d05-06a_addendum_field_survey_and_material_testing

technology platform for transport, infrastructure and public space

Guideline on PCN Assignment in the Netherlands Field survey and material testing Addendum to CROW-report D05-06 Theme: Infrastructure

Addendum to CROW-report D05-06 1

CROW is the national technology platform for transport, infrastructure and public space. This non-profit organization allows central and provincial government, local councils, water boards, building trade organizations, manufacturers, consultancies, public transport organizations and educational institutes to work together in pursuit of their common interests through the design, construction and management of roads and other traffic and transport facilities. Active in research and in issuing regulations in the fields of civil and traffic engineering, CROW has developed broadly supported knowledge products. In doing so, CROW focuses on distributing its specific expertise to all target groups. CROW

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Content 1 Introduction .....................................................................................................................................4 2 Standard survey program for flexible and rigid pavements.............................................................5

2.1 Flexible pavements ..............................................................................................................5 2.1.1 H/FWD-equipment ..................................................................................................5 2.1.2 Execution of falling weight deflection survey.........................................................5 2.1.3 Drilling and coring on flexible pavements ..............................................................6

2.2 Rigid pavements ..................................................................................................................7 2.2.1 H/FWD equipment ..................................................................................................7 2.2.2 Execution of falling weight deflection survey on runways and taxiways. ..............7 2.2.3 Drilling and coring on rigid pavements...................................................................8

2.3 Laboratory testing ................................................................................................................9 2.3.1 Asphalt concrete cores.............................................................................................9 2.3.2 Cement concrete cores and cement bound base material ........................................9

2.4 Reporting the measurements................................................................................................9 3 Worked examples ..........................................................................................................................11

3.1 Flexible pavement..............................................................................................................11 3.1.1 General information...............................................................................................11 3.1.2 Information derived from deflection measurements & core information..............11 3.1.3 Determination of properties of bituminous material .............................................11 3.1.4 Subgrade properties ...............................................................................................12 3.1.5 PCN-calculation ....................................................................................................13 3.1.6 PCN-code ..............................................................................................................15 3.1.7 PCN-reporting format............................................................................................16

3.2 Rigid pavement ..................................................................................................................19 3.2.1 General information...............................................................................................19 3.2.2 Information derived from deflection measurements & core information..............19 3.2.3 Determination of cement concrete properties........................................................19 3.2.4 Subgrade properties ...............................................................................................19 3.2.5 PCN-calculation ....................................................................................................20 3.2.6 PCN-code ..............................................................................................................22 3.2.7 PCN-reporting format............................................................................................22

Related reading material and references.................................................................................................25


1 I n t r o d u c t i o n

CROW-report 05-06 provides guidance on the PCN assignment for reporting the bearing strength of airport pavements using the ACN-PCN system. This addendum describes the measurement program comprising of field measurements and laboratory testing as well as the determination of the material performance properties. The addendum closes with worked examples for a flexible runway pavement and rigid taxiway pavement.


2 S t a n d a r d s u r v e y p r o g r a m f o r f l e x i b l e a n d r i g i d p a v e m e n t s

The recommended field survey for flexible pavements standard comprises of deflection measurements, coring and material testing. The survey described herein is practised in the Netherlands. Naturally one may deviate, however, the field program presented fully complies with CROW-report 05-06. The field survey discerns the following type of pavements: Runways (R), Taxiways (T), Intersections (INT), Aprons (APR) and shelter aprons (SAPR). Since the use of the MicroPaver pavement management program is widely spread in the Netherlands, naming and relocation of the measurements according to MicroPaver is recommended.

2.1 Flexible pavements

2.1.1 H/FWD-equipment The falling weight deflection survey must be carried out with a H/FWD capable of inducing a load varying between 100 and 200 kN. The device must have a valid CROW-certificate, with the adjustment factor for deriving uniform deflections. A copy of the certificate must be provided when entering the contract.

2.1.2 Execution of falling weight deflection survey. - The test load should be such that the maximum deflection ranges between 300 and 600 µm. Per

station or test position, three tests should be executed. The deflection profile of the last drop will be used for the evaluation;

- The tests on runways are to be carried out in four lanes parallel to the centreline marking. These

are arranged at the centreline, 3.5 m left of centreline, 5.0 m right of centreline and at a distance of 10.0 m to the centreline. Tests should commence from the runway end with the low designation to the runway end with the high end number. Tests are to be carried out at intervals of 100 m. The distance between the tests locations of the four lanes must have an interval of 25 m. This is achieved by shifting the starting points every 25 m (e.g. at 0, 25, 50 and 75 m respectively);

- The number of tests to be executed on taxiways (T) depends on the width of the taxiway (refer to

Table 1). Tests are to be carried out at intervals of 50 m.


