604 - COLD RECYCLED ASPHALT CONSTRUCTION (CIR)
600-40 Before and after opening to traffic, maintain the su rface of the recycled pavement in a condition suitable for
the safe movement of the traffic. Remove all loose particles that develop on th e pavement surface by power brooming. When there is a significant change in mix proportions, weather conditions or other controlling factors, the Engineer may require construction of a new test strip to check target density.
f.Surface Treatment or Overlay. When required by the Engineer, apply a light application of asphalt material (smoke coat) on the recycled surfa ce, and blot with fine sand, as necessary. Before placing a HMA surface course , or other applicable surface treatme nt, allow the CIR asphalt material to cure until the moisture of the material is a maximum of 2.0%, or approved by the Engineer. Under dry conditions, the CIR should comply with the moisture requirements within 48 hours. Cover each day’s production of CIR material with any subsequent treatment or overlay, as designated in the Contract Documents, within 21 calendar days. If the CIR material requires patching before the 21 days have expired, and damage is not the result of the Contracto r’s operations, KDOT will pay for the patching. If the Contractor has not covered the CIR material by the end of the 21-day period and the material requires patching, the Contractor shall be responsible for the patching. Begin patching within 3 days of being notified by the Engineer of required patching.
g.Maintenance of Traffic. Perform traffic control according to DIVISION 800 .
h.Weather and Seasonal Limitations. Complete milling, adding the liquid binder and laydown between May 1 and September 30, when the ambient air temperature is greater than 50°F and rising, the weather is not rainy or foggy and the weather forecast does no t call for freezing temperat ure within 48 ho urs after placement. The above requirement may be waived, when approved in writing by the Engineer.
i.Pavement Smoothness. Evaluate pavement smoothness according to SECTION 603 . 604.4 MEASUREMENT AND PAYMENT The Engineer will measure cold recycled asphalt material by the Station, along the centerline. On divided highways, the Engineer will measure cold recycled asphalt material by the Station, along the centerline of each divided direction. This includes all widened and irregular areas and irregular variations in depth. The Engineer will measure lime (hydrated) (slurry) and th e various types of emulsified asphalt by the ton. The Engineer will measure blotter sand by the cubic yard in the truck at the point of usage. The Engineer will not measure water for separate payment. Payment for "Cold Recycled Asphalt Material", "Lime (Hydrated) (Slurry)" and "Emulsified Asphalt (CSS) (Special)" at the contract unit prices and "Blotter Sand (Set Price)" and "Emulsified Asphalt (CSS-1H or SS-1H) Cure (Set Price)" at the contract set unit prices is full compensation for the specified work. 605 - SURFACE RECYCLED ASPHALT CONSTRUCTION
600-41 Section 605
SURFACE RECYCLED ASPHALT CONSTRUCTION 605.1 DESCRIPTION Construct the hot-in-place recy cling of the existing asphalt surface as specified in the Contract Documents. The activities associated with this work include heating the existing pavement, scarifying and/or hot milling the existing surface, adding a rejuvenating agent, mixing, spr eading, leveling and compacti ng the recycled material. This process is referred to as Hot In-Place Recycled As phalt Pavement (HIR). The term surface recycling and HIR are synonymous in the specification. BID ITEMS UNITS Surface Recycling (*) Station Asphalt Rejuvenating Agent Ton *Thickness 605.2 MATERIALS
a.Asphalt Rejuvenating Agent (ARA). Provide ARA that complies with DIVISION 1200 .
b.Contractor Mix Design. When the specified thickness of the HIR is greater than or equal to 2 inches, submit a mix design complying with TABLE 605-1 . In the mix design, analyze the mixture at a minimum of 3 different ARA contents starting with 0.5% at the low end. Run the indirect tensile strength test (KT-60) at the lowest ARA content. Run the Asphalt Pavement Analyzer (AASHTO T 340) at the highest ARA content. TABLE 605-1: SURFACE RECYC LE MIX DESIGN REQUIREMENTS Property Test Method Limits Air Voids at 30 gyrations, (%) KT-58, KT-15, & KT-39 Report Tensile Strength, (psi min) KT-56 75 Retained Strength based on cured stability, (% min) KT-56 80 Rut Resistance, (mm max) AASHTO T 340 8 Thermal Cracking, (oC max) KT-60 -22 Testing procedures: Core the pavement to obtain Reclaimed Asphalt Pavement (RAP) for the mix design. Break down the RAP (repre senting the depth of the HIR) to a maximum particle size of 1 inch. The compaction temperature range for KT-58 is 200ºF to 250ºF. Perform all tests on plugs that are compacted to 30 gy rations, thus the air void criteria stated in KT-56, KT-60 and AASHTO T 340 are waived. Use procedure III when performing KT-15. 605.3 CONSTRUCTION REQUIREMENTS
a.Pavement Preparation. Before commencing surface recycling, re move all material from the surface of the pavement which would be detrimental to the HIR or would not comply with the design criteria of subsection 605.2b .
