Characterization of Reinforced Asphalt Pavement Structures Built over Organic Soils Employing Falling Weight Deflectometer

2010 ◽  
Author(s):  
Khaled Sobhan ◽  
K. P. George ◽  
Daniel Pohly ◽  
Hesham Ali
Keyword(s):  
Asphalt Pavement ◽  
Organic Soils ◽  
Falling Weight Deflectometer ◽  
Pavement Structures ◽  
Falling Weight

scholarly journals Comparisons between Asphalt Pavement Responses under Vehicular Loading and FWD Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Song Yang ◽  
Bing Qi ◽  
Zhensheng Cao ◽  
Shaoqiang Zhang ◽  
Huailei Cheng ◽  
...  
Keyword(s):  
Critical Strain ◽  
Asphalt Pavement ◽  
Field Measurements ◽  
Flexible Pavement ◽  
Fe Model ◽  
Wide Range ◽  
Vehicular Speed ◽  
Pavement Structures ◽  
Falling Weight ◽  
Strain Responses

The strain responses of asphalt pavement layer under vehicular loading are different from those under falling weight deflectometer (FWD) loading, due to the discrepancies between the two types of loadings. This research aims to evaluate and compare the asphalt layer responses under vehicular loading and FWD loadings. Two full-scale asphalt pavement structures, namely, flexible pavement and semirigid pavement, were constructed and instrumented with strain gauges. The strain responses of asphalt layers under vehicular and FWD loadings were measured and analyzed. Except for field measurements, the finite element (FE) models of the experimental pavements were established to simulate the pavement responses under a wide range of loading conditions. Field strain measurements indicate that the asphalt layer strain under vehicular loading increases with the rising temperature roughly in an exponential mode, while it decreases with the rising vehicular speed approximately linearly. The strain pulses in the asphalt layer generated by FWD loading are different from those induced by vehicular loading. The asphalt layer strains generated by FWD loading are close to those induced by low vehicular speed (35 km/h). The results from the FE model imply that the asphalt layer strains under FWD loading and vehicular loading are distributed similarly in the depth profile. For flexible pavement, the position of critical strain shifts gradually from the bottom of the asphalt layer to the mid-depth of the layer, as the temperature increases. For semirigid pavement, the position of critical strain is always located at the intermediate depth of the asphalt layer, regardless of temperatures.

Influence of Cracking Damage on Deflection Basin Test Data of FWD

2014 ◽  
Vol 620 ◽  
pp. 55-60 ◽  
Author(s):  
Xin Qiu ◽  
Xiao Hua Luo ◽  
Qing Yang
Keyword(s):  
Probabilistic Approach ◽  
Asphalt Pavements ◽  
Falling Weight Deflectometer ◽  
Layer System ◽  
Linear Elastic ◽  
Distribution Features ◽  
Pavement Structures ◽  
And Performance ◽  
Falling Weight ◽  
Non Destructive

With the popularization of falling weight deflectometer (FWD) to calculate the stiffness related parameters of the pavement structures, non-destructive evaluation of physical properties and performance of pavements has taken a new direction. FWD backcalculation is mathematically an inverse problem that could be solved either by deterministic or by probabilistic approach. A review of the currently used backcalculation procedures indicates that the calculation is generally based on a homogeneous, continuous, and linear elastic multi-layer system. Identifying effective data of dynamic deflection basins seems to be an important task for performing modulus backcalculation. Therefore, the main objective of this paper was to discuss the distribution features of dynamic deflection basins of asphalt pavements with crack distresses, and present the reasonable criteria to filter the testing data of FWD deflection basins. Finally, the study aims to validate the established criteria by conducting in-situ case study.

