experimental study on structural response of rigid pavements...

22nd ARRB Conference – Research into Practice, Canberra Australia, 2006

© ARRB Group Ltd and Authors 2006 1

EXPERIMENTAL STUDY ON STRUCTURAL RESPONSE OF RIGID PAVEMENTS UNDER MOVING TRUCK LOAD

M. Y. Darestani, David P. Thambiratnam and A. Nataatmadja, Department of Urban Design, Queensland University of Technology, Australia Daksh Baweja, Rinker Australia, Australia

ABSTRACT

The structural adequacy of a rigid pavement can normally be predicted based on its structural response to the applied loads. While considerable knowledge of pavement behaviour under static loads is available word-wide, only very limited number of studies have been carried out in the past to determine the effect of dynamic loads on rigid pavement deteriorations. Hence, opinions differ as to which type of load (static or dynamic) results in greater values of base deflection or flexural stress.

In the present study, a rigid pavement test section consisting of two jointed reinforced concrete pavements and two jointed plain (unreinforced) concrete pavements was constructed and tested under both quasi-static and dynamic truck loads. Truck load was allowed to wander at predetermined locations on top of the instrumented pavement. Nominal speeds from 5 km/h to 55 km/h were used in the study. Various devices including strain gauges, displacement transducers, vertical accelerometers and thermocouples were installed at different depths along the test section. A total of 5184 time history responses of the test section were recorded. Results indicate the importance of dynamic analysis in rigid pavement design.

INTRODUCTION

The serviceability and longevity of rigid pavement constructions depend on the rate of pavement deterioration which is a function of factors such as material properties, climatic effects and vehicular load characteristics. As the main reason behind deterioration and delamination processes, cracks can be considered as a tensile failure in concrete pavements. Cracks can occur at any location within the pavement where tensile stresses exceed the concrete flexural strength. Tensile stresses are induced in a rigid pavement due to bending action of concrete base under vehicular as well as climatic forces. The pavement response to these loads can be individually calculated and be then superimposed to determine the total value of stresses or deflections provided that the pavement materials exhibit an elastic behaviour. While current rigid pavement design procedures are well established, questions still remain as to the accuracy of the assumptions used.

Most recent rigid pavement design guides have been based on empirical-mechanistic approaches. Field data derived from the American Association of State Highway and Transportation Officials research (AASHTO, 1962) have been widely used in the empirical part of design procedures. While the mechanistic part of design guides provides required information on calculation of the critical stresses and deflections in pavements, the empirical part specifies possible failure modes of pavements under applied loads. The predominant failure modes in many rigid pavements are faulting and fatigue cracking (Roesler et al., 2000). However, the most critical failure mode in AASHTO (1962) test sections was erosion of subbase or subgrade materials

Vehicular loads have been assumed as static loads in rigid pavement design guidelines because dynamic analyses and experimental tests on rigid pavement in the past showed that dynamic loads has no effect on pavement responses. For instance, AASHTO (1962) showed that an increase in vehicle speed from 3.2 to 95.6 km/h decreases the value of pavement



responses by about 29 per cent. However, recent analytical studies of rigid pavements under dynamic loads (Bhatti and Stoner 1998, Liu and Gazis 1999) indicated that significant effects of dynamic loads were observed when surface roughness was taken into account. Furthermore, Izquierdo et al. (2002) found that velocity can noticeably change the value of base deflections or stresses of a plain concrete pavement resting on a subbase with low stiffness under very heavy truck loads.

Analytical dynamic analysis of Jointed Plain (unreinforced) Concrete Pavement (JPCP) and Jointed Reinforced Concrete Pavement (JRCP) under different moving axle group loads (Darestani et al., 2006) indicates vehicle speed has a significant effect on pavement responses even when a smooth surface is considered. Furthermore, diagonal, corner, and transverse cracking may be addressed by consideration of vehicle speed. However, no recent experimental test on rigid pavement dynamic responses has been conducted to demonstrate the effect of heavy vehicle velocity on rigid pavement damage.

