AIRCRAFT PAVEMENTS. DESIGN and Construction.

Bruce Rodway

Australian Society for Concrete PavementsForum for Airports and Ports. 22nd June 2009

Damage to Jet Engines and Propellers

• The worst concrete pavement is one that releases concrete fragments from its joint edges throughout its life. These loose fragments can be released without warning. They can damage propellers and can be sucked into jet engines, and at worst can cause engine failure in flight.

B747 engine damage

KSAP Eastern Apron, 30 years old. Cork joints. Very few spalls.

Qantas freight apron, Sydney Airport

Mobile Accelerated Loading Facility (ALF) testing at Beerburrum, Queensland

ALF

US FULL-SCALE TESTS on HIGHWAY PAVEMENTS

Airbus A380-562 tonnes

A380 (27 tonnes per wheel)

Antonov 225: 600 tonnes, 28 wheels

6802-Highway truck

95021265C17 transport

1,65030218B52 bomber

1,4001978Boeing B737

1,55028217B787 Dreamliner

1,57030366Airbus A340-600

1,52027352Boeing B777-300 ER

1,40024400Boeing B747

1,34027562Airbus A380

1,00020600Antonov 225

Tyre Pressure (kPa)

Wheel Load(tonnes)

Weight (tonnes)

Aircraft

Excavation for aircraft test pavements, US Corps of Engineers, Vicksburg Mississippi, 1966.

C5A US Military Transport. 350 tonnes

C5A-Simulating Test Roller

Test Roller Guidelines

Failure under B747 Roller

Corps of Enginees, Rigid pavement load test.

Corps of Engineers. Rigid pavement load test.

US Corps of Engineers CBR Curve

0

0.001

0.002

0.003

0.004

0.005

0.006

0 2000 4000 6000 8000

Coverages

Vertical Strain

HALFWAY

275 m

18 m

US Accelerated Loading Facility

FAA Test Facility. 8-wheel loading

FAA Test Facility-Flexible pavement deformation

Concrete test area-B777 static load test.

Concrete Warping Cracks

High-Strength Subgrade Rigid Test Item

Lane 2

Lane 3

Lane 1

Slab 1 Slab 2 Slab 3 Slab 4 Slab 5

NORTH

100 Feet

60 Feet

Feb 14>Feb 14

<Feb 14

A380 Airbus pavement load test

Patched Continuously Reinforced Concrete Taxiway, Chicago Airport

Changi multi-patched taxiway

Asphalt rutting, Dubai

Installation of heating coils at US test facility.

Transverse sawn contraction joint (“dummy” joint).

Cages for transverse dowels, Denver

COATING DOWELS

Crooked dowels

Cracks due to misaligned dowels

Edge slump correction of slipformed concrete,530mm thick at Chicago Airport

Slipformed concrete. Deviated edge to be removed by sawing

Edge Slump, 530mm slipformed concrete

Slipformer ‘straddling’ forms. Brisbane Airport’s International Apron, 400mm thick

Slipformer placing 500mm thick concrete between forms at New Delhi airport

��������������� ������������������

��������������� ������������������������������������ ���������������� ������ ������������������� ��������������������!����������� ������ ����� ��������

���������!���������������� ����������

!���"������������� ��

Austroads design vs. Heavy Aircraft design Methods

Subgradestrain

Austroads Heavy Aircraft Ratio

0.0005 618 x106 1.5 x 106 410:1

0.001 4.4 x 106 15,000 290:1

0.002 30,000 160 190:1

Predicted Load Repetitions to Failure for identical subgrade strains

Questions?

0.001

0.01

1 10 100 1000 10000

N

εεεεN

k b= ��

��ε

�A damage model relates pavement life to a computable indicator of damage such as subgrade compressive strain, etc.

� The models are of the form:

Damage models

Nk b

= ����ε

strainrepetitions to failure

Effect of wheel load on pavement rutting for equal subgradestrains

0

500

10000 0.005 0.01 0.015 0.02 0.025

Vertical Strain

Depth (mm)

20 tonne

4 tonne

4 tonne20 tonne

Top of subgrade

Effect of wheel load on load pulse shape at subgrade

level

-0.005

0

0.005

0.01

0.015

0.02

0.025

0 200 400 600 800 1000 1200

Distance (mm)

Ver

tica

l Str

ain

20 tonne

4 tonne

4 tonne

20 tonne

Airfield concrete-Differences from Road and Building concrete.

• Lower maximum slump of 50mm• Larger maximum stone size of 38mm (1.5 inches)• No steel reinforcement• River gravel not used• Flyash not used• Can’ t be pumped• Thicker than roads (400mm vs 250mm)• Slipforming not used on airfields in Australia• Strength measured by beams not cylinders• Must be water cured for 24 hours, not membrane

12 June 1994