HMA Fatigue in FAARFIELD 

Federal Aviation 

Administration 

Presented to: REDAC 

By: Navneet Garg, Ph.D. 

Date: March 3, 2021 
 

 

HMA Fatigue in FAARFIELD 

 FAARFIELD is a computer program for airport pavement 

thickness design. FAA AC 150/5320-6F. 

 Old HMA Fatigue Model: Heukelom & Klomp [1962]

log10(C) = 2.68 – 5 x log10(εh) – 2.665 x log10(EA) 
 

 

AASHTO T321-14, Standard Method of Test for Determining 

the Fatigue Life of Compacted Asphalt Mixtures Subjected to Repeated Flexural Bending 
1000000 

b£J u 

.5 ~ 100000 

= Q 

4-. ~ 

z "'d 

"'d i_3 10000 

E o ·-a.. ...... 

"'d a ~ v5 1000 

p.. 

100 

100 1000 

AN ENERGY APPROACH FOR AIRPORT PAVEMENT 

LOW DAMAGE FATIGUE BEHAVIOR • fatigue data --line of equality 

10000 100000 1000000 

Measured fatigue life, Nf 

By: 

Shihui Shen and Samuel H, Carpenter Civil and Enviroomental Engineering Depanment 

University of Illinois al Urbana-Champaign 

Utt>ana, ll 61802 

USA 

Phone: (217) 244-6064; Fax: (217) 333-1924 

sshen2@uiuc-edu 

scarpent@uiuc.edu 
(l) 

t,::; 1.E-02 -0.. 

8 

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on 

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> 

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(.) 1.E-06 

·

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~ 1.E-07 0-. 

1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 

PV from original fatigue test 

• Plateau Value Data - line of equality ! 

AN ENERGY APPROACH FOR AIRPORT PAVEMENT 

LOW DAMAGE FATIGUE BEHAVIOR 

By: 

Shihui Shen and Samuel H. Carpenter 

Civil and Environmental Engineering Department 

Unive rsity of Illinois al Urbana-Champaign 

Urbana, IL 61802 

USA 

Phone: (217) 244-6064; Fax: (217) 333-1924 

sshen2@ufuc-@du scarnent@uiuc.edu 
 

 

 

 

 

 

 

 

H 

II III 

Plateau Stage Nf~ 

Lo~d Cycles 

HMA Fatigue in FAARFIELD 

 New HMA Fatigue Model: Carpenter et.al. [1997, 2000, 2001, 2007] 

Nf = 0.4801 x PV-0.9007 

PV = 44.422 x εh

5.14 x S2.993 x VP1.85 x GP-0.4063 

where PV is the estimated value of RDEC plateau value (dimensionless), 

S is HMA flexural stiffness (psi), 

εh is horizontal strain at the bottom of the asphalt layer, 

VP is the volumetric parameter, and 

GP is gradation parameter. 

(AASHTO T321-14, Standard Method of Test for Determining 

the Fatigue Life of Compacted Asphalt Mixtures Subjected to 

Repeated Flexural Bending) 
 

 

 

 

HMA Fatigue in FAARFIELD 

VP = Va/(Va+Vb) 

GP = (PNMS-PPCS)/P200 

where 

Va is air voids, 

Vb is asphalt content by volume, 

PNMS is the % of aggregate passing the nominal maximum size sieve, 

PPCS is the % of aggregate passing the primary control sieve, and 

P200 is the % of aggregate passing the #200 (0.075 mm) sieve. 
1000 

900 

800 

700 ... 

0 

'T 

0.. 

'5 600 

E 

~ "' 500 · ~ ., 

C 

-~ 

,;; 400 ., 

~ 

~ 300 

200 

100 

0 

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 

FAARFIELD Predicted Passes to Failure 

CC7 – Perpetual Pavements 
 

 

 

Pavement Cross Sections 

12 inch 10 inch 15 inch 

39 inch 34 inch 37 inch 

LFP-1N LFP-2N LFP-3N 

5 inch 5 inch 8 inch 

8 inch 8 inch 

41 inch 29 inch 29 inch 

LFP-4N LFC-5N LFS-6N 

P401 HMA 

SURFACE 

DRAINABLE 

BASE 

P154 SUBBASE 

P209 CRUSHED 

STONE BASE 

SUBGRADE 

(CBR 5-6) 
• Standard NAPTF wander pattern. 