In order to address the aforementioned problems, a fully instrumented rigid pavement test section consisted two concrete bases namely, JPCP and JRCP was constructed and tested under either quasi-static or dynamic truck loads. This paper describes the test procedure and presents some significant outcomes of the test.

PROJECT DESCRIPTION

An experimental work on rigid pavement performance under dynamic truck loading has been conducted by Queensland University of Technology (QUT) and a major Australian concrete producer, Rinker Australia, at Rinker sand quarry in Oxley Creek, southwest of Brisbane. This location was selected since a weighbridge is available to provide data on truck loads, number and type of axle groups which can be recorded for long term pavement performance monitoring. Furthermore, geotechnical information on subgrade properties including soil classification, soil profile and texture, bulk density, the Atterberg limits, and CBR, which had been derived from surface and depth explorations of the site in 2001, is available in Readymix archive at Milton Branch.

The test section has 32 m length, 5.1 m width and 250 mm thickness. It consists of two JPCP and two JRCP which have been constructed over 150 mm concrete subbase resting on a stiff subgrade (CBR = 14%). The widths and lengths of the concrete bases are 3.6 m and 4.6 m for JPCP and 3.6 m and 10 m for JRCP, respectively. The concrete subbase (32.5 x 5.5 m) was constructed on top of a sand layer with maximum aggregate size of 3 mm. The thickness of the sand layer was about 15 mm. The sand layer was placed on the subgrade layer to firstly create a separation between subbase and subgrade and secondly, to develop a level platform for subbase. The subbase was left to shrink for one week before constructing the concrete bases and shoulder.

Figure 1 shows the layout of the test section. An additional JPCP section (1.4 m x 3.6 m) is placed at each longitudinal end of the test section to restrain the free transverse edges and simulate the conditions of a long stretch of pavement.



Figure 1: Layout of the test section

A mesh reinforcement layer of round bar with a diameter of 9 mm was used in the JRCPs. Two vertical locations of reinforcement namely close to top surface layer of the concrete base (50 mm deep from top surface layer) and close to bottom surface layer of the concrete base (200 mm deep from top surface layer) were considered in this study to determine the effects of reinforcement location on the pavement responses and consequently the damage progress.

Voids (250 mm L x 150 mm W x 250 mm H) were formed by inserting expanded polystyrene blocks at the intersection between the transverse and the longitudinal joints along the confined edge of the pavement to install linear displacement sensors. Steel sections (25 mm x 25 mm x 3 mm), 1500 mm long each, were driven into the subgrade as appropriate and used as mounting poles of the displacement sensors. Only 350 mm of the total length of these steel poles protruded above the subgrade surface layer. Note that the centre of the mounting pole’s cross section was located 20 mm away from free edge and at the centre of void formed along the confined edge.

Shoukry et al. (2002) mentioned that the contact stress between loaded round dowels and concrete can be quite high Although round dowels are the most widely used in pavements, research elsewhere showed that different shaped dowels such as flat plates and oval dowel bars can increase the bearing area without increasing the cost or mass of the dowel bar. Therefore, flat plate dowels that are widely used for slabs on ground were employed for this study. With the use of flat plate dowels, the effect of dowel locations within the concrete base can be studied.

Each transverse joint was dowelled by eight flat plate dowels (300 mm x 50 mm x 6 mm). Since one side of the dowel was coated by a PVC sleeve, longitudinal movements of the concrete bases on both sides of the transverse joint were not restrained. Dowels were vertically positioned at three different depths to determine the effects of dowel positions on load transfer efficiency (LTE) of joints and pavement performance. The locations of the dowels (measured from the top of the concrete base) were 55 mm, 125 mm (at mid-depth) and 200 mm (see Figure 1).

One of longitudinal edges of the test section was confined by a shoulder. Hence, round tie bars (12 mm Ø, 1000 mm long) were positioned at middle depth of longitudinal joints. Four tie bars were used in each JPCP and eight in each JRCP.

