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APT Testing of Modular Pavement Structure ‘Rollpave’ and Comparison with
conventional asphalt motorway structures
L.J.M. Houben
Delft University of Technology, Faculty of Civil Engineering and Geosciences,
Road and Railway Engineering
P.O. Box 5048, 2600 GA Delft, The Netherlands
Phone: + 31 15 2784917
Fax: + 31 15 2783443
E-mail: [email protected]
J. van der Kooij
Ministry of Transport, Public Works and Water Management,
Road and Hydraulic Engineering Institute
P.O. Box 5044, 2600 GA Delft, The Netherlands
Phone: + 31 15 2518268
Fax: + 31 15 2518555
E-mail: [email protected]
R.W.M. Naus
Dura Vermeer Infrastructuur B.V.
P.O. Box 459, 2130 AL Hoofddorp, The Netherlands
Phone: + 31 23 5482965
Fax: + 31 23 5482979
E-mail: [email protected]
P.D. Bhairo
Dura Vermeer Infrastructuur B.V.
P.O. Box 459, 2130 AL Hoofddorp, The Netherlands
Phone: + 31 23 5482968
Fax: + 31 23 5692310
E-mail: [email protected]
Date of submission: May 4, 2004
Word count:
4100 (till List of Tables)
Figures and tables: 3000 (3 tables + 9 figures)
Total:
7100 words
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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ABSTRACT
This paper describes the Accelerated Testing with the LINTRACK-facility of the
innovative ‘Rollpave’ test pavement that was developed within the theme ‘Modular
Pavement Structures’ of the project ‘Roads for the Future’ of the Dutch Ministry of
Transport, Public Works and Water Management.
The concept of ‘Rollpave’ is a thin pre-manufactured asphalt wearing course
that is rolled on a reel. On site, after unrolling this asphalt layer is bonded to the
underlying asphalt through a new sophisticated technique based on electromagnetic
waves.
In the test pavement this pre-manufactured wearing course was constructed
over 120 mm ScorepaveM (an asphalt mix containing modified bitumen and partially
steel slags), resting on 120 mm conventional asphalt and 250 mm cement-bound
asphalt granulate base over the sand subgrade.
In the main wheel track of the test pavement 500,000 75 kN wide base tyre
load repetitions (with lateral wander) have been applied and in the edge track, just
along the longitudinal joint between 2 wearing course strips, 20,000 canalised 75 kN
wide base tyre load repetitions. The load repetitions were applied divided over 3
pavement temperature conditions (‘winter’, 20ºC and 40ºC) that are representative for
the winter, spring and autumn, and summer in the Netherlands.
During the very heavy loading the development of rutting was regularly
measured and some typical results, both for the main wheel track and for the edge
track, are included in the paper.
A superior rutting behaviour of the ‘Rollpave’ test pavement reveals from a
comparison with 6 earlier tested asphalt motorway test pavements with only or mainly
conventional asphalt mixes.
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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INTRODUCTION
Some 6 years ago the Dutch Ministry of Transport, Public Works and Water
Management has launched the project ‘Roads for the Future’, in which private
companies were encouraged to develop innovative pavement structures for the year
2030. Within the project various themes were distinguished, one of them being
‘Modular Pavement Structures’. Within this theme, pavement structures build up of
modules (that can easily and fast be replaced if necessary, e.g. because of damage)
should be developed that furthermore give a considerably greater reduction of traffic
noise than the porous asphalt (drainasphalt) wearing course that is normally applied
on motorways in the Netherlands.
Within the theme ‘Modular Pavement Structures’ four (out of some 20) ideas
were selected for actual construction at the (non-heavily loaded) entrance/exit of a
gasoline station along the motorway A50. These four test pavements were constructed
in the autumn of 2001 and there a number of practical tests have been done, such as
braking tests, traffic noise measurements and replacement of part of each test
pavement after a car was put on fire (1).
To investigate the structural integrity, the same four test pavements were also
constructed at the outdoor test area of the Road and Railway Engineering Department
of the Delft University of Technology and subjected to repeated heavy loadings by
means of the LINTRACK APT facility.
