410Microsurfacing

Microsurfacing

410.1DESCRIPTION

1 This section describes the requirements for applying microsurfacing material.

410.2MATERIALS

1 Provide materials in accordance with the following:

Material Subsection Aggregate for Microsurfacing 803 Cement 801 Hydrated Lime 820 Polymer-Modified Emulsified Asphalt 804.3 Water 814

2 Provide polymer-modified, quick-set CQS-1HP emulsified a sphalt; co mmercially available type I or type II portland cement or hydrated lime; and other additives as needed to accelerate or retard the breaking point and set times or improve the resulting finished surface.

410.3EQUIPMENT

410.3.1 Emulsified Asphalt

1 Provide tank trucks and on-site storage tanks in accordance with Subsection 407.3, Equipment.

410.3.2 Microsurfacing

1 Provide a self-propelled, continuous load paver (manufactured exclusively for microsurfacing application) that is a continuous-flow mixing unit capable of accurately delivering proportionate amounts of aggregate, emulsified asphalt, cement, additives, and water to a revolving multi-blade, twin- shafted mixer, and of dischar ging a continuous flow of thoroughly mixed product. Equip the machine with:

and water to maintain an adequate supply to the proportioning controls during nurse vehicle exchange;

applying microsurfacing;

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immediately ahead and outside of the spreader box;

predetermined amount of cement at the same time and place the aggregate is incorporated; and

movement during application.

2 Ensure that the self-loading devices, opposite-side driving stations, and forward and reverse controls are of the original manufacturer’s design. Do not use individual slurry trucks.

3 Provide individual volume or weight [mass] controls and a visible means of observation of the meters for proportioning each material added to the mix. Calibrate each proportioning device and properly mark for identification.

4 Equip the aggregate feed to the mixer with a revolution counter or similar device to determine the amount of aggregate used at any time.

5 Provide a positive displacement type emulsion pump and equip with a revolution counter or similar device to determine the amount of emulsion used at any time.

6 For spreading the microsurfacing mixture, provide a mechanical type spreader box attached to the paver and equip with rotating paddle shafts or spiral augers to agitate and spread the material throughout the box. Provide a leading edge seal and an adjustable trailing edge seal that acts as a final strike-off. Design and operate the unit to ensure a free flow of material to the trailing edge seal. Provide the spreader box with suitable means to shift the box. Provide rubber squeegees sized to match the width of material placed.

7 Provide a rut filling box when required in accordance with Subsection 410.4.8.2, Transverse Depressions/Cracks and Longitudinal Ruts/Cracks.

8 Provide truck platform scales in accordance with Section 109.1.4, W eighing Procedures and Equipment. The engineer may approve the use of hopper scales.

410.4CONSTRUCTION

410.4.1 General

1 Arrange for a representative of the emulsified-asphalt supplier to meet with the engineer and the microsurfacing contractor’s field personnel before placing the test

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section. Ensure that the representative is present on the first day of placement. Address at a minimum, production, materials, supply, and calibration of the continuous -load paver.

2 Provide weigh tickets in accordance with Subsection 109.1.4.2, Documentation, for documenting the weight [mass] of the aggregate in the transfer trucks at the time and place of loading into the mixing machine. With the approval of the engineer, invoices may be accepted in lieu of the weigh tickets.

3 Before beginning microsurfacing operations, calibrate the mixing unit in the presence of the engineer. Before loading into the hauling units, the engineer will test aggregate gradation to ensure it meets the requirements of Subsection 803.7, Aggregate for Micorsurfacing, at the stockpile.

4 Carry enough material in the spreader to ensure complete coverage but avoid overloading. Do not allow lumping, balling, or unmixed aggregate.

5 Ensure that the material is:

6 Do not spray water directly into the spreader box while placing material.

7 Formulate the material to allow use by traffic within one hour of application without damaging the surface or vehicles. Stop application early enough each day to allow safe travel over the work before dark.

