SECTION 413: SINGLE-MACHINE HO T IN-PLACE SURFACE REPAVING
413.1 Description
This Work consists of recycli ng the existing asphalt surface i n a simultaneous multi-step process of cleaning, heating, milling, scarifying, rejuvenating (if required), spreading, and leveling. This Work also consis ts of placing and compacting ne w HMA or WMA Material over the recycled surface. The Contract may require the Contractor to blend the recycled Material with an asphalt-rejuvenating agent.
413.2 Materials
413.2.1 Rejuvenating Agent The Contractor shall provide an agent that will rejuvenate the existing Roadway binder
properties. The Contractor shall extract, recover, and combine the existing Roadway’s asphalt Material with a virgin asphalt binder per AASHTO M 323, Appendi x A, such that the combination of the rejuvenating agent with the existing Roadway asphalt binder will meet the AASHTO M 320 requirements for the required PG asphalt grade in the approved mix design.
413.2.2 Hma
The Contractor shall provide HMA Material in accordance with S ection 416 “Minor Paving”, Section 423, “HOT MIX ASPHALT (HMA) (MAJOR PAVING)”, o r WMA Material in accordance with Section 424, “Warm Mix Asphalt (WMA).” The Contractor shall provide a HMA mix design in accordance wi th Subsection 423.2, “Materials” or a WMA mix desig n in accordance with Subsection 4 24.2, “Materials.” The State Materials Bureau must approve the HMA or WMA mix design before the beginning of the Work.
413.3 Construction Requirements
413.3.1 Equipment
413.3.1 1 General
At the Pre-Construction Conference, the Contractor shall: 1. Notify the Project Manager of the type of Equipment that wil l be used; 2. Deliver the Equipment to the Pr oject in time for the Project Manager’s evaluation; 3. Submit a Quality Control Plan in accordance with the most re cent Department’s Contractor Quality Control Guidelines for the Project Manager’s approval; 4. Provide a machine with a single, self-propelled mobile unit capable of heating, scarifying, rejuvenating, mixing, leveling the existing surface Material, and immediately laying new hot-mix Material over the recycled surfa ce; 5. Demonstrate the rate, depth, and recycling capabilities on t he Roadway before beginning operations; and 6. Correct or replace any deficiency, if the Equipment or recyc ling operations do not meet requirements.
413.3.1 2 Heating Unit
Section 413: Single-Machine Hot In-Place Surface Repaving Page 187 The Contractor shall use a height-adjustable heating unit that is specifically designed to heat the upper layer of asphalt pavement. The unit shall heat the asphalt pavement in a manner that: 1. Will not burn, char, coke, or scrub the recycled mix; 2. Will meet State and local air quality requirements; 3. Will not pose health risks or damage to property; 4. Will not break aggregate particles; and 5. Will produce enough heat to soften the pavement to at least a depth of one (1) inch. The Contractor shall apply the heat under an enclosed or shiel ded hood so that blasting or scrubbing of the existing pavement is eliminated. The Contr actor shall use Equipment that can apply heat uniformly under controlled atmospheric condition s to eliminate free oxygen under the heating chamber. 413.3.1.3 Milling/Scarifying Unit The Contractor shall use a unit that can remove pavement to a minimum depth of one
1.inch. The unit shall loosen the in-place asphalt pavement to a minimum depth of one
1.inch without excessively breaking the aggregate. The Contr actor shall use a unit equipped with automatic height, grade, and cross slope controls with eno ugh power to push the scarifiers through the high spots and create a leveled surface.
413.3.1 4 Rejuvenating Agent Storage Unit
The Contractor shall use a thermostatically-controlled storage unit to maintain the rejuvenating agent at a constan t, Supplier-specified temperatur e.
413.3.1 5 Metering Unit
The Contractor shall: 1. Use a unit that can uniformly apply the rejuvenating agent t o the milled and scarified Material. The unit shall incorporate a meter for continuous qu antity verification; 2. Vary the applied amount in direct proportion to the recyclin g system’s operating speed and synchronize with the amount of Material milled or sca rified; and 3. Not vary the rejuvenating agent’s application rate by more t han +/- 0.5% of the rate defined in the mix design.
