Bsi bs en 12697 22 2003 (2007)

www bzfxw com Copyright European Comm Provided by IHS under lice No reproduction or network BRITISH STANDARD BS EN 12697 22 2003 Incorporating amendment no 1 Bituminous mixtures — Test methods for hot[.]

Large size devices

6.1.1.1 Wheel fitted with a 400 × 8 pneumatic tyre without tread pattern and having a track width of

(80 ± 5) mm The pneumatic tyre pressure shall be (600 ± 30) kPa

NOTE The Trelleborg T522 BV Extra or Special 6-ply type pneumatic tyre is suitable for this test

6.1.1.2 The travel of pneumatic tyre relative to the specimen shall be (410 ± 5) mm

6.1.1.3 The frequency of travel (outward and return) shall be (1,0 ± 0,1) Hz

6.1.1.4 The rolling load applied to the test specimen shall be (5000 ± 50) N at the centre of the test specimen, measured at least when the device is static

6.1.1.5 The centre line of the tyre track shall be not more than 5 mm from the theoretical centre of the test specimen

6.1.1.6 The angle of skew shall be (0,0 ± 0,5)°

Mould(s) of internal dimensions (500 × 180 × 50) mm or (500 × 180 × 100) mm, all dimensions ±2 mm, capable of withstanding the test conditions without distortion

A depth gauge is utilized to measure local deformation, $ m_{ij} $, with an accuracy of ±0.2 mm, within a measurement area ranging from 5 mm² to 10 mm² Additionally, a contact-free sensor may be employed if it yields equivalent results.

A ventilated enclosure is equipped with a temperature probe that ensures the temperature within the test specimen is consistently maintained at ±2 °C of the predetermined set point (refer to Figure 1).

Copyright European Committee for Standardization

Provided by IHS under license with CEN

Temperature sensor(s) suitable for installation within a compacted bituminous test specimen and for the measurement of air temperature

Temperature monitoring indicator to record the temperature within the test specimen, as shown in Figure 1

The steel supporting plate must have a surface unevenness of less than 1 mm when measured diagonally with a steel rule Additionally, its thickness should ensure that deflection under the specified test conditions of this European Standard does not exceed 0.5 mm.

Non-stick chemical, such as glycerized sodium oleate.

Extra large Devices

6.2.1 Device simulating a rolling load which shall include:

Wheel fitted with a 6.00-R9 pneumatic tyre without tread pattern and having a track width of (110 ± 5) mm

6.2.1.2 The travel of pneumatic tyre relative to the specimen shall be (700 ± 5) mm

6.2.1.3 The time of travel (outward and return) shall be (2,5 ± 0,5) s

6.2.1.4 The rolling load applied to the test specimen shall be (10000 ± 100) N at the centre of the test specimen, measured at least when the device is static

6.2.1.5 The centre line of the tyre track shall be not more than 20 mm from the theoretical centre of the test specimen

6.2.1.6 The angle of skew shall be (0,0 ± 0,5)°

The internal dimensions of the mould are 700 × 500 mm, with a tolerance of ±5 mm, ensuring it can endure test conditions without distortion The height of the mould matches the nominal thickness of the test specimen at the ends, while the height of the side edges either matches or exceeds the nominal thickness by a maximum amount.

Laser sensors can accurately measure local deformation to within ±0.2 mm and are designed to assess rut depth with a maximum interval of 2 mm across at least three cross-sections, as illustrated in Figure 2.

A ventilated enclosure maintains a set temperature regulated by a probe within the test specimen, ensuring that the temperature remains within ±3 °C of the specified value.

Temperature sensor(s) suitable for installation within a compacted bituminous test specimen and for the measurement of air temperature

Temperature monitoring indicator to record the temperature within the test specimen, as shown in Figure 2.

Small size devices

The wheel-tracking apparatus features a loaded wheel that applies pressure to a securely held sample on a table This setup allows for either the table or the wheel to move back and forth, while a monitoring device tracks the rate of rut formation on the test specimen's surface It is essential that the vertical play in the loaded wheel mechanism remains below 0.25 mm.

