scholarly journals PREDICTION OF DEPTH TEMPERATURE OF ASPHALT LAYERS IN HOT CLIMATE AREA

2018 ◽  
Vol 24 (7) ◽  
pp. 516-525 ◽  
Author(s):  
Nader Solatifar ◽  
Mojtaba Abbasghorbani ◽  
Amir Kavussi ◽  
Henrikas Sivilevičius
Keyword(s):  
Linear Regression Analysis ◽  
Field Measurements ◽  
Falling Weight Deflectometer ◽  
Actual Measurement ◽  
Temperature Variations ◽  
Hot Climate ◽  
Actual Field ◽  
Pavement Temperature ◽  
Falling Weight

In determination of flexible pavement layers moduli using Falling Weight Deflectometer (FWD), the pavement depth temperature should be determined and then the moduli should be corrected into a reference temperature. As direct measurement of pavement temperature is time consuming and is difficult to be determined in trafficked roads, some models are developed to predict temperature of asphalt layers through pavement depth, including BELLS model. The objective of this research is to determine correlation between actual measurement and prediction of temperature variations through asphalt layers with applying BELLS model. Ten new and rehabilitated pavement sites were selected in hot climate regions in Khuzestan and Kerman provinces in southern part of Iran. In typical hot summer days, pavement temperatures were measured at half and at one-third of the depth of asphalt layers and FWD testing were performed. Results indicated that a linear regression analysis of BELLS predicted temperatures versus measured values, provides very good correlation with actual field measurements of temperatures through the asphalt layers. Furthermore, predictions were more precise in rehabilