2.01  SCOPE AND PURPOSE
Colored Micro-Surfacing shall consist of mixing a synthetic bitumen emulsion, pigment, aggregate, additives, and water and spreading the mixture on a surface or pavement where shown on the plans, as specified in these specifications and the special provisions, and as directed by the Engineer.

Colored Micro-Surfacing is a specialized material and is similar to a standard Micro-Surfacing, however, the synthetic bitumen emulsion based colored Micro-Surfacing is highly resistant to wear. The high bonding strength of the polymer-modified binder ensures durable bonding to the pavement surface and increases the life of the pavement. The colored Micro-Surfacing enhances appearance and provides high-visibility marking and delineation of bike lanes, crosswalks, pedestrian areas, and traffic calming schemes.

Colored Micro-Surfacing shall be MACRO®-COLOR™ by Valley Slurry Seal Company or pre-approved equal.

2.02  MATERIALS

The materials for colored Micro-Surfacing immediately prior to mixing shall conform to the following requirements: 2.02 (a)  Synthetic Bitumen Emulsion

Synthetic Bitumen Emulsion is a cationic, slow setting emulsion based on synthetic bitumen, to which polymers have been added. The emulsion is designed in such a way that the mixing with fine aggregates and a small portion of cement will result in a rapid setting system. The Synthetic Bitumen Emulsion shall be “milky” white in color prior to the addition of the pigment and shall cure to a transparent film. The synthetic bitumen emulsion shall conform to the following requirements.

2.02 (b) Pigment Paste
The pigment paste shall be a mixture of pigment (45-55%) and water (45-55 %) and shall meet the following requirements:

2.02 (c)  Water
           Water shall be potable.

2.02 (d)  Aggregate
           Aggregate shall consist of sound, durable, crushed stone or crushed gravel and approved mineral filler. The material shall be free from vegetable matter and other deleterious substances. Aggregates shall be 100% crushed with no rounded particles. The percentage composition by weight of the aggregate shall conform to the following grading:

2.02 (e)  Mineral Filler                                         
The mineral filler shall be either Portland cement or other approved mineral fillers, if required. Portland cement if used, shall be commercially available Type I or II and shall be free of lumps and clods.

2.03  MIX DESIGN
At least 7 working days before colored Micro-Surfacing placement commences, the Contractor shall submit to the Engineer for approval a laboratory report of tests and proposed mix design covering the specific materials to be used on the project. The percentage of synthetic bitumen emulsion and pigment paste proposed in the mix design shall be within the percentage range specified in Section 2.04 “Proportioning.”

The Contractor shall submit sample plates of the proposed colored mix for pre-approval prior to construction.

The tests and mix design shall be performed by a laboratory capable of performing the applicable International Slurry Seal Association (ISSA) tests. The proposed colored Micro-Surfacing mixture shall conform to the requirements specified when tested in accordance with the following tests:

1. Mixing test must pass at the maximum expected air temperature at the project site during application.
2. Using project source aggregate asphalt emulsion and set-control agents if used.

The laboratory test results shall be provided in a report and shall be signed by the laboratory that performed the tests and mix design and shall show the results of the tests on individual materials, comparing the test results to those required by the specifications. The report shall clearly show the proportions of aggregate, filler (as determined from the tests, minimum and maximum), water (minimum and maximum), asphalt solids content based on the dry weight of aggregate and set-control agent usage. Previous laboratory reports covering the same materials may be accepted provided they are made during the same calendar year.

2.04  PROPORTIONING

The synthetic bitumen emulsion shall be added at a rate determined by the mix design and within the following range of percent by mass of the dry aggregate.

The pigment paste shall be added to synthetic bitumen emulsion at a rate that will allow the cured colored Micro-Surfacing to comply with the color reference in Section 2.02B “Pigment Paste.” The pigment paste shall not exceed four percent by mass of the dry aggregate.

The pigment paste shall be pre-mixed with the synthetic bitumen emulsion.

A job mix design shall be submitted by the Contractor for approval by the Engineer that conforms to the specification limits, and that is suitable for the traffic, climate conditions, curing conditions and final use.

The colored Micro-Surfacing mixture shall be proportioned by the operation of a single start/stop switch or lever that automatically sequences the introduction of aggregate, synthetic bitumen emulsion, pigment paste, admixtures, if used, and water to the pug mill.