b.Heating and Scarifying Operations. Use a series of heaters, milling units and/or scarifiers to uniformly heat and recycle the existing pavement to the specified depth. Flames on the pavement can be prevented by heating the roadway more slowly us ing additional heaters. Intermittent or occasional flaming on the roadway or in the windrow that extinguishes on its own within 10 seconds is permissible, but if in the opinion of the Engineer it is detrimental to the final product, production will cease. In addition, production will cease when smoke is being produced continuously. (Smoke caused when the heaters pass over a maintenance patch is excluded from this 605 - SURFACE RECYCLED ASPHALT CONSTRUCTION
600-42 clause.) The Contractor and Engineer will agree to a cour se of action to prevent this overheating before production
is resumed. If flames or excessive smoke persists, th en production is ceased until th e Contractor modifies the operation and can demonstrate acceptable results without ex cessive smoke or flames on the pavement or in the windrows. When the depth of the HIR is more than 1 inch, heat the material in lifts not more than ¾ inches. When heating in multiple lifts, remove each lift at a uniform dept h across the full width of the recycled pavement. This material may be windrowed when heating the next lift. Use equipment complying with SECTION 155 . Provide adequate provisions for equipment calibration. Remove from the roadway milled or scarified material that can not be placed with a paving unit due to equipment breakdown or malfunction. Bring these removed areas to grade using a HMA approved by the Engineer.
c.Process Control.
1.Depth Check. The Engineer will determine the dept h per KT-47. The moving average of 3 consecutive tests shall equal or exceed the contract depth. If the 3-poi nt moving average is less th an the contract depth, KDOT will assess a Surface Recycling Pay Adjustment using Equation 1. The pa y adjustment will correspond to those segments within the 3-point moving average that were deficient in depth. Equation 1: TM1)S(400 P Where: P is the Surface Recy cling Pay Adjustment, ($0.00) S is the number of stations (single lane) in penalty, (0.00) M is the Measured Depth 3-point moving average, (0.000 feet or 0.00 inches) T is the Plan Depth, (0.000 feet or 0.00 inch es). T and M shall be the same unit of measure. If 4 consecutive 3-point moving average values are less than the contract depth, stop production and evaluate the process with the Engineer. Change the process to the satisfaction of the Engineer before production is resumed. If the next 2 tests are deficient in thickness, E quation 2 will be used for the remainder of the project. The Engineer reserves the option to term inate production until a satisfactory agr eement is reached anytime the 3-point moving average value is less than the contract depth for more than 2 consecutive tests. Equation 2: TM1)S(900 P If both KDOT and the Contractor agree that recycling to the contract depth would be detrimental to the project, the unit price will be negotiated for the reduced de pth before proceeding with th e project, and the Engineer would create a change order ( SECTION 104 ) for the item at the new unit price.
2.Temperature Requirements: Heat the HMA being scarified and/or hot milled to a minimum of 190ºF prior to scarifying and/or hot milling. Maintain the temp erature of the HIR, directly behind the paver, between 190ºF and 300ºF. HIR temperatures take n within 2 feet of each other, transver se to the roadway, shall not vary by more than 30ºF. HIR temperatures taken within 10 feet of each other, transverse to the roadway, shall not vary by more than 50ºF. If these temperature requirements are not satisfied within 1 hour after a discrepancy is discovered, the HIR train will be stopped and the Engineer and Contr actor will determine a course of action to correct the deficiency before the HIR train proceeds.
d.Rejuvenating and Mixing Operations. After heating and scarifying and/or hot milling, uniformly add the ARA and thoroughly mix the HIR. Include all of the pr eviously scarified and/or hot milled material into the mixing operation.
e.Spreading and Compacting Operations. Immediately following heating, scarifying, adding ARA and mixing operations, begin work to fulfill the requirements of one of the following operations:
1.Operation Number 1.
a.Spread and finish the rejuvenated mixture with an acceptable paving unit.
b.Provide density using an approved rolling procedure. Use a minimum of 2 Self-Propelled Smooth-Faced Steel Rollers complying with SECTION 151 . The Engineer will determine the initial approved rolling procedure from densities obtained with various roller combinations. 605 - SURFACE RECYCLED ASPHALT CONSTRUCTION
600-43 Density will be determined by using a nuclear gauge. Use the approved rolling procedure.