This paper mainly describes the rutting behaviour of one of these test
pavements, called the ‘Rollpave’ pavement structure, under the APT testing. First the
LINTRACK facility, the structure of the ‘Rollpave’ test pavement and the loading and
measuring program are briefly described. Next the development of the rutting on the
two loaded wheel tracks is discussed. Then a comparison of the measured rutting
behaviour with the one of six earlier tested pavements with conventional asphalt
mixes is made. Finally the main conclusions from the APT testing of the ‘Rollpave’
test pavement are given.
LINTRACK APT FACILITY
LINTRACK is a facility for Accelerated Load Testing of full-scale pavements. The
facility is jointly own by the Road and Railway Research Laboratory of the Delft
University of Technology and the Road and Hydraulic Engineering Institute of the
Dutch Ministry of Transport, Public Works and Water Management. LINTRACK is
located at the outdoor test area of the Road and Railway Research Laboratory of the
Delft University.
The linear LINTRACK facility primarily consists of a dual steel gantry (total
length 20 m), along which a loading carriage can move forward and backward (2). A
single dual or wide base truck wheel can be mounted in the loading carriage, which
can pivot up and down relative to the upper part. The wheel load is adjustable from 15
to 100 kN and is applied by pneumatic bellows between upper and lower part of the
loading carriage.
The total running length of the loading carriage wheel is about 12 m. The
maximum speed is 20 km/h, but lower speeds are also possible. To reach 20 km/h,
acceleration and deceleration each take about 4 m, so 4 m measuring length remain.
About 500 forward and 500 backward wheel movements per hour can be
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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accomplished. Each full-length forward or backward wheel movement is counted as a
‘load repetition’.
A bogie, running on rails, supports either end of the steel gantry. These 55 m
long rails run perpendicular to the gantry along the whole test area. The bogies are
electrically powered and can move the entire installation laterally over the test section
during the forward and backward movement of the loading carriage. This allows
application of lateral wander, up to 1 m to either side of the wheel track centre line.
To shelter the test sections from climatic influences as rain or sunshine during
testing, the entire installation is covered with a hall (23 m long, 6 m wide and 5 m
high) that moves with the installation. Furthermore, a heating system with infrared
radiators was implemented in 1997. This system enables control of the pavement
temperature during testing, up to 30ºC to 35ºC (depending on the wind speed) above
ambient temperature.
‘ROLLPAVE’ TEST PAVEMENT STRUCTURE
The ‘Rollpave’ test pavement was constructed on the location of another test
pavement that already had been tested within the framework of a 3-years research
project into the development of rutting on asphalt motorway pavements (3,4,5). The
Road and Hydraulic Engineering Institute of the Dutch Ministry of Transport, Public
Works and Water Management and the Road and Railway Research Laboratory of the
Delft University of Technology have jointly performed this rutting research project.
The ‘Rollpave’ test pavement was created by first milling 150 mm of the
existing test pavement and then constructing two layers of ScorepaveM asphalt mix
and finally a thin pre-manufactured asphalt wearing course. The total pavement
structure consisted of:
30 mm pre-manufactured wearing course (including bonding layer) after compaction
50 mm ScorepaveM asphalt mix
70 mm ScorepaveM asphalt mix
30 mm STAC (Stone Asphalt Concrete), with 50% partial recycling; this remained
after milling a layer that originally had a thickness of 80 mm
90 mm STAC, also with 50% partial recycling
250 mm AGRAC (cement-bound asphalt granulate) base layer
about 5 m Eastern Scheldt sand on top of the natural clay subgrade.
ScorepaveM is a new asphalt mix, developed by Dura Vermeer Infrastructuur B.V., in
which the natural aggregates are partially replaced by steel slags aggregates and that
contains a polymer-modified bitumen. It is claimed by the supplier that this mix has a
very good resistance against permanent deformation. The 2 ScorepaveM layers have
been constructed at August 13, 2002 with normal road construction equipment.
After pre-manufacturing the thin asphalt wearing course was rolled on a reel.
On the ‘Rollpave’ test pavement site, this thin asphalt layer was unrolled at August
29, 2002. Bonding to the underlying ScorepaveM asphalt layer and compacting was
done at August 30, 2002. The bonding is realized by means of an innovative switch
on/off system. This reversible bonding system is based on selective and wireless
heating of a bond-layer by electromagnetic waves (Figure 1). The bond-layer consists
of a bituminous membrane, which is reinforced with a synthetic layer (6).
