32 nd Eastern Region Annual Airports Conference Eastern Region Laboratory Procedures Manual ERLPM

1. 32nd Eastern Region Annual Airports ConferenceEastern Region LaboratoryProcedures ManualERLPM Guillermo Felix P.E Eastern Region Paving Engineer

2. Presentation outline • Why do we have this workshop? • The consultant’s world a) Pavement design b) Specifications for hot mix bituminous materials • Eastern Region laboratory Procedures Manual (ERLPM) versus Asphalt Institute MS-2 manual • How this workshop helps me? – List of people familiar with ERLPM • Workshop agenda

3. Why do we have this workshop? • Traditional ways of determining quality of bituminous mixes (up to 1974) • Using average (media: Sum of all values/n) • Using ratio (H+ L)/2 • Statistical analysis – Eastern Region Specification (1974) • Air voids (laboratory and Mat-in-place) • Military handbook re-written as Eastern Region Laboratory Procedures Manual • Two specs: HQ and AEA

4. Why do we have this workshop? • Eastern Region versus national specification • National spec uses statistical method and establishes plant air voids and mat-in-place density as acceptance criteria. It uses the AI MS-2 • Introduction of VMA instead of VFA • Re-sampling • Introduces outlier method to discharge a test result

5. Current specification • Basically the same nationwide. Few exceptions which will be covered during the workshop • Found in AC 150/5370-10 (currently 10C) • ERLPM versus Asphalt Institute MS-2. References to ERLPM recently removed • List of people familiar with ERLPM and NICET • Eastern Region and other regions

6. The consultant’s world • Pavement Design: Selection of pavement structure • Preparing contract specifications: using approved FAA specification selecting the appropriate elements

7. Pavement Design • Arrangement of layers to transmit loads (aircraft) to a prescribed area on the surface of the earth • Philosophy of load distribution: two philosophies • Loads are transmitted gradually, like a trapezoid, from the surface of the pavement to the top level of soil (flexible) • Loads are widely distributed like a beam (Rigid) • Sub grade: level surface of soil where pavement layers will be placed. Strength expressed in CBR for flexible pavement and K value for rigid pavement • Bituminous pavement are considered Flexible

8. FLEXIBLE Surface course Base course Sub base course/frost protection layer Sub grade – prepared support

9. RIGID PAVEMENT

10. Failure Mode in Flexible Pavement Vertical and Horizontal Strain

11. Typical Flexible Pavement Structure Basic Premise of CBR method: Provide sufficient “cover” above each layer to protect that layer from shear failure Assumed Failure at subgrade

12. Two methods • CBR: empirical method that uses graphs. This method WILL disappear very soon • Layer Elastic Theory: mechanistic method that uses strength of material for each layer. This method is known as LEDFA and will be included in the new AC 150/5320-6E (draft) as FAARFIELD

13. Criteria for Pavement Design • Loads: Expressed in aircraft weight, load distribution (gear type) and repetition (annual departures) • Strength of different layers: expressed in CBR for the CBR method or material characteristic for FARFIELD method. • Soil strength: expressed as CBR

14. Flexible Pavement Design Three Basic Design Parameters • Subgrade Support • (CBR) • Design Aircraft • Gear type and Gross Load • Traffic • Annual Departures

15. Aircraft weight

16. Gear Configurations

17. Design aircraft • Determine for each aircraft, using weight/gear configuration/traffic what is the required pavement thickness • Select the aircraft requiring the largest thickness • Using equivalent factors covert the annual traffic of all other aircraft to the design aircraft

18. Convert Aircraft to Design Aircraft R1 = equivalent annual departures by the design aircraft R2 = annual departures expressed in design aircraft landing gear W1 = wheel load of the design aircraft W2 = wheel load of the aircraft in question

19. CBR Method • Determine the design aircraft • Using the landing gear configuration select the appropriate pavement design chart • Determine the total thickness of pavement, needed to protect the sub grade, using aircraft weight, annual departures and sub grade strength • With an assumed CBR of 20 for sub base, determine the pavement thickness to protect the sub base • Calculate the thickness of the sub base as the difference of the two thickness calculated • Calculate the thickness of base by subtracting the “minimum surface thickness

