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.
3-13 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 cold -milling mach ines designed to mill or shred the existing roadway materials rather than crush or fracture the materials are not allowed as an alternative to the reclaimer. The Contractor shall ensure a full and homogeneous distribution of the liquid calcium chloride stabilizing agent. The reclaimer 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. Additional passes shall be provided as necessary to pulverize the material to meet the gradation as required. The Contractor shall inspect the condition of the cutting teeth on a daily basi s, replace all worn and broken cutting teeth, and keep the cutting drum fully maintained and in good working condition at all times. 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 shall 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.
e.Pressure Distributor . The distributor for surface application of the solution shall be capable of applying liquid calcium chloride in accurately measured quantities at any rate between 0.1 gallons to 2.0 gallons per square yard of roadway surface, at any length of spray bar up to 20 feet. The distributor shall be capable of maintaining a uniform rate o f distribution of material regardless of change in grade, width, or direction of the road. The distributor shall be equipped with a digital volumetric accumulator capable of measuring gallons applied and distance traveled. The volume and measuring device s hall be equipped with a power unit for the pump so that application is by pressure, not gravity. The spray nozzles and pressure system shall provide a sufficient and uniform fan-shaped spray of material throughout the entire length of the spray bar at all times while operating and shall be adjustable laterally and vertically. The spray shall completely cover the roadway surface receiving the treatment.
3-14 311.04 Construction Requirements .
a.General Requirements . Any manholes, valve covers, or other buri ed 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 shal l 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 stru ctures (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 remo ved material with stabilized full depth pulverized material that has been fully mixed and treated with the applicable stabilization agent. Damage to these surfaces and buried structures shall be repaired at the expense of the Contractor. 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 specific the width of existing pavement. The base material shall be finished within a grade tolerance of ± 1 inch. Any deviation shall not extend for more th an 50 feet. The required crown or superelevation shall be maintained.
c.Stabilization . The stabilizing agent shall be calcium chloride and shall be delivered to the reclaimer and distributed by the reclaimer in such a way as to ensure a uniform distribut ion across the roadway, at a rate of 0.75 gallons to 0.90 gallons per square yard, with a reclaim depth as shown on the Plans. Following base compaction, shaping, fine grading, and finish compaction and rolling, a final capping of 0.10 gallons to 0.25 gall ons per square yard of liquid calcium chloride shall be applied with the pressure distributor to the finished surface. Total calcium chloride application rate from the combined processes shall be targeted at 1.0 gallons per square yard.
3-15 The Contracto r shall provide a method for verifying that the correct amount of calcium chloride
solution 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 forw ard speed of the reclaimer. At no time shall 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 material. 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 i n order to complete all pulverization and mixing activities across the full width of the roadway within 36 hours.
d.Compaction . For compaction of the FDR, the moisture content shall be within the range of the optimum moisture content ± 2%. The Contracto r 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 pri or 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 ne w 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 Engineer will require a new control section to establish a new TMD.
e.Maintenance . The completed and cured FDR may be opened to traffic as approved by the Engineer. The Contractor shall protect 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 directed by the Engineer at no additional cost to the Agency. Portions of the FDR damaged by rain shall be reconstructed at the C ontractor’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.
3-16 311.05 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 311.05A . TABLE 311.05A – 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. Gradation failures shall require the Contract or to take action to adjust the process to achieve compliant material. Additional aggregate added to correct gradation s hall meet the requirements of Subsection 704.05 (b). 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 the Engineer onsite and on request.
b.Control Section . Control sections shall be con structed to establish the target density and moisture content at the beginning of the FDR, and through the project as needed. The Con tractor 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 roller. The control section shall be full lane width and a minimum of 500 feet long, or as approved by the Engineer. No further recycling 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 unle ss equipment substitution is approved by the Engineer.
3-17 The Engineer may require an additional test section and additional process control sampling to
investigate the suitability of substituted or changed equipment. If the control section does not mee t the requirements of this specification, or the target density is not determined from buildup testing, then the Contractor shall modify the 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 determine the optimum moisture content. Four quarter point samples shall be taken from the initial test section and combined to produce a representative sample . This representative sample shall be tested for gradation using AASHTO T 27 and optimum moisture content in accordance with AASHTO T 180, Method D using a minimum of four moisture contents. The initial control section 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 and combined to produce a representative sample and tested for gradation using AASHTO T 27. 311.06 METHOD OF MEASUREMENT . The quantity of Full Depth Re clamation, Calcium Chloride 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 will be made for overlapping areas. The quantity of Calcium Chloride for FDR, Calcium Chloride to be measured for payment will be the number of gallons used in the completed and accepted work, as determined from the load tickets or other method as approved by the Engineer. 311.07 BASIS OF PAYMENT . The accepted quantity of Full Dep th Reclamation, Calcium Chloride 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 designated 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 addition al compensation will be provided for multiple passes of the reclamation equipment and additional shaping, grading, and compacting.
3-18 The accepted quantity of Calcium Chloride for FDR, Calcium Chloride will be paid for at the Contract
unit price gallon. Payment will be full compensation for furnishing, handling, and placing the material specified. 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 con sidered incidental to reclamation pay 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. 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. Payment will be made under: Pay Item Pay Unit 311.0100 Full Depth Reclamation, Calcium Chloride ................................ .............. Square Yard 311.5100 Calcium Chloride for FDR, Calcium Chloride ................................ ......... Gallon
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.
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 300–306 of 1,380.