2309.01 GENERAL.
This work shall consist of recycling the existing asphalt pavement surface by heater scarification, and resurfacing with HMA.

2309.02 SURFACE RECYCLING BY HEATER SCARIFICATION.
Heater scarification and resurfacing shall be part of a multi-step process of asphalt surface rehabilitation that consists of preparing the existing asphalt surface, softening the surface with heat, scarifying the surface, and thoroughly stirring or tumbling and leveling the mixture in preparation for an asphalt surface course overlay. The work will include furnishing and placing the new surface course.

A. Materials.
Materials for the surface course shall meet requirements for the type of mixture specified.

B. Equipment.

1. Heater Scarifier.
Equipment for preheating, heating, and scarifying shall be a type that has operated successfully on similar work for the Contracting Authority, or equipment proven through test results or other previous experience or both, that is satisfactory to the Engineer. Test results and other previous experience may be submitted to the Engineer, prior to the letting, for review.

Preheating and heater scarification equipment shall be designed for the purpose of pavement heating and shall be capable of producing at least 10 million BTUs per hour (10 GJ/h). Heat shall be applied under an enclosure or shielded hood.

Scarifying shall be accomplished with pressure loaded rakes or scarifiers. Where scarifying to an existing curb and gutter line is required, the scarifying unit shall be equipped to scarify and move away from gutter aprons a 1/2 inch (13 mm) by 4 foot (1.2 m) path of existing material. The scarifier shall be of a type to insure continuous and undiminished pavement contact without damaging utility accesses and valve boxes.

The leveling unit shall be capable of distributing the heated and scarified material over the width being processed to produce a uniform cross section. The leveling device shall have the capability of windrowing excess material to one side for removal when necessary. The heater scarification operation shall be capable of processing at a rate of at least 1500 square yards per hour (1250 m²/h) over a minimum one lane width of 12 feet (3.6 m).

2. Hot Mix Asphalt Construction Equipment.
Equipment for batching, mixing, hauling, placing, and compacting the surface course shall meet requirements for the type of mixture specified.

C. Paving Plant Operation.
Paving plant operations shall meet requirements for the type of mixture specified.

D. Construction.

1. Surface Preparation.
Base repair, if required, shall meet requirements of Section 2212. Locations of full depth patches will be designated by the Engineer.

The pavement surface to be heater scarified shall be prepared by cleaning trash, debris, earth, or other deleterious substances present in sufficient quantity to interfere with the work to be performed.

2. Heating and Scarifying.
The pavement surface shall be evenly heated and scarified for the full width designated in the contract documents as a continuously moving operation. The combination of preheater and heater scarification units shall be such as to be able to process a minimum of 1500 square yards per hour (1250 m²/h) without charring and/or otherwise damaging the existing pavement material through exposure to heat or fire. Processing shall be at this rate except when limited by rate of delivery of the overlay mixture. The heating operation shall be controlled to prevent open flame from exiting from under the heater. The Engineer may require that the operation be stopped when the prevailing wind velocity exceeds approximately 10 mph (16 km/h), and a potential hazard exists or heating and scarifying are not possible.

The minimum depth of scarification shall be 3/4 inch (20 mm) at the highest points, such as the edge and the high point between the wheel paths. The minimum depth of scarification shall also be 1/2 inch (15 mm) at the lowest points, such as the wheel paths. The required depth of scarification may be changed by the contract documents. The scarifiers shall scarify the pavement to at least the depth specified with pressure loaded scarifiers that plow through the pavement and loosen it without fracturing or segregating the aggregates. The surface temperature of the old pavement shall be below 475°F (245°C) during heating, and the heated material shall have a temperature in a range between 220°F to 260°F (105°C to 125°C), measured immediately behind the heater scarifier. The remixed layer shall be uniformly and evenly heated throughout. Uncontrolled heating, causing differential softening of the upper surface, will not be permitted. The heating operation shall extend at least 4 inches (100 mm) beyond the width of the scarification on both sides.

When a heater scarifier pass is being made adjacent to a previously placed mat, all damaged material shall be removed and replaced.

3. Leveling.
Following the heater scarification, the surface shall be leveled to provide a uniform cross slope. The method used to redistribute and level the scarified material shall be an approved system of augers with a strike off plate or screed which is an integral part of the scarifying machine or an asphalt paving machine meeting the requirements of Article 2001.19; this attachment or machine shall follow the scarifier as closely as practical.

4. Hot Mix Asphalt Surface Course Overlay.
After reshaping the scarified mix and before the temperature drops below 170°F (77°C), a uniform layer of new surface course material shall be placed at the rate shown in the contract documents. The Engineer may direct additional mixture to be added to correct irregularities. Equipment for placing and finishing the new surface shall meet requirements of Article 2001.19, except that a non self propelled paving machine attached to the heater scarifier may be used provided the screeding unit complies with requirements of that specification.

When a self propelled paving machine is used, placement of the new surface shall be within 400 feet (120 m) of the scarification operation or before the surface temperature cools to 170°F (77°C), whichever occurs first.

Provisions shall be made for alignment and control of the scarification operation. The method used shall be subject to the approval of the Engineer.

E. Compaction of Mixture.
After the new surface course is spread, all the mixture shall be promptly and thoroughly compacted in accordance with Article 2303.03, E, 2.

F. Joints.
Joints shall be constructed in accordance with the requirements of Article 2303.03, F, and as shown in the contract documents.

G. Finished Surface.
Finished pavement elevations shall comply with requirements of the contract documents. The finished cross slope shall be a plane surface with a slope as shown.

All edges, radii, and handwork shall produce a neat, finished product.

H. Safety Procedures.
Prior to construction in cities, towns or built up areas, the Contractor shall solicit a recommended safety procedure to be followed from the fire chief and shall follow these recommendations. In addition to any other recommendations, the following procedure shall be followed:

1. Owners of underground utilities in the areas shall check the areas for possible gas leaks in or around their lines;

2. The city shall check storm sewers and sanitary sewers in the area for accumulations of sewer gas;

3. Service stations and other businesses handling flammable fuels shall be advised not to dispense these fuels while the heater burner is being operated within 100 feet (30 m) of their business places;

4. The operation shall be planned so as to be as safe as possible for persons and properties adjacent to the work, including the traveling public. This route shall be kept open to traffic, the Contractor shall limit the operation so as to provide for this traffic, and the Contractor may be required to conduct the work during periods of light traffic.

The Contractor shall take such additional precautions as is reasonable for the safety of the operation.

The Contractor shall hold the Contracting Authority and the State harmless for any damage or loss resulting from an accident, during the heating operation, caused by failure to fulfill the obligations as outlined in these requirements.

2309.03 LIMITATIONS.
Article 2303.03, D, shall apply.

2309.04 METHOD OF MEASUREMENT.

A. Surface Recycling by Heater Scarification.
The areas satisfactorily prepared, heated, scarified, leveled, and resurfaced (new mix excluded) will be computed in square yards (square meters), of surface recycling by heater scarification as provided in Article 2303.05, A, 2.

B. Hot Mix Asphalt Surface Course.
Hot Mix Asphalt Surface Course, of the type specified, will be measured as provided in Article 2303.05.

2309.05 BASIS OF PAYMENT.

A. Surface Recycling by Heater Scarification.
For the square yards (square meters) of Surface Recycling by Heater Scarification, measured as provided above, the Contractor will be paid the contract unit price per square yard (square meter). This payment shall be full compensation for furnishing all labor and materials for surface recycling by heater scarification as described above.

B. Hot Mix Asphalt Surface Course.
Hot Mix Asphalt Surface Course of the type specified, will be paid for as provided in Article 2303.06.