3-19 Section 312 – Full Depth Reclamation, Emulsion
312.01 DESCRIPTION . This work shall consist of performing full depth reclamation (FDR) by pulverizing the underlying material, mixing with emulsified asphalt and Portl and cement, fine grading, and compacting the homogenous base materials to the depth, width, grade, and desired density specified in the Contract. 312.02 MATERIALS . Materials shall meet the requirements of the following subsections: Portland Cement ................................ ................................ ................................ ......... 701.0 2 Anionic Emulsified Asphalt ................................ ................................ ....................... 702.02(a) Cationic Emulsified Asphalt ................................ ................................ ...................... 702.02(b) Water ................................ ................................ ................................ .......................... 745.01 Emulsified asphalt for base stabilization shall be type, HFMS -2, HFMS -2h, HFMS -2s, MS-2h, CMS -2h, SS-1h, CSS -1, or CSS -1h as recommended by the Contractor mix design. The pulverized material shall consist of the existing pavement blended with underlying subbase material and additional aggregate material and shall conform to the gradation requirements of Table 312.02A . TABLE 312.02A – FDR GRADATION REQUIREMENTS Sieve Designation Percentage by Mass (Weight) Passing Square Mesh Sieves 3 inch (75.0 mm) 100 1-1/2 inch (37.5 mm) 80 – 100 No. 4 (4.75 mm) 30 – 60 312.03 EQUIPMENT .
a.General Requirements . Any additional equipment used by the Contractor beyond th at specified below shall be approved by the Engineer based on its suitability to produce results meeting the specification requirements.
b.Reclamation . The Contractor shall use a self -propelled, traveling rotary reclaimer or equivalent machine capable of cutting through existing roadway material to depths of up to 16 inches with one pass. The equipment shall be capable of pulverizing the existing pavement, base, and subgrade in-place, and mixing any added materials to the specified depth. The cu tting drum shall have the ability to operate at various speeds (rpm), independent of the machine’s forward speed, to control oversized material and gradation.
3-20 The Contractor shall provide and use equipment that will produce the completed FDR -emulsion
base as specified herein. In addition, the equipment used shall be capable of automatically metering the emulsion with a variation of not more than ± 2% by weight of the emulsion. Calibration records shall be provided to the Engineer before use of any equi pment as requested. The Contractor shall maintain all equipment in a satisfactory operating condition. The Contractor shall ensure a full and homogeneous distribution of the emulsified asphalt stabilizing agent. In concert with this requirement, the recla imer shall be equipped with a means for the Engineer to continually monitor reclamation depth or, alternately, the QC data shall be immediately available at all times. The reclaimer drum shall rotate in the opposite direction of the reclaimer tires or as per the manufacturer’s recommendation. The Contractor shall inspect the condition of the cutting teeth on a daily basis, replace all worn and broken cutting teeth, and keep the cutting drum fully maintained and in good working condition at all times. Th e inability of the reclaimer to produce the required design objectives will subject the equipment to rejection by the Engineer and require QC plan amendments to address equipment faults.
c.Compaction . The Contractor shall use a vibratory pad -foot roller having a dynamic force of 25 tons for breakdown compaction and shall perform intermediate rolling using a single steel drum roller of 12 tons to 14 tons. A pneumatic tire roller shall be used for finish rolling to create a close - knit texture. Additional co mpaction equipment may be used by the Contractor to achieve desired compaction. 312.04 CONSTRUCTION REQUIREMENTS .
a.General Requirements . For quantity calculation and construction purposes, a Portland cement content of 1.0% was used to estimate the req uired Portland cement tonnage for this work. Cement has been included in the work to expedite the FDR curing process. Agency personnel and equipment shall be allowed free and full access to the project site at no additional compensation due the Contracto r to allow for any and all sampling required to assess compliance with the provisions of this specification. The Contractor will afford the Agency all traffic control operations and provide means to extract samples as requested to achieve this effort.
