will be divided into equal lots at the discretion of the aggregate supplier, but in no case will the lot exceed 1000 tons. Each lot will be divided into three equal sublots. Under the direction and supervision of the Representative obtain a sample for each sublot. All three samples for each lot will be tested and the Representative will determine the percent within limits (PWL) according to Section 106.03(a)3. If results indicate a PWL for the material less than 90, the Representative will reject the stockpile. If the test results for each lot meets the specification and are in compliance with Table A, the entire lot is acceptable for shipment to the project. If the test results fail to meet the specifications, the lot will be rejected. Retesting for lot acceptance will be performed as described above. All acceptance testing will be performed by the Representative. All test results will be recorded on a TR-4126A aggregate report form.

requirements from Table A and the method of blending must be approved in writing by the DME/DMM before the start of work. Include on the QC Plan a detailed description of equipment used to blend aggregates, a list of supplier codes for aggregates being blended, and the percentages of each aggregate being blended. Set up a portable laboratory at the blending site equipped to perform PTM No. 616 and PTM No. 100 tests for acceptance of aggregates on the project. The Contractor’s aggregate technician must be a PennDOT certified aggregate technician before performing any aggregate testing at the staging area in the presence and direction of the Representative. Aggregates will be accepted as specified in Section 483.3(i). Provide aggregate for use in all mixture Types including each application of a double application of a mixture Type having the SRL designation indicated in the bid proposal. An aggregate designation or blends, equal to or better than that specified, may be supplied.

strip. The test strip will be prohibited on a limited access highway. Construct a test strip to demonstrate the mixture's ability to be laid in multiple stone thicknesses and to be opened to traffic within one hour after placement. Construct the test strip in the same manner and condition as required on the project. Construct the test strip over one- full lane width and between 100 feet and 550 feet long. Apply the mixture at a n application rate representative of the application rate for the project. Test the mixture according to ISSA Test Method TB 102 in the presence of the Representative. The Representative will evaluate and approve the test strip based on its ability to be opened to traffic within one hour and on its ability to have a set time of 10 minutes, maximum, as determined by ISSA Test Method TB 102. Do not continue with work until the Representative has approved the test strip. The Representative does not have the authority to waive or eliminate the test strip requirement. If this work is to be performed a test strip is mandatory. The test strip will be payable as specified in Section 483.4.

Unless otherwise directed in writing by the District Executive, satisfactorily correct pavement not meeting the following criteria:

rates deviate from the acceptable ranges in Table C will be considered defective work. Failure to meet the acceptable ranges in Table C will require an additional minimum 15 pounds per square yard application or the District Executive, with the concurrence of the Director of the Bureau of Construction and Materials, may allow the Contractor to leave the defective lot in place. The Department will pay for the defective lot at 50% of the contract unit price.

• No areas of excess emulsified asphalt (flushing) greater than 5% of the finished surface area. Areas of excess emulsified asphalt are characterized by a smooth, shiny surface that may be tacky to the touch. Bleeding at joints is not allowed.

• No tear and/or drag marks greater than 1 inch wide and 3 inches long.

• No more than 12 tear and/or drag marks greater than 1/2 inch wide and 4 inches long per 10 feet of a lane.

• No clumps and/or other foreign objects greater than 1 1/2 inch in diameter.

• No completed sections of micro-surfacing which exhibit washboard or ripple patterns exceeding 100 linear feet. If these areas exist , they will be considered defective work, as determined by the Representative, and will require surface correction.

• No longitudinal streaks with greater than a 1/4-inch ridge, bump or depression, as measured with a 10-foot-long straightedge.

than a 1/4-inch bump, ridge, or depression as measured with a 12 -foot straightedge. Do not overlap longitudinal joints more than 4 inches, except on irregular roadway widths when approved by the Representative.

along the roadway lane, shoulder, and/or curb lines. Place edges flush with curbs. Place edges with no more than ±3 inches horizontal variance in any 100 feet of roadway.

to prevent pick-up and until directed by the Representative.

483.4MEASUREMENT AND PAYMENT—

Under the direction and supervision of the Representative complete measurements based on the combined tonnages of aggregate, filler, and polymer -modified emulsified asphalt actually used; computed as follows:

• Aggregate. Measure aggregate quantity using the calibrated, dry weight from the aggregate control device. Make a deduction for moisture naturally occurring in the aggregate by using PTM No. 513.

• Filler. Compute filler quantity from the fines feeder control device.

• Polymer-modified emulsified asphalt. Compute polymer-modified emulsified asphalt quantity by weight used.