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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The wearing course is manufactured in 2.5 m wide strips. On the test
pavement two strips were laid next to each other, so a longitudinal joint was created.
This joint has been filled with a joint filling material.
Figure 2 gives a schematic top view of the ‘Rollpave’ test pavement. In the figure the
longitudinal joint between the two strips of pre-manufactured wearing course and the
location of the two loaded wheel tracks (the main track R and the edge track R) is
shown; the reserve main track L has not been loaded at all. Also the three cross
profiles, where rutting measurements have regularly been done, are given.
Furthermore the two locations per main wheel track, where thermocouples for
registration of the pavement temperature during the Accelerated Loading have been
built-in, are shown with the depth and cross position of each of the 4 thermocouples.
The thermocouples build in to control the infrared heating system (for the test
conditions 20ºC and 40ºC), so to control the temperatures within the test pavement
structure, are located in between the main track and the edge track; these
thermocouples are not shown in Figure 2.
LOADING AND MEASURING PROGRAM
As indicated in the former chapter, on the ‘Rollpave’ test pavement two wheel tracks
have been subjected to Accelerated Load Testing (see also Figure 2).
The main wheel track R is considered to be representative for practice.
Therefore on this wheel track a realistic simulation of the lateral wander of truck
traffic has been applied, i.e. a Laplace distribution (that is truncated for practical
reasons) of the lateral position of the wheel centre. Based on measurements of lateral
wander of truck traffic on Austrian motorways, the standard deviation of the original
(non-truncated) Laplace distribution was taken as 0.19 m and the maximum distance
to the wheel track centre line was 0.30 m (7).
The edge wheel track R, located just along the longitudinal joint between the
two strips of pre-manufactured wearing course, is considered to be the most critical
wheel track. In practice this longitudinal joint will however be situated at a nonintensively loaded position within the road’s cross-section. In the research therefore a
limited number of load repetitions was applied on the edge wheel track without lateral
wander, so canalised traffic loadings.
In the research on the ‘Rollpave’ test pavement only one type of tyre was involved,
i.e. a standard wide base tyre (385/65 R 22.5) for trailer axles. The tyre load was
always 75 kN (simulating heavily overloaded axles of 150 kN) while the tyre pressure
was constantly 0.9 MPa (9 bar).
The Accelerated Pavement Testing of both wheel tracks has been done at 3
temperature conditions, i.e. during ‘winter’ and at temperatures of 20ºC and 40ºC at
the pavement surface. These conditions represent average temperatures in pavement
structures in the Netherlands in winter, spring and autumn, and summer respectively.
The number of wide base tyre load repetitions per wheel track per temperature
condition is given in Table 1. This table learns that the main wheel track R has been
subjected to a total number of 500,000 load repetitions and the edge wheel track R to
20,000 load repetitions in total.
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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During the Accelerated Pavement Testing of both wheel tracks the development of the
rutting was regularly measured by means of a transverse profilometer (2). In each
wheel track these measurements were performed in 3 cross-sections.
The transverse profilometer consists of a measuring wheel, moving in an
aluminium frame. The frame is positioned on steel pins attached to each wheel track.
The pins ensure correct and repeatable positioning, and serve as a reference level. The
pins are positioned at 1.7 m on either side of the wheel track centre. This distance
appears to be outside the rutting profile. The transverse profilometer records the
surface level of the pavement with an accuracy of 0.1 mm, at intervals of 10 mm.
From the measured rutting profiles the development of the rut depth
parameters c, d, e and g and the areas A1 to A3, see Figure 3, were analysed. The
most important parameter is the practical rut depth (g), which is defined as the
maximum height difference between the rutting profile and a straightedge, laid over
the rutting profile. In this paper only the practical rut depth measurement results will
be presented.
RUTTING BEHAVIOUR ON MAIN WHEEL TRACK R
As could be expected, the rutting on the main wheel track R due to the repeated wide
base tyre load repetitions (with lateral wander) remained very limited for the winter
and for the 20ºC test conditions (see Figure 7):
- due to 250,000 load repetitions at winter condition the practical rut depth in the 3
cross-sections was only 0.5 to 1.0 mm;
- due to only the 125,000 load repetitions at 20ºC the practical rut depth varied
between 1.0 and 1.25 mm;
- so after in total 375,000 load repetitions at low to moderate temperatures the
practical rut depth was only 1.5 mm to 2.2 mm.