To minimise the effect of drying shrinkage and differential temperature gradients in concrete pavements, a friction reducer layer may be placed between concrete base and subbase. Consequently, bonded, unbonded, and partially bonded boundary conditions between concrete base and subbase may be created depending on the value of the friction coefficient between these layers.



Most analytical research conduced in the past was based on fully bonded or fully unbonded boundary condition between concrete base and subbase (Heath and Roesler, 1999). The use of debonding materials usually results in partially unbonded boundary condition between concrete base and subbase (Zhang and Li, 2001). Note that fully unbonded conditions could only be achieved by using a double layer of polyethylene sheets (Tarr et al., 1999). In contrast, Yu et al. (1998) stated that friction between concrete base and subbase is sufficient to produce bonded behaviour even if polyethylene sheets are placed between them. In reality, only devices such as anchor or shear stud can create a fully bonded boundary condition.

As structural responses of concrete pavements to vehicular load are highly affected by boundary condition between concrete base and subbase (Tarr et al., 1999), half of the test section incorporated a single layer polyethylene sheet between the base and subbase (see Figure 1) to determine the effects of debonding on the dynamic responses of the test pavement.

Evaporation retardant was poured at top surface of the concrete base during levelling to protect the concrete bases against plastic shrinkage. The results of a concrete pavement analysis by the Authors (Darestani et al. 2006) showed the importance of dynamic analysis even when a smooth surface is considered. To verify these results, the concrete surface was subsequently floated by a power trowel. Note that an increase in pavement roughness will result in higher induced dynamic responses (Bhatti and Stoner, 1998; Liu and Gazis,1999).

Zollinger et al. (1994) indicated that early-age sawing methods with sawing depths less than 0.25d (d=slab depth), should provide better crack control than conventional methods with depths of 0.25d or 0.33d. Sawing sooner with early-age saws can take advantage of larger changes in the concrete's surface moisture content or surface temperature, which has been shown to induce cracking (Okamoto et al., 1994). Therefore, transverse joints were prepared using soft sawing method three hours after initial set. The width and depth of the saw cuts were 10 mm and 50 mm, respectively. The width of the sawcut joints allowed easy installation of instrumentation wires across the test section.

An unreinforced shoulder with 1.5 m width and 250 mm thickness was poured about 15 hours after constructing the concrete bases. It contains five dowelled transverse joints. Four flat plate steel dowels were installed at each transverse joint. Dowel dimensions are similar to those used in the concrete bases. Due to problems with the concrete saw, transverse joints of shoulder were saw-cut 36 hours after initial set.

INSTRUMENTATIONS

A total of 120 electrical gauges including 120Ω electrical strain gauges (ESGs), linear displacement transducers (LDTs) and strain gauge based vertical accelerometers have been used to investigate the structural response of the test pavement under either static or dynamic loads.

Since recent research (Choubane and Tia 1995, Health and Roesler 1999) showed a strong interrelationship between temperature gradients and damage potential of concrete base, four thermocouples were evenly installed at different depth within the concrete bases. Recording of temperature gradients was started 24 hours after initial set.

Two types of ESGs, namely embedded and standard (glued to surface layer of structure), have been used. Embedded strain gauges should be fully covered by concrete to accurately measure the induced strains in the concrete. Hence, they were installed at a depth of 225 mm from the top of the concrete base using a rebar chair. The locations of the strain gauges are shown in Figure 2 while those of the LDTs and accelerometers are shown in Figure 3. Note that none of LTDs was installed close to the first and the last transverse joints or in the additional JPCP sections (1.4 m x 3.6 m, see Fig. 1) as load transfer efficiency of these transverse joints may be affected by the dimensions of these additional sections.