Table 1 Test lanes for deflection survey on taxiways (T)

Width taxiway Lanes located at distances of

12,0 m Centreline, 3.5 m left of the centreline 15,0 m Centreline, 3.5 m left and 5 m right of the centreline 22,5 m Centreline, 3.5 m left and 7.5 m right of the

centreline - The number of tests to be executed on pavement sections not being runways or taxiways depends

on the surface area of the test section (refer to Table 2). A minimum number of tests is required depending on the total area of a test section. The measurement interval should be such that the measurements on all lanes are carried out proportionally to the surface area with an interval depending on the number of tests to be carried out (refer to Table 2).

Table 2 Number of tests on sections not being runways or taxiways

Surface area m² Number of measurements

till 1.000 m² 6 till 3.000 m² 12 > 3.000 m² 15

- The falling weight device should be equipped with a minimum of 6 and preferably 7 or 9

geophones or deflection transducers. The transducers are arranged at distances of 0, 300, 600, 1000, 1500 and 2000 mm from the load plate. Additional transducers should be placed in the vicinity of the loading plate, e.g. at 200 and 500 mm and at a larger distance of the loading plate, e.g. at 2500 mm.

- Prior to commencing measurements on a lane, and shortly after, the pavement temperature must

be measured at a pavement depth of 15 cm. The air and surface temperature should be registered at each test location.

- For processing the data, the following information must be submitted:

o Surface temperature (°C) o Difference between local time and UT (hours) o Time of testing (hour) o Time of testing (minutes past hour) o Longitude of test site (degrees) o Mean air temperature of previous day (°C)

2.1.3 Drilling and coring on flexible pavements - Determination of pavement sections, based on the results of deflection measurements - Per pavement section, one construction core should be drilled up to a depth of 1.0 m. The core

location should be such that it matches the location of the so-called 50-percentile deflection location of all lanes and test locations per section. (refer to Table 1).

- Depending on the total area, one or two additional asphalt cores must be extracted. These should

be located at the 85- and 15-percentile deflection location respectively. - The diameter of the core should be at least 100 mm or 150 mm depending on the type of required

material testing.


- The GPS-location and the cored thickness and type of construction materials should be reported. The GPS- coordinates must re converted into the ‘Rijksdriehoeknet’ in the Netherlands.

- The borehole must be filled with fresh concrete and a minimum thickness of 100 mm hot asphalt.

Measurements must be taken to obtain sound adhesion between the two materials. Sub settlement is not allowed and should be repaired instantly.

Table 3 Number of cores to be drilled on flexible pavement sections

Surface area Pavement type Number of cores

≤ 5000 m² All One construction core R, T, APR One construction and two asphalt cores SAPR One construction core per shelter apron > 5000 m² Misc., INT One construction core; one asphalt core

2.2 Rigid pavements

2.2.1 H/FWD equipment The falling weight deflection survey must be carried out with a H/FWD capable of inducing a load varying between 100 and 200 kN. The device must have a valid CROW-certificate, with the adjustment factor for deriving uniform deflections. A copy of the certificate must be provided when entering the contract.

2.2.2 Execution of falling weight deflection survey on runways and taxiways.

- The test load should be such that the maximum deflection is about 200 µm. Per test location, three tests are to be executed. The deflection profile of the last drop is used for the evaluation;

- Tests on concrete pavements concern runway ends, overruns,

taxiways, aprons and shelter aprons; - The falling weight device should be equipped with a minimum of 6

geophones, arranged at distances of 0, 300, 600, 1000, 1500 and 2000 mm from the load plate. Additional transducers should be placed in the vicinity of the loading plate, e.g. at 200 and 500 mm and at a larger distance of the loading plate, e.g. at 2500 mm or can be used for deflection transfer measurements across joints.

- At each measurement, the designation of the measurement location,

the position on the slab, time of measurement and surface temperature must be recorded.

- Depending on the size of the section a minimum of at least six slabs

must be measured. - Of every test slab, three load positions must be tested on that slab.