The tyre must have an outside diameter between 200 mm and 205 mm and be fitted to the wheel It should be treadless with a rectangular cross profile, having a width of $w \pm 1$ mm, where $w = 50 \pm 5$ mm The thickness of the tyre should be $20 \pm 2$ mm, made of solid rubber with a hardness of $80 \pm 5$ IRHD units, measured according to ISO 7619 and ISO 48 Hardness verification can be conducted in accordance with ISO 48.

6.3.1.3 Means of applying a load to the wheel: The wheel load under standard test conditions shall be w N

70050 , measured at the level of the top of the test specimen and normal to the plane of the sample table

NOTE This loading may conveniently be achieved by the use of a weighted cantilever arm

The sample table is designed to securely hold a core specimen with a minimum diameter of 200 mm or a rectangular laboratory-prepared test specimen It ensures that the upper surface remains horizontal and aligned with the required tracking plane, while also positioning the specimen's center for symmetrical tracking motion.

The wheel-tracking machine is designed to allow the test specimen to move back and forth under a loaded wheel or for the loaded wheel to move over a fixed specimen, maintaining a horizontal plane The tyre track's center-line must remain within 5 mm of the specimen's theoretical center Additionally, the contact area of the tyre should exhibit simple harmonic motion relative to the top surface of the test specimen, covering a total travel distance of (230 ± 10) mm at a frequency of (26.5 ± 1.0) load cycles per 60 seconds.

This type of motion is best accomplished using a reciprocating drive from a flywheel; however, other drive mechanisms can also be effective as long as they meet the specified motion requirements.

The carriage and frame must be constructed from steel, featuring minimum internal dimensions of 260 mm by 300 mm When the carriage is under operating load, vertical play at its four corners should not exceed 0.25 mm, and the bottom plate must have a thickness of at least 8 mm.

6.3.1.7 Device to measure the vertical position of the loaded wheel to ±0,2 mm with a range of not less than 20,0 mm

Means for temperature control such that the temperature of the test specimen during testing is uniform and maintained constant at the specified temperature ±1 °C

NOTE A constant temperature room enclosing the machine or a water bath are two methods of meeting this requirement

Straightedge, at least 300 mm long

Callipers capable of measuring the thickness of a test specimen to an accuracy of ±1 mm

Small-size devices for use with cores

The equipment listed in 6.3.1 to 6.3.4 with the apparatus listed in 6.4.2 to 6.4.7

Abrasive disc circular saw capable of cutting through !200 mm diameter cores" of compacted bituminous mixtures to provide a nominally ridge-free surface

The core clamping assembly consists of two stiff plates made of steel, glass, or other suitable materials, along with clamping blocks designed to securely hold the prepared core in position while it is embedded in the holding medium.

Clamping blocks must be made from a durable material that can support the weight of the loaded wheel and should feature a central hole designed to fit cores with diameters around 200 mm.

Cleansing solvent, e g mixture of 90 % acetone and 10 % kerosene by volume, for cleaning the rubber tyre after use

Holding medium, e.g plaster of Paris or a polyester resin and hardener

Containers for mixing the holding medium (disposable paper cups are suitable)

Spirit level, at least 100 mm long

Sampling and manufacture

The component materials shall either be

 Laboratory produced bituminous mixtures, mixed in accordance with !EN 12697-35:2004+A1" or

 Plant produced bituminous mixtures, sampled in accordance with EN 12697-27

!The test specimens shall be compacted in their moulds in accordance with

According to EN 12697-33:2003+A1 and EN 12697-32:2003+A1, the bulk density must be measured either by dimensions as specified in EN 12697-6:2003+A1 or through alternative methods after extracting the sample from the mould Additionally, when measuring the rut depth or wheel-tracking rate of a mixture, the bulk density of the specimens should not vary by more than ±1% from the mean bulk density.

For large size devices and without specific requirement, the thickness of the specimen shall be:

 50 mm for mixtures intended to be used in layers less than or equal to 50 mm;

 100 mm for mixtures intended to be used in layers greater than 50 mm

For extra-large size devices without specific requirements, the specimen thickness should be 60 mm For large and extra-large size devices where thickness is specified, it must be determined accordingly.

