344FULL DEPTH RECLAMATION

344.1DESCRIPTION—This work consists of in -place pulverizing and mixing a combination of existing

roadway material layers, stabilizing additives, and imported aggregate or RA P material, as required, to specified depths and grading, and compacting the mixed materials to form a new pavement base layer upon which an asphalt overlay, or a surface treatment is applied. This work is defined as full -depth reclamation (FDR), and often includes the incorporation of additional materials based on an approved FDR mix design.

344.2MATERIAL—

which may include bound pavement layers, aggregate subbase material, and subgrade material, such that 95% of the material passes the 2-inch sieve.

14 or provide reclaimed aggregate material (RAM) meeting the specified size (e.g., AASHTO No. 57) as required by the approved mix design.

processed RAP material with 95% passing the 2-inch sieve.

included in the approved mix design. Potential additives are not limited to the materials listed below. Those listed below include references to sections with additional information.

1.a Emulsified Asphalt Material. Section 702, Class CMS-2, SS-1h, CSS-1h, SS-1hP, HFMS-2 or CSS-1hP.

2.a Portland Cement. Section 701

2.a.1 Portland Cement Slurry . Section 701 Portland Cement Slurry must be produced at a concrete plant listed in Bulletin 42 and supplied in Ready Mix Concrete Trucks approved by the DME/DMM. Other slurries must be provided in distributor and tanker trucks equipped with a recirculating pump and/or agitation system to prevent settling of the materials before application.

2.a.1.a Admixtures. Section 711.3

2.b Hydrated Lime. Section 723

2.c Supplementary Cementitious Material. Section 724

2.d Lime Pozzolan. Section 725

roadway materials according to Publication 242 Pavement Policy Manual. A formal design protocol should be followed to optimize the performance of the pavement section. After selecting the appropriate stabilizing additive(s), develop a mix design following the appropriate mix design procedures for the stabilizing additive(s) as follows:

TABLE A Mix Design Procedure for Primary Stabilizing Additive Type Primary Stabilizing Additive Mix Design Procedure Asphalt Pub. 27 (Bulletin 27) Chemical (Portland Cement, Hydrated Lime, Supplementary Cementitious Material**& Portland Cement Slurry)

Pub. 242 Appendix J.3 Calcium Chloride PTM No. 106 *, Pub. 242 Appendix J.3 *When used as the primary stabilizing material, calcium chloride should be applied as a minimum 35% solution at a rate between 0.10 to 0.15 gallons per square yard for each inch of depth reclaimed. **Calcium oxide is used to activate the cementitious performance of Supplementary Cementitious Material.

Submit the mix design for the FDR work as specified in Section 108.03.

344.3CONSTRUCTION—Comply with applicable environmental standards. Appropriate equipment and

techniques should be used to protect adjacent properties from fugitive dust or other material components of the FDR process. Dry additive will not be applied when the wind conditions are such that blowing additives become objectionable to traffic or adjacent property owners. Manual and/or gravity (tail gate) spreading of the additives is unacceptable. Stabilization may be accomplished using asphalt material, Portland cement or other chemical stabilization materials, or calcium chloride according to the recommendations of the FDR Best Practices found in Publication 242 and approved in the project mix design.

size of 2 inches in the greatest dimension, blend, shape, and compact the FDR materials.

cutting through existing roadway to depths of up to 16 inches, or as required by the design, with one pass. The equipment must also be capable of pulverizing “in -place” the existing pavement, subbase, and subgrade materials, at a minimum width of 8 feet, and mixing any added materials to the specified depth. The cutting drum must have the ability to operate at various speeds (rpm), independent of th e machine’s forward speed, to control oversized material and gradation. Use a machine equipped with a computerized integral liquid proportioning system capable of regulating and monitoring the water application rate relative to depth of cut, width of cut, and speed. Connect the water pump on the machine to the water supply tanker or distributor by a hose, and mechanically or electronically interlock the flow of water with the forward ground speed of the machine. Mount the spray bar to allow the water to be injected directly into the cutting drum/mixing chamber. Provide equipmen t capable of mixing water, dry or liquid stabilizing additives, emulsion, and the pulverized pavement into a homogenous mixture.

Keep the cutting drum fully maintained and in good condition at all times throughout the project. Equipment such as road planers or cold -milling machines designed to mill or shred the existing roadway rather than crush or fracture them is not allowed.

1.a Use equipment capable of automatically metering liquids in the mixture and ensure thorough mixing of the reclaimed materials. Use equipment that is alsoable to record the volumes metered.

