1. DGAC/STAC Infrastructure research
Current Research Work
FAA Airport Pavement Working Group
Atlantic City, NJ
24-26 April, 2011

2. Main research topics
French rational design method for airfield pavements
Materials characterization and testing methods : material exchange FAA <-> DGAC/STAC
Dynamic F/HWD data analysis
Towards a rational PCN
Reliability of friction measurements
Water depth modeling on runways
25 april 2012

3. French rational design method for airfield pavements
A new technical manual
A rational method used in France for highway design for more than 30 years
Development of the airfield rational design method from the highway one.
First restricted to new flexible airfield pavement.
25 april 2012

4. French rational design method for airfield pavements
2 steps :
Mechanical design
Freeze / thaw verification
The mechanical design in 6 steps :
1/ Gathering the data and design parameters (traffic, layers thicknesses, material types and characteristics, risk coefficient…)
25 april 2012

5. French rational design method for airfield pavements
2/ Stresses / Strains calculation with an isotropic linear elastic multilayered model
Discretization of the horizontal calculation planes (x,y) located at heights zk using a grid (xi, yj, zk).
x : longitudinal axis of the moving load
y : transverse direction
Calculation planes located at:
the HMA base
(horizontal extensions)
the top of the unbound layers (vertical contractions)
25 april 2012

6. French rational design method for airfield pavements
3/ Individual damage calculation without wandering
Deformations induced by the set of moving loads of a landing gear taken into account through the "Miner law continuous integration ":
(x) : longitudinal deformation variation
25 april 2012

7. French rational design method for airfield pavements
4/ Individual damage calculation with wandering
5/ Cumulated damage calculation
6/ Iterative calculations, setting of the layers’ thickness so that:
- dcumulated  1 (and lower than 1),
- technological limits regardings materials are satisfied.
25 april 2012

8. French rational design method for airfield pavements
The technical manual and its software are achieved
Next steps :
trial period by experts to get a feedback
diffusion to all the users
and further applications : overlay design, rigid pavement design, rational ACN/PCN.
25 april 2012

9. Materials characterization and testing methods
To compare US and French material properties and behaviour
To compare US and French testing methods used for materials characterization
To compare US and French rational design methods
Analysis of NAPTF data to validate/refine this rational design method. The method has been calibrated using the results of two Airbus full-scale testing programs (flexible PEP and HTPT)
25 april 2012

10. Materials characterization and testing methods
Materials exchange FAA <-> DGAC/STAC :
French materials received by FAA November 2010:
Asphalt materials from 1995 facility:
101x69x20 cm block (includes surface and base HMA layers).
Asphalt materials from Bonneuil instrumented facility:
63x54x21 cm block (includes surface and base HMA layers).
6 HMA cores of varying depth.
Approximately 150 kg of bagged GNT2 (capping layer) from Bonneuil instrumented facility.
US testing is achieved
25 april 2012

11. Materials characterization and testing methods
Materials exchange FAA <-> DGAC/STAC :
U.S. material samples received by STAC April 2011:
(2) Econocrete (lean concrete) beams, Item P-306, in steel molds.
(3) Econocrete (lean concrete) cylinders, Item P-306.
(2) Blocks of asphalt base material, Item P-403.
(4) Buckets and (1) bag of crushed aggregate base material, Item P-154 (Crushed quarry screenings).
All materials from NAPTF test items.
French testing has just been completed
25 april 2012

12. Materials characterization and testing methods
And now, in progress :
Comparison and data analysis of the results obtained by FAA and DGAC/STAC
25 april 2012

13. French HWD pavement testing methodology (flexible pavements)
A new technical guide for:
1) pavement testing
2) data analysis:
Backcalculation
Critical strains calculations
Determination of pavement residual life, and/or bearing capacity (Single Wheel Load, PCN?)
Consistent with the new design guidance
25 april 2012

14. Dynamic F/HWD data analysis
Technical guide and associated software (PREDIWARE) almost achieved
Next steps:
validation by a user committee
release
Next studies:
overlay design
rigid pavement assessment
25 april 2012

15. Towards a rational PCN Study in progress, a new work axis :
The aim is to cross the work done on the rational design method and on the HWD data analysis to develop a method to calculate a rational PCN.
25 april 2012

16. Reliability of friction measurements
Aims of the study based on the IMAG device
To identify, quantify and reduce uncertainties
To be more confident in friction results
First step : Identification of all the parameters affecting the measurements.
25 april 2012

17. Reliability of friction measurements
The main parameters are : Calibration, Tire (wear, pressure), Water depth, Speed, Slip rate, Horizontality of sensors
25 april 2012

18. Reliability of friction measurements
The results :
LFC = LFCread  0,10 at 95 km/h
LFC = LFCread  0,09 at 65 km/h
LFC = LFCread  0,08 at 40 km/h
To compare with :
25 april 2012

19. Water depth modeling on runways
Modeling of the runway characteristics with the VANI device
Transverse and longitudinal slopes
Evenness
Macro-texture
Friction (micro-texture)
25 april 2012

20. Water depth modeling on runways
Modeling of water flow lines based on VANI data
Development of a software to predict the water depth on the runway during a rainy period or a thunderstorm.
Input data :
VANI data
rain intensity (weather data)
Output data :
Water depth
Flow model
25 april 2012

21. Thank you BROUTIN Michael Michael.broutin@aviation-civile.gouv.fr
STAC/IA Infrastructures Aéroportuaires

22. French HWD pavement testing methodology (flexible pavements)
Dynamical FE modelling
Surface AC 
Base AC
UGA
Subgrade
Load
plate
p(t) L H
Structure G9 G8 G7 G6 G5 G4 G3 G1
ur=0
uz=0
Use of histories instead of only peak values for backcalculation step
25 april 2012