For mixtures intended for application at varying thicknesses, the specimen thickness should be set at the nearest point within the design thickness range, ideally around 2.5 times the upper sieve size of the mix.

For small-sized devices, the nominal thickness of the specimen should correspond to the thickness at which the mixture is applied on the road If the mixtures are intended to be laid at varying thicknesses, the nominal thickness should be the closest point within the specified design thickness range.

 25 mm for mixtures with upper sieve size less than 8 mm;

 40 mm for mixtures with upper sieve size larger or equal to 8 mm and less than 16 mm;

 60 mm for mixtures with upper sieve size larger than or equal to 16 mm and less than or equal to 22 mm;

 80 mm for mixtures with upper sieve size larger than 22 mm and less than or equal to 32 mm

For specimen to be used on large size devices, the temperature sensors shall be inserted into the test specimen; for temperature monitoring, as shown in Figure 1

Cut specimens of sufficient size so that they can be sawn to form rectangular test specimen of

(175 ± 0,2) mm × (490 ± 0,2) mm for large size devices or (690 ± 10) mm × (490 ± 10) mm for extra-large size devices or at least 260 mm × 300 mm for small size devices For each test, cut at least

 two test specimens for large and extra-large size devices;

 six test specimens for small size devices with procedure A; or

 two test specimens for small size devices with procedure B

The locations from which the specimens are taken shall be selected in accordance with EN 12697-27

For small size devices, the number of core specimens with a diameter of more than !200 mm" shall be in accordance with Table 1

For specimens to be used on large size devices, insert one temperature sensor into the test specimen; for temperature monitoring, as shown in Figure 1

For specimens to be used on extra-large size devices, insert one temperature sensor into the test specimen; for temperature monitoring, as shown in Figure 2

Each cut or cored specimen shall be marked to indicate the direction of traffic flow

If necessary for specimen of rolled asphalt or gussasphalt with pre-coated chippings, cut the test surface using a circular saw so that it is flat

Thickness and surface regularity

The specimen's thickness in the measuring zone must not vary from the nominal thickness by more than 2.5 mm for nominal thicknesses of 50 mm or less, and by more than 5% for nominal thicknesses exceeding 50 mm.

To assess the specimen, position the straightedge along the lower face at different points and measure the maximum gap If a gap exceeding 5 mm is detected and cannot be rectified through sawing or plaster of Paris bedding, the specimen should be rejected.

To ensure accurate measurement of the test specimen's thickness, take readings at four points: at 90° intervals for cores and at the midpoint of each side for rectangular specimens The measurements must not deviate from the nominal thickness by more than 2.5 mm for specimens with a nominal thickness of 50 mm or less, and by no more than 5% for those exceeding 50 mm The average of these four measurements will be recorded as the official thickness of the test specimen.

Place the straightedge across a diameter of the face to be tracked and reject any specimen with a distortion of more than 2 mm Repeat for three further diameters separated by approximately 45°.

Transport and storage of unmounted specimens

After sampling pavement according to EN 12697-27, unmounted test specimens must be transported to the laboratory at a maximum temperature of 30 °C, ensuring the test surface remains horizontal Additionally, the specimens should be maintained at a temperature not exceeding 25 °C during testing.

Upon arrival at the laboratory, unmounted test specimens extracted from pavement or manufactured in-house should be stored horizontally with the test surface facing up, and maintained at a temperature not exceeding 25 °C.

Wheel tracking tests should not be conducted on materials that have been compacted for less than 2 days Additionally, all specimens within the same test series must be of similar age, specifically within a range of ±10%.

Record the actual age of the specimens in days on the test sheet.

Sample preparation

The test specimen must be tested in its original mould or in a mould with dimensional differences of less than 0.5 mm Ensure the mould is securely attached to the supporting plate If the dimensional difference exceeds 0.5 mm, use plaster of Paris to fill the gap between the mould and the sample.

For small-sized devices, prepare samples measuring between 10 mm and 20 mm shorter than the internal length and width of the test form, and then cast plaster of Paris around the test specimen.