The rutting at the 40ºC test condition is more interesting and therefore some results
will be shown graphically.
Figure 4 presents the temperatures within the pavement structure prior to and
during the Accelerated Testing of the main wheel track R. The initial pavement
temperature (hour # 90) was around 14ºC. After somewhat more than 2 days of
continuous heating the Accelerated Testing started at hour # 144. Figure 4 learns that,
due to the more or less continuous heating, during testing the temperature gradient is
extremely small: the (controlled) temperature 25 mm below the pavement surface
(thermocouples V4P2TD) is around 40ºC and 200 mm below the pavement surface
(thermocouple V4P2TD) it still is 37ºC to 38ºC. In real pavement structures the
temperature difference is much greater due to daily variation in air temperature and
sun radiation.
Figure 5 presents the rutting in the central cross profile 2 during the 125,000
load repetitions applied at the 40ºC test condition. Due to the applied lateral wander a
rather symmetrical rutting profile develops with very small heaves just besides the
wheel track.
The rutting profiles in the cross sections 1 and 3 are very similar, in cross
section 2 the rutting is somewhat more pronounced (this has also been observed at the
other 2 temperature test conditions). In Figure 6 the practical rut depth (see Figure 3)
in the 3 cross profiles due to only the 125,000 load repetitions, applied at the 40ºC test
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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condition, is presented. The result after 125,000 load repetitions is a practical rut
depth of 7.0 mm in the cross profiles 1 and 3 and 8.4 mm in the cross profile 2.
Finally Figure 7 gives the practical rut depth in the 3 cross profiles as a function of the
total number of load repetitions. This graph thus includes the 250,000 load repetitions
applied at winter test condition (2ºC to 9ºC), the 125,000 load repetitions applied at
20ºC and the 125,000 load repetitions applied at 40ºC. The huge effect of the asphalt
pavement temperature on the development of rutting is obvious. After 500,000 load
repetitions (with lateral wander) the practical rut depth varies between 8.7 mm (cross
profile 1) and 10.7 mm (cross profile 2).
RUTTING BEHAVIOUR ON EDGE WHEEL TRACK R
Also on the edge wheel track R the development of rutting due to the repeated wide
base tyre load repetitions (canalised, so without lateral wander) remained limited for
the winter test condition and for the 20ºC test condition (see Figure 9). After in total
15,000 load repetitions at low to moderate temperatures the practical rut depth was
2.75 mm to 4.4 mm.
Similar to the main wheel track R, also on the edge wheel track R the development of
rutting was far greater at the 40ºC test condition compared to the other two test
conditions. The temperatures within the pavement structure during Accelerated
Testing are not shown as they were very similar to the ones given in Figure 4.
As an example, the rutting in cross profile 2 on the edge wheel track during
the 5,000 load repetitions is presented in Figure 8. The practical rut depth during the
whole of 20,000 load repetitions is given in Figure 9. The total practical rut depth
after 20,000 load repetitions (canalised, so without lateral wander) varies between
10.0 mm (cross profile 3) and 12.1 mm (cross profile 2). Again the greater part of the
rutting occurs at the 40ºC test condition.
When comparing the rutting on the edge wheel track R and that on the main wheel
track R, the following remarks can be made:
- the edge wheel track exhibits somewhat more rutting than the main wheel track,
despite the fact that the applied number of (canalised) load repetitions was only
8% of the number of load repetitions (with lateral wander) on the main wheel
track;
- also due to the canalised loadings, the slopes of the rutting profiles on the edge
wheel track are quite steep; this is especially the case at 100 mm left of the centre
of the wheel track, and that is the location of the longitudinal joint between the
two strips of pre-manufactured asphalt wearing course.
COMPARISON WITH RUTTING BEHAVIOUR ON CONVENTIONAL
ASPHALT PAVEMENTS
Prior to the Accelerated Testing of the ‘Rollpave’ test pavement, in the period 19982001 four asphalt motorway pavements have been subjected to Accelerated Testing
by means of the LINTRACK-facility, where the 3rd and 4th pavement were each
divided into 2 sections. Table 2 gives an overview of these earlier tested pavement
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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structures (the ‘Rollpave’ test pavement was actually constructed on the location of
Test Pavement 3), which were constructed on an existing 5 m thick sand sub-base,
resting on the natural clay subgrade.