An eDaQ dynamic data acquisition system with 48 channels including 16 specific channels for strain gauges and 32 general purpose inputs was used to record time history responses of each individual instrumented point of the test section. InField analysis software developed by Monash University was utilised for data processing. Since the eDaQ data acquisition system only has 48 channels, three different recording setups were utilised. Each setup utilised 32 switchable channels and 16 dedicated channels. Half of switchable channels were always connected to 10 ESGs and 6 LDTs to provide benchmark readings.

Figure 2: Locations of strain gauges

MATERIAL PROPERTIES

The subgrade soil was a silty clay loam with a compacted bulk density of 2.18 t/m3 (AS1141.4). The maximum dry density of the soil was 1.86 t/m3. Particle size distribution (AS1141.12) showed that 70.7 per cent of aggregate was finer than 0.075 mm. Liquid limit, plastic limit and plasticity indices of the fines were 22.8, 14 and 8.8 per cent, respectively. Subgrade CBR was 14 per cent. The average 28-day concrete compressive and flexural strengths were 7.3MPa and 1.55MPa for the subbase, 50.5MPa and 5.45MPa for the bases and 38.5MPa and 4.1MPa for the shoulder, respectively.

Figure 3: Locations of linear displacement sensors and vertical accelerometers



VISUAL MONITORING OF THE TEST SECTION

The test section was closely monitored for the first 28 days after casting the concrete base. The first top-down crack occurred within 2 days after casting at the middle of JRCP where mesh reinforcement layer had been positioned close to top surface layer of the base (Fig. 4). Two random surface cracks of about 150 mm long were also noticed in the same concrete base at the same time. It should be noted that this part of the test section did not have a debonding layer between concrete base and subbase. All the above mentioned cracks were very fine hairline cracks. Other bases showed no cracks. Crazing cracks were observed in all concrete bases one week after initial concrete set suggesting inadequate curing or ineffective evaporation retardant. Apart from being unsightly, these cracks do not affect the structural integrity of the concrete.

Two shrinkage top-down transverse cracks were initiated close to transverse joints in the shoulder (see Figure 4) within 36 hours after casting. It should be noted that transverse joints in the shoulder were sawed after the cracks had appeared. Another transverse crack occurred 2 weeks after casting in the depth of shoulder and at the middle length of it where shoulder has 10 m long and had a partially bonded interface between base and subbase. During this period, two small diagonal cracks (100 mm long) were also initiated in the concrete bases close to the transverse joints. No additional visible cracks were noticed in the concrete bases or shoulder during the first 28 days. However, the width of one of the transverse cracks in the shoulder increased by about 2 mm (see Figure 4). In the long run, the crack widening may decrease the load transfer efficiency of transverse joint in the shoulder due to the possible corrosion of dowels and may also result in joint faulting.

Figure 4: Locations of cracks in the test section

As mentioned earlier, the subbase was left to shrink for one week before constructing the concrete bases and shoulder. Hence, several transverse, longitudinal and diagonal cracks were initiated and propagated in it due to environmental forces.

TRUCK CHARACTERISTICS, MOVEMENT AND SPEED

A semi-trailer truck with a gross weight of 477.3 kN was used to apply traffic load in one direction. Truck contains three different axle groups namely Single Axle Single Tyre (SAST), Tandem Axle Dual Tyre (TADT) and Triple Axle Dual Tyre (TRDT) of 60.6 kN, 206.2 kN and 210.5 kN respectively. Tyre inflation pressure in all tyres was set to be 750 kPa.



Figure 5: Tyre and axle group configurations

Exact measurement of tyre contact area could be done using methods such as the multiple overlay technique (Sharma and Pandey, 1996). However, for simplicity, in this study the contact area was determined by measuring the size of imprint left by the tyre on top of the base after spraying paint around the tyre. Information on truck configuration and tyre pavement contact area are shown in Figure 5.