8 Stop production if two corrective actions fail to result in the production of material as specified.

410.4.2 Weather and Seasonal Limitations

1 Place microsurfacing material from June 1 to September 30. Apply when pavement temperature is at least 60 °F [15 °C] or higher and the air temperature is 50 °F [10 °C] and rising. Do not apply in fog or rain, when the finished product is at risk of freezing within 24 hours, or if weather conditions will prevent use by traffic in one hour.

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410.4.3 Quality Control Plan

1 The department requires a written quality control plan. Give the engineer two copies at the preconstruction conference. Nonadherence to the plan may cause the engineer to suspend work. Include the following minimum information:

including those for crushing, hauling, and stockpiling, provide the make, type, location, frequency of inspection, frequency and procedures for calibrating weighing and metering devices, and all certifications issued for the facility.

For placing operations, provide the make and type of equipment, frequency of inspection and maintenance, frequency of and procedures for calibrating control devices, frequency of and procedures for verifying calibration, and all certifications issued for the equipment.

lines of authority for quality control in all aspects of microsurfacing, including crushing and stockpiling. Include the names, phone numbers, and qualifications of the people responsible for quality control.

aggregate samples for the mix design, the method for determining sampling times and locations during production, collection procedures, and the testing and reporting of results.

aggregate production the laboratory mix design is performed, the qualifications of the organization performing the design, and the name, address, and phone numbers of the person responsible.

inspection, adjustments to mixture, and test results on a daily basis. Record field observations, inspections, and measurements as they occur in a permanent duplicating field book or diary. Make copies of daily entries and records available to the engineer upon request.

necessary when the material does not meet specifications. As a minimum, include in the process a written notification to the engineer of what will be done when a problem is identified.

ection Construction. Provide information on the location and construction procedures of the test section.

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start each aspect of the work, including crushing, stockpiling, mix design, and placement of material.

410.4.4 Quality Acceptance

1 The department is responsible for quality acceptance testing. Aggregate gradation lot size is defined by the department as the quantity of produced aggregate, represented by five tests or a maximum of 5000 ton [5000 t]; a sublot is the quantity represented by one test. The exact tonnage may vary due to production suspension, construction schedules, or other acceptable reasons. Except in unusual situations, the engineer will use lots consisting of five samples. When necessary because of production changes or suspension, lots of from three to seven samples may be used. Partial lots with less than three samples will be included with the previous lot for analysis. Lot size will be controlled by tonnage and a lot may span several days of production.

2 Obtain aggregate gradation samples in accordance with Subsection 800.2 (3), Point of Sampling. To determine lot size, measure tonnage by belt scale or another method approved by the engineer.

410.4.5 Job Mix Formula (JMF)

1 Submit a completed mix design developed by an approved testing laboratory to the engineer for approval at least 14 calendar days before placing microsurfacing. Address in the mix design the proportions of aggregate, polymer- modified emulsified asphalt, cement, water, and other additives required to achieve maximum stability (ASTM D 1560) at a minimum emulsion content . Include with the mix design report the manufacturer, brand, type, and percentages of the aggregate, asphalt emulsion, and additives (to both mix and emulsion) and aggregate test results for sand equivalent, LA abrasion, and when required, results in accordance with T able 803.6.2-1, Polish- Resistant Aggregate Requirements. Provide a new mix design if any of these characteristics are changed.

2 With the mix design, submit to the engineer an aggregate sample and JMF in accordance with Table 410.4.5-1, Aggregate JMF Tolerance.