In Table 2 the various abbreviations have the following meaning:
AGRAC = Cement-bound Asphalt Aggregate base course; this is 100% Recycled
Asphalt Aggregate with 3.5% cement added to it
STAC = Stone Asphalt Concrete; nowadays on motorways this asphalt mix is
commonly used for bituminous base layers as well as for the binder layer;
the mix contains 50% Recycled Asphalt Aggregate and 50% natural
aggregate, and on average 4.5% standard bitumen of penetration grade
40/60 is added to it
MSTAC = Modified STAC (with modified bitumen Esso Multigrade 76-28 instead
of standard bitumen)
OAC
= Open Asphalt Concrete; this asphalt mix, in the past on motorways
commonly used for the binder layer, also contains 50% Recycled Asphalt
Aggregate and 50% natural stone aggregate; on average 5.0% standard
bitumen of penetration grade 40/60 is added to it
DAC
= Dense Asphalt Concrete; the numbers 80/100 and 45/60 refer to the
penetration grade of the standard bitumen; this asphalt mix was applied
as wearing course on motorways until roughly 1990; the mix contains
only natural stone aggregates and the bitumen content is 6 to 6.5%
MDAC = Modified DAC (with polymer-modified bitumen Flexxipave 106 instead
of standard bitumen)
PAC
= Porous Asphalt Concrete (drainasphalt); nowadays this stone skeleton
asphalt mix has to be applied for new wearing courses on motorways for
reasons of traffic noise reduction; the mix contains only natural stone
aggregates and on average 4.5% standard bitumen of penetration grade
70/100; the air voids content is 20 to 22%
SMA
= Stone Mastic Asphalt; this stone skeleton mix contains natural stone
aggregates and standard bitumen of penetration grade 70/100, in an
amount of 7.0 to 8.0% (depending on the grading)
On each of the 6 test sections, mentioned in Table 2, various wheel tracks were
subjected to Accelerated Testing, only at 40ºC test condition, with one specific type of
(dual or wide base) tyre. In this paper only the development of the practical rut depth
on those wheel tracks of the 6 test sections, that were repeatedly loaded with the same
standard wide base tyre as the ‘Rollpave’ test pavement, is presented.
It is of importance to note that the magnitude of the standard wide base tyre
load on the earlier tested 6 test sections was 45 kN while on the ‘Rollpave’ test
pavement the load was 75 kN! All the other test conditions were exactly the same.
The development of the practical rut depth at 40ºC due to the standard wide
base tyre loadings on all test sections is given in Table 3. The data from the earlier
tested 6 test sections can be found in (3,4,5), the data from the ‘Rollpave’ test
pavement are taken from Figure 6.
It appeared from an experiment, done on one of the earlier tested 6 test sections, that
at 40ºC and at constant speed the load equivalency factor with respect to rutting has a
power of nearly 1 for wide base tyre loadings with constant tyre pressure (0.9 MPa).
This means that the rut depth is proportional to the magnitude of the load. This is
explained by the fact that a change in the magnitude of the load only results in a
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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change of the length of the contact area (so in a change of the loading time) while the
width of the contact area remains constant. Assuming that this is also valid for the
‘Rollpave’ test pavement, it means that 1 applied wide base tyre load of 75 kN is
equivalent to 75/45 = 1.65 to 1.7 wide base tyre load of 45 kN with respect to rutting
at 40ºC.
Taking into account the magnitude of the wide base tyre load, Table 3 thus shows a
superior behavior of the ‘Rollpave’ test pavement in comparison with the earlier
tested asphalt test sections with merely or mainly conventional asphalt mixes. This
excellent behavior has to be attributed to the high resistance to permanent
deformation, i.e. the great shear strength, of the ScorepaveM asphalt mix.
CONCLUSIONS
Comparison of Figure 7 and Figure 9 learns that a limited number (20,000, divided
over 3 temperature conditions) of canalised 75 kN wide base tyre load repetitions in
the edge track, just along the longitudinal joint between the pre-manufactured asphalt
strips, results in somewhat more rutting than a great number (500,000, pro rata
equally divided over the same 3 temperature conditions) of 75 kN wide base tyre load
repetitions, with lateral wander, in the main track of the ‘Rollpave’ test pavement.