These are the slab interior, transverse edge, and longitudinal edge. The relocation of a test slab with the test position is denoted by placing a number before the slab number. The code for the interior, transverse


and longitudinal position is 1, 2 and 3 respectively. As an example, code 2.5 indicates, that this is a measurement on a transverse edge of slab no. 5.

- The slabs to be measured are located near the centreline in the heaviest loaded portion of the

pavement. By ‘waving’ when measuring the longitudinal joints, both construction and shrinkage joints are measured (see Figure).

- The location of the measured slabs must be indicated in a drawing. - The deflection measurements on the transverse and longitudinal edge can be combined with the

load transfer measurement across the joint. The geophones normally located at 2,000 and 2,500 mm during interior testing, are placed directly at the joint and in such a way that the distances from the centre of the loading place to these geophones are equal. The measurements as well as the deflection ratio of the deflection of the unloaded to loaded slab are to be reported.

- The length of the joints of the slabs under evaluation will be measured. - If not all geophones are located on the test slab, this will be recorded and reported in an event list. - Should a test slab be cracked, it will be reported in the event list. - The number of cracked slabs of the pavement section must be reported as a percentage of all slabs.

2.2.3 Drilling and coring on rigid pavements - Per pavement section, one construction core should be drilled up to a depth of 1.0 m. The core

location should be such that it matches the location of the so-called 50-percentile deflection location of all the interior test locations.

- Depending on the total area, one or two additional concrete cores will be drilled. These should be

located at the 85- and 15-percentile deflection location respectively. Table 4 Number of cores to be drilled on concrete pavement sections Surface area Pavement type Number of cores

≤ 5000 m² All One construction core R, T, APR One construction and two concrete cores SAPR One construction core per shelter apron > 5000 m² Misc., INT One construction core; one concrete core

- The diameter of the core should be at least 100 mm or 150 mm depending on the type of required

material testing. - The GPS-location and the cored thickness and type of construction materials should be reported.

The GPS- coordinates must re converted into the ‘Rijksdriehoeknet’ in the Netherlands. - The borehole must be filled with fresh concrete and a minimum thickness of 100 mm hot asphalt.

Measurements must be taken to obtain sound adhesion between the two materials. Sub settlement is not allowed and should be repaired immediately.


2.3 Laboratory testing

2.3.1 Asphalt concrete cores - Of each cylinder, the total thickness and the thicknesses of the subsequent layers must be

measured. - The properties of the bottom asphalt layer govern the performance of the asphalt pavement. The

following properties of the base material must be determined: o The degree of compaction and void content; o The penetration at temperatures of 25 and 35°C, TRing&Ball and the Penetration Index

(PI) on a mixture of recovered bitumen; o The Master curve by performing a frequency sweep in an indirect tension test. The

thickness of the sample should be 40 mm. The frequency sweep is to be performed at 20°C and at frequencies of 1, 2, 3, 5.9, 19.6 and 55.6 Hz and again at 1Hz for verification. All frequencies are to be reported and the slope m = d(Smix)/d(log t) is to be determined and reported;

o Calculation of the volumetric components Vbit, Vaggregate and Vair.

2.3.2 Cement concrete cores and cement bound base material - Of each cylinder, the total thickness must be measured (EN 13863-4:2004). Should the concrete

be placed in a two layer system, the thickness of both layers must be reported as well. - The dynamic modulus of the cement concrete and cement bound base material must be determined

with a so-called CSI-betontester (CSI concrete tester). The dynamic modulus must be reported according to NEN 5979.

- Of every cement bound layer (foundation and slab), the compressive strength according to EN

12504-1:2000 and EN 12390-3:2001, and the volumetric mass (EN 12390-7:2000) must be determined.

2.4 Reporting the measurements A measurement report contains a description of the measurements, results and findings. A measurement report must be prepared per airport. The measurements must be reported as a hardcopy and digitally. First as a draft report; after discussion it will be accepted and finalized. The written report should contain following topics: - Relocation of the pavement sections and test locations - Type of pavements and executed measurement program - The CROW-certificate of the H/FWD device(s) used for the measurements - The test devices used in the evaluation - Date(s) of measurement and conditions during measurement - Drawing of the measured slabs - Tables of the deflection measurements with subsections and location of the 15, 50 and 85-

percentile deflection. The H/FWD-data is also to be reported digitally in an Excel-file. The format of this file will be provided by the client

- The determination of the percentile point, location of the construction coring and asphalt or concrete core

