293 MATERIALS
308.04 Materials
RBC shall consist of a homogenous ble nd of reclaimed asphalt pavement, RAP, and base materials that are co mbined with asphalt emulsion, water, and when required, recycling additives such as corrective aggregate or cement. Cement recycling additives used in asphalt emulsion stabilized RBC may be dry powder or slurry with a minimum dry solids content of 60%. The actual materials used are dependent on the FDR mix 60 design and project requirements. Materials for use in RBC shall be in accordance with the following: Asphalt Emulsion ........................................................ 902.01(b)3 Corrective aggregate to adjust gradation or supplement material volume:
1.Coarse or Dense Graded Aggregate, Class C or Higher ....................... 904.03
2.Fine Aggregate .............................................. 904.02 70
3.RAP, shall be the product resulting from the cold milling or crushing of an existing asphalt pavement. The RAP coarse aggregate shall be processed so that 100% passes the 1 1/2 in. (37.5 mm) sieve. Portland Cement, Type I .............................................. 901.01(b) Water ........................................................................... 913.01 A Type D certification in accordance with 916 shall be provided for the RBC.
308.05 Mix Design The FDR mix design shall be in accord ance with ITM 594 and comprised of
existing RAP, existing base material, asphalt emulsion, and if necessary, recycling additives. The mix design and all associated testing shall be performed using samples of the existing pavement and base material from the project site representing the reclaiming depth. Sampling, testing, and th e mix design shall be performed by a design laboratory that is AASHTO re:source accr edited for soil, aggregates, HMA, and asphalt emulsion. Additional mix designs shall be performe d when the in-place material changes 90 significantly in order to establish representative mixes for the entire job. The Contractor shall obtain all samples require d to develop the mix design. One sample per lane mile of planned RBC shall be the minimum sampling frequency for mix design preparation. Mix designs shall be submitted for approval at least five calendar days prior to the JITT and shall include results of all tests performed. If new materials are added, a new 308.05 294 mix design, including the updated test results, shall be submitted at least one day prior to implementation. CONSTRUCTION REQUIREMENTS
308.06 Roadway Preparation Snowplowable raised pa vement markers shall be removed in accordance with
808.11(e) prior to FDR operations. Grass and other vegetation shall be re moved from the edge of the existing pavement to prevent contamination of the RBC during milling operation. Grade adjustments of existing structures shall be made in accordance with 720.04 110 except existing structures shall be lowered prior to FDR operations, properly covered and filled with material compatible with the FDR mix design to maintain traffic. All areas of soft or yielding subgrade, as shown on the plans or as directed, shall be corrected prior to pulverization operations. 308.07 Equipment The equipment shall be capable of pulve rizing the existing asphalt pavement and base materials. The equipment used for mixing the pulverized materials with asphalt emulsion, water, additives, and corrective aggregate, when required, shall be capable 120 of producing a homogenous and uniformly blended RBC. The equipment used for placement of the RBC shall be capable of placement in accordance with 105.03. Spreaders or distributors used to apply dry powder additives, additive slurry storage and supply equipment, motor grader, compaction equipment, and water tracks shall be in accordance with 307.07. Mixing and reclaimi ng equipment shall be in accordance with 307.07(c), except that the mixer or reclaimer shall be fitted with an integrated water and asphalt emulsion injection system capable of introducing both materials into the cutting drum during the 130 mixing process. The metering device shall be capable of automatically adjusting the flow of material to compensate for any variation in the amount of reclaimed material introduced into the mixing chamber. The water or asphalt emulsion shall be calculated on a volumetric basis tied to a speed gauge, ft/min, using a calibrated mete r that is capable of accurately measuring the amount of material to within 0.5% of the rate required. Automatic digital readings shall be displayed for both the flow rate and total amount of reclaimed material in appropriate units of weight and time.
308.08 Weather Limitations FDR operations shall be performed when the ambient temperature is 50°F or above. The FDR shall not be performed when the soil, aggregate, or subgrade is frozen 308.06
295 or when freezing temperatures are anticipat ed within seven days of the end of RBC placement. The Engineer may restrict work wh en the heat index is greater than 100°F. The FDR shall not be performed before May 1 or after October 1.