Table 410.4.5-1 Aggregate JMF tolerance Sieve Size Job Mix Formula Tolerance (%) Passing No. 4 [4.75 mm] -5 to +5 Passing No. 8 [2.36 mm] -5 to +5 Passing No. 16 [1.18 mm] -5 to +5 Passing No. 30 [600 µm] -5 to +5 Passing No. 50 [330 µm] -4 to +4 Passing No. 100 [150 µm] -3 to +3 Passing No. 200 [75 µm] -2 to +2

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3 Ensure the tests shown in T able 410.4.5-2, T esting Requirements, meet the requirements at the minimum emulsion content. Because some systems require longer times for the emulsified asphalt to adhere to the stone, a modified Marshall Stability Test

Table 410.4.5-2 Testing Requirements Test Procedure Description Specification ISSA TB139 Wet Cohesion @ 30 minutes (set), minimum @ 60 minutes (traffic), minimum 31 kg-in [12 kg-cm] 51 kg-in [20 kg-cm] or Near Spin ISSA TB109 Excess Asphalt by LWT Sand Adhesion, maximum 50 g/ft² [538 g/m²] ISSA TB114 Wet Stripping, 90% minimum Pass ISSA TB100 Wet Track Abrasion Loss One Hour Soak, maximum Six Day Soak, maximum 50 g/ft² [538 g/m²] 75 g/ft² [807 g/m²] ISSA TB147 Lateral Displacement, maximum 5% Specific Gravity after 1,000 Cycles of 125 lb [57 kg], maximum 2.10 ISSA TB144 Classification Compatibility, minimum 11 grade points (AAA, BAA) ISSA TB113 Mix Time @ 77 ºF [25 ºC], minimum Controllable to 120 seconds

410.4.6 Surface Preparation

1 Immediately before applying material, thoroughly clean the roadway surface of extraneous materials, including vegetation, dirt, mud, and loose material and prewet as necessary. Application may begin when there is no standing water present and the surface is damp.

410.4.7 Test Section

1 Construct a test section of enough quantity to evaluate the mix design for initial and final set curing times, surface appearance, and final profile; obtain the engineer’s approval before beginning normal placement. Include all aspects of the specified work in the test section, including transverse depression and crack filling, longitudinal rut and

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crack filling, strike-off pass, and finish pass. Ensure that the depth of material placed for the transverse depression and crack filling and longitudinal rut and crack filling portions of the test section are equal to the project’s maximum specified depth. Construct another test section if a new mix design is required in accordance with Subsection 410.4.5, Mix Design, or if either breakdowns or stops and starts in operations exceed five per day.

410.4.8 Application

410.4.8.1 General

1 Provide a leading edge seal that allows no loss of the mixture at the contact point with the roadway surface.

2 Center the material placement over the depression, rut, crack, or lane-width. If specified, perform transverse depression and crack filling and allow time to cure completely before performing longitudinal rut and crack filling, strike-off, or finish passes.

3 Keep to a minimum the use of hand squeegees to achieve the required surface tolerance and appearance. Do not leave excess buildup, uncovered areas, or an unsightly appearance.

4 Place longitudinal joints on lane lines.

5 Provide straight lines along the shoulder edges with no run-off. Ensure straight lines at intersections. If necessary, use a suitable material to mask-off the end of streets to provide straight lines. Do not let edges vary horizontally more than ± 2 in [± 50 mm] in any 100-foot [30 m] length.

410. 4.8.2 Transverse Depressions/Cracks and Longitudinal Ruts Cracks

1 Where longitudinal rut depth exceeds 3/8 in [10 mm], spread the material with a rut box to fill ruts. Fill both ruts if one rut exceeds 3/8 in [10 mm].

2 Overfill transverse depressions and cracks and longitudinal ruts and cracks to 1/8 in [3 mm] per 1/4 in [6 mm] of material as a crown to provide for consolidation by traffic. For material used in transverse depression and crack filling, longitudinal rut and crack filling, and strike-off passes, reduce the asphalt emulsion content 1.0 percent from the design emulsion content. Taper the material onto the existing pavement on both edges of the rut to provide a smooth transition. Create a smooth, uniform seam wherever two passes join between the rut. Remove rough and uneven seams, and apply new material at no additional cost to the department.

