All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure Management

Advanced Airport Pavement
Design and Evaluation Method

Asphalt Pavements Evaluation
Using FWD
National Institute for Land andInfrastructure Management
MLIT, JAPANObjectives
T Background
U Bearing Capacity
U Structural Integrity
U Deteriorated Portion

T In situ Survey
T Criteria
U Deflection, Stress, Strain

T Dynamic Analysis
U Impact Load by FWD, Moving Wheel Load1

All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure Management

SystemT 200kN-FWD with 7 Deflection
T In Accordance with the Current DesignMethod

NDT for Asphalt Pavements
T CBR Design Method
T Evaluation Criteria: Strain (AC, SG)
T Temp.: 20℃, Freq.: 2, 10Hz
T Overlay Thickness Calculation
T Rough Evaluation

by D02

All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure Management

Strain Criteria
1500ε (10-6)

Coverage

1000

5000εv

500

40000
5000
εt

40000
0051015CBR (%)

20AC Strain in Loading Test
1000
8800-6ε t (10 )600

criteria



65¦¡

400
20007{05No. T01000 {2000 75000 8OL 1015CBR (%)

NT¦56¡203

All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure Management

Strain at Construction Stage
1500

base binder surface
εv z5ε (10-6)εt10007ε v criteria

TTTTTTTUTTTUUTUUUUU
33U333333U
5
5
555UU5U 5ε t criteria{{{{{{{{
7777777775000

051015CBR (%)

20Overlay Thickness
1000

ε(10-6)z800
U600

εvcriteria

εv
εtz400U200zε tcriteria

U00100200

Overlay Thickness (mm)4

All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure Management

Required Overlay Thickness
Overlay Thickness (mm)200mea av
East150 West
1005000500 1000 1500 2000 2500 3000
Distanse from End (m)Deflection Criteria
D0 (mm)2
Granular Base Course
1.5
10.5

Design Coverage
5000
20000
10000
40000

00 2 4 6 8 10 12 14 16 18 20
CBR(%)

5

All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure Management

Flowchart for AP Evaluation
Deflection Measurement
Deflection Correction
Design Input
OK

D0 Comparison

UnnecessaryNG

Backcalculation
OKε t , ε v Comparison

Unnecessary

NG

Overlay Thickness Calculation

Dynamic & Static Analysis
T Dynamic Analysis
U Impact load generated by FWD

250800LoadDeflections

600
D0150400
100
D2505000102030Time (msec)

40200050

Deflection (µm)

Load (kN)200

Dynamic vertical displacement (mm)U Moving wheel load by aircraft
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
-2024

6810Time (sec)6All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure Management

Elastic Modulus by Backcalculation
Elastic modulus (MPa)8000
M ethod of back-calculation
S tatic
D ynam ic

7000
6000
5000
4000
6040200

A sphalt C oncrete

S ubgrade

FWD Deflection-3

Deflection (1x10 mm)

0200

StaticDynamic

400
600

Measured Deflection

800
10000500

1000 1500 2000 2500

Distance from the plate center (mm)7All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure Management

Vertical Displacement in Loading
Test
Vertical Displacement (mm)

2.6
2.4
2.2

Dynamic

2.0
1.8

Measured
Displacement

1.6
1.4

Static1.2

110100

1000

10000

Load Repetitions

Strain in Loading Test-6ε (1x10 )2500

Static Analysis
Dynamic Analysis

2000εv

1500

εt

1000
50001101001000
Load Repetitions

100008All Rights Reserved, Copyright (C) 2004, National Institute for Land and Infrastructure ManagementConclusion
T Asphalt Pavements Evaluation using FWD
U Detailed Evaluation: Strain (AC, SG)U Overlay Thickness
U Rough Evaluation: D0
U Difference between Static & Dynamic Analysis (E, ε)9