308.09 Pulverization The existing pavement shall be pulverized and stabilized in separate operations. Corrective aggregate, when required, sha ll be spread onto the existing surface in 150
accordance with 307.07(a). The pre-determined full depth of asphalt pavement and base materials shall be pulverized, alon g with the corrective aggregate, to a homogenous mixture. The mixture may be br ought to the desired moisture content during this process by means of surface a pplication or through the mixing or reclaiming equipment’s integrated fluid injection system for dust control. The base course shall not contain subgrade, roots, sod, topsoil, weeds, wood or any material deleterious to its reaction with the asphalt emulsion. For asphalt emulsion stabilized RBC, the pulverization shall produce a gradation WKDWKDVSDVVLQJWKHLQ PP VLHYHDQGSDVVLQJ WKH1R PP 160 sieve. When paving fabric is encountered during the pulverization operation, the Contractor shall make the necessary changes in equipment or operations so that incorporation of shredded fabric into the RBC does not affect the performance parameters or inhibit placement or compaction of the RBC. The Contractor shall be required to remove and properly dispose of oversized pieces of paving fabric. The Contractor shall make the necessary adjust ments in equipment or operations so that the shredded fabric in the recycled material is no more than 5 sq in. No fabric piece shall have a dimension exceeding a length of 4 in. 170 Rubberized crack filler, durable pavement markings, loop wi res, and other non- pavement materials shall be removed from the roadway during the pulverization process. Residual materials that cannot be completely removed may be incorporated into the mixture if the Contractor can demonstrate that those added materials will not adversely affect performance. Any such materials retained in the mixture shall be appropriately sized and blended so as to not adversely affect the strength of the RBC. 180
308.10 Injection
An additive used in asphalt emulsion stabilized RBC may be dry powder or slurry and the Contractor shall address the app lication methods and f ugitive dust control procedures in the QCP when dry powder materials are used. The pulverized surface shall be scarified or knifed prior to applying materials in slurry form to prevent runoff or ponding. Any dry additives used shall be spread onto the pulverized surface using a mechanical spreader. The pulverized material shall be mixed with the stabilizer and additives as required by the mix design to create a homogeneous RBC. 308.10 296 The in-place moisture conten t of the material shall be within -1% to +2% of the 190 design moisture content as determined by the mix design. Asphalt stabilizing materials shall have an application tolerance determined by adding ±0.25% to the percent total asphalt emulsion content. The asphalt emulsion shall be incorporated into the pulverized material at the initial rate shown in the approved mix design. Sampling and mix design may determine different levels of asphalt emulsion at various portions of the project. The Contractor can request the asphalt emulsion percentage to exceed the upper 200 tolerance provided the mix design requirements are satisfied at the requested percentage. The request will be subject to approval by the Engineer.
308.11 Control Strip and Compaction
A minimum 500 ft long control strip sha ll be constructed on the first day of production to verify the construction process meets the requirements as specified. The control strip shall allow the Contractor to: (a) demonstrate the equipment, materials and processes proposed can produce an RBC layer in accordance with specification 210 requirements;
b.determine the optimal rates for the asphalt emulsion, water and any additives recommended for the reclaimed material;
c.determine the sequence and manner of rolling necessary to obtain specified density requirements in one uniformly compacted layer. The RBC density shall be achieved with the same equipment, materials, construction methods and dens ity requirements used on the accepted control strip. A 220 new control strip shall be constructed if cha nges are made outside the tolerances of the original mix design, equipment or construction methods. The processed material shall be uniformly compacted in one layer to a minimum of 95% of the maximum density. Maximum density shall be determined in accordance with AASHTO T 180 at the required QC frequency from a representative sample collected after injection but prior to compaction. Compaction shall be monitored in accord ance with AASHTO T 310 in the direct transmission mode and continue to reach a minimum of 95% of the established 230 maximum density during the control strip and for the remainder of the compaction operation. Compaction equipment shall be in accordance with 307.07(e). Initial compaction shall be within 500 ft of the reclaiming unit using either a vibratory pad-foot roller, a 308.11 297 pneumatic tire roller or a combination of the two. The pass counts shall continue to increase until the cleat indentations from the pad-foot roller are no more than 3/16 in. in depth and light can be seen between the pad-foot and RBC interface or there are no wheel impressions from the pneumatic tire roller remaining in the RBC. 240 The asphalt emulsion stabilized material shall be bladed and shaped by a motor grader in accordance with 307.07(d) to remove any remaining roller marks or indentations then leveled in accordance with 301.07. The profile grade and cross- section of the RBC shall be finished within a tolerance of ±1/2 in. from the plan RBC elevation prior to profile milling. Intermediate and final compaction shall be applied to the bladed and shaped RBC using either a pneumatic tire roller, a single or double drum vibratory steel roller, or a combination of the two. Finish rolling shall not be performed in vibratory mode. The compaction operation shall be performed while the RBC remains in a workable 250 condition and continued until roller marks no longer appear. Any type of rolling effort that causes cracking, displacement or other type of pavement distress shall be discontinued until such time as the problem can be resolved and approved by the Engineer. The QC technician shall be on site, observing all compaction efforts and approving areas as they reach minimum rela tive compaction. Care shall be taken to not over compact the mat. 260 All tests shall be conducted at the stated QC testing frequencies throughout FDR operations. 308.12 Maintenance The Contractor shall maintain the RBC until the surface course has been constructed. Any damage to the completed recycled material shall be repaired by the Contractor prior to the placement of new asphalt concrete or final surface sealing. Patching shall be in accordance with 304. The excavated patch areas shall be filled and 270 compacted with HMA or RBC material as di rected by the Engin eer. No payment will be made for damage or repair unless approved by the Engineer.
