614 – HMA BASE (REFLECTIVE CRACK INTERLAYER (RCI)
600-80 Section 614
HMA BASE (REFLECTIVE C RACK INTERLAYER (RCI)) 614.1 DESCRIPTION Construct the HMA-reflective crack interlayer ( RCI) as designated in the Contract Documents. BID ITEMS UNITS HMA-RCI (PG 70-28 RCI) Ton Quality Control Testing (HMA) Ton 614.2 CONTRACTOR QUALITY CONTROL REQUIREMENTS Perform quality control testing according to subsection 602.2 . Develop control charts for the mix characteristics listed in Table 614-7 . 614.3 MATERIALS
a.Asphalt Binder. Provide PG 70-28 RCI binder that complies with SECTION 1202 , with this exception: Post a legible copy of the latest bill of lading fo r the Asphalt Binder on or near the gyratory compactor. Use the mixing and compaction temperatures shown on the bill of lading; however, the maximum mixing or compaction temperature is 340ºF, unless otherwise approved by the Field Materi als Engineer. Notify the Engineer if the mixing or compaction temperature changes. Exception: The mixing temperature may be increased no more than 10oF above the maximum mixing temperature shown on the bill of lading provided all the following are met:
1.The air temperature is below 70oF
2.The plant has not produced mix earlier in the day.
3.Do not exceed a mix temperature of 350oF.
4.No truck has returned for its second load of the day. Once a previously loaded truck returns for its next load, reduce the temperature to not higher than the maximum mix temperature shown on th e bill of lading, not to exceed 340oF.
b.Reclaimed Asphalt Pave ment (RAP) and Recycled Asphalt Shingles (RAS). Do not use RAP or RAS in the RCI.
c.Aggregates . Provide aggregates that comply with SECTION 1103 .
d.Combined Aggregates. Provide combined aggr egates for the mixes requ ired in the Contract Documents as shown in TABLE 614-1 . Mixes may use any combination of aggregate and mineral filler supplements complying with the applicable requirements in TABLES 1103-1 and 1103-2 . Provide materials with less than 0.5% moisture in the final mixture. The maximum quantity of crushed steel slag used in the mix is 50% of the total aggregate weight. Natural sand shall be called SSG-1, SSG-2, etc. in the mix design.
e.Contractor Trial Mix Design. A minimum of 10 working days before the start of HMA production, submit in writing to the DME for review and approval, a proposed JMF for each combin ation of aggregates. For each JMF submitted, include test data to demonstrate that mixtures comply ing with each proposed JMF shall have properties specified in TABLE 614-1 for the designated mix type at the Recommended Percent Asphalt (P br). Submit the proposed JMF on forms provided by KDOT. Submit the worksheets used in the design process to include at a minimum the mix properties listed in TABLE 614-2 . Contact the DME to determine if additional information should be submitted. Provide sufficient material as identified in TABLE 614-3 . Submit for the Engineer’s review and approval, the test data listed in TABLE 614-4 for each blend and the pr oposed JMF. Provide a mix that meets the requirements in TABLE 614-5 . 614 – HMA BASE (REFLECTIVE CRACK INTERLAYER (RCI)
600-81 For each aggregate used in the mix design, determine the specific gravity using KT-6. This may be
accomplished while the project is being constructed or anytime during the 12 months preceding the start of construction on a project. If construction has not yet begun, notify the DME 5 working days prior to obtaining the material for the specific gravity test so that companion samples may be obtained at the same time. If construction has already begun on the project, then determine the specific gravity values of the individual aggregates before 10,000 tons of HMA is produced. Provide the test results to the DME within 14 days of sampling the material. If the producer of the aggregate has been required to submit material to KDOT for a new Official Quality test, since the time the Contractor ran the specific gravity tests, th en perform KT-6 on the aggr egate currently produced. Do not use the specific gravity values obta ined from these tests in the mix design calculations for current projects, unless mutually agreeable to both parties. Use the information, as soon as it becomes available, as part of the process to verify and update the “Mon thly Hot Mix Aggregate Specific Grav ity Values” posted on KDOT’s Internet site. For RCI mixes, the optimum percentage of asphalt mate rial is the percentage that yields the design air voids at N des (50 gyrations) and complies with the other requirements of the specifications. Submit test results for all design criteria. The values from the approved mix design become the values in the initial job mix formula (JMF) for the RCI. These values remain in effect for the JMF un til a written request by the Contractor for a change is approved by the Engineer. Provide a new mix design when any change in materials occurs from those used in the mix design, unless waived by the DME. TABLE 614-1: COMBINED AGGREGATE REQUIREMENTS Mix Designation Percent Retained - Square Mesh Sieves ⅜" No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 No. 200 RCI 0 0-15 1-25 13-47 41-68 74-91 88-99 94.0-99.0
1.Aggregate Adjustment Limit: Do not exceed a 7% adjustment on any single sieve from the approved mix design to the Job Mix Formula (JMF). Submit a new mix de sign when requesting a change beyond this limit.