- Determination of pavement sections


- Graphs of the defection measurements and cumulative sum of each section. This data is to be reported in the provided Excel file format. The results of a section should be reported in a separate file

- The laboratory testing is to be reported in a separate chapter of the measurement report - The measurements and calculations of the frequency sweep incl. graphs of the master curve Smix

versus log t - A description of the digital files The following information is to be delivered digitally: - The original, unprocessed H/FWD measurement files (in a readable format) - Tables of the deflection measurements with subsections and location of the 15, 50 and 85-

percentile deflection. The H/FWD-data is also to be reported digitally in an Excel-file. The format of this file will be provided by the client

- The results of the laboratory testing must be reported in the Excel spreadsheet containing the deflection measurements. The results will be reported in a separate tab sheet within that Excel file

- The measurements and calculations of the frequency sweep incl. graphs of the master curve Smix - log t


3 W o r k e d e x a m p l e s

This chapter deals with the evaluation of the asphalt runway 06/24 of Utopia civil airport and one of the concrete taxiways of Utopia military airbase. The data used herein is purely fictitious and is used for demonstration purposes only. Since deflection measurements are relatively standard, the example focuses on the procedure for determining material properties and assessing a technical PCN value rather than presenting tables and graphs of H/FWD-measurements.

3.1 Flexible pavement The flexible pavement of rwy 06/24 has been constructed in 1996. The PCN is to be reported for the next 10 years.

3.1.1 General information The following traffic information has become available:

Table 5 Historic and forecasted load data rwy 06/24

Aircraft designation Departures per annum

1. F28 Mk 1000 HPT 400 2. B737-200 1,500 3. B757-200 1,000 4. B767-300 1,500 5. L1011-1 400 6. B747-400 800

3.1.2 Information derived from deflection measurements & core information Let’s assume the following information has become available from the survey: - Flexible pavement comprises of 240 mm asphalt and a 250 mm thick furnace slag base (source:

core information) - Back calculated moduli:

o E_asphalt = 6,000 MPa o E_furnace slag = 400 MPa o Subgrade = 100 MPa

3.1.3 Determination of properties of bituminous material The laboratory testing comprised of determining the bitumen properties, volumetric content analysis and a velocity sweep analysis. Based on this information, the transfer function of the bituminous concrete layer can be determined using Appendix 1 of the Guideline. The general relationship is

( ) )log(n)klog(Nlog rasph ε−= Where: Nasph = number of allowable load cycles to failure of asphalt concrete εr = strain at bottom of asphalt layer (m/m) k, n = model and material parameters. The values of k an n can be estimated using the relationships presented hereafter.


amas

masest V03514.0n173.0541.0

nn

−+=

where nest is the estimated slope of the asphalt mix under consideration and Va is the volume percentage of voids (% v/v). nmas is the theoretical value of the slope of the fatigue transfer function, which is derived from a frequency sweep. Using linear regression analysis a function between the stiffness modulus and the loading time can be assessed. The slope of this relation is:

( ))t(logd

Slogdm xmi=

with: m = slope of the master curve Smix = stiffness modulus of the asphalt (MPa) t = loading time (ms) nmas is assessed from:

m2nmas =

The parameter k is calculated using:

( ) ( ) b&ra

b

mixestest T0721.0PI928.0

VV

149.0Vblog332.2S3209n762.3589.6klog −++++−=

Where: kest = estimated value of intercept of fatigue function for mixture under consideration nest = estimated value of slope of fatigue function for mixture under consideration Smix = stiffness modulus of the asphalt (MPa) Va = volume percentage of voids (% v/v) Vb = volume percentage of bitumen (% v/v) PI = penetration index (-) Tr&b = Temperature of ring and ball test Let’s assume that testing has been done and using the above mentioned formulae resulted in the following transfer function:

( ) ( )rasph log725.5980.11Nlog ε−= Where: Nasph = number of allowable load cycles to failure of asphalt concrete (in millions of cycles) εr = strain at bottom of asphalt layer (µm/m)

3.1.4 Subgrade properties The Shell 85% relationship with values of 17.289 and –4.000 is used in the PCN-evaluation.

( ) ( zs log000.4289.17Nlog )ε−= Where: Ns = number of allowable load applications (in millions of cycles) C0, C1 = material constants εz = compressive strain on top of the subgrade (µm/m)


3.1.5 PCN-calculation The first step in the PCN-calculation is to determine the critical pavement layer. This is done by calculating the total Miner damage for a period of 20 years (from 1996 to 2016, i.e. date of construction until 2006, extending to the year 2016 for the 10 year PCN-evaluation).

