3-6 SECTION 310 – FULL DEPTH RECLAMATION
310.01 DESCRIPTION . This work shall consist of performing full depth reclamation (FDR) by
pulverizing the existing pavement together with underlying base course material, mixing with water, fine grading, and compacting the homogenous base mate rials to the depth, width, and desired density specified in the Contract.
310.02 MATERIALS . Materials shall meet the requirements of the following subsections:
Water ................................ ................................ ................................ .......................... 745.01 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 310.02A . TABLE 310.02A – FDR GRADATION REQUIREMENTS Sieve De signation 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
310.03 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 paveme nt, base, and subgrade in-place, and mixing any added materials to the specified depth. The cutting drum shall have the ability to operate at various speeds (rpm), independent of the machine’s forward speed, to control oversized material and gradation. The Contractor shall provide and use equipment that will produce the completed FDR base as specified herein. The Contractor shall maintain all equipment in a satisfactory operating condition. Equipment such as road planers or milling machines designed to mi ll or shred the existing roadway materials rather than crush or fracture the materials are not allowed as an alternative to the reclaimer. 3-7 The reclaimer shall be equipped with a means for the Engineer to continually monitor reclamation depth or, altern ately, 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. Additional passes shall be provided as necessary to pulverize th e material to meet the gradation as required. 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 time s. The inability of the reclaimer to produce the required objectives will subject the equipment to rejection by the Engineer.
c.Grading . The power grader and any replacement graders shall have grade control automation.
d.Compaction . The Contractor sha ll use a vibratory pad -foot roller having a dynamic force of 25 tons for breakdown compaction and shall perform finish rolling using a single steel drum roller of 12 tons to 14 tons. Additional compaction equipment may be used by the Contractor to achieve the desired compaction.
310.04 Construction Requirements .
a.General Requirements . 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 sh all 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, including stopping pulverization and reclamation at these obstructions 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 pulverized material that has been fully mixed. Damage to these surface and buried structures shall be repaired at the expense of the Contractor. 3-8 Longitudinal joints between successive reclamation passes shall overlap a minimum of 6 inches. The Contractor shall provide a sufficient number of mixing cycles 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 36 hours. Reclaimed sections shall be paved over with bituminous concrete in the same year they were reclaimed.
b.Geometry and Limits of Pulverization, Reclamation, and Grading . The pulverized material shall extend to the depth and width established in the Plans, or if not specified, the width of existing pavement. The base material surface shall be finished within a tolerance of ± 1 inch. Any deviati on shall not extend for more than 50 feet. The existing crown or superelevation shall be maintained.
c.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 b eing achieved with little or minim al compactive effort, then the Engineer will require a new control section to establish a new TMD.
d.Maintenance . The completed and cured FDR may be opened to traffic as approved by the Engineer. The Contractor shall pro tect and maintain the reclaimed base in good condition until all work is accepted. Required density and moisture content of the finished base shall be maintained until it is paved over. Any imperfections discovered shall be repaired by the Contractor as di rected by the Engineer at no additional cost to the Agency. Portions of the FDR damaged by rain shall be reconstructed at the Contractor’s expense. Dust control shall be conducted on the FDR sections to reduce the production of nuisance dust and reduce th e hazard to traffic. When a dust control agent is not specified on the Plans, water or calcium chloride shall be used. 3-9 310.05 QUALITY CONTROL .
a.General Requirements . The Contractor shall perform all process control and quality control sampling and testing, at the minimum frequencies specified in Table 310.05A . TABLE 310.05A – 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 Gradation 1 per day AASHTO T 27 Density testing locations shall be sited at various transverse offsets within the lanes. The Contractor shall provide the Engineer with written copies of all proc ess 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 the Engineer onsite and on request.
b.Control Section . Control sections shall be con structed t o establish the target density and moisture content at the beginning of the FDR, and through the project as needed. The Contractor shall construct a control section to assure the Agency 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 roller . The control section shall be full lane width and a minimum of 500 feet long, or as approved by the Engineer. No further reclaiming 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 control sections and performing the FDR work on the project unless equipment substitution is approved by the Engineer. 3-10 The Engineer may require an additional control section and additional process control 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 Con tractor shall modify the procedure and either construct another control section or reconstruct the original control section until suitable results are obtained. The control section shall be used to determine the optimum moisture content and determine if supplemental aggregate is needed to meet the gradation requirements. Four quarter point samples shall be taken from the initial control section and combined to produce a representative sample . The representative sample shall be tested for gradation using AASHTO T 27 and optimum moisture content in accordance with AASHTO T 180, Method C using a minimum of four moisture contents.
310.06 METHOD OF MEASUREMENT . The quantity of Full Depth Reclamation to be measured for
payment will be the number of square yar ds constructed to the depth specified, complete in place in the accepted work. No allowance will be made for overlapping areas. If the depth of base to be reclaimed must be adjusted in the field, the first 2 inches of additional or decreased depth will not be paid for directly, but will be considered incidental to the Full Depth Reclamation item. If the change in depth exceeds 2 inches, the number of square yards pulverized at the revised depth will be multiplied by the result of dividing the total depth ac tually pulverized by the original depth designated on the Plans to create an equivalent number of square yards for which payment will then be made.
310.07 BASIS OF PAYMENT . The accepted quantity of Full Depth Reclamation will be paid for at the
Contract u nit 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 designated materials; constructing tes ts 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 provided for multiple passes of the reclama tion equipment and additional shaping, grading, and compacting. 3-11 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 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 cluded in the Contract. Payment will be made under: Pay Item Pay Unit 310.0100 Full Depth Reclamation ................................ ................................ ............ Square Yard 3-12 SECTION 311 – FULL DEPTH RECLAMATION, CALCIUM CHLORIDE
311.01 DESCRIPTION . This work shall consist of performing full depth reclamation (FDR) by
pulverizing the underlying material, mixing with liquid calcium chloride, fine grading, and compacting the homogenous base materials to the depth, width, grade, and desired density specified in the Contract, and capping with a surface application of liquid calcium chloride.
311.02 MATERIALS . Materials shall meet the requirements of the following subsections:
Water ................................ ................................ ................................ .......................... 745.01 Calcium Chloride for Full Depth Reclamation ................................ .......................... 746.02 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 311.02A . TABLE 311.02A – FDR GRADATION RE QUIREMENTS 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
311.03 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 mixing unit with liquid injection. The equipment shall be capable of pulverizing the existing pavement, base, and subgrade in -place, and mixing any added materials to the specified dep th. The cutting drum shall have the ability to operate at various speeds (rpm), independent of the machine’s forward speed, to control oversized material and gradation. The reclaimer shall have a full width spray bar consisting of a positive displacement p ump interlocked to the machine speed so that the amount of liquid calcium chloride being added is automatically adjusted with changes in machine speed, up to 5.0 gallons per square yard (± 0.02 gallons per square yard ). Individual valves on the spray bar shall be capable of being turned off as necessary to minimize application overlap on subsequent passes. Liquid calcium chloride for stabilization shall only be introduced via the reclaimer and shall not be pre -applied to the road surface in front of the rec laimer.
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 294–299 of 1,380.