Furthermore, the shape of the rutting profile in the edge track is different, i.e. a
narrow profile with rather steep slopes, that is especially critical for motorbikes. This
implies that a sound construction of the longitudinal joint is essential.
Nevertheless the ‘Rollpave’ test pavement has exhibited a resistance against
rutting that is superior to that of earlier tested asphalt motorway test sections with
only or mainly conventional asphalt mixes.
REFERENCES
(1) Dommelen, A.E. van, J. van der Kooij, L.J.M. Houben and A.A.A. Molenaar.
LinTrack APT Research supports accelerated implementation of innovative pavement
concepts in the Netherlands. Paper submitted for 2nd International Conference on
Accelerated Pavement Testing, Minneapolis, USA, September 25-29, 2004.
(2) Groenendijk, J. Accelerated testing and surface cracking of asphaltic concrete
pavements. PhD Thesis, Delft University of Technology, Delft, 1998.
(3) Houben, L.J.M. Final Report on Research into Rutting of Asphalt Concrete
Pavements. Report 7-02-200-44M. Road and Railway Research Laboratory, Delft
University of Technology, Delft, 2002.
(4) Houben, L.J.M., C.H. Vogelzang, and A.E. van Dommelen. LINTRACK Rutting
Research Project – ALT Testing Program. Proceedings of the 6th International
Conference on the Bearing Capacity of Roads, Railways and Airfields (Lisbon, 24-26
June 2002). A.A. Balkema Publishers, Lisse, The Netherlands, 2002, Volume 2 pp.
1233-1245.
(5) Houben, L.J.M., A.A.A. Molenaar, A. Miradi, and A.E. van Dommelen. Research
into Rutting on Asphalt Motorway Pavements. Proceedings of the 3rd International
Symposium on Maintenance and Rehabilitation of Pavements and Technological
Control, University of Minho, Guimarães, Portugal, 2003, pp. 273-291.
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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(6) Naus, R.W.M., P.D. Bhairo, J. van Montfort and W. Giezen. Rollpave – Prefab
road for rapid construction. Proceedings 3rd Eurasphalt & Eurobitume Congress,
Vienna, 12–14 May 2004.
(7) Dommelen, A.E. van, and L.J.M. Houben. Random generation of Laplace
frequency distribution for the lateral wheel position for the LINTRACK rutting
research program. Report 7-99-200-25M. Road and Railway Research Laboratory,
Delft University of Technology, Delft, 1999.
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LIST OF TABLES
TABLE 1 Applied number of 75 kN wide base tyre load repetitions in the wheel
tracks.
TABLE 2 Pavement structure of the earlier tested pavements/sections.
TABLE 3 Practical rut depth (40ºC test condition) due to standard wide base
tyre loadings on main wheel track (75 kN on ‘Rollpave’ test pavement, 45 kN on
other test sections).
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LIST OF FIGURES
FIGURE 1 Principle of selective and wireless heating of only the bond-layer.
FIGURE 2 Schematic top view of the ‘Rollpave’ test pavement with longitudinal
joint, wheel tracks, cross profiles for rutting measurements and location of
thermocouples.
FIGURE 3 Schematic rutting profile due to wide base tyre loadings.
FIGURE 4 Temperature (test condition 40ºC) at different depths within the
pavement structure on location 2 as a function of the number of load repetitions
(and the time) during the Accelerated Testing on main wheel track R.
FIGURE 5 Rutting in cross profile 2 of the main wheel track R as a function of
the number of load repetitions (test condition 40ºC).
FIGURE 6 Practical rut depth in the 3 cross profiles of the main wheel track R
as a function of the number of load repetitions (test condition 40ºC).
FIGURE 7 Cumulative practical rut depth in the 3 cross profiles of the main
wheel track R as a function of the total number of load repetitions (test
conditions winter plus 20ºC plus 40ºC).
FIGURE 8 Rutting in cross profile 2 of the edge wheel track R as a function of
the number of load repetitions (test condition 40ºC).
FIGURE 9 Cumulative practical rut depth in the 3 cross profiles of the edge
wheel track R as a function of the total number of load repetitions (test
conditions winter plus 20ºC plus 40ºC).
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TABLE 1 Applied number of 75 kN wide base tyre load repetitions in the wheel
tracks.