7.4.2 Specimen extracted from pavements 7.4.2.1 Cut specimen

Carefully insert each specimen into the mould to prevent any distortion and ensure it remains stationary Achieve proper contact between the specimen and the mould's bottom and side walls by using plaster of Paris for bedding.

Position the core specimen on a glass or steel plate with the testing surface facing down Place two clamping blocks upside down around the core specimen, ensuring that the wheel-tracking path aligns with the designated direction of road traffic flow.

Fill the space above and around the core specimen to slightly overflowing with some freshly mixed holding medium

Slide a second glass or steel plate on top using sufficient pressure to expel most of the excess holding medium

When the holding medium has set, remove the mounted core from between the plates and trim off any remaining excess holding medium using the steel straightedge

Ensure the core specimen's surface is level by using a straightedge and feeler gauge, verifying that deviations do not exceed 2 mm from the clamping block surfaces If misalignment occurs, disassemble the setup and repeat the mounting process until proper alignment is achieved.

8 Procedure for carrying out a single measurement

Large size devices

To ensure accurate test results, keep the pneumatic tyre clean and free from any adhering material from the specimen to avoid spurious heating Maintain the tyre pressure at (600 ± 30) kPa throughout the test by using a suitable device or by regularly monitoring and adjusting the pressure at each stoppage.

With the enclosure at a temperature between 15 °C and 25 °C, set the machine in motion until the test specimen has undergone 1000 load cycles

Take initial measurements of the profile of each test specimen at the 15 predetermined locations shown in Figure 3, where m 0j is the initial measurement at the j location

To ensure accurate testing, the specimen must be set at the designated test temperature The air temperature, monitored by a probe on the mould's side wall, should not exceed 75 °C for test temperatures of 60 °C or lower, and must remain within 15 °C above the test temperature for higher values The specimen should be conditioned under these parameters for 12 to 16 hours before testing.

After setting the machine in motion, halt it to measure the rut depth at the 15 designated locations illustrated in Figure 3, following the completion of the specified load cycles of 1000, 3000, and 10000.

The testing regime involves conducting 30,000 load cycles, with additional tests at 30, 100, 300, and 100,000 cycles, excluding conditioning cycles It is essential to maintain the specimen's temperature within ±2 °C during the tests The test concludes once the specified number of load cycles is reached or when the mean rut depth is achieved.

, exceeds 18 mm If the test is not completed, restart the machine after allowing sufficient time

17 for the test specimen to return to the set temperature unless the rut depth measurement has been made automatically without opening the temperature controlled enclosure

Prior to measuring the rut depth at the 15 locations, measure the temperature of the test specimen

The test shall be carried out on at least two specimens.

Extra-large size device

To ensure accurate test results, keep the pneumatic tyre clean and free from any specimen material to avoid false heating Maintain the tyre pressure at (600 ± 30) kPa throughout the test by using a suitable device or by checking and adjusting the pressure at the start and end of each test.

Set the specimen at the test temperature The test specimen shall be conditioned under these conditions for a period of 14 h to 18 h prior to testing

Initiate the machine and conduct the initial slab profile measurement using a laser at a minimum of three cross-sections, as indicated in Figure 2 The lasers are positioned at specified locations, after which automated load cycles and profile measurements are performed Profile assessments occur after 100 and 200 cycles.

The testing regime involves subjecting specimens to load cycles ranging from 500 to 30,000, while ensuring that the temperature remains stable within ±3 °C The test concludes once the specified number of load cycles is reached or when the mean rut depth is achieved.

Prior to measuring the rut depth, measure the temperature of the test specimen

The test shall be carried out on at least two specimens.

Small size devices

If the specimens are to be tested in air (Procedure A or B), they are to be conditioned at the specified test temperature ±1 °C for a period prior to testing of:

— a minimum of 4 h for specimens with a nominal thickness equal to or less than 60 mm;

— a minimum of 6 h for specimens with a nominal thickness larger than 60 mm;

For testing specimens in water (Procedure B), immerse the test specimen in water at the designated temperature, maintaining an accuracy of ±1 °C, until thermal equilibrium is achieved within the specimen, and ensure this duration is no less than the specified time.

