404SEAL COAT

404.01Description

This work shall consist of one or more applications of asphalt material, each followed by an application of cover aggregate in accordance with 105.03.

404.02Quality Control

Seal coat, SC, shall be constructed acco rding to a QCP prepared and submitted by the Contractor in accordance with ITM 803, Contractor Quality Control Plan for Seal Coat. 10

The QCP shall be submitted to the Engineer at least 15 days prior to commencing seal coat operations.

MATERIALS

404.03Asphalt Material

The type and grade of asphalt material sh all be in accordance with the following:

Asphalt Emulsion, RS-2, AE-90, 20 AE-90S, or HFRS-2.................................................... 902.01(b)

404.03

404.04Cover Aggregate

Aggregate shall be in accordance with the following requirements. When slag is used as an alternate to natural aggregate, adjustments will be made in accordance with

904.01, to compensate for differences in specific gravity

Coarse Aggregates*, Class B or Higher Size No. 8, 9, 11, 12, SC 11, SC 12, or SC 16 ...... 904.03 Fine Aggregate, Size No. 23 or 24 .............................. 904.02 30

* Coarse aggregate type required shall be in accordance with

904.03(d)1 for ESAL categories 2 or 3

The types of seal coats shall be as follows:

Type (see Note 1) Application Cover Aggregate Size No. and Course Rates of Application per sq yd Aggregate, lb Asphalt Material, Gal. at 60°F 1 or 1P (see Note 2) Single 23, 24 12 - 15 0.12 - 0.16 2 or 2P Single 12, SC 12 14 - 17 0.29 - 0.33 3 or 3P Single 11, SC 11, SC 16 16 - 20 0.36 - 0.40 4 or 4P Single 9 28 - 32 0.63 - 0.68 5 or 5P Double Top: 12, SC 12 Bottom: 11, SC 11, SC 16 16 - 19 16 - 20 0.41 - 0.46 0.28 - 0.31 6 or 6P Double Top: 11, SC 11, SC 16 Bottom: 9 18 - 22 28 - 32 0.62 - 0.68 0.42 - 0.46 7 or 7P Double Top: 11, SC 11, SC 16 Bottom: 8 18 - 22 28 - 32 0.62 - 0.68 0.42 - 0.46 Note 1 – AE-90S and SC aggregates shall be used for Type P seal coats, except SC aggregate requirement will not apply to seal coat used on shoulders. Note 2 – HFRS-2 shall not be used with Type 1 seal coat.

SC aggregates shall be 85% one face a nd 80% two face crushed. The Flakiness Index in accordance with ITM 224 shall be a maximum of 25%. Non SC aggregates shall have a minimum crushed particle perc entage of 70%. Determination of crushed particles shall be made from the mass weight of material retained on the No. 4 (4.75 40 mm) sieve in accordance with ASTM D5821.

CONSTRUCTION REQUIREMENTS

404.05Weather Limitations

Asphalt material shall not be applied on a wet surface, or when other weather conditions would adversely affect the seal coat. Seal coat shall not be placed when the ambient or pavement temperature is below 60°F. Seal coat shall not be applied to travel 404.04

lanes or auxiliary lanes before May 1 or after October 1, but may be applied to shoulders within the above temperature range. 50

404.06Equipment

A distributor, rotary power broom, pneumatic tire roller, and aggregate spreader in accordance with 409.03 shall be used.

404.07Preparation of Surface

Surfaces to be sealed shall be patched as shown on the plans or as directed, brought to proper section and grade, and compacted.

The surface shall be cleaned of all loose ma terial prior to seal coat application. 60 Sealing operations may not commence until the surface is approved.

All castings, detector housings, and snowplowable raised pavement markers shall be covered prior to applying the asphalt material to prevent coating with seal coat. These coverings shall be removed prior to opening to unrestricted traffic.

404.08Applying Asphalt Material

Asphalt material shall be applied in a uniform continuous spread over the section to be treated. The quantity of asphalt material to be applied per square yard shall be in accordance with the QCP. During application, minor adjustments to the application 70 rate shall be made in accordance with the QCP.

The asphalt material shall not be spread over a greater area than can be covered with the cover aggregate within the trucks at the site.

The spread of the asphalt material shall be no wider than the width covered by the cover aggregate from the spreading device. Operations shall allow asphalt materials to chill, set up, dry, or otherwise impair retention of the cover coat.

404.09Application of Cover Aggregate 80

Within 1 minute of the application of the asphalt material, cover aggregate shall be spread in quantities as required. Spreading shall be accomplished such that the tires of the trucks or aggregate spreader do not contact the uncovered and newly applied asphalt material.

404.10Rolling Operation

The aggregate shall be seated with at least three roller applications. A roller application is defined as one pass of the roller over the width sealed. The first roller application shall be completed within 2 minutes of aggregate application, with the final application completed within 30 minutes after the cover aggregate is applied. The 90 rollers shall not be operated at speeds that will displace the cover aggregate from the asphalt material.

404.10

404.11Sweeping Operation

Excess cover aggregate shall be removed from the pavement surface by brooming no later than the morning after placement of the seal coat. The brooming shall not displace the imbedded aggregate. A second brooming operation shall be performed prior to opening to unrestricted traffic in accordance with 101.36.

404.12Protection of Surface 100

Traffic shall not be allowed on the freshly sealed surfaces until final rolling application is complete. The seal coat shall be protected by keeping traffic off the freshly sealed surface or by controlling traffic speed in accordance with the QCP. Traffic shall not displace the embedded aggregate.

Any areas with minor bleeding will be covered with fine aggregate or other approved blotting material.

404.13Method of Measurement

Seal coat will be measured by the square yard of the seal coated surface. 110

Patching will be measured in accordance with 304.06.

404.14Basis of Payment

Seal coat will be paid for at the contract unit price per square yard complete in place.

Patching will be paid for in accordance with 304.07.

Payment will be made under: 120

Pay Item Pay Unit Symbol

Seal Coat, ______ ...................................................................... SYS type Seal Coat, ______ P .................................................................. SYS type

The cost of determination of asphalt ma terial and cover aggregate application rates, sweeping and rolling operations, blotting material, and other incidentals shall be 130 included in the cost of the pay items.

The Contractor shall adjust application rates as directed by the Engineer within the limits set out herein. No additional payment will be made for additional materials necessary to meet the required application rates within the specified limits.

404.11