SlurrySealSpecification410.pdf

Section 410. — SLURRY SEAL

Description

410.01 This work consists of applying an asphalt slurry seal or a polymer modified micro-surfacing mix on an existing pavement surface.

Slurry seal type is designated as shown in Table 703-8 with following residual asphalt contents:

Type I — Residual asphalt between 10.0 and 16.0 percent

Type II — Residual asphalt between 7.5 and 13.5 percent

Type III — Residual asphalt between 6.5 and 12.0 percent

410.02 Conform to the following Subsections:

Aggregate 703.11 Emulsified asphalt 702.03 Emulsified asphalt, polymer modified 702.03(d) Mineral filler 725.05 Water 725.01(c)

Construction Requirements

410.03 Composition of Mix (Job-Mix Formula). Furnish a slurry seal or micro-surfacing mixture of aggregate, water, emulsified asphalt, or polymer modified asphalt and additives according to ASTM D 3910 and ISSA T 114. Conform to the applicable aggregate gradation in Table 703-8 and the residual asphalt contents in Subsection 410.01.

Submit a written job-mix formula for approval at least 14 days before production that meets the mix design requirements in ISSA A105 for emulsified asphalt slurry seal and ISSA A143 for micro-surfacing. Submit the following:

(a) Aggregate gradation values. The representative value for each sieve size for the aggregate blend.

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

(c) Aggregate samples. 100-pound sample of each aggregate.

(d) Emulsified asphalt sample. Source of and 5-gallon sample of the emulsified asphalt to be used in the mix.

(e) Mineral filler samples. 50-pound sample of each proposed mineral filler, when applicable.

The job-mix formula will be evaluated for approval.

410.04 Equipment. Furnish equipment with the following capabilities:

(a) Mixing equipment.

(1) Self-propelled;

(2) Continuous-flow mixing;

(3) Calibrated controls;

(4) Easily readable metering devices that accurately measure all raw material before entering the pugmill;

(5) Automated system for sequencing in all raw material to ensure constant slurry mix;

(6) Mixing chamber to thoroughly blend all ingredients together;

(7) Fines feeder with an accurate metering device for introducing additive into the mixer where the aggregate is introduced into the mixer;

(8) A pressurized water system with a fog-type spray bar capable of fogging the surface immediately ahead of the spreading equipment at a rate of 0.03 to 0.06 gallons per square yard;

(9) Proportioning system that is accurate for measuring all material independent of the engine speed;

(10) Minimum speed of 60 feet per minute and maximum speed of 180 feet per minute;

(11) Minimum storage capacity of 7 tons; and

(12) Capable according to ISSA Performance Guidelines A 105 or A 143.

(b) Mechanical-type single squeegee spreader box.

(1) Attaches to the slurry seal mixer;

(2) Flexible squeegee in contact with the surface to prevent loss of slurry;

(3) Adjustable to ensure a uniform spread over varying grades and crowns;

(4) Adjustable in width with a flexible strike-off; and

(5) Augers for uniform flow to edges.

(c) Auxiliary equipment. Furnish hand squeegees, shovels, and other equipment necessary to perform the work.

Provide cleaning equipment including, but not limited to, power brooms, air compressors, water flushing equipment, and hand brooms for surface preparation.

410.05 Surface Preparation. Clean the existing surface of all loose material, dirt, or other deleterious substances by approved methods.

410.06 Weather Limitations. Apply the mixture when the air temperature in the shade and the surface temperature are at least 45 °F and rising and when the weather is not foggy, rainy, or overcast. Do not apply when there is a danger that the finished product will freeze within 24 hours.

410.07 Application. Mix the materials using a slurry seal mixer. Fog the surface with water immediately preceding the spreader.

Blend the additive with the aggregate using the fines feeder. Pre-wet the aggregate in the pugmill immediately before mixing with the emulsified asphalt.

Mix the surfacing materials a maximum of 4 minutes. Ensure the mix is of the desired consistency as it leaves the mixer and conforms to the approved job-mix formula. Adjustment of the mineral filler and the emulsified asphalt content during construction may be approved to adjust for variations in field conditions.

Carry sufficient mix in the spreader to completely cover the surface. Spread the mix with a mechanical-type single squeegee spreader box. In areas not accessible to the spreader box, use hand squeegees to work the mix.

Allow treated areas to completely cure before opening to traffic. Cure is complete when clear water can be pressed out of the mix with a piece of paper without discoloring the paper.

410.08 Acceptance. See Table 410-1 for sampling and testing requirements.

Emulsified asphalt or polymer modified asphalt will be evaluated under Subsections 106.03 and 702.09.

Aggregate for surfacing mixture will be evaluated under Subsections 106.02 and 106.04.

Construction of the surfacing will be evaluated under Subsections 106.02 and 106.04.

Measurement

410.09 Measure the Section 410 items listed in the bid schedule according to Subsection 109.02.

Payment

410.10 The accepted quantities will be paid at the contract price per unit of measurement for the Section 410 pay item listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05.

Section 410. — SLURRY SEAL