Figure 1 The asphalt layer is critical. The cumulative miner damage after 20 years of use is 52,7% (versus 18,6% of the subgrade).

The next step is to determine the aircraft having the highest ACN. The load characteristics and ACN-values at MTOW and OEW are to be used in the PCN-assessment. The critical aircraft is the B747-400.


Table 6 Determination of critical aircraft based on historic and forecasted fleet mix

LOAD DATA (historic and forecasted) Aircraft designation Departures

per annum MTOW

kg OEW

kg ACNMTOW ACNOEW Source

1. F28 Mk 1000 HPT 400 29,484 16,550 15B 7B ADM Fokker2. B737-200 1,500 61,462 32,902 33B 16B ADM Boeing3. B757-200 1,000 109,316 60,260 32B 14B ADM Boeing4. B767-300 1,500 159,755 80,853 48B 21B ADM Boeing5.L1011-1 400 195,952 108,862 56B 27B ICAO 6. B747-400 800 395,987 178,459 62B 22B ADM BoeingCritical aircraft B747-400 Lateral wander (mm) 2,400 (strip width 0.25 m) Residual pavement life (years) or Miner sum (%) 52.7

A total number of 22,964 passes of a B747-400 will result in a failure of the asphalt layer M = 100%). In the PCN-evaluation, the Miner sum in only 52,7%. This amount of cumulative damage (CDF) is achieved when a number of 12,102 B747-400 has covered the pavement.

Figure 2 Determination of CDF for B747-400

The final step in the PCN-calculation is to calculate the allowable gross weight of the aircraft (AGW), and to determine the ACN of the B747-400 at that gross weight. This value is assigned as the PCN value of the pavement under evaluation.


Figure 3 Calculating the allowable gross weight and ACN @ AGW

The PCN-value of the flexible pavement is 84, based on layer 1.

3.1.6 PCN-code The ICAO PCN pavement strength reporting system involves publishing a five (5) part strength code in the form of for example 51 FDWT for flexible pavements or for example 62 RBWT for rigid concrete pavements. Briefly, the first number is the reported PCN value on a scale of 1 to about 130, with 1 representing a weak pavement and 130 a very strong pavement. The second part of the code is either an "F" for flexible pavement systems or "R" for rigid pavement systems. The third part is a letter code A, B, C, or D indicating the subgrade/bearing strength, with A representing a high supporting strength and D a very low strength. The fourth part indicates the tire pressure limitation in MPa if applicable (X, Y, Z otherwise W). The fifth and final part of the PCN code indicates the evaluation method used to determine the pavement strength - "T" if derived from an engineering study or "U" if based on satisfactory aircraft usage.

Table 7 PCN reporting format

PCN Pavement Type Subgrade category Tire pressure Evaluation method R – Rigid

F – Flexible A – High B – Medium C – Low D – Ultra Low

W – No Limit X – to 1.5 MPa Y – to 1.0 MPa Z – to 0.5 MPa

T – Technical U - Using Aircraft

The ranges of subgrade strength covered by these categories are shown in Table 8.


Table 8 Ranges of standard subgrade strength

Subgrade Category

Pavement Type

Characteristic Subgrade Strength Range of Subgrade Strengths

Rigid 150 MN/m2/m All k values above 120 MN/m2/m A - High Flexible CBR 15% All CBR values above 13% Rigid 80 MN/m2/m 60 to 120 MN/m2/m B - Medium Flexible CBR 10% CBR 8% to CBR 13% Rigid 40 MN/m2/m 25 to 60 MN/m2/m C - Low Flexible CBR 6% CBR 4% to CBR 8% Rigid 20 MN/m2/m All k values below 25 MN/m2/m D - Ultra Low Flexible CBR 3% All CBR values below 4%

Unless there is a particular reason for limiting the tire pressure, the tire pressure is coded W. The result of the PCN-evaluation is: PCN 84 F/B/W/T

3.1.7 PCN-reporting format The PCN is to be published in an Aeronautical Information Publication (AIP). The calculated PCN is to be submitted to the national Civil Aviation Authority (CAA). In the Netherlands a special format is mandatory. An example of this format is given below.