Three longitudinal coloured lines were drawn at different locations on top of the concrete bases to help driver maintain the truck movement at a certain distance from the longitudinal joints. These include a red line close to the free longitudinal edge of the pavement, a blue line close to the confined longitudinal joints of the test section and a yellow line between them to symmetrically apply the truck loading on both sides of the centre line of the test section. The truck was driven along the aforementioned lines at various nominal speeds including 5, 20, 35 and 55 km/h. Higher speeds could not be achieved in this study as they would need a longer acceleration distance. Pavement time history responses under moving truck load were recorded thrice for each individual speed and position of the applied load to accurately determine the structural responses of the test section. In total, 5184 time history responses of the test section were recorded. Real truck speeds for each individual channel were finally calculated based on the configurations and distance between axle groups and pavement time history responses.

RESULTS AND DISCUSSION

Differential temperature gradients and loss of moisture content through the depth of the concrete base may affect the pavement response. However, since the variation in ambient temperature during the tests was small (less than 1ºC), pavement curling can be assumed to remain constant in the analysis. Nevertheless, a finite element analysis may help to develop a better understanding on the effects of the aforementioned factors on the dynamic response of concrete pavements. This analysis is currently being done by the Authors of the current paper and the results will be published elsewhere.

InField analysis software was used to develop time history responses of the concrete bases, JPCP and JRCP, under moving truck load for different locations within the test section. Results were then redrawn to appropriate scales using Microsoft Excel for comparison. The dynamic amplification (DA), which is defined as (Dynamic response / Static response)-1) ×100, was then calculated for each individual channel. Whilst DA varies with truck speed, only the maximum and the minimum captured DA are presented and discussed in this paper. Results can be summarized as follows:

Concrete base deflection

A comparison between base deflections at the corner and at the mid-length of free edge was firstly done for results validation as corner deflection was expected to be greater than other



deflections. Furthermore, for subsequent validation processes, it was also expected that base deflections along a free edge would be higher than the corresponding deflections along a confined edge. Result shows that base deflection decreases from the corner of free edge towards mid-span and confined edge. Base deflection at the corner is about 60 per cent greater than those at the middle of the free edge.

Concrete base deflection is strongly affected by truck speed so that dynamic amplification varies between 55 per cent and 313 per cent depending on the base type, interface between base and subbase and location of measurement. Greater dynamic amplifications occur along the confined longitudinal edge of the test section though the base deflection values of these points are relatively lower than those along the free longitudinal edge. Figure 6 as an example of the current study outputs shows time history base deflections for different speeds at the corner of free longitudinal edge (DL7, see Figure 5) in JPCP. The critical truck speed (which creates maximum base deflection) depends on several factors such as the location of measurement and the type of concrete base. Hence, medium speed in some cases results in greater base deflection (Figure 7).

Figure 6: Time history deflection responses for different speeds at DL7

Vertical location of reinforcement layer also affects base deflection responses. Results of the current study show that base deflections in JRCP where reinforcement was located close to the top of the concrete base is about twice the values from other JRCP where reinforcement was located close to bottom of the concrete base (Figure 8).



Figure 7: Time history deflection responses for different speeds at DR13

Study of dowel performance under moving truck load indicates that load transfer devices at transverse joints exhibit a stiffer behaviour under dynamic load (higher speed) than quasi-static load (lower speed). In other words, the value of load transfer efficiency (LTE% = (deflection of unloaded slab / deflection of loaded slab) ×100) of transverse joints under dynamic load is slightly greater than static load. Results also indicate that the value of LTE in transverse joints under truck loads is not constant and depends on type of axle groups, the applied load and truck speed (Fig. 9).

Figure 8: Time history deflection responses in JRCP for different reinforcement locations



Figure 9: Time history deflection responses at transverse joint (truck speed 49 km/h)

A comparison between time histories of base deflections at the corner of the confined edge (Figure 10) shows the importance of dowel position in depth of concrete base. The base deflection under TADT and TRDT significantly decreases when dowels are positioned at the mid-depth of the concrete base. On the other hand, with dowels placed close to the top of the concrete base, lower base deflection results under SAST loading. Hence, for the flat dowels used in this work, the best dowel location would be at, if not slightly above, the middle of the concrete base depth. As mentioned earlier, none of the LTDs was installed close to the first and the last transverse joints or in those JPCP having 1.4 m length (see Figure 3).