Achieve the maximum density before the temperature of the HIR falls below 160 F. Do not crush the aggregate. When the ma t temperature falls below 160 F, roller marks may be removed from the mat with a self-propelled Smooth-Faced Steel Roller operated in the static mode. If there is a significant change in factors affecting density, such as weather or compaction equipment, the Engineer will reevaluate and modify the rolling pr ocedure as required. Stop the HIR operation whenever rolling is not being performed according to the approved rolling procedure .
c.Maintain the rejuvenated pavement surface un til the surface treatment shown in the Contract Documents is completed. When required, apply a tack coat before placing the surface treatment. If a seal coat, asphalt seal, micro-surfacing or u ltra-thin bonded asphalt su rface is included in the Contract Documents, allow the HIR surf ace to cure 1 week before sealing.
2.Operation Number 2. Use an asphalt paver equipp ed with automatic grade cont rol to spread and finish the amount specified of the new asphalt surface material. SECTIONS 601 and 602 apply. If a HMA overlay is included in the contract, place the HM A and surface recycle concurrently, or the 2 materials may be blended and laid as 1 lift.
f.Weather and Seasonal Limitations. Construct surface recycling when the surface is dry, and the weather is not foggy or rainy. Only construct surface recycling between May 1 and September 30, when either the minimum ambient air temperature or th e road surface temperature shown in TABLE 605-2 is met. TABLE 605-2: MINIMUM HIR TEMPERATURE REQUIREMENTS Existing Surface Type Ambient Air Temperature (oF) Road Surface Temperature (oF) On HMA Surface 50 55 On Asphalt Seal Surface 55 60
g.Pavement Smoothness. Evaluate pavement smoothness according to SECTION 603 . 605.4 MEASUREMENT AND PAYMENT The Engineer will measure surface recyc ling by the Station, along the cent erline. On divided highways, the Engineer will measure surface recycling by the Station, alo ng the centerline of each divided direction. This includes all widened and irregular areas and irregular variations in depth. The Engineer will measure asphalt rejuvenating agent by the ton. Payment for "Surface Recycling" and "Asphalt Rejuvenating Agent" at the contract unit prices is full compensation for the specified work. The bid item Surface Recycling Pay Adjustment will be an item added to the contract. 606 - MICROSURFACING
600-44 Section 606
MICROSURFACING 606.1 DESCRIPTION Spread a mixture of modified emulsified asphalt, mineral aggregate, water and additives on a prepared surface as specified in the Contract Documents. BID ITEMS UNITS Aggregate for Microsurfacing Ton Emulsified Asphalt (*) (Modified) Ton Mineral Filler Ton *Designated Type and Grade 606.2 MATERIALS Provide materials that comply w ith the applicable requirements. Emulsified Asphalt ................................................................................................ DIVISION 1200 Aggregate for Mi crosurfacing ............................................................................... DIVISION 1100 Water ..................................................................................................................... DIVISION 2400 Conduct aggregate acceptance te sts at the point of usage. Use a Cationic Type CSS-1HM emul sified asphalt complying with SECTION 1202 . For mineral filler, use any recognized brand of non-air-entrained portland cement that is free of lumps and acceptable to the Engineer. Provide a Type "C" certification for any proposed additives. The Engineer will test materials according to th e Contract Documents an d Appendix B-Sampling and Testing Frequency Chart-Quality Cont rol/Quality Assurance Specifications. 606.3 CONSTRUCTION REQUIREMENTS
a.Mix Design.
1.Job Mix Formula. Develop and submit the job mix formula and certified test results meeting the criteria in TABLE 606-1 for the Engineer’s approval. Include aggregate type and gradation, percentage of modified emulsion, water and cement by weight of dry aggregate in the mix. TABLE 606-1: MICROSURFACING MIX DESIGN REQUIREMENTS Property Test Requirements Wear Loss (Wet Track Test) ASTM D6372 (1 hr soak) (6 day soak) 50 g/ft2, maximum 75 g/ft2, maximum Wet Cohesion ASTM D6372 @ 30 minutes @ 60 minutes 10 in-lbs, minimum 17 in-lbs, minimum Wet Stripping ISSA TB-114 90%, minimum Mix Time @ 77oF ISSA TB-113 Controllable to 120 seconds, minimum
2.Proportioning. Use the proportions in TABLE 606-2 unless otherwise shown in the Contract Documents. Do not begin microsurfacing until the Engineer appr oves the mix design, materials, and construction. 606 - MICROSURFACING 600-45 TABLE 606-2: MICROSURFA CING MIX PROPORTIONING Material Units Value Mineral Aggregate lbs/SY dry weight 15, minimum Modified Emulsion Percent residue by weight 6.5, minimum Mineral Filler Percent by weight of dry aggregate 1.0 to 3.0 * Additive Percent by weight of dry aggregate As required * Unless otherwise approved by the Engineer.