1.b Maintain equipment as specified in Section 108.05(c).

pneumatic tire roller for breakdown and intermediate rolling if the FDR is emulsion or foamed asphalt based and is less than 8 inches in depth. Use a 25-ton vibratory padfoot roller for initial breakdown if FDR is 8 inches or deeper. Perform finish rolling using a single or tandem steel drum static roller of 12 to 14 tons.

fall, below 40F within the subsequent required 7 -day cure period. Do not perform reclamation in rain, or if rain is anticipated within 2 hours of completion of the work. Cement slurry with accelerating admixtures may be used in periods of cooler temperatures with the written approval of the DME/DMM. Do not place cement slurry mixtures with accelerating admixtures when the air temperature is anticipated to fall below 35F within the first 24 hours following placement.

Identify the equipment, personnel, and processes to be used during the work. Ensure that all equipment is operational and functional before deployment to the job site. All equipment must be properly calibrated before application. This calibration should be verified through the test strip. Operators of water and additive applicators must keep proper records of the amount of material applied and the times of application. Describe means of establishing and controlling centerline, proposed crown and any existing or proposed superelevations.

FDR process including final compaction and shaping. Verify application rates for materials incorporated into the FDR process including stabilization materials and water. Identify and correct aspects of the work not conforming to the contract requirements before proceeding with full production work. If aspects of the work are not found to be adequately controlled to produce the desired mixed and refinished reclaimed roadway, construct additional test strips until the necessary control is established. After completing the test strip and demonstrating that the minimum density can be achieved as specified in 344.3(e)3.a, determine n=1 density of the FDR according to PTM No. 402 for each 3,000 square yard lot.

depth specified. Shape the pulverized material to the approximate line and grade. Adding Calcium Chloride during pulverization is acceptable.

additive(s), and water according to the mix design and at the mix design recommended moisture content. Maintain adequate liquids in the mixture to ensure thorough mixing of the reclaimed material, aggregates, RAP , and stabilizing additives. If conditions change, make field adjustments to obtain a satisfactory FDR material. If slurries are used, use Ready Mix Concrete Trucks or equip the distributor and tanker trucks with a re-circulating pump and/or agitation system to prevent settling of the materials before application. If using slurry delivered in Ready Mix Concrete Trucks, verify “cement” application rate by calculating the weight of cement contained in the mixer truck and the area covered by the slurry after discharge by the Ready-Mix Concrete Truck. The cement slurry producer must supply a written record of the amount of cement, water, and admixture with each load of cement slurry. Evenly and uniformly distribute the cement slurry, over the area of the prepared subgrade, calculated to provide the required application rate. Accelerating or retarding admixtures maybe added to the cement slurry with the written approval of the DME/DMM.

compacted maximum density at optimum moisture content according to PTM No. 106. Demonstrate that the minimum specified density can be achieved during paving of the compaction control strip. After completing the compaction control strip and establish the roller pattern as specified in Section 344.3(e)3.a , determine n=1 density according to PTM No. 402 for each 3,000-square yard lot. Commence rolling at the low side of the course. Leave 3 to 6 inches from any unsupported edge(s) unrolled initially to prevent distortion. Compact the entire reclaimed area using the number of uniform passes of compaction equipment determined from the control strip, ensuring that uniform density is achieved throughout. Complete compaction of chemically stabilized reclaimed material within 4 hours of the water/additive mixing operation.

3.a Compaction Control Strip. Establish a roller pattern that achieves at a minimum the density specified in Section 344.3(e)3 by the construction of at least one 300 -foot long control strip during initial reclamation. The compaction control strip may be contained within the project startup test strip. Take nuclear density reading tests according to PTM No. 402 after each pass of the compaction equipment. The properly calibrated nuclear gauge must be operated in direct transmission mode. Continue compaction with each piece of equipment until no appreciable increase in density is obtained by additional passes. Upon completion of compaction, make a minimum of ten tests at random locations according to PTM No. 1 to determine the average in -place density of the compaction control strip. Provide density results to the Representative for verification to the minimum density requirements as specified in Section 344.3(e)3. If the density of the compaction control strip is less than the minimum density specified in Section 344.3(e)3, but the base course is uniform in texture, stable, and otherwise acceptable, provide additional compaction. If additional compaction does not achieve the minimum density, construct another compaction control strip to verify that the minimum density is achievable with the FDR process and mix design in use. Take a minimum of ten tests at random locations according to PTM No. 1 to determine the average in place density of the new compaction control strip. The minimum density for the new control strip is 98% of the control strip density.