GENERAL INFORMATION

Date of submission n/a Name and code of airport

Utopia

PCN-evaluation life 10 years Residual life n/a Date of PCN-evaluation 26-01-2006 Runway, taxiway or

apron Runway

Year of revision n/a Designation of pavement 06/24 Name of evaluator Marc Stet Year of construction 1996 Software used for PCN Pavers v2.52 Year of rehabilitation n/a Valid until (max 10 years) 2016 Approved by: n/a

STRUCTURAL PAVEMENT DATA

Material type

Num

ber o

f lay

er

(top-

dow

n)

Con

stru

cted

th

ickn

ess (

mm

)

Stiff

ness

mod

ule

(MPa

)

subg

rade

reac

tion

and/

or sh

ear

mod

ulus

(k,G

) (10

-

2 M

Pa/m

m,

Pois

son’

s con

stan

t (-

)

Fatig

ue tr

ansf

er

Func

tion

Flex

ural

st

reng

th(M

Pa)

Sour

ce

Asphalt concrete 1 240 6,000 0.35 Lab. Testing Furnace slag 2 250 400 0.35 n/a Subgrade 3 100 0.35 85% Shell Classification method of subgrade strength DCP-testing Critical pavement layer Asphalt Design criterion of critical layer Asphalt strain criterion Statistical % of material characteristics 50% Statistical % of fatigue characteristics 50% asphalt strain criterion; 85% subgrade criterion Concrete slab dimensions (length x width x thickness)

n/a

List sources used to assess data: CROW Guideline on PCN (CROW-report 05-06)

Comment:

LOAD DATA (historic 10 y and forecasted 10y) Aircraft designation Departures

per annum MTOW

kg OEW


1. F28 Mk 1000 HPT 400 29,484 16,550 15B 7B 2.B737-200 1,500 61,462 32,902 33B 16B 3.B757-200 1,000 109,316 60,260 32B 14B 4.B767-300 1,500 159,755 80,853 48B 21B 5.L1011-1 400 195,952 108,862 56B 27B 6.B747-400 800 395,987 178,459 62B 22B Critical aircraft B747-400 Lateral wander (mm) 2,400 (strip width 0.25 m) Residual pavement life (years) or Miner sum (%) 52.7


TECHNICAL PCN report PCN time period (years) 10 y Allowable ACN-load of critical aircraft (kg) 558,8738 (141.1%)

- Value 84 - Pavement type F - Subgrade Category B - Tire Pressure W - Evaluation method T

PCN Reporting format 84 F/B/W/T Comment of Evaluator:


3.2 Rigid pavement Taxiway ‘East’ of Utopia airbase was constructed in 2001. The PCN is evaluated in 2006 for a period of 15 years.

3.2.1 General information The pavement is 22.5 m wide and comprises of non reinforced, jointed concrete slabs. The dimensions of the slab panels are 5.00 x 3.75 m² (six slabs across the pavement). The taxiway is used by the following fleet mix:

Table 9 Fleet mix twy

Aircraft designation Departures per annum

1. C-130 Hercules 4000 2. C17-A 60 3. F16D 9,000 4. B737-400 150

3.2.2 Information derived from deflection measurements & core information Let’s assume the following information has become available from the survey: - Coring resulted in a constructed slab thickness of 280 mm. The base comprises of 250 mm

granular slag (source: core information) - The back-calculated elastic moduli from the interior measurements are:

o E_concrete = 34,000 MPa o E_slag = 600 MPa o E_subgrade = 100 MPa

- Deflection transfer across joints 42.9 %

3.2.3 Determination of cement concrete properties Appendix 2 of the Guideline explains on how to assess the properties of the cement concrete. The average flexural concrete strength of concrete under dynamic loading can be estimated from the compressive strength by:

( ) ( )( ) mckbr /8'f05.005.1h6.13.1f γ++−= Where: fbr = flexural strength (MPa) h = slab thickness (m) f’ck = compressive strength (MPa) γm = material factor for concrete under tension γm = 1.2 Having determined a compressive strength of 45.0 MPa, the flexural strength is calculated at 5.29 MPa. The Guideline recommends the use of the so-called UEC-fatigue relationship.

3.2.4 Subgrade properties For concrete pavements, the strength of the subgrade is expressed as a k-value. The back-calculated elastic modulus of 100 MPa is converted to a k-value of 0.045 MPa/mm using McCullough’s relationship presented in Appendix 3 of the Guideline. Having a strength of 45 MN/m2/m, the subgrade strength is classified as ‘Low’ (C; see


Table 8). The granular base contributes to the slab’s support. The subgrade’s k-value can be upgraded to 0.088 MPa/mm for a thickness of 250 mm and an elastic modulus of 600 MPa.