To conduct the test, securely mount the specimen in the clamping assembly of the wheel-tracking machine and fix it to the machine's table Attach a thermocouple approximately 20 mm below the surface for specimens conditioned in air, ensuring the temperature remains within ±1 °C of the specified test temperature If the surface is sticky, apply a light dusting of talc or steatite.

Allow five cycles of the wheel before the test is commenced

Monitor the rut development with either an automatic displacement measuring device or a dial gauge

To measure vertical displacement using an automatic displacement measuring device, initiate the machine and record the initial vertical displacement, denoted as $ r_0 $ Subsequently, take readings after every (25 ± 1) load cycles, ensuring that the center of the test specimen remains within 10 mm of the center point of the loaded area at the midpoint of the traverse.

To measure using a dial gauge, position the test specimen within 10 mm of the center of the loaded area at the midpoint of the traverse Begin by recording the initial vertical position of the loaded wheel, denoted as $ r_0 $ Then, operate the machine and record the vertical displacement after every (25 ± 1) load cycles, ensuring to center the specimen for each reading as done for the initial measurement.

Continue tracking for 1000 load cycles or until a rut depth of 15 mm is reached, whichever is the shorter

To ensure accurate measurements, initiate the machine and record the vertical displacement of the wheel initially, followed by at least 6 or 7 readings within the first hour, and subsequently, one reading for every 500 load cycles The vertical position of the wheel is determined by the average value of the specimen's profile over a ±50 mm length around the center of the loading area at the midpoint of the traverse, with measurements taken at a minimum of 25 evenly spaced points It is essential to measure the vertical position of the wheel without stopping the machine, continuing the tracking process throughout.

10000 load cycles are applied or until a rut depth of 20 mm is reached whichever is the shorter

9 Calculation and expression of results

Large size devices

9.1.1 Calculation of the measured proportional rut depth

Calculate the measured proportional rut depth, P i , of specimen for the set of measurements, i, from the

15 values of local deformation, m ij , and the specimen thickness, h, using the following relationship

P i is the measured proportional rut depth, in percent (%);

19 m ij is the local deformation, in millimetres (mm); m 0j is the initial measurement at the j location; h is the specimen thickness, in millimetres (mm)

Plot the graph of \$\ln(P_i)\$ versus \$\ln(N)\$ for each specimen of the same composition tested Exclude any rut depth values at \$N\$ load cycles if the rut depth exceeds 15% of the specimen's thickness after those cycles.

9.1.3 Calculation of the mean value P

To calculate the mean value $ P $ of $ P_i $ for two or more specimens with identical composition, ensure that they are tested at the same void content level and subjected to the same number $ N $ of load cycles.

9.1.4 Calculation of the test temperature

Calculate the test temperature as the average of the temperatures recorded before each set of measurements.

Extra-large size device

The program computes the average rut depth in each cross-section by analyzing at least 30 measurement points within 60 mm of the center of the loaded area The rut depth for each cross-section is determined by subtracting the reference level, recorded at the start of the test, from the mean rut depth value.

The measured proportional rut depth of specimen, P i , is the mean value of proportional rut depth in each measured cross-section: h n m

The proportional rut depth, denoted as \$P_i\$, is expressed as a percentage (%), while \$m_n\$ represents the measured rut depth in a specific cross-section, measured in millimeters (mm) The variable \$n\$ indicates the number of cross-sections that have been measured, and \$h\$ refers to the thickness of the specimen, also measured in millimeters (mm).

9.2.2 Calculation of the mean value P XL

To determine the mean value $ P_{XL} $ of $ P_i $ for two or more specimens with identical composition, it is essential to maintain the same level of void content and the same number $ N $ of load cycles during testing.