413.3.1 6 Blending Unit The Contractor shall use a unit that can mix the scarified Mat erial with the rejuvenating
agent to produce a uniform, c onsistent final product.
413.3.1 7 Spreading and Leveling Unit
The Contractor shall: 1. Use a unit equipped with automatic grade controls, capable o f uniformly spreading and leveling the blended recycled Material; 2. Use a unit equipped with a leveling blade and auger capable of moving recycled Material in a transverse direction to the center of the windrow ; 3. Equip the unit with a recycling screed to partially compact the recycled mix before placing the top layer of new HMA or WMA; and Section 413: Single-Machine Hot In-Place Surface Repaving Page 188 4. Coordinate the repaver speed with the production of the HMA o r W M A p l a n t t o achieve a continuous operation.
413.3.1 8 Compaction Equipment
The Contractor shall use Equipm ent in accordance with Section 423.3.4, “Equipment.”
413.3.2 Construction Details
413.3.2 1 Cleaning of Existing Pavement Surface
Before beginning hot in-place recycling, the Contractor shall clean the existing pavement surface of non-asphalt Material s by blading and brooming or oth er methods approved by the Project Manager.
413.3.2 2 Heating, Milling/Scarifying, and Processing
The Contractor shall: 1. Evenly heat, mill, scarify, and rework the in-place asphalt surface to a minimum depth of one (1) inch, in accordance with the Plans; 2. Heat the existing pavement sur face with continuously moving heaters to scarify the pavement to at least a one (1) inch average depth in a single p ass; 3. Keep the surface temperature of the remaining in-place pavem ent below 475 °F and produce reclaimed mix at a temperature of at least 225 °F; 4. Extend the heating operation at least four (4) inches beyond the width of scarification on both sides; 5. Immediately scarify the heated pavement with scarifying shan ks spaced so that they cover the surface without leaving ridges; 6. Mount the shanks to allow control from the operator’s platfo rm; and 7. Scarify and cut through the pavement at a level that comes w ithin 1/4 inch of the finished pavement’s grade and cross slope. If required, the Contractor shall uniformly apply the rejuvenat ing agent to the Material immediately after milling and scarifying.
413.3.2 3 Placing and Compacting
The Contractor shall: 1. Uniformly spread and level the recycled mixture to the width , finished grade, and cross slope, shown in the Contract; 2. Place a new layer of HMA or WMA on top of the recycled pavin g material using a four (4)-section vibratory screed after partially compacting th e recycled mixture with the recycling screed; 3. Perform this in one (1) continuous operation while the tempe rature of the recycled mix is at least 225 °F; and 4. Compact the Material in accor dance with Section 423.3.5, “Pl acement Operations.”
413.3.2 4 Temperature Requirements
The Contractor shall maintain the temperature of the asphalt M aterial between 225 °F and 300 °F when measured immediately behind the laydown machine .
413.3.2 5 Joints
The heating unit shall heat a minimum of four (4) inches beyon d the width of recycling. The Contractor shall construct j oints in accordance with Sectio n 423.3.5.4, “Joints.”
413.3.2 6 Debris and Waste Material Disposal
The Contractor shall dispose of debris and waste material in a n environmentally safe manner at locations approved by the Project Manager.
413.3.2 7 Weather Limitations
The Contractor shall not perform hot in-place recycling of asp halt pavement when the Roadway surface is wet or when weather conditions prevent the p roper handling, finishing, and compacting of the asphalt mixture.
413.3.2 8 Surface Tolerance
The Contractor shall place the compacted surface of recycled p avement material or new HMA Material in accordance with Section 423.3.5.5, “Surface Tol erances.”
413.3.2 9 Plan Surfacing Depths
The Contractor shall monitor and record the Material depth of the compacted recycled pavement Material or new HMA or WMA Material throughout the pla cement operations. The Contractor shall perform this task in accordance with the Depar tment’s Minimum Testing and Acceptance Requirements and as approved by the Project Manager. The Project Manager will address a deficiency of more than 0.5 inches in-place comp acted thickness as follows: 1. Accept the in-place compacted thickness at a reduced payment ; or 2. Reject the in-place mixed Material.