2.Do not use RAP in the RCI design.
3.The flat and elongated particles in the combined coar se aggregate shall not exceed 10% for the total sample.
4.The maximum percent moisture in the final mixture shall not exceed 0.5.
5.There are no criteria for CAA, FAA, or D/B ratio. TABLE 614-2: MIX PROPERTIES Property AbbreviationTest Method Additional Information Air Voids V a KT-15 & KT-58 Calculated from G mm and G mb. Run at the P br. Recommended Percent Asphalt Pbr Produce a mix with a V a of 4.5%. Theoretical Maximum Specific Gravity G mm KT-39 Rice Test. Sand Equivalent SE KT-55 Bulk Specific Gravity of HMA Gmb KT-15 Compacted Mix Property. Percent G mm at N des %G mm @ N des % KT-15 Use G mm value from KT-39. Calculated from Gyratory Compaction height data, G mm, and G mb. Voids in Mineral Aggregate VMA KT-15 & KT-6 Calculated from G mb, G sb, Pb. Voids Filled with Asphalt VFA Calculated from VMA and V a @ N des. Formulas for calculations are in the Superpave Volumetric Mixture Design and Analysis Handbook. 614 – HMA BASE (REFLECTIVE CRACK INTERLAYER (RCI)
600-82 Table 614-3: Mater Ial Submittals
Submittal Quantity Descriptio n Additional Information Aggregate for KT-15 3 Samples Sized for 6 inch Plugs Comply with Job Mix Gradation. Aggregate for KT-39 2 Samples Sized for G mm Testing Comply with Job Mix Gradation. Binder for KT-15 As Needed Sized for 3 Plugs at P br Binder for KT-39 As Needed Sized for 2 G mm Tests Each Aggregate for KT-6 As N eeded Specific Gravity Test Uncompacted HMA Sample 35 lbs Cool sample to room temperature If transported hot and compacted within 2 hours, then requirement to cool sample may be waived by the DME. Gyratory Plugs at N des 2 Plugs Compacted at P br Compacted to N des TABLE 614-4: TEST DATA SUBMITTALS Submittal Information Asphalt Binder Source, Grade, Specific Gravity, Mixi ng and Compaction Temperature from the Producer of the asphalt binder. Each Aggregate Source and Producer, including Legal Description. Gradation of Each Aggregate Percentage Retained to nearest 1% (e xcept nearest 0.1% for No. 200 sieve) Material Proportioning Proportion of each material is shown in percentage of aggregate. Composite Gradation Based on Gradation of Each Aggregate and Material Proportioning. Composite Gradation Plot Plotted on KDOT Form 712 (0.45 power graph paper). Asphalt Binder Added Percentage to nearest 0. 01% based on total weight of the mixture. Aggregate Percentage of flat and elongated particles in the coarse aggregate Sand Equivalent SE for the combined virgin aggregates. TABLE 614-5: RCI MIX REQUIREM ENTS FOR DESIGN SUBMITTAL MIX CHARACTERISTIC CRITERIA Sand Equivalent (SE), minimum, % 45 Gyratory Compaction Revolutions, N des 50 Air Voids (V a) target, %(1) 4.5(2) VMA, minimum, %(1) 18.0 VFA, minimum, %(1) 70 Hveem Stability (AASHTO T-246) @ 140oF), 4" (100 mm) molds, minimum(1) 18.0 Flexural Beam Fati gue (AASHTO T-321) (3), 2000 microstrain, 10 Hz., 98% ± 1.0 of Gmb @ N des, 59oF (Age samples for 4 hours at 275oF before compaction, reference AASHTO R30 Section 7.2) 200,000 cycles
1.Criteria based on 50 gyrations (N des).
2.Complete all tests on the mix producing 4.5% air voids at 50 gyrations. If the mix does not meet the requirements for all t ests, then change the target air voids to correlate to the mix that do es meet all the test requirements. Use this for all target air voids during production. The target asphalt binder c ontent during production (JMF) will be the asphalt binder content from the approved mix design that yields the target air voids. Submit a new mix desi gn to include the Hveem Stability and Flexural Beam Fatigue Test ing when a new target asphalt binder content or target air voids is requested.
