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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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