3.2.5 PCN-calculation In plain concrete pavements, the joints at the slab’s edge are critical and determine the load-carrying capacity of the pavement. The first step is to determine which joint is the most heaviest trafficked one. From Figure 4 it can be depicted that the longitudinal edge located at a distance of 3.75 m is more trafficked than the longitudinal edge at the centreline.

Figure 4 The longitudinal edge at 3.75 m is the heaviest trafficked slab edge.

The Cumulative Miner Damage Factor (CDF) at the longitudinal edge is 41.5%.


The critical aircraft for the PCN-assignment is the C17A Globemaster, having ACN’s of 52R and 22R at a low subgrade strength (category C).

Table 10 Determination of critical aircraft based on historic and forecasted fleet mix

LOAD DATA (historic and forecasted) Aircraft designation Departures

per annum MTOW

kg OEW


1. C-130 Hercules 4,000 73,028 36,623 38R 6R ETL 1110 2. C17A Globemaster 60 261,300 121,600 52R 22R ETL 1110 3. F16D 9,000 17,272 7,727 16R 6R ETL 1110 4. B737-400 150 64,864 33,643 45R 21R ADM BoeingCritical aircraft C17A Globemaster Lateral wander (mm) 1,000 Residual pavement life (years) or Miner sum (%) 41.5

Similarly to the flexible example, the allowable number of passes is calculated. The pavement can sustain 7,847 passes until structural failure.

Figure 5 Allowable number of C17A coverage’s on longitudinal edge

The PCN-evaluation is based on a 20 year period in which a CDF of 41.5 % occurs. This is equal to 3,253 C17A coverage’s. This CDF is arrived at an allowable gross weight of 308,334 kg (see Figure 6; 1.18 times MTOW). The ACN at this aircraft weight is 58R.


Figure 6 Determination of PCN-value

The PCN-value of the rigid pavement is 67, based on the longitudinal edge.

3.2.6 PCN-code The PCN-code is similarly composed as in the flexible example (see § 3.1.4). - Pavement type: Rigid R - Subgrade category Low C - Tire pressure No limit W - Evaluation method Technical T The result of the PCN-evaluation is: PCN 67 R/W/C/T

3.2.7 PCN-reporting format In the Netherlands, a prescribed format is to be used to report the PCN. The format is used by the Netherlands CAA as a Directive.


GENERAL INFORMATION

Date of submission n/a Name and code of airport

Utopia

PCN-evaluation life 15 years Residual life n/a Date of PCN-evaluation 26-01-2006 Runway, taxiway or

apron Taxiway

Year of revision n/a Designation of pavement Taxiway east Name of evaluator Marc Stet Year of construction 2001 Software used for PCN Pavers v2.52 Year of rehabilitation n/a Valid until (max 10 years) 2016 Approved by: n/a

STRUCTURAL PAVEMENT DATA

Material type

Num

ber o

f lay

er

(top-

dow

n)

Con

stru

cted

th

ickn

ess (

mm

)

Stiff

ness

mod

ule

(MPa

)

subg

rade

reac

tion

and/

or sh

ear

mod

ulus

(k,G

) (10

-

2 M

Pa/m

m,

Pois

son’

s con

stan

t (-

)

Fatig

ue tr

ansf

er

Func

tion

Flex

ural

st

reng

th(M

Pa)

Sour

ce

Cement concrete 1 280 34,000 0.15 UEC 5.277 Test Slag 2 250 600 0.088 0.35 n/a n/a Subgrade 100 0.045 n/a n/a n/a Classification method of subgrade strength DCP Critical pavement layer Concrete slab Design criterion of critical layer Fatigue cracking, UEC Statistical % of material characteristics 50 Statistical % of fatigue characteristics 50 Concrete Slab dimensions (length x width x thickness in mm)

5000x3750x280

List sources used to assess data: CROW Guideline on PCN (CROW-report 05-06) Comment: LOAD DATA (historic 5y & forecasted 15y) Aircraft designation Departures

per annum MTOW

kg OEW


1. C130 Mk3 4,000 73,028 36,600 38R 6R ETL 1110 2. C17A 60 261,300 121,600 52R 22R ETL 1110 3. F16D 9,000 17,272 7,727 16R 6R ETL 1110 4. B737-400 150 64,864 33,643 45R 21R Boeing Critical aircraft C17 A Globemaster Lateral wander (mm) 1,000 Residual pavement life (years) or Miner sum (%) 41.5