Calibrated flow meters shall be provided to measure both the addition of water and liquid additives to the pug mill. If necessary for workability, a retarding agent, that will not adversely affect the seal, may be used.

Water, and retarding agent if used, shall be added to ensure proper workability

The color Micro-Surfacing shall be mixed in a self-propelled mixing machine equipped with a continuous flow pugmill capable of accurately delivering and automatically proportioning the aggregate, synthetic bitumen emulsion, pigment paste, water and additives to the pugmill. The pugmill shall be a double shafted, multi-blade pugmill mixer capable of minimum speeds of 200 revolutions per minute.

The mixing machine shall have sufficient storage capacity of aggregate, emulsified synthetic bitumen, and water to maintain an adequate supply to the proportioning controls.

The mixing machine shall be equipped with hydraulic controls for proportioning the material by volume to the pugmill. Each material control device shall be calibrated, properly marked, preset and lockable at the direction of the Engineer. The mixing machine shall be equipped with a peristaltic pump to insure proper delivery of synthetic bitumen emulsion without shearing the emulsion. Other types of pumps are not allowed. The mixing machine shall be equipped with a water pressure system and nozzle type spray bars to provide a water spray immediately ahead of the spreader box.

The mixing machine shall be equipped with an approved fines feeder that provides a uniform, positive, accurately metered, pre-determined amount of a mineral filler, if used, at the same time and location that the aggregate is fed.

The colored Micro-Surfacing mixture shall be uniformly spread by means of a controlled spreader box conforming to the following requirements:

The spreader shall have strips of flexible rubber belting or similar material on each side of the spreader box and in contact with the pavement to prevent loss of colored Micro-Surfacing from the box. The box shall have baffles, or other suitable devices, to insure uniform application on super-elevated sections and shoulder slopes. Spreader boxes shall be maintained in such a manner as to prevent chatter (wash boarding) or other surface defects that will affect the esthetic value of the finished colored Micro-Surfacing mat.

The rear flexible strike-off blade shall make close contact with the pavement and shall be capable of being adjusted to the various crown shapes so as to apply a uniform colored Micro-Surfacing.

Colored Micro-Surfacing mixture, to be spread in areas inaccessible to the controlled spreader box, may be spread by other approved methods.

The colored Micro-Surfacing shall not be placed if either the pavement or the air temperature is below 55 ° F (13 ° C) and falling, but may be applied when both the air and pavement temperature is 45 ° F (7 ° C) or above and rising. The mixture shall not be applied if high relative humidity prolongs the curing beyond a reasonable time.

Before placing the colored Micro-Surfacing, the pavement surface shall be cleaned by sweeping, flushing or other means necessary to remove all loose particles of paving, all dirt and all other extraneous material.

48 hours prior to the colored Micro-Surfacing operations, the contractor shall notify all residents, businesses and agencies with an approved written notice detailing the streets and limits of work to be done along, with the hours of work. The contractor shall also post all streets with temporary "No Parking - Tow Away" signs at 50 foot (15m) staggered intervals. These signs shall also state the day of the week and hours of no parking.

Immediately before commencing the colored Micro-Surfacing operations, all surface metal utility covers (including survey monuments) shall be protected by thoroughly covering the surface with an appropriate adhesive and paper or plastic. No adhesive material shall be permitted to cover, seal or fill the joint between the frame and cover of the structure. Covers are to be uncovered and cleaned of colored Micro-Surfacing material by the end of the same workday.

Hand tools shall be available in order to remove spillage. Ridges or bumps in the finished surface will not be permitted. The mixture shall be uniform and homogeneous after spreading on the existing surface and shall not show separation of the emulsion and aggregate after setting.

Adequate means shall be provided to protect the colored Micro-Surfacing from damage from traffic until such time that the mixture has cured sufficiently so that the colored Micro-Surfacing will not adhere to and be picked up by the tires of the vehicles.

For the purpose of this project, the construction zone is defined to include all stockpile staging areas and travel routes to/from streets where the colored Micro-Surfacing is to be applied.

The Contractor shall abide, at all times, to the State of California , Department of Transportation's "Manual of Traffic Controls for Construction and Maintenance Work Zones" as applicable to this project.

Any deviations from the specifications shall not be made without prior written approval from the project engineer.

2.07 Measurement

Colored Micro-Surfacing will be measured and paid for by the square foot for the actual surface areas covered.

2.08 Payment