3-21 The emulsified asphalt and cement contents used in production may vary throughout the project
and be adjusted by the Contractor based on the results of QC testing or other variables as identified by the Agency or the Contractor to maintain an optimized f inished product. Any manholes, valve covers, or other buried structures shall be protected from damage prior to beginning work. Construction operations shall be sequenced such that the entire roadway width is reclaimed and compacted to the depth specified on the Plans . The length of reclaimed base pulverized shall not exceed the length that can be completely pulverized, mixed, and compacted in the same working day. The compacted material shall provide a stable surface for traffic as directed by the Engineer. The Contractor shall protect any surface or buried structures (bridges, culverts, slabs, utilities, shallow drainage pipes, etc.) during pulverization and chemical stabilization, including stopping pulverization and reclamation at these obstruct ions when required. When approaching any surface or shallow buried structures, the Contractor shall terminate mechanical pulverization or mixing a minimum distance of 2 feet from said structure. The Contractor shall remove the unpulverized material through other means and take care not to damage the structure. The Contractor shall replace the removed material with full depth treated material that has been fully mixed and treated with the applicable chemical. Damage to these surfaces and buried structures wi ll be repaired at the expense of the Contractor.
b.Design Criteria . The FDR mix design shall meet the design criteria requirements of Table 312.04A . TABLE 312.04A – DESIGN REQUIREMENTS Test Method Criteria Indirect tensile strength, dry subset, AASHTO T 283 40 psi , min. Ratio of residual asphalt to cement 2.5 to 1, min.
3-22 (c) Mix Design . The Contractor shall develop an FDR mix design consisting of blended aggregate,
RAP, emulsified asphalt, and Portland cement. To obtain material to develop the mix design , the Contractor shall sample existing pavement to represent the reclaimed aggregate s that would be expected to result from the first pass of the reclamation process. A minimum of four samples representative of the quarter points of the entire length of the project shall be taken. The sampling process may occur either before or after mill ing, however, if it occurs before milling, any alternate means of removing the excess pavement to conduct the simulation shall be approved by the Engineer. The Contractor shall develop and submit a material sampling plan for review and approval by the Agen cy a minimum of 5 working days prior to obtaining mix design samples. At a minimum, the sampling plan shall include the number of samples, location of samples, and the method of sampling and backfilling. Additional FDR and subbase blends may be required in design analysis as directed by the Engineer. AASHTO R 109 shall be the method used to develop a mix design in accordance with AASHTO M 347, except only meeting specified design requirements in Table 312.04A . The resultant job mix formula (JMF) shall co ntain the percent passing each sieve, emulsified asphalt type and content as a percent of total FDR material, cement content as a percent of total FDR material, maximum density, and recommended water content range as a percentage of dry FDR material. A minimum of 10 working days shall be allowed for evaluation of the submitted mix design. A copy of all test data used in developing the mix design, including graphs, shall be required with the submittal of the mix design. The Engineer may approve changes in the design’s job -mix formula or discontinue use of the design if placement, finishing, or compaction characteristics are determined to be unsatisfactory.
d.Geometry and Limits of Pulverization, Reclamation, and Grading . The stabilized material shall extend to the Plan depth and width of the roadway and shall not be more than 2 inches narrower nor more than 6 inches wider than the Plan edge of stabilized material. Stabilized material that spreads over the edges and creates a surface crust that is less than the full depth indicated on the Plans is not considered to be full depth emulsified asphalt stabilized material and shall be reclaimed to meet the Plan requirements as directed by the Engineer. The design depth and line of stabilized material shall be fully homogenous of emulsion stabilizer, shaped, graded, and compacted to within 1 inch of the design depth.