9.2.3 Calculation of the test temperature

Calculate the test temperature as the average of the temperatures recorded before each set of measurements

Small size devices

For each test specimen, determine the mean rate of increase of track depth, TR, in microns per load cycle

(àm/cycle), from the following summation provided that the test continued for at least 5 min:

The total readings taken at 100 load cycle intervals for up to 1000 load cycles, excluding the initial reading, is represented by TR = n (6) The change in vertical displacement from the initial value, r0, to the relevant reading, ri, is measured in millimeters.

(mm); n 15 is the number of load cycles for rut depth to reach 15 mm

If the range of values from six determinations exceeds 1.1 times their mean, the value with the greatest deviation from the mean will be discarded Should the range still exceed 1.1 times the mean after this adjustment, the test will be considered void.

The wheel-tracking rate of the material under test, WTR, in microns per cycle, shall be calculated from

WTR is the wheel-tracking rate, in microns per load cycle (àm/cycle);

TR m is the mean value of the determinations of TR, in microns per load cycle (àm/cycle); w is the width of the tyre applying the load, in millimetres (mm);

L is the load applied, in newtons (N)

The wheel-tracking rate of the tested material must be reported to the nearest 0.1 àm/cycle Any discarded determinations should be classified and reported as outliers.

For test specimens with a wheel-track deformation depth of less than 15 mm after 1000 load cycles, the rut depth is determined by the difference in vertical displacement between the initial value, $ r_0 $, and the tenth reading, $ r_{10} $.

For each test specimen for which the depth of wheel-track deformation reaches 15 mm before 1000 load cycles, the rut depth shall be equal to

15 n mm (8) where n 15 is the number of load cycles for rut depth to reach 15 mm

The rut depth R D for the material under test is the mean rut depth of the specimens to ±0,1 mm

9.3.2 Procedure B in air 9.3.2.1 Wheel-tracking slope in air

The wheel-tracking slope, in mm per 10 3 load cycles, is calculated as:

WTS AIR is the wheel-tracking slope, in millimetres per 10 3 load cycles; d 5 000 , d 10 000 is the rut depth after 5000 load cycles and 10000 load cycles, in millimetres (mm)

9.3.2.2 Mean wheel-tracking slope in air

The result of the test is the average WTS AIR of the two specimens

If the test concludes before reaching 10,000 load cycles, the wheel-tracking slope must be determined from the linear section of the rut depth curve, ensuring it spans at least 2,000 load cycles.

9.3.2.3 Mean proportional rut depth, PRD AIR , in air

The proportional rut depth for the material under test at N cycles is the mean proportional rut depth of the two (or more) specimens to ±0,1 %

9.3.2.4 Mean rut depth, RD AIR , in air

The rut depth for the material under test at N cycles is the mean rut depth of the two (or more) specimens to ±0,1 mm

9.3.3.1 Wheel-tracking slope in water

The wheel-tracking slope in water, in mm per 10 3 load cycles, is calculated as:

WTS W is the wheel-tracking slope, in millimetres per 10 3 load cycles; d 5 000 , d 10 000 is the rut depth after 5000 load cycles and 10000 load cycles, in millimetres (mm)

9.3.3.2 Mean wheel-tracking slope in water

The result of the test is the average WTS W of the two specimens

If the test concludes before reaching 10,000 load cycles, the wheel-tracking rate must be determined from the linear section of the rut depth curve, ensuring it spans a minimum of 2,000 load cycles.

9.3.3.3 Mean proportional rut depth, PRD W

The proportional rut depth in water for the material under test at N cycles is the mean proportional rut depth of the two (or more) specimens to ±0,1 %

The rut depth in water for the material under test at N cycles is the mean rut depth of the two (or more) specimens to ±0,1 mm

Obligatory information

10.1.1 Obligatory information for each test specimen

The test report must detail essential information for each test specimen, including sample identification, bulk density prior to testing along with the determination method, and the testing temperature It should also specify the mean thickness of the specimen, including any identifiable layers, and reference the standard's number and date Additionally, the report must indicate whether the sample was tested using large, extra-large, or small devices, and for small devices, whether it followed Procedure A, Procedure B in air, or Procedure B in water Finally, any test conditions, operational details not covered by the standard, and any anomalies that may have influenced the results should be documented.