308.13 Curing
Before placing the final surfacing, the asphalt emulsion stabilized RBC shall remain in-place for a minimum of three days and meet one of the following conditions:
a.there is less than 3.0% moisture remaining in the mixture, or
b.the in-place moisture contents ha ve remained constant at 50% or less 280 of the design optimum moisture content for a continuous time period of five days. 308.13 The planned method and duration of curing for asphalt emulsion stabilized RBC shall be in accordance with the QCP. The specified surface course shall be placed within two weeks of the RBC final cure, but no later than November 1. 308.14 Proofrolling The asphalt emulsion stabilized RBC shall be proofrolled in accordance with 203.26 using a tandem or tri-axle dump truck loaded to the legal limit. The Engineer 290 will determine the corrective remediation limits for any area that has deflection or rutting greater than 1/2 in. The Contractor shall rework the areas that fail proofrolling by re-pulverizing and re-stabilizing the RBC in-place at no additional cost or by removing the RBC and stabilizing the subgrade with subgrade trea tment Type IC in accordance with 207. The reworked areas shall be proofrolled for final acceptance. In locations of failing subgrade, the RBC shall be removed and subgrade treatment 300 Type IC shall be placed in accordance with 207. HMA patching, Type B shall be placed in accordance with 304 in place of the RBC.
308.15 Milling
The entire surface of the asphalt emulsion stabilized RBC shall be scarified in accordance with 306.04 in preparation for the overlay. Liquidated damages will not apply. Construction engineering in accordance with 105.08(b) shall be provided.
308.16 Underdrain Installation Underdrain installation in accordance with 718, when required, shall begin after 310
proofrolling has been completed. 308.17 RBC Overlay The overlay atop the RBC shall be as shown on the plans. The overlay shall be placed after proofrolling has been completed. The RBC shall be swept of all loose material and standing water with a rotary power broom in accordance with 409 immedi ately prior to placing the surface. The RBC shall be swept lightly to avoid damage to the RBC. A tack coat shall be required only for the HMA overlay and shall be applied to the RBC in accordance with 406 immediately following sweeping operations. Monuments shall be reestablished in accordance with 615.10.
308.18 Opening to Traffic Opening to traffic shall occur after suffic ient cure time in ac cordance with 308.13
has been applied to the RBC so traffic will not initiate raveling or permanent 308.14 299 deformation. All loose particles that may develop on the pavement surface shall be removed by a rotary power broom in accordance with 409. 330 After opening to traffic, the surface of the RBC shall be maintained for the safe movement of traffic. 308.19 Method of Measurement The RBC will be measured by the squa re yard, complete in place. Asphalt emulsion will be measured by the ton. Subgrade treatment will be measured in accordance with 207.05. Corrective aggregate used to adjust the RBC gradation will be measured by the 340 ton of material used. HMA patching, Type B will be measured in accordance with 304.06. Milling will be measured in accordance with 306.10. Re-established monuments will be measured in accordance with 615.13. Removal of snowplowable raised pavement markers will be measured in accordance with 808.12. Portland cement will be measured by the ton.
308.20 Basis of Payment 350
The RBC will be paid for as full depth reclamation at the contract unit price per square yard, complete in place. Asphalt emulsion will be paid for at the contract unit price per ton, complete in place. Subgrad e treatment will be paid for in accordance with 207.06. Corrective aggregate used to adjust th e RBC gradation will be paid for at the contract unit price per ton, complete in place. HMA patching, Type B will be paid for in accordance with 304.07, for the thickness shown on the plans. Milling will be paid for in accordance with 306.11. Re-established monuments 360 will be paid for in accordance with 615.14. Removal of snowplowable raised pavement markers will be paid for in accordance with 808.13. Portland cement will be paid for in accordance with 104.03. The change order will include direct material costs, delivery costs, and shall not include any other markups. Payment will be made under: Pay Item Pay Unit Symbol 370 Corrective Aggregate, FDR ....................................................... TON Full Depth Reclamation ............................................................. SYS Stabilizing Material, Asphalt Emulsion ..................................... TON Stabilizing Material, Portland Cement ...................................... TON 308.20 The costs of the RBC mix design and QC testing shall be included in the cost of the full depth reclamation. The costs associated with removal of grass and vegetation, rubberized crack filler, durable pavement markings, loop wires and other non-pavement materials shall be 380 included in the cost of the full depth reclamation. The costs associated with pulverizing, stabilizing, compacting, curing, and maintenance of the RBC shall be included in the cost of the full depth reclamation. The cost associated with mixing water shall be included in the cost of the full depth reclamation. The cost associated with aggregate, wh en used to supplement material volume, shall be included in the cost of the corrective aggregate pay item. 390 When portland cement is a required stabilizing material, costs associated with mixing, installation, compaction, curing, and maintenance shall be included in the cost of the full depth reclamation. The cost associated with ag gregate, when used to adju st the RBC gradation, shall be included in the cost of th e corrective aggregate pay item. In the locations of failing subgrade, removal of the RBC shall be included in the cost of the subgrade treatment. 400 308.20 301 DIVISION 400 – ASPHALT PAVEMENTS
Source: Indiana Standard Specifications, 2024 Edition. Pages 307–314 of 1,248.