Wheel track
Main track R (with lateral wander
Edge track R (without lateral wander)
Temperature at pavement surface
uncontrolled
controlled
(winter 2002/2003)
2ºC – 9ºC
20ºC
40ºC
250,000
125,000
125,000
10,000
5,000
5,000
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
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TABLE 2 Pavement structure of the earlier tested pavements/sections.
Test pavement 1
40 mm DAC
80/100
60 mm OAC
Test pavement 2
40 mm DAC
45/60
60 mm OAC
Test pavement 3
50 mm PAC
60 mm STAC 60 mm MSTAC
(section 3a)
(section 3b)
80 mm STAC
90 mm STAC
250 mm AGRAC
Test pavement 4
40 mm MDAC 40 mm SMA
(section 4a)
(section 4b)
60 mm STAC
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TABLE 3 Practical rut depth (40ºC test condition) due to standard wide base
tyre loadings on main wheel track (75 kN on ‘Rollpave’ test pavement, 45 kN on
other test sections).
Test section
1
2
3a
3b
4a
4b
Rollpave
0
1
2
Wheel trackº
V2D80L
V2D45L
V1ZOAR
MV1ZOA2
V2ZOAMR
MV2ZOAM2
V1DABR
V2SMAR
Ntot1
33,000
36,000
20,750
21,000
19,811
19,575
69,000
34,000
125,000
1,000
5.0
2.7
1.4
1.4
1.4
1.4
0.8
1.3
1.1
2,000
7.2
3.2
1.6
2.1
2.0
2.2
1.7
1.8
1.5
5,000
10.4
4.6
4.3
3.9
4.5
4.1
2.2
4.1
1.5
Average practical rut depth (mm) after N =
10,000 20,000 35,000 50,000 70,000
15.3
20.6
30.3
5.2
9.9
13.6
6.8
10.7
6.2
9.3
7.1
11.2
6.5
9.4
3.8
4.9
6.2
7.0
8.3
7.9
11.3
16.6
2.8
3.7
4.5
5.0
5.6
100,000
125,000
6.3
7.5
codes for wheel tracks on test sections 1 to 4b according to (3,4,5)
total number of standard wide base tyre load repetitions applied on the varies wheel tracks
the LINTRACK testing has taken place around 3 month later than the testing of the other wheel track on the same
section
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
FIGURE 1 Principle of selective and wireless heating of only the bond-layer.
16
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
Centre of test pavement
Supports for profilometer measurements on main track R
17
Location [4]: thermocouples:
D (depth 25 mm): x = 125 cm
C (depth 50 mm): x = 130 cm
B (depth 100 mm): x = 135 cm
A (depth 200 mm): x = 140 cm
Location 2 id
150 cm
150 cm
Main track R (x = 125 cm)
100 cm
100 cm
X
Edge track R (x = 18 cm)
Y
Main track L (x = -125 cm) cm)
Supports for profilometer measurements on main track L
Delft University of Technology
W&S research
Lab. for road Lab.
and railway
FIGURE 2 Schematic top view of the ‘Rollpave’ test pavement with longitudinal
joint, wheel tracks, cross profiles for rutting measurements and location of
thermocouples.
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
X
A1
A2
d
e
c g
A3
north
south
FIGURE 3 Schematic rutting profile due to wide base tyre loadings.
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APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
19
FIGURE 4 Temperature (test condition 40ºC) at different depths within the
pavement structure on location 2 as a function of the number of load repetitions
(and the time) during the Accelerated Testing on main wheel track R.
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
20
FIGURE 5 Rutting in cross profile 2 of the main wheel track R as a function of
the number of load repetitions (test condition 40ºC).
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
21
FIGURE 6 Practical rut depth in the 3 cross profiles of the main wheel track R
as a function of the number of load repetitions (test condition 40ºC).
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
22
FIGURE 7 Cumulative practical rut depth in the 3 cross profiles of the main
wheel track R as a function of the total number of load repetitions (test
conditions winter plus 20ºC plus 40ºC).
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
23
FIGURE 8 Rutting in cross profile 2 of the edge wheel track R as a function of
the number of load repetitions (test condition 40ºC).
APT Testing of Modular Pavement Structure “Rollpave” and Comparison With....
24
FIGURE 9 Cumulative practical rut depth in the 3 cross profiles of the edge
wheel track R as a function of the total number of load repetitions (test
conditions winter plus 20ºC plus 40ºC).