3.AASHTO T-321 will be used for an alysis with the following exceptions: Section 8.7 Replace the last sentence with the following: This stiffness is the Initial Beam Mo dulus, which is used as a referen ce for determining the specimen failure. Section 8.8: Delete the second sentence. Section 8.9: Delete the last sentence. Section 9.1.3: Change “Flexural Stiffness” to “Beam Modulus” Section 9.1.6: Replace this section with the following: Normalized Modulus = (Beam Modulus x Cycl e Number) / (Initial Beam Modulus x 50) Figure 6 - Plot the Normalized Modulus x Cycles versus Load Cycles (Repetitions) Section 9.1.7 and Sect ion 9.1.8: Delete Section 9.1.9: Replace with the following: 614 – HMA BASE (REFLECTIVE CRACK INTERLAYER (RCI)
600-83 Failure Point – Failure is defined at the maximum or peak Normalized Modulus when Normalized Modulus x
Cycles is plotted versus Load Cycles. Section 9.1.10: Delete Section 10.4, Table 2: Change the last two headings to “Normalized Modulus” and “Nor malized Modulus x Cycles”, respectively Section 10.7: Delete Section 10.8: Replace with the following: Prepare a plot of Normalized Modulus x Cycles versus load cycles TABLE 614-6: MIX DESIGN TEST DATA SUBMITTALS Submittal Information Minimum of 1 Mix Design As a minimum, 1 mix design at the P br Gmm Determined at each binder content. Individual and Bulk Specific Gravity Tests Provide results for a minimum of 2 specimens at each binder content. Percent Air Voids Provide % Va in the mixture for each binder content when compacted to N des gyratory revolutions along with copies of the Gyratory graphs. Percent VMA Provide %VMA at each binder content. 614.4 CONSTRUCTION REQUIREMENTS
a.Plant Operation. Adjust all plant operations to operate continuously.
1.Preparation of the Asphalt Bi nder. Heat the asphalt binder to within a range as specified in SECTION 601. When heating the asphalt binder to the specified temperat ure, avoid local overheating. At all times, provide a continuous supply of the as phalt binder to the mixer at a uniform temp erature. Asphalt binder received from the refinery at temperatures less than 37 5°F may be used as received, if the requirements regardin g the reheating of asphalt binder in SECTION 601 are met.
a.Commingling of Asphalt Binders. Do not a dd or commingle asphalt binders from 2 or more sources into a storage tank. If this occurs, th e contents of the storage tank are considered contaminated. Do not use the contents of the st orage tank on the project, except as follows: It is permissible, at the Contractor’s option, to thoroughly mix the contents of the tank and request sampling of the mixture. Submit the sample to the MRC for testing. Do not use the asphalt binder until approved, and when needed, a new mix design evaluation is completed.
b.Asphalt Binder Sources. Before changing as phalt binder sources on a project, obtain approval from the DME. A new JMF may be required.
2.Preparation of Mineral Aggregate. When the mineral aggregate is composed of 2 or more ingredients, combine as shown in the approved JMF.
a.Temperature Requirements. Dry the aggregate fo r the mixture and heat to a temperature to obtain an asphalt-aggregate mixture temperature immediately after mixing within the 75 to 150 second Saybolt viscosity range of the aspha lt binder used. Obtain the temperature for this viscosity range from the MRC or the Asphalt Binder Producer. No mixing or compaction temperatures are to exceed 340ºF without approval from the Field Mate rials Engineer. The minimum temperature may be revised by the DME provided it is demonstrated that satisfactory results may be obtained at a lower temperature. In such event, deliver the HMA to the paver at a temperature sufficient to allow the material to be satisfactorily placed and comp acted to the specified density and surface tolerance requirements.
3.Preparation of HMA. Introduce asphalt binder into the prepared aggregate in the proportionate amount determined by the P br in the JMF.
a.Basis of Rejection. HMA will be rejected if th e aggregate, as it is discharged from the drum or the pugmill, contains sufficient moisture to cause foaming of the mixture, or if the temperature of the aggregate is such that the as phalt-aggregate mixture temperatur e is outside the range specified in SECTION 601 .
b.Mixing Time. Operate drum mixers at a rate to provide uniform aggregate coating in a continuous operation. For batch and continuous ty pe plants, the minimum wet mixing time is 40 seconds. In all cases, mix a sufficient time to produce a uniform mixture in which all the aggregate
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 317–320 of 978.