Section 409 — Micro Surfacing

Description

409.01This work consists of applying a polymer- modified micro surfacing mix on a pavement surface.

Material

409.02Conform to the following Subsections: Micro surfacing aggregate 703.10(b) Mineral filler 725.05 Polymer- modified emulsified asphalt for micro surfacing 702.02(b) Water for construction 725.01(c)

Construction Requirements

409.03Qualifications. At least 14 days before starting micro surfacing work , submit a ré sumé for the foreperson describing experience on at least five micro surfacing projects of similar complexity for approval.

409.04Composition of Mix (Job -Mix Formula). Submit a written JMF for micro surfacing which complies with ISSA A143, Recommended Performance Guidelines for Micro Surfacing for approval at least 14 days before production. Include the following:

(a)Aggregate gradation values. Percent passing fo r each sieve size for the aggregate blend;

(b)Emulsified asphalt content. Residual asphalt content, as a percent by mass of dry aggregate;

(c)Polymer- modifier. Type and quantity of polymer -modifier solids based on the residual asphalt content; (d) Aggregate samples. 80-pound sample of each aggregate;

(e)Polymer- modified emulsified asphalt sample. 1-gallon sample with a production certification conforming to Subsection 106.03(b) ;

(f)Mineral filler samples. 10-pound sample of each proposed minera l filler; and

(g)Proposed application rate. Use ISSA A143 for guidance.

409.05Equipment.

(a)Mixing and proportioning equipment. Conform to ISSA A143.

(b)Spreading equipment. Conform to ISSA A143.

(c)Secondary strike -off. Conform to ISSA A143.

(d)Sweeper. Provide a sweeper conforming to the following:

(1)Self-propelled;

(2)Vertical broom pressure control; and

(3)Vacuum capability.

(e)Pneumatic -tire rollers. Provide rollers conforming to the following:

(1)Self-propelled;

(2)10-ton gross mass with a tire pressure of 50 pounds per square inch; and

(3)Water -spray system.

(f)Auxiliary equipment. Provide hand squeegees, shovels, and other equipment necessary to perform the work. Provide power brooms, air compressors, water flushing equipment, and hand brooms to clean the pavement surface. Other equipment of proven performance may be used in addition to or instead of this equipment if approved.

409.06Surface Preparation. Conform to Subsection 406.04(a) .

409.07Weather Limitations. Apply only when the following apply:

(a)Ambient air temperature is above 45 °F;

(b)Surface temperature in the shade is above 45 °F;

(c)Weather is not foggy or overcast; and

(d)Precipitation or temperatures below 32 °F are not anticipated for at least 24 hours after application.

409.08Calibration. Calibrate mixing equipment according to ISSA A143. Submit calibration results before starting production. 409.09 Production Start- Up Procedures.

(a)Preparatory phase meeting. Conduct a pre -surfacing preparatory phase meeting according to Subsection 153.06(a) at least 3 days before the start of surfacing operations.

(b)Control strip. On the first day of placement, construct one 300-foot -long control strip, one lane wide. Construct control strip on the project at an approved location . Construct the control strip using material, lay -down, and rolling procedures intended for the entire project. Start the control strip at the proposed application rate. Adjust the application rate for the surface conditions, if needed. Cease produ ction after construction of the control strip until the material and the control strip are evaluated and accepted. Repeat the control strip process until an acceptable control strip is produced. Acceptable control strips may remain in place and will be accepted as a part of the completed surface treatment. Correct rejected control strips. Use these start -up procedures if changing construction procedures, if resuming production after a termination of production due to unsatisfactory quality according to Subsection 106.04, or the starting of a new construction season.