• 

• 

63 & 64 65 & 66 61 & 62 

51 & 52 59 & 60 53 & 54 57 & 58 

43 & 44 45 & 46 41 & 42 47 & 48 39 & 40 

19 & 20 35 & 36 21 & 22 33 & 34 23 & 24 31 & 32 

1 & 2 17 & 18 3 & 4 15 & 16 5 & 6 13 & 14 

-4 -3 -2 . 1 0 1 

55 kips (245 kN) wheel load 

6-wheel gear . 

55 & 56 

49 & 50 37 & 38 

25 & 26 29 & 30 

7 & 8 11 & 12 

2 3 

144 

144 

27 &28 

9 & 10 

4 

1372 mm 

• Standard NAPTF wander pattern. 

• 55 kips (245 kN) wheel load 

• 6-wheel gear. 

Traffic Tests 
rack Monjtoring 

500 -r----.,.....---,------,------,------,-----,-----,---......., ·-:::::t::·:---:_.J::((:t:t. _:t:t-:::::;::: . + :t: .. :---1 •• ::"(ft):: . : :-+· .. ::::r. ::::' ... :::: .. ::::: :::::::. 

450 

400 

350 

1 

~ 300 

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c-

(l)_ 250 

gi 

< t; 200 

~ 

u 150 

100 

50 

0 

· - LFP1 -N ·~···!· .. t···~··· ···t···~···1· .. t··· ···! ... t .. ·t· .. 1 ·· ···!···!···t···t .. ··+··+·-l···+··· ··-~···+···!···i··· ··+·+··+ ... !··· 

• ii~~ :l I l !ill;~;~:.•• ~1l li;!~ l!i: ii~ i ·>··· ·••❖ ·f··· ···+···~···i···+·· ... ; ... ,(-... ; ... ; ... ···!···i···+···f··· ···+···!···i···+··· ···t···+···!···l··· ... ~·-·{···+···!··· 

: .... LFS6.N_:~:::~:::f- + -- ---~----~---:···;·:, ··::;_~;-~;:! ::::~:::~---+···t··· -··+···!···~----~--: :::j ---~---~·-·!·· :::~:::1 ·-f··-~--

:::F::r::~:::;::: .. +-+ .. ~ ·+·: :::t:::~:::j. ~- --~---+ ..+-+· -j :t -+ .. +- -.. +·::!:·l:::±:· ... ~. --~--rf:- .. +·-~_··+···t·· · ·!•··+ .. ·~•· ! ·· ···~••·!•··~ ~-- ·••+···~·-i· ~···· +·-~·-+··i ·· ·••·l•·+··+··•f·• ··-+··+··i·-·+· · ·••!· .. t !···!··· ··+··~ ·+··+·· ···!···t···~··+·· ···~···!·· ·······-···•···•·· + .. ~ .. -~···! ··+· ·! 

·······-··········· 

.· ···+···~···i 

·••: ... ... ! ... ~ .. ·! -~- -

... !!·"!, ... ~? ···,!_ ··· ··+·+·. ·.-~ ...···!·"~""' :::·:. ... ;.•+· . ; ; . ••• ; ..• ,c, ••• ; ••• j ....... _ ........ .. ... ; ... : .... ; ... ; .. . ··-: .. ·:-.. :···: ·······-·········· ... , ........... !·•· 

... !· .. ~----~ ... , ... 

··+·+ .. +··+·. 

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.. ·! .. ·f .. + .. •!·_• . .. ; ... ~ .. .: ... : .. 

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... L.L .. ~---l,.· ··+·-~···+···!··· 

:Jl :r. :ii.::::::L: ::+:U··:!··· M::Li::: :::=:::::::i:::L :::i:::l:::i:::i::: 

0 5000 10000 15000 20000 

Passes 

25000 30000 35000 40000 

Crack Monitoring 

HMA Strain Pass to Coverage N1from FAARFIELD N1from Full-Scale APT Ratio (N1 APT/ 

Section (from FAARFIELD) PV (P/C) Ratio Passes Coverages Passes I Coverages N1 FAARFIELDl 

PP-1 0.000524 2.14E-06 0.650 40000 61538 NO CRACKS OBSERVED 

PP-2 0.000657 6.86E-06 0.730 15385 21075 

PP-3 0.000781 l.67E-05 0.790 7407 9376 21450 I 27152 2.90 

PP-4 0.000932 4.14E-05 0.860 3636 4228 11814 I 13737 3.25 

PREDICTED & OBSERVED FATIGUE LIFE