20. CBR 75,000 60,000 45,000 30,000 Gross Aircraft Weight, lb Annual Departures 1,200 3,000 6,000 15,000 25,000 Thickness, in. CBR Design Procedure - Sample Design Curve Unique curve required for each gear type Ideally need a new curve for each gear due to wheel spacing and tire pressure

21. CBR 75,000 60,000 45,000 30,000 Gross Aircraft Weight, lb Annual Departures 1,200 3,000 6,000 15,000 25,000 Thickness, in. CBR Design Procedure - Sample Design Curve Unique curve required for each gear type Ideally need a new curve for each gear due to wheel spacing and tire pressure. Each curve has a minimum surface thickness

22. Typical designed pavement structure

23. Transforming pavement section Using layer equivalence factors the thickness of each layer can be modified using higher strength material

24. CBR Method “Layer Equivalency”Base layer thickness to a standard section Table 3-6Convert Item P-154 to: Table 3-7Convert P-154 to:

25. CBR Method “Layer Equivalency”Base layer thickness to a standard section Table 3-8 Convert Item P-209 to: Table 3-9 Convert P-209 to:

26. NEW DESIGN METHOD LAYERED ELASTIC DESIGN LEDFAA/FAARFILED

27. Layered Elastic – why? • New aircraft weight and gear type exceeded assumption on CBR method • It was the only tool to design B777 and NLAs • Use mechanistic approach with each layer strength/deformation characteristic • Calculates damage of each aircraft in the mix • It uses computer software • Latest version in FARFIELD as part of AC 150/5320-6E (draft)

28. Aircraft Grew in Size A330-200469,000 lbs A300 B2304,000 lbs A380-800F1,305,000 lbs A340-600807,000 lbs B747-800 at 970,000 lbs B-747-400873,000 lbs B-777-300752,000 lbs B-767-700451,000 lbs DC-10-30583,000 lbs DC 8-71358,000 lbs

29. Sample Gear Configurations

30. Horizontal Strain and Stress at the bottom of the asphalt Vertical Subgrade Strain Flexible Pavement Failure Modes Pavement failure modes in LEDFAA are the same as all flexible design methods

31. Flexible Pavement Failure Modes Layered Elastic theory versus CBR procedure CBR Method Not Defined CBR CBR CBR LAYERED ELASTIC METHOD SURFACE ES, S, h BASE EB, B, hB SUBBASE ESB, SB hSB SUBGRADE ESG, SG hSG E = Elastic Modulus h = thickness μ = Poisson’s Ratio CBR = California Bearing Ratio

32. CUMULATIVE DAMAGE FACTOR (CDF) for Traffic Model • Sums Damage From Each Aircraft - Not From Equivalent Aircraft • CDF = Summation ni / Ni where: • ni = number of load repetitions from individual aircraft • Ni = allowable load repetitions of individual aircraft • When CDF = 1, Design Life is Exhausted • Must Input Traffic Mix, NOT Equivalent Aircraft

33. LEDFAA now FAARfield

34. Computer Design Click on desired pavement section Then click on the project where the section will besaved

35. Pavement Design Enter Traffic Mixture Certain aircraft mayappear in the list twice. This is to address thepresence of wing gearsand belly gears LEDFAA treats these as two aircraft however the weightand departures areinterlocked

36. LEDFAA v1.3 Sample Design Working with a pavement section The selected sample pavement will appear The structure may be modified if desired

37. LEDFAA v1.3 Sample Design Modifying a pavement section Select the layer type you want to include Change P-209 to P-154 in this example Click OK

38. Layers transformation • Both methods allow for transformation of pavement structures by using different material quality • Lower quality materials in base and sub base can be replaced with higher quality materials • The thickness can be reduced by this transformation • Use of P-401 versus P-403

39. Preparing contract specifications • AC150/5370-10 • Three bituminous specifications • Section 110 and 110

40. Specification for Hot Bituminous pavement AC 150/5370-10C • P-401 Surface course and defined by AC 150-5320-6 Requires most testing and estimates a quality level • P-402: Porous Friction Course rarely used • P-403: base (binder) course, stabilized sub-base course, less than 12,500 lbs aircraft Has a pass/fail