3-23 (e) Stabilization . The stabilizing agent shall be emulsified asphalt as specified in the JMF and shall be
delivered to the reclaimer and distributed by the reclaimer in such a way as to ensure a uniform distribution across the roadway. The Contractor shall provide a method for verifying that the correct amount of emulsion is being applied uniformly to the entire depth of the reclaimed layer and shall also provide a means for the Engineer to continually monitor, in real time, the forward speed of the reclaimer. At no time sh all the reclaimer have a forward speed greater than 30 feet per minute unless the Contractor otherwise demonstrates that the stabilizer is fully and evenly mixed throughout the full depth of the finished FDR material. Longitudinal joints between successiv e reclamation passes shall overlap a minimum of 6 inches. The Contractor shall provide a sufficient number of mixing passes so that the minimum 6 inch overlap is achieved. The Contractor shall sequence the operations in order to complete all pulverization and mixing activities across the full width of the roadway within the same work shift. Longitudinal cold joints are not allowed in the emulsified asphalt stabilized base.
f.Compaction . For compaction of the FDR, the moisture content shall be within the range of the optimum moisture content ± 2%. The Contractor shall monitor the moisture content using a moisture meter or as otherwise approved or directed by the Engineer. If the optimum moisture content is not attained, then the material shall be reworked to bring the moisture content back into specification prior to completing further operations. The FDR shall be compacted to 95% to 105% of the target maximum density (TMD). If two out of three consecutive density test results are outside of the allowable range, the Contractor will be required to construct a new test section to establish an updated TMD. If the Engineer determines that the TMD is apparently incorrect, as evidenced by being achieved with little or minim al compactive effort, then the Engin eer will require a new control section to establish a new TMD.
g.Curing and Maintenance . After the FDR has been compacted, traffic, including the Contractor’s equipment, shall not be permitted on the pulverized pavement for a minimum of 2 hours unless otherwise approved by the Engineer. Prior to placement of any bituminous overlay, the pulverized pavement shall be allowed to cure until the free moisture is reduced to 2% or less, by total weight of mix in accordance with AASHTO T 217 . However, the FDR shal l be covered by bituminous pavement within 14 calendar days of being mixed and compacted.
3-24 The Contractor shall protect and maintain the FDR in good condition until all work is accepted.
Such maintenance shall be performed by the Contractor at the Co ntractor’s expense. Maintenance shall include immediate repairs of any defects that may occur. If it is necessary to replace any processed material, the replacement shall be full depth, with vertical cuts, using treated material with strength properties eq uivalent to the original FDR material. No skin patches will be permitted. Portions of the FDR damaged by rain shall be reconstructed at the Contractor’s expense. Dust control shall be taken on the FDR sections to reduce the production of nuisance dust and reduce the hazard to traffic. When a dust control agent is not specified on the Plans, water or calcium chloride shall be used.
h.Weather and Seasonal Limitations . Emulsified asphalt stabilization shall not be performed when soil temperatures are expect ed to be less than 40°F within the next 72 hours or freezing temperatures within 7 calendar days of curing operations unless requested and subsequently authorized in writing by the Engineer. Stabilization shall not occur when rainfall is reasonably expected within 24 hours of emulsion application. The Contractor shall monitor the weathe r and sequence operations accordingly and provide necessary repairs to work that has been damaged by inclement weather. The Contractor shall not perform stabilization from September 1st to May 15th, inclusive, unless requested in writing and subsequently a pproved by the Engineer. The quality control program shall adequately address these factors. 312.05 QUALITY CONTROL .
a.General Requirements . The Contractor shall sample, test, and evaluate the FDR process in accordance with the procedures and minimum frequencies specified in Table 312.05A . TABLE 312.05A – MINIMUM QUALITY CONTROL FREQUENCIES Test or Action Frequency Test Method Density 1 per 1,000 feet per lane AASHTO T 310 or ASTM D7830 Moisture content 3 per day AASHTO T 217 , AASHTO T 255 , AASHTO T 310 , or ASTM D7830 Yield for cement and emulsion 2 per day at even intervals Tank check Gradation and asphalt content of final product 1 per day AASHTO T 30 (dry), AASHTO T 164 , or AASHTO T 308
3-25 Density testing locations shall be sited at various transverse offsets within the lanes.