.

Figure 10: Comparison between dowel positions based on critical speed



Induced tensile stresses

Tensile stresses are also affected by truck speed. Dynamic amplification of tensile stresses varies between -10.8 and +108.9 per cent. A small number of recorded stress time histories shows a decrease in the magnitude of tensile stresses when truck speed increases. Most time history stress responses suggest a need to consider dynamic loading in rigid pavement design. Figure 11 is an example of recorded stress time history where dynamic loads result in greater stress values than static loads.

Figure 11: Time history stress responses in JRCP at TCL12 for different truck speeds

Although dynamic amplification shows the significance of dynamic analysis, it does not mean that the location where tensile stress is greater than of other locations has a greater dynamic amplification. For instance, the maximum dynamic amplification at TCL12 (Figure 11) is about 3½ times more than the maximum dynamic amplification at TCL8 (Figure 12), however, the maximum tensile stress for each individual speed at TCL8 is relatively greater than those at TCL12. Further observations can be made when the location of TCL12 and TCL8 are taken into account (see Figure 2). Both strain gauges, TCL12 and TCL8, were installed close to transverse joints, in the same distance from free edge and at top surface layer of the JRCP where reinforcement has been located close to the bottom of the base. Boundary conditions between base and subbase for both points were similar. However, dowels were located close to the top of the concrete base for TCL12 and at the mid-depth of the concrete base for TCL8. A comparison between maximum induced tensile stresses at TCL12 and TCL8 for each individual speed indicates that tensile stresses at transverse joints increase by 87.5, 9.4, 45.1 and 6.1 per cent with truck speeds (real truck speeds) of 5 (4.8), 20 (16.5), 35 (32.2) and 55 (44.3) km/h, respectively, when dowels are located at the mid-depth of the concrete base.



Figure 12: Time history stress responses in JRCP at TCL8 for different truck speeds

Tensile stresses in both JRCPs are greater than those in JPCP. While the difference in panel lengths may have contributed to the results (the length of uncracked concrete base panel in JRCP is about twice the length of concrete base panel in JPCP), the reinforcement may also have some effects. Note that no crack was observed in JPCP and JRCP where reinforcement was positioned close to the bottom surface layer of the concrete base. Commonly, the recommended position of the longitudinal steel is between 1/3 and 1/2 of the depth of the base as measured from the surface. However, effects of reinforcement location on pavement dynamic tensile stresses in the current study are still unclear at this stage as analyses of time history responses have not lead to a specific conclusion.

Vertical acceleration in concrete bases

Results of the current study indicate that vertical acceleration in rigid pavements depends on the distance between transverse joints, boundary conditions between base and subbase, provision of shoulder or adjacent traffic lane, and traffic wander. An increase in length of concrete base panel or the use of bonded interface between base and subbase can increase the vertical base acceleration. This acceleration also increases when the moving load is applied close to free longitudinal edge of the pavement. Provision of shoulder or adjacent traffic lane decreases the vertical acceleration in the concrete bases.

Results of the current study indicate that the absolute concrete base vertical acceleration varies between 0.001 g and 0.62 g, in proportion with the nominal truck speed ranging between 5 km/h and 55 km/h. It is known that acceleration and speed of structural deflection induce dynamic forces in a structure. This dynamic force may increase or decrease at the certain time depending on the magnitudes of acceleration and speed. Consequently, at certain location, the tensile stress in this experimental rigid pavement may either increase or decrease due to the dynamic loading effect. Understandably, slab curling and warping can affect these results. Further study will therefore be carried out on these factors by means of finite element techniques.

CONCLUSION

A fully instrumented rigid pavement test section including JPCP and JRCP was constructed and tested under quasi-static and dynamic truck loading. Information on the test section, instrumentation layout, material properties and truck characteristics were described.