3.Aggregate and Asphalt. Screen the aggregate for lumps, and weigh it before delivery to the lay down machine. Weigh the emulsified asphalt. Th e Engineer will approve the screens and scales. Provide individual volume or weight c ontrols for proportioning each item to be added to the mix. Calibrate and mark each material control device. Locate the devices to be accessible for ready calibration, and place so the Engineer can determine the amount of each material used at any time. Mineral filler may be added at the loading facility, provided the Engineer approves accurate proportioning and metering devices, and there is no detrimental effect on the final product.
b.Surface Preparation. Immediately before applying the micros urfacing, thoroughly clean the surface of the roadway of all foreign material and pre-wet as required.
c.Ruts. When shown in the Contract Documents, fill ruts, utility cuts and depressions in the existing surface before placing the final surface. Cover ruts and irre gularities of less than ½ inch in depth with a full width scratch coat. Accomplish the scratch coat by usin g a rigid rear seal in the spreading equipment. Independently fill ruts greater than ½ inch in depth using a rut filling spreader box 5 to 6 feet in width. Crown ruts filled with a rut filling spreader box to compensate for compaction. Ruts in excess of 1 ½ inches require multiple passes with the spreader box to restore the original cross section. When multiple passes are required, carry traffic overnight on each rut-filling pa ss before a subseque nt filling pass is made.
d.Mixing and Spreading. Mix and spread the microsurfacing materials with a self-propelled machine capable of accurately delivering and proportioning all of the required components. Operate the machine continuously while loading, eliminating construction joints. Do not use lumping, balling or unmixed aggregate. Place longitudinal joints on lane lin es. Do not overlap or leave gaps in longitudinal joints. Construct a finished microsurface with a uniform te xture and free of scratches, tears and other surface irregularities. Repair the surface if any of these conditions exist: more than 1 surface irregularity that is ¼ inch or wider and 10 feet or longer in any 100 foot section of the microsurface; more than 3 surface irregularities that are ½ inch or wider and more th an 6 inches long in any 100 foot section of the microsurface; or any surface irregularity that is 1 inch or wider and more than 4 inches long. Construct finished, uniform, longitudina l and transverse joints in the micros urface. Repair the joints if any of these conditions exist: build-up of microsurface ma terial at the joints; uncovered areas at the joints; longitudinal joints with more than ½ inch vertical space betwee n the surface and a 4 foot straightedge placed perpendicular to the joint; or transverse joints with more than ¼ inch vertical space between the surface and a 4 foot straightedge placed perpendicular to the joint. Construct the edges of the microsurface to follow the cent erline, lane lines, shoulder lines and curb lines. Repair edges that vary more than ± 3 inches from a 100 foot straight line (or a 100 foot arch on a curved section). Use methods approved by the Engineer to correct deficiencies in the microsurface. Construct a dense, repaired surface with a uniform texture. 606 - MICROSURFACING
600-46 e. Curing. Provide adequate means to protect the microsur face from damage by traffic until the mixture
has cured sufficiently. Allow the surface of microsurfacing to cure so as to not adhere to or be picked up by the tires of vehicles. Allow traffic to use the microsurfacing when cured. Cure the material used for filling wheel ruts a minimum of 24 hours before the full width coverage is applied.
f.Maintenance of Traffic. Maintain traffic according to DIVISION 800 and the following: Station 1 flagger immediately ahead of the application of the microsurfacing material and 1 flagger immediately behind the section being cured. Display suitable speed limit signs and “fresh oil” sign s. Move the signs forward with the flaggers as the work progresses. Suspend application of the microsu rface early enough each day to permit traffic to safely travel over the completed work before sunset. Repair any traffic damage to the mi crosurface at Cont ractor expense.
g.Seasonal and Weather Limitations. Construct the microsurfacing between May 1 and October 15. Do not place microsurfacing when the ambi ent air temperature is less than 50ºF, or the weather is foggy or raining, and the air temperature is forecaste d to go below 32ºF within 24 hours following the placement.
h.Observation Period. The Engineer, along with th e Contractor, will inspect the microsurfacing 30 days after work is completed on the microsurfacing. Repair ar eas where there is no cover material left in place (bare areas) as directed by the Engineer: In 5% the wheel paths; and Individual areas ≥ 10 square yards; and Where the total square yards of bare areas is greater than 5% of the total square yards of the seal.
g.Pavement Smoothness. Microsurfacing is excluded from profilograph testing, and not eligible for pay adjustments. 606.4 MEASUREMENT AND PAYMENT The Engineer will measure aggregate for microsurfaci ng, emulsified asphalt (modified) and mineral filler by the ton. No deduction will be made for moisture in th e aggregate. When sacked portland cement is used, 1 sack equals 94 pounds. Water used for pre-wetting the pavement surface and mix water is subsidiary to ot her bid items and will not be measured for separate payment. Material used to correct surface deficiencies in the microsurfacing will not be measured for payment. Payment for "Aggregate for Microsurfacing", "Emulsif ied Asphalt (Modified)" and "Mineral Filler" at the contract unit prices is full comp ensation for the specified work.
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 277–283 of 978.