413.3.3 Contractor Quality Control
413.3.3 1 Contractor Quality Control for Materials
The Contractor shall place new HMA Materials in accordance wit h Section 423.3.6.1, “Contractor Quality Control” or WMA Materials in accordance wit h Section 424.3.6.1, “Contractor Quality Control,” except take random test samples f rom the HMA or WMA windrow before the Material goes through the paver.
413.3.3 2 Contractor Quality Control for Compaction
See Section 423.3.6.1.2, “Contractor Quality Control for Compa ction.”
413.3.3 4 Project Verification Testing
New HMA Material is subject to Independent Assurance Testing i n accordance with Section 423.3.6.4, “Independent Assurance Testing.” New WMA Ma terial is subject to Independent Assurance Testing in accordance with Section 424.3. 6.4, “Independent Assurance Testing.”
413.3.4 Department Quality Assurance
Section 413: Single-Machine Hot In-Place Surface Repaving Page 190 413.3.4.1 Department Quality Assurance for HMA New HMA Materials shall meet the requirements of Section 423.3 .6.2.1, “Acceptance,” and new WMA Materials shall meet the requirements of Section 42 4.3.6.2.1, “Acceptance,” with the exception that the Department will base Acceptance on random test samples taken from the HMA or WMA before the Material goes through the paver.
413.3.4 2 Department Quality Assurance Testing for HMA Compacti on
The Contractor shall meet the requirements of Section 423.3.6. 2.1 “Acceptance” or Section 424.3.6.2.1, “Acceptance.” The Project Manager will gr ant an exception to the mean density requirement of at least 93% of the theoretical maximum density if the Contractor can demonstrate that a minimum of 93% cannot be reasonably obtained because of the conditions of the existing Pavement Structure or Subgrade Materials. If t he Project Manager grants this exemption, the Contractor shall construct a Roadway test strip and develop a HMA or WMA compaction process to get the highest possible density based on an approved roller’s density gain per pass, in accordance with Section 423.3.4.4, “Compactio n Equipment.” The Project Manager will approve the process (except for the Roadway test s trip) before paving operations begin. In no case shall the percentage of theoretical maximum density exceed 98% nor fall more than three (3) percentage points lower than the target den sity. If a lot does not meet either of these density requi rements, the Project Manager will do the following: 1. Accept and pay for the lot of HMA or WMA Material at 50% of the Bid Item Unit Price; or 2. Reject the in-place Material and require the Contractor to r emove and replace. If the Project Manager determines that the mean measured densi ties are consistently higher, but not to exceed 93%, or lower than the current lot’s target density, the Project Manager may establish a new Acceptance lot on the Project.
413.3.4 3 Department Quality Assurance Testing for HMA/WMA Smoo thness
If the Contract requires two (2) or more lifts of new HMA/WMA Material, place in accordance with Section 401, “Pavement Smoothness Measurement.” For the purposes of this section, Hot Recycled Insitu Material is not defined as HM A.
413.4 Method of Measurement
If the Contract requires HMA, the Department will measure it i n accordance with Section 423.4, “Method of Measurement.”
413.5 Basis of Payment
The Department will pay for new HMA Material in accordance wit h Section 423.5, “Basis of Payment.” Pay Item Pay Unit Single-Machine Hot In-Place Surface Repaving Square Yard HMA or WMA Sampling and Testing by the Contractor Lump Sum Rejuvenating Agent Gallon
413.5.1 Work Included in Payment
Section 413: Single-Machine Hot In-Place Surface Repaving Page 191 The Department will consider as included in the payment for th e pay item(s) listed in this section and will not measure or pay separately for the followin g Work: 1. Recycling existing in-place a sphalt surface in a multi-step process of cleaning, heating, milling, and rejuvenati ng (if required), spreading and leveling; 2. Placing and compacting new HMA/WMA over recycled surface; 3. Shipping/Delivery of new HMA/WMA to Project site; and 4. Development of the Contractor Quality Control Plan in accord ance with Section 902, “Quality Control.” Section 414: Cold Milling Page 192
Source: New Mexico Standard Specifications for Highway and Bridge Construction, 2019 Edition. Pages 0–0 of 974.