41. PART V – FLEXIBLE SURFACE COURSES ITEM P‑401 PLANT MIX BITUMINOUS PAVEMENTS DESCRIPTION 401‑1.1 This item shall consist of pavement courses composed of mineral aggregate and bituminous material mixed in a central mixing plant and placed on a prepared course in accordance with these specifications and shall conform to the lines, grades, thicknesses, and typical cross sections shown on the plans. Each course shall be constructed to the depth, typical section, andelevation required by the plans and shall be rolled, finished, and approved before the placement of the next course. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * This specification is intended to be used for the surface course for airfield flexible pavements subject to aircraft loadings of gross weights greater than 12,500 pounds (5670 kg) and is to apply within the limits of the pavement designed for full load bearing capacity. The dimensions and depth of the “surface course” for which this specification applies shall be that as is defined by the Engineer’s pavement design as performed in accordance with FAA Advisory Circular 150/5320-6, current edition. For courses other than the surface course, such as stabilized base courses, binder courses and/or truing and leveling courses; for pavements designed to accommodate aircraft gross weights of 12,500 pounds (5670 kg) or less; and for pavements intended to be used for roads, shoulder pavements, blast pads, and other pavements not subject to full aircraft loading, specification Item P-403 may be used. State highway department specifications may be used for shoulders, access roads, perimeter roads, stabilized base courses under Item P-501, and other pavements not subject to aircraft loading. When state highway specification are approved, include all applicable/approved state specifications in the contract documents. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

42. ITEM P‑403 PLANT MIX BITUMINOUS PAVEMENTS(BASE, LEVELING OR SURFACE COURSE) DESCRIPTION 403‑1.1 This item shall consist of a [ ] coursecomposed of mineral aggregate and bituminous material mixed in a central mixing plant and placed on a prepared course in accordance with these specifications and shall conform to the lines, grades, thicknesses, and typical cross sections shown on the plans. Each course shall be constructed to the depth, typical section, andelevation required by the plans and shall be rolled, finished, and approved before the placement of the next course. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Specify base and/or leveling course(s). Surface course may also be specified but only for those pavements designed to accommodate aircraft of gross weights less than or equal to 12,500 pounds (5,670 kg) or for surface course of shoulders, blast pads, service roads, etc. Item P-401 is to be specified for surface courses for pavements designed to accommodate aircraft gross weights greater than 12,500 pounds (5,670 kg). This specification is to be used as a base or leveling course for pavements designed to accommodate aircraft of gross weights greater than 12,500 pounds (5,670 kg). State highway department specifications may be used in lieu of this specification for access roads, perimeter roads, stabilized base courses under Item P-501, and other pavements not subject to aircraft loading, or for pavements designed for aircraft gross weights of 12,500 pounds (5,670 kg) or less. Where a state highway department specification is to be used in lieu of this specification, the state specification must have a demonstrated satisfactory performance record under equivalent loadings and exposure. When a density requirement is not specified by a state specification, it is to be modified to incorporate the language found in paragraphs 403-5.1, 403-5.2 and 403-5.3. When state highway specification are approved, include all applicable/approved state specifications in the contractdocuments.

43. Aircraft weight for P-401 • 12,500 lbs. but less than 60,000 Lbs. • 60,000 Lbs or more

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47. Writing the specification – P-401 • Selection of aircraft weight • Selection of gradation and asphalt cement • Use of recycle material (RAP)? • Selection of method of payment

48. Consultant decision on P-403 • Specification for Stabilized Bituminous Base • Binder Course • Truing and Leveling Courses • Testing requirement has been reduced: pass/fail condition

49. What to expect in contract documents • One P-401 with one gradation or, • One P-401 specification with two gradation. Usually the gradation at the bottom is grater (1 -3/4” maximum size aggregates) because it uses less asphalt, and the smaller aggregate size gradation at the top (1/2” maximum size aggregate) for more smooth surface • One P-401 on top and P-403 on the bottom

50. What is the ERLPM • Eastern Region Laboratory Procedures Manual • Born in the Eastern Region to use statistical methods to determine quality versus range or media (average) • Origen – Military specs • Document to be used in combination with P-401. required in Eastern Region • Provide forms for project submittal - Appendices