409.10Application. Fog the surface with water in front of the spreader. Blend the additives with the aggregate. Pre -wet the aggregate in the pugmill before mixing with the polymer- modified emulsified asphalt. Mix the surfacing material for no more than 4 minutes. Ensure the mix is of uniform consistency as it leaves the mixer and conforms to the approved JMF. Apply micro surfacing material at the application rate determined from the control strip. Adjust mineral filler and polymer- modified emulsified asphalt content during construction if approved to adjust for variations in field conditions. Clean the spreader box before the start of each work shift. Carry sufficient mix in the spreader to completely cover the surface. Spread the mix with a spreader box. In areas not accessible to the spreader , use hand squeegees to provide uniform coverage and match the finish of spreader. Remove streaks and transverse ripples as defined by ISSA A143 from the finished surface. Provide straight lines along curbs and shoulders and do not allow runoff onto these areas. Provide straight and neat starting and ending joints by masking surfaces. Mask surfaces to provide straight and neat longitudinal or transverse joints at required locations (such as intersections and irregular shaped areas). For transverse joints, use a butt joint. Use building paper placed over previously placed micro surfacing or other suitable methods to avoid double placement of micro surfacing. Remove ridges or bumps in the finished surface. For longitudinal joints, place joints on lane lines. Use half passes and odd- width passes only in turnouts and parking areas. Do not use half passes for the last pass in paved areas. Overlap longitudinal joints no more than 3 inches. Limit the elevation difference at joints to less than ¼ inch. Start rolling after the mixture has cured to the point where it will not pick up on the roller tires. Roll parking areas and turnouts with at least two full -coverage passes with the roller. Rolling the mainline roadway is not required. Allow treated areas to cure before opening to traffic. Cure is complete when clear water can be pressed out of the placed mix with a white piece of paper without discoloring the paper. Do not allow traffic in parking areas or pullouts for at least 48 hours after completing application. Remove and dispose of material spills and associated debris at the end of each shift according to Subsections 203.05 and 203.07. Two weeks to one month after completion of micro surfacing application and before placing permanent pavement markings, sweep the entire treated surface. Dispose of swept material according to Subsection 203.07.

409.11Acceptance. See Table 409-1 for sampling, testing, and acceptance requirements. Micro surfacing aggregate will be evaluated under Subsections 106.02 and 106.04. Mineral filler will be evaluated under Subsections 106.02 and 106.03. Polymer- modified emulsified asphalt will be evaluated under Subsections 106.03 and 106.04. Provide a production certification with each load of polymer- modified emulsified asphalt. Construction of the micro surfacing will be evaluated under Subsections 106.02 and 106.04.

Measurement

409.12Measure the Section 409 pay items listed in the bid schedule according to Subsection 109.02 .

Payment

409.13The accepted quantities will be paid at the contract price per unit of measurement for the Section 409 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 . Table 409-1 Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Source

Micro

surfacing aggregate for surface mixture(1) Measured & tested for conformance (106.04 & 105) Quality − Subsection

703.101 per material type Source of material Yes Before producing −

Process

control (153.03 ) Gradation − AASHTO T 27 & T 11 2 per day per stockpile Crusher belt (during production) No 24 hours Not required if using a pre -crushed commercial source

Polymer -

modified emulsified asphalt(2) Measured & tested for conformance (106.04 ) Quality − Subsection 702.02(b) 1 per material type Emulsified asphalt supplier Yes, 2 1-quart samples Before incorporating into work − Table 409-1 (continued) Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Production

Micro

surfacing aggregate for surface mixture(1) Measured & tested for conformance (106.04 ) Gradation (See Table 703 -6 for applicable sieves) − AASHTO T 27 & T 11 1 per 10,000 yd2 Stockpile Yes 24 hours −

Polymer -

modified emulsified asphalt(2) Measured & tested for conformance (106.04) Quality − Subsection 702.02(b) 1 per day Mixing equipment or point of delivery Yes, 2 1-quart samples − Tested by

Government

Process

control (153.03 ) Placement temperature − − Daily at start- up &

Contractor

determined thereafter Mixing equipment No Before incorporating into work −

(1)Applies to each aggregate grade provided.

(2)Applies to each asphalt material provided.