10.1.2 Obligatory information for laboratory prepared test specimens

The test report for laboratory-prepared specimens must include essential details such as the identification and proportions of component materials in the mix, the manufacturing method and type of mixer used for the bituminous mixture, the compaction method of the test specimen, the date of sample manufacture, the age of the test specimen at the time of testing along with its storage conditions, and the number of specimens of the same composition that were tested.

10.1.3 Obligatory information for test specimens taken from a pavement by coring

The test report for pavement core samples must include essential details such as the date, time, and location of sampling, if known; the date of compaction, if applicable; and information regarding the availability of a sampling certificate, along with a copy if required.

10.1.4 Obligatory information for test specimens tested on large or extra large devices

For test specimens evaluated on large or extra-large devices, the test report must include the proportional rut depth, denoted as P LD or P XL, at the specified number of cycles.

10.1.5 Obligatory information for test specimens tested on small size devices

For small-sized device tests, the test report must include specific details: Procedure A requires the wheel-tracking rates for each individual test specimen, the average wheel-tracking rate (WTR) for groups of six specimens, and the mean rut depth (RD) after 1000 load cycles.

The procedure for testing in air includes measuring the wheel-tracking slope (WTS AIR) of individual test specimens, as well as calculating the mean wheel-tracking slope for groups of two or more specimens if necessary Additionally, it involves determining the proportional rut depth (PRD AIR) at 10,000 cycles for individual specimens and the mean proportional rut depth for the same number of cycles Finally, the rut depth (RD AIR) at 10,000 cycles is also assessed for each individual specimen.

24 i) mean rut depth, RD AIR , at 10000 cycles

In Procedure B for water testing, the mean wheel-tracking slope (WTS W) is calculated for each group of two or more test specimens as needed Additionally, the mean proportional rut depth (PRD W) is assessed at 10,000 cycles, along with the mean rut depth (RD W) at the same cycle count.

Complementary information

General

The reliability of test results is influenced by the preparation of samples, whether conducted in a laboratory or sourced from pavement, as well as the size of the devices employed Additionally, there is a scarcity of data from national trials regarding these specific conditions.

Laboratory prepared samples, proportional rut depth, large size devices

The precision values are given in Table 3

NOTE The precision data was determined from an experiment conducted in France in accordance with ISO 5725 in

In 1992, twelve laboratories conducted tests using specimens provided by the organizing laboratory, with results reflecting the average rut depth measured on two specimens Data from one laboratory was excluded at 10,000 load cycles, while data from two laboratories was excluded at each of the other load cycles The tests were performed at a temperature of 60 °C.

Samples cored from a pavement and laboratory prepared samples, wheel-tracking rate, small-size devices, conditioning in air

small-size devices, conditioning in air

The precision values are given in Table 4

The precision data were obtained from experiments in the UK following ISO 5725 standards The initial experiment in 1992 involved eleven laboratories using cores provided by the organizing laboratory, but data from one laboratory was excluded due to a high number of outliers.

In a 1994 experiment involving seven laboratories, cores were supplied by the organizing laboratory to assess laboratory-made samples Both experiments were conducted at a test temperature of 45 °C, and the results represent the average wheel-tracking rate across six specimens, with measurements converted from mm/h.

Table 3 — Precision values for proportional rut depth from laboratory prepared specimen

Test result level Repeatability conditions, r Reproducibility conditions, R

Table 4 — Precision values for wheel-tracking rate from cores (Procedure A)

Test result level Repeatability conditions, r

Samples microns per cycle microns per cycle microns per cycle 2,1 0,5 1,0

3 sensitive element of test, temperature measurement probe

Figure 1 — Large size device location of temperature measurement

6 turning place of the wheel

Figure 3 — Location of measuring points for large size devices

ISO 5725, Accuracy (trueness and precision) of measurement methods and results

Tiêu đề	Bituminous Mixtures — Test Methods For Hot Mix Asphalt — Part 22: Wheel Tracking
Trường học	British Standards Institution
Chuyên ngành	Standards
Thể loại	standard
Năm xuất bản	2003
Thành phố	Brussels

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Số trang	32
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