Effectiveness of static and dynamic backcalculation approaches for asphalt pavement

2020 ◽  
Vol 47 (7) ◽  
pp. 846-855
Author(s):  
Dandan Cao ◽  
Changjun Zhou ◽  
Yanqing Zhao ◽  
Guozhi Fu ◽  
Wanqiu Liu
Keyword(s):  
Asphalt Concrete ◽  
Elastic Moduli ◽  
Complex Modulus ◽  
Asphalt Pavement ◽  
Falling Weight Deflectometer ◽  
Fixed Frequency ◽  
Dynamic Approach ◽  
Layer Effect ◽  
Static Approach ◽  
Falling Weight

In this study, the field falling weight deflectometer (FWD) data for asphalt pavement with various base types were backcalculated through dynamic and static backcalculation approaches, and the effectiveness of backcalculation approaches was studied. Asphalt concrete (AC) was treated as a viscoelastic material and the complex modulus was obtained using the dynamic approach. The dynamic modulus at a fixed frequency was computed for comparison purposes. The coefficient of variance and the compensating layer effect were assumed as two characteristics for the effectiveness of backcalculation approaches. The results show that the layer property from the dynamic backcalculation approach for different stations were more consistent and showed smaller coefficient of variance, which were more appropriate for the characterization pavement behavior. The elastic moduli from the static approach were more variable and exhibited a compensating layer effect in which a portion of the modulus of one layer was backcalculated into other layers. The dynamic approach is more effective than static approaches in backcalculation of layer properties.

Interpretation of Transverse Profiles to Determine the Source of Rutting within an Asphalt Pavement System

2005 ◽  
Vol 1905 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Claude Villiers ◽  
Reynaldo Roque ◽  
Bruce Dietrich
Keyword(s):  
Surface Layer ◽  
Literature Review ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Falling Weight Deflectometer ◽  
Relative Contribution ◽  
Transverse Profile ◽  
Falling Weight ◽  
Different Sources

The transverse profilograph has been recognized as one of the most accurate devices for the measurement of rut depth. However, interpretation of surface transverse profile measurements poses a major challenge in determining the contributions of the different layers to rutting. A literature review has shown that the actual rutting mechanism can be estimated from a surface transverse profile for determination of the relative contribution of the layers to rutting. Unfortunately, much of the research yielded no verification or data. In addition, some techniques presented cannot be used if the rut depth is not well pronounced. Other techniques may be costly and time-consuming. The present research developed an approach that integrates ( a) falling weight deflectometer and core data along with 3.6-m transverse profile measurements to assess the contributions of different pavement layers to rutting and ( b) identifies the presence (or absence) of instability within the asphalt surface layer. This approach can be used regardless of the magnitude of the rut depth. On the basis of the analysis conducted, absolute rut depth should not be used to interpret the performance of the asphalt mixture. In addition, continued instability may not result in an increase in rut depth because the rutted basin broadens as traffic wander compacts or moves the dilated portion of the mixture. The approach developed appears to provide a reasonable way to distinguish between different sources of rutting. The conclusions drawn from analysis of the approach agreed well with observations from the trench cuts taken from four sections.

Use of falling weight deflectometer time history data for the analysis of seasonal variation in pavement response

2010 ◽  
Vol 37 (9) ◽  
pp. 1224-1231 ◽  
Author(s):  
Kate Deblois ◽  
Jean-Pascal Bilodeau ◽  
Guy Doré
Keyword(s):  
Phase Angle ◽  
Time History ◽  
Test Site ◽  
Flexible Pavement ◽  
Dissipated Energy ◽  
Falling Weight Deflectometer ◽  
History Data ◽  
The Road ◽  
Pavement Structures ◽  
Falling Weight

This paper presents the results of an exploratory analysis of falling weight deflectometer (FWD) data collected on a large project about the spring thaw behaviour of pavements. The test site includes four test sections, two of which are conventional flexible pavement structures, whereas the other two are built with a cement-treated base. The aim of this study is to verify the applicability of using FWD time history data to evaluate damage to a road during the thawing period. The applicability of the analysis techniques is verified through the phase angle and dissipated energy. The data analyzed were obtained from tests conducted with an FWD on one flexible pavement test section. The results obtained showed a clear difference between the winter, thawing, and summer periods. It was found that the phase angle and dissipated energy can be used to evaluate the road damage during the thawing period through quantification of the phase angle and dissipated energy. These factors can also be used to describe the pavement behaviour in terms of elasticity and viscoelasticity.

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