Pavement performance under environmental conditions was studied during the first 28 days after casting. Truck loading was subsequently applied at different location of the pavement. Time history responses were recorded for nominal truck speeds between 5 km/h to 55 km/h.

Investigation of the recorded time history responses of the test section indicates the importance of dynamic analysis in pavement design. Results also indicate that dowel position can strongly influenced the pavement responses. Furthermore, the base deflection in JRCP decreases when reinforcement was located close to bottom surface layer of the concrete base. Further studies are needed to determine effects of reinforcement position on induced dynamic stresses of the pavement.

Since variation in subgrade property, differential temperature gradients and loss of moisture contents within the concrete base may influence the dynamic responses of the concrete pavement, finite element analysis approaches shall be carried out to address the effects of these parameters on dynamic responses of concrete pavements. This work is currently in progress and the results will be subsequently published.

REFERENCES

American Association of State Highway and Transportation Officials, 1962, ‘The AASHO Road Test’, Highway Research Board of the NAS-NRC Division of Engineering and Industrial Research, Report 5, Special Report 61E, Washington D. C., USA

Bhatti M. A., Stoner J. W., 1998, ‘Nonlinear Pavement Distress Model Using Dynamic Vehicle Loads’, ASCE, Journal of Infrastructure System, Vol. 4, Issue 2, p. 71-78

Choubane B., Tia M., 1995, ‘Analysis and Verification of Thermal-Gradient Effects on Concrete Pavement’, ASCE, Journal of Transportation Engineering 121.1, p. 75-81

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Health A. C. and Roesler J. R., 1999, ‘Shrinkage and Thermal Cracking of Fast Setting Hydraulic Cement Concrete Pavements in Palmdale, California’, Preliminary Report Prepared for California Department of Transportation

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Liu C., Gazis D., 1999, ‘Surface Roughness Effect on Dynamic Response of Pavements’, ASCE, Journal of Transportation Engineering, p. 332-337

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Sharma, A.K. and Pandey, K.P., 1996, ‘The Deflection and Contact Characteristics of Some Agricultural Tyres with Zero Sinkage’, Journal of Terramechanics, 33(6), p. 293-299



Shoukry A. N., William G. W., and Riad M., 2002, ‘Characteristics of Concrete Contact Stresses in Doweled Transverse Joints’, The International Journal of Pavement Engineering, Vol. 3 (2), UK, p. 117-129

Tarr S.M, Okamoto, P.A., Sheehan M.J. and Packard R.G., 1999,’Bond Interaction Between Concrete Pavement and Lean Concrete Base’, Transportation Research Record, 1668, Transportation Research Board, Washington D.C.,USA, p. 9-17

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Zhang J. and Li V. C., 2001, ‘Influence of Supporting Base Characteristics on Shrinkage-Induced Stresses in Concrete Pavements’, ASCE, Journal of Transportation Engineering, November/December, USA, p. 455-462

Zollinger, D.G.; Tang, T. and Xin, D., 1994, ‘Sawcut Depth Considerations for Jointed Concrete Pavement Based on Fracture Mechanics Analysis’. Transportation Research Record, No. 1449, Transportation Research Board, Washington D. C., USA, p. 91-100

ACKNOWLEDGEMENTS

The original work of this study was sponsored by the Queensland University of Technology (QUT), Australia, and Rinker Australia, under R&D project RD835. Thanks are expressed to Glenn Carson (Rinker) for the assistance in project planning and execution and to Arthur Powell (QUT) for his contributions in instrumenting the test section.

AUTHOR BIOGRAPHIES

M.Y. Darestani - PhD Student, School of Urban Development, Queensland University of Technology

David P. Thambiratnam – Professor, School of Urban Development, Queensland University of Technology

A. Nataatmadja – Senior Lecturer, School of Urban Development, Queensland University of Technology

Daksh Baweja – Principal Engineer, Rinker Australia

experimental study on structural response of rigid pavements...

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