Gradation failures shall require the Contract or to take action to adjust the process to achieve compliant material. Additional aggregate material added to correct gradation shall meet the requirements of Subsection 704.05 (b). Quality control records shall include all sampling events, testing events, and process changes with accurate time and location data. The Contractor shall submit QC records and summaries to the Engineer by 1:00 p.m. on the next working day. The Contractor shall make all test results, including randomly sampled densities, availabl e to the Engineer onsite and on request. The Contractor shall cease recycling operations whenever one of the following occurs:
1.The computed yield of each additive differs from the approved JMF by 10% or more.
2.The Contractor fails to follow the app roved QC plan.
3.The finished product is visually segregated, unstable, or otherwise defective, as determined by the Engineer. Recycling operations shall not resume until the Contactor and the Agency agree on the corrective action to be taken.
b.Quali ty Control Plan . The Contractor shall submit a quality control plan (QC plan) to the Engineer a minimum of 14 calendar days prior to initiating FDR operations and shall not commence FDR operations until the QC plan is accepted by the Engineer. The QC plan shall address any items that affect the quality of the recycling process including, but not limited to, the following:
1.QC Plan Administrator . The QC plan administrator shall be identified in the QC plan and shall list their past experience on FDR projects stabilized with emulsion. They shall:
a.Be a full -time employee of the Contractor or an independent consultant not involved with the acceptance activities of the project .
b.Have a minimum of four years of experience in quality control activities in construction operations .
c.Have full authority to institute actions necessary for successful implementation of the QC plan.
3-26 (2) Quality Control Technician . The quality control technicians (QCT) shall be responsible for
conducting qu ality control and inspection activities to implement the QC plan. There may be more than one QCT on a project. They shall:
a.Be a full -time employee of the Contractor or an independent consultant with a minimum of two years of experience in quality contro l activities in field construction operations .
b.Have completed the requirements for the applicable testing by the Northeast Transportation Training and Certification Program (NETTCP) for Soils and Aggregate Inspector, or an equivalent regional program .
c.Have full authority to institute actions necessary for successful implementation of the QC plan.
3.Minimum Quality Control Parameters . Minimum quality control parameters are:
a.Make and type of reclaimer.
b.Make and type of rollers and their respecti ve location.
c.Gradation and asphalt content results.
d.Moisture content behind the reclaimer.
e.Emulsion application rate.
f.Water addition rate and distribution.
g.Mixing via drum speed, reclaimer ground speed, and depth.
h.Accurate moisture densit y curves and targets.
i.Specifics of the testing methods used for density and moisture content.
j.Final density after compaction (both passes).
k.Curing plan.
3-27 (c) Control Section . Control sections shall be con structed to establish the TMD and verify moisture
content at the beginning of the FDR, and through the project as needed. The Contractor shall construct a control section to assure the Engineer that the Contractor’s equipment and procedures are suitable for the work specified and establish the target maximum density and moisture content. The TMD shall be the density determined from buildup, when the density readings show an increase in dry density of less than 1 pcf for the final four roller passes of each r oller. The control section shall be full lane width and a minimum of 500 feet long, or as approved by the Engineer. No further reclamation shall be performed until all aspects of the control section and the TMD are approved by the Engineer. The Contractor shall use the same equipment for building both the accepted test sections and performing the FDR work on the project unless equipment substitution is approved by the Engineer. The Engineer may require an additional test section and additional process con trol sampling to investigate the suitability of substituted or changed equipment. If the control section does not meet the requirements of this specification, or the target density is not determined from buildup testing, then the Contractor shall modify t he procedure and either construct another test section or reconstruct the original test section until suitable results are obtained. The control section shall be used to verify the optimum moisture content . Four quarter point samples shall be taken from t he initial test section and combined to produce a representative sample . This representative sample shall be tested for optimum moisture content in accordance with AASHTO T 180, Method D using a minimum of four moisture contents. The initial control se ction shall be used to determine if supplemental aggregate is needed to comply with the gradation requirements. Four quarter point samples shall be taken from the initial test section , combined to produce a representative sample, and tested for gradation u sing AASHTO T 30. The Contractor shall provide the Engineer with written copies of all process control and quality control results by 1:00 p.m. on the next working day, including test locations. The Contractor shall make all test results available to t he Engineer onsite and on request.