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3 At the end of each pass, taper the mixture and construct a transition to the existing pavement. Fill one rut only with each pass of the surfacing machine. Let traffic compact the material to fill transverse depressions and cracks and longitudinal ruts and cracks for at least five calendar days before placing additional material.

410.4.8.3 Strike-Off Pass

1 Where rut depths are less than 3/8 in [10 mm], make a full-width strike-off pass with a full width spreader box, using a metal strike-off plate. Apply only enough material to fill the surface voids and level the surface.

2 Extend material 3 in [75 mm] from lane edges and taper onto the existing pavement to form a smooth transition. At the beginning and end of each pass, taper and apply the mixture to form a transition with the adjacent microsurfacing or existing pavement.

410.4.8.4 Finishing Pass

1 When specified, make a full-width finish pass with a full-width spreader box once the individual ruts are filled or the strike-off pass is completed. Taper the material onto the existing pavement at both edges of the lane to form a smooth transition. At the beginning and end of each pass, taper the mixture and form a transition to the adjacent microsurfacing or existing pavement.

410. 4.8.5 Final Surface

1 Immediately cease operations and make appropriate adjustments if surface appearance or tolerance criteria are not met.

oversized aggregate or spreader box residue, in the finished surface. If excessive streaking (defined as more than four drag marks greater than ½ in [12.5 mm] wide and 4 in [100 mm] long or 1 in [25 mm] wide and 3 in [75 mm] long in any 270 ft² [25 m²] area) develops, stop placement until corrected. Obtain the engineer’s approval before restarting.

measured by placing a 10-foot [3 m] straightedge over the surface.

Construct transverse and longitudinal joints where microsurfacing passes meet to be uniform in appearance and level with the adjacent microsurfacing. Do not overlap longitudinal joints more than 3 in [75 mm]. Do not allow an elevation difference between joints and the adjacent surface greater than ¼ in [6 mm] deep, as measured by placing a 10-foot [3 m] straightedge over the joint.

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410.4.9 Final Clean-up

1 Remove microsurfacing material and debris from areas not treated, such as gutters, intersections, and shoulders on a daily basis.

410.4.10 Acceptance

1 The engineer will reject material placed without an approved mix design. Remove by milling and replace at no additional cost to the department. Repair completed microsurface that is damaged by traffic at no additional cost to the department.

2 The engineer will accept:

Asphalt Material.

Aggregate.

410.5MEASUREMENT and PAYMENT

410.5.1 General

1 The engineer will measure Microsurfacing (Aggregate) by the short ton [metric ton] in the transfer trucks at the time and place of loading into the mixing machine as documented on the weigh tickets or invoices; no deduction will be made for moisture in the aggregate.

2 The engineer will measure Microsurfacing (Emulsified Asphalt) by the short ton [metric ton] in accordance with Subsection 109.1.3, Measurement Methods.

3 The department will pay as follows:

Pay Item

Pay Unit Measure to the Nearest Pay to the Nearest Microsurfacing (Aggregate) TON [t] 0.05 ton [0.05 t] 0.05 TON [0.05 t] Microsurfacing (Emulsified Asphalt) TON [t] 0.01 ton [0.01 t] 0.01 TON [0.01 t]

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410.5.2 Pay Adjustment

410.5.2.1 Emulsified Asphalt

1 If the samples for a truckload are not received by the Materials Program within seven calendar days of sampling, in accordance with Subsection 407.4, Construction, the engineer will reduce the payment by as much as 25 percent for that load.

2 The engineer may reduce the payment for emulsified asphalt that does not meet specifications but is accepted in accordance with Subsection 113.2, Acceptance of Asphalt Materials.

410.5.2.2 Aggregate

1 The engineer will evaluate the gradation for microsurfacing aggregate in accordance with Subsection 1 13.1, Acceptance of Aggregate, and adjust payment accordingly.