3.b Moisture Content. Verify the original moisture content of the road material to be reclaimed before starting work. The moisture content can be determined according to ASTM D2216, ASTM D44643, or AASHTO T 265. Make appropriate adjustment between the moisture content determined at the time of mix design sampling and current moisture content by adjusting the design recommended water application rate. The moisture content for compaction must achieve the optimum moisture content as determined from the project mix design but cannot exceed optimum by more than 3%.

centerline, grades and/or cross -slope of the proposed roadway. Avoid excessively working the chemically stabilized FDR material, which may detrimentally affect the ultimate strength of the stabilized layer.

on the reclaimed material during the 7-day cure period. Appropriate traffic signs must be posted to prevent heavy traffic on the constructed base until completion of base curing and application of the overlay. For chemical stabilization, maintain the reclaimed layer in a damp condition by the daily application of water to the surface, or the application of an emulsified asphalt prime material followed by an asphalt fog seal at a residual asphalt rate between 0.02 and 0.10 gallons per square yard, or Tack Coat as specified in Section 460. Apply while FDR material is at optimum moisture content, but not exceeding more than 3%. The rate of curing depends on many factors. In favorable weather conditions (no rain, sunshine, low humidity, high temperature), curing can take place at a considerably faster rate. Sufficient curing and strength gain could take from 2 or 3 days to at least 2 weeks depending on the type and amount of materials used and the climatic conditions. FDR should be proof rolled with a vehicle similar to the heaviest vehicle expected in traffic, or base opening on a strength measurement of the FDR, before opening to traffic. Same day return to car traffic at posted safe speeds is possible. In general, the constructed base could be opened to light traffic (vehicles under 5 tons) 2 hours after completion of the base c onstruction, with proof rolling. For emulsified asphalt stabilized roadways, the moisture content should be at 50% of the design optimum moisture content or 3% total moisture content, whichever is reached first, before overlay. No damage should be apparent at slow

speed, less than 10 miles per hour. Immediately correct the damage. Otherwise verify strength by testing as covered under 344.3(g).

both transversely and longitudinally. Satisfactorily correct any 3,000 -square yard lot where the average surface irregularity exceeds 1/2 inch under a 10-foot template or straightedge, based on a minimum of at least three measurements within the lot. Provide a minimum final surface cross slope of 1/4-inch per foot, or as otherwise required by the project design.

and procedures as specified in Section 901. Provide MPT until the road can be opened to traffic as specified in Section 344.3(h).

for surface tolerance as specified in Section 344.3( e)6, for density as specified in Section 344.3( e)3, and strength as follows. Any lot failing to meet the acceptance criteria will be identified for rework. Cores may be taken to determine the extent of the failing area. Once a failed area has been identified, develop and obtain approval of a new mix design. F ailed areas must be reclaimed again with the additional stabilizing material, as necessary, to achieve the required acceptance criteria. Fill core holes remaining outside the reworked area with an approved repair material listed in Bulletin 15. Make a minimum of three standard Proctor samples according to ASTM D1633 for strength testing for each lot size of 3,000 square yards. Wrap the specimens in plastic wrap, seal in an airtight, moisture proof bag and cure the test specimens for a period of 7 days. Follow PTM No. 1 for selecting sample locations from the reclaimed material after addition of the stabilizing additive . For emulsion based mixes or mixes stabilized with foamed asphalt, an accepted alternative approach will be compaction of specimens with the Superpave Gyratory Compactor (SGC) to a thickness between 2 and 3 inches using 50 gyrations.

inch when tested according to Bulletin 27. This requirement is for specimens compacted in the SGC to a thickness between 2 and 3 inches.

square inch in 7 days when tested according to ASTM D1633 for the roads to be surfaced with less than a 3-inch overlay or asphalt surface treatment. Achieve an unconfined compressive strength value of 280 to 500 pounds per square inch in 7 days for roads to be surfaced with an asphalt overlay of 3 inches or greater. For emulsion based mixes as well as mixes stabilized with foamed asphalt, the minimum compressive strength requirement will be 280 pounds per square inch. If the average of the specimens does not meet the minimum required strength listed above, rework will be required. Chemically stabilized material tested to strengths greater than 900 pounds per square inch may result in shrinkage cracking, and rework will be required.

been achieved. Limited local light vehicular traffic may be allowed once the reclaimed material has obtained a stable condition. Repair damage resulting from local traffic. Do not allow trucks to use the road until the above referenced 7-day strength has been achieved.

344.4MEASUREMENT AND PAYMENT—

1.a Chemical Additive. Gallon or Ton.

1.b Emulsified Asphalt Material. Gallon.

1.c Calcium Chloride Additive. Gallon.

1.d Magnesium Chloride Additive. Gallon.