3-28 312.06 METHOD OF MEASUREMENT . The quantity of Full Depth Reclamation, Emulsion to be
measured for payment will be the number of square yards constructed to the depth specified, complete in place in the accepted work. No allowance for overlapping areas will be made. The quantity of Emulsified Asphalt for FDR, Emulsion to be measured for payment will be the number of hundredweight used in the completed and accepted work, as determined from the load tickets or other method as approved by the Engineer. The quantity of Portland Cement for FDR, Emulsion to be measured for p ayment will be the number of tons of material in place in the completed and accepted work, as determined from the load tickets or other method as approved by the Engineer. 312.07 BASIS OF PAYMENT . The accepted quantity of Full Depth Reclamation, Emulsion will be paid for at the Contract unit price per square yard. Payment will be full compensation for furnishing, handling, transporting, and placing the necessary materials; pulverizing; adding, or removing moisture; shaping, placing, and compacting the desi gnated materials; constructing tests strips; conducting tests; maintaining the finished base until it is paved over and for furnishing all labor, tools, equipment, and incidentals necessary to complete the work. No additional compensation will be provide d for multiple passes of the reclamation equipment and additional shaping, grading, and compacting. Water used to adjust the moisture content prior to pulverization to achieve compaction of the pulverized material, will not be paid for directly but will be considered incidental to the Full Depth Reclamation, Emulsion item. Water used for dust control after the reclamation will be incidental to the reclamation pay item. Calcium chloride used for dust control after the reclamation will be paid for separately under the appropriate Section 609 pay item in the Contract. The accepted quantity of Emulsified Asphalt for FDR, Emulsion will be paid for at the Contract unit price per hundredweight. Payment will be full compensation for furnishing, handling, and placin g the material specified. The accepted quantity of Portland Cement for FDR, Emulsion will be at the Contract unit price per ton. Payment will be full compensation for furnishing, handling, and placing the material specified. Subbase of Crushed Gravel, Fine Graded used to correct gradation or geometric deficiencies will be paid for under the appropriate subbase item included in the Contract .
3-29 Payment will be made under:
Pay Item Pay Unit 312.0100 Full Depth Reclamation, Emulsion ................................ ........................... Square Yard 312.5 100 Emulsified Asphalt for FDR, Emulsion ................................ .................... Hundredweight 312.5200 Portland Cement for FDR, Emulsion ................................ ........................ Ton
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4-1 Divisio N 400
SURFAC E COURSE S AND PAVEMENT SECTION 401 – AGGREGATE SURFACE COURSE 401.01 DESCRIPTION . This work shall consist of furnishing and placing a wearing course of approved aggregate on a prepared surface. 401.02 MATERIALS . Materials shall meet the requirements of the following subsections: Aggregate Surface Course ................................ ................................ ......................... 704.12(a) Aggregate Surface Cou rse, Paths and Trails ................................ .............................. 704.12( b) 401.03 PLACEMENT . The aggregate shall be placed and properly shaped using equipment that allows the typical cross -section and design grade to be attained. Should aggregate segregation occur, the Contractor shall remove and replace the segregated material or manipulate it until uniform gradation is obtained. The minimum layer thickness for placement of any aggregate surface material shall be 2 inches after compaction, and the maximum layer thickness shall be 8 inches after co mpaction. All layers shall be placed and compacted at approximately equal thickness. In the placement of layers, all joints shall be staggered at least 12 inches. After each layer of surface material is placed, it shall be thoroughly compacted to a uniform density of not less than 95% of the maximum dry density as determined by AASHTO T 99, Method C , or to the satisfaction of the Engineer . Suitable and effective equipment, meeting the approval of the Engineer, shall be used to obtain a true and even surface during compaction. All holes or depressions found during the compacting shall be filled with additional material, reworked, and compacted. If required, water shall be uniformly applied over the aggregate material during compaction in an amount necessary t o produce proper consolidation. The aggregate shall be thoroughly compacted by an approved power roller with a minimum weight of 8 tons, by an approved rubber -tired roller, or by other approved methods.
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 307–318 of 1,380.