TECHNICAL PCN report PCN time period (years) 15 Allowable ACN-load of critical aircraft (kg) 309,205

- Value 67 - Pavement type R - Subgrade Category C - Tire Pressure W - Evaluation method T

PCN Reporting format 67 R/C/W/T Comment of Evaluator:


4 R e l a t e d r e a d i n g m a t e r i a l a n d r e f e r e n c e s

1. Braam, C.R. and C. Chr. Bouquet. Closer look at tensile strength of concrete. (in Dutch: De treksterkten van beton nader beschouwd). Cement Magazine, no. 7, p72-75.2003.

2. Van Cauwelaert, F.. Pavement design and evaluation. The required mathematics and applications. ISBN 2-96000430-0-6. Edited by M.J.A. Stet. Federation of the Belgian Cement Industry, Brussels Belgium, 2004.

3. CROW. The PCN Runway Strength Rating and Load Control System. State of the art study 2003/2004. Edited by M.J.A. Stet. CROW-report 04-09. Ede, The Netherlands, www.crow.nl, 2004.

4. CROW. Guideline on PCN Assignment in the Netherlands. Guideline on Airport Pavement Strength Rating and Directive for Reporting. Edited by M.J.A. Stet. CROW-report 05-06. Ede, The Netherlands, www.crow.nl,2005.

5. HoSang, V. et al. Field Survey and Analysis of Aircraft Distribution on Airport Pavements. Research in Airport Pavements. Special Report 175, Transportation Research Board, Georgia, USA, 1978.

6. International Civil Aviation Organization (ICAO). International Standards and Recommended Practices, Aerodromes, Annex 14 to the Convention on International Civil Aviation, Volume 1 Aerodrome Design and Operations, 4th edition, International Civil Aviation Organization, 2005.

7. International Civil Aviation Organization (ICAO). Aerodrome Design Manual. Part 3, Pavements, Second edition, ICAO, 1983.

8. Medani, T and A. Molenaar. Fatigue Characteristics of asphalt mixes. Heron. Volume 45, No 3. TNO Buildings and Construction Research, 2000.

9. Pavers. Homepage of the Pavers Team, www.pavers.nl, 2006. 10. Stet, M.J.A., Thewessen. H.P.M. and Van Cauwelaert, F. PAVERS: Pavement Evaluation and

Reporting Strength software; PCN Assessment using PAVERS software, Pavers Pavement Team, www.pavers.nl, 2001.

11. Stet, M.J.A., Thewessen, H.P.M. and Van Cauwelaert, F. The Pavers system. A tool for the (re)design of flexible and rigid pavement. FAA worldwide airport technology transfer conference. Atlantic City, New Jersey, USA, 2004.

12. Stet, M.J.A., Van Cauwelaert, F. The elastic length: key to the analysis of multi-layered structures. 5th International CROW-workshop on fundamental modelling of the design and performance of concrete pavements. Istanbul, Turkey, 2004. ISBN: 90 6628 407 2. CROW Record 24. CROW, Ede, the Netherlands.

13. Stet, M.J.A. and Verbeek, J.P. The PCN Runway Strength Rating and Load Control System. 1st European CROW-workshop on airport pavements. Amsterdam Airport Schiphol, the Netherlands, 2005. ISBN: 90 6628 449 8. CROW Article no. 938. CROW, Ede, the Netherlands.

14. CROW. Uniforming Evaluation method Cement concrete pavements (in Dutch: Uniformering Evaluatie methode Cementbeton verhardingen). Publication 136. CROW, Ede, the Netherlands, 1999.


http://www.crow.nl/

http://www.crow.nl/

http://www.pavers.nl/

http://www.aperio.nl/

Colophon Publisher: CROW, Ede Edition: May 2006 Author: Marc Stet Production: CROW, publishing department CROW report D05-06/a ‘Field survey and material testing’ Addendum to CROW-report D05-06 ‘Guideline on PCN Assignment in the Netherlands’. This report can be downloaded from www.crow.nl/shop


http://www.crow.nl/shop

d05-06a_addendum_field_survey_and_material_testing

Documents

flexible pavements

crowreport d05

crow galvanistraat

rigid pavements

public transport organizations

weight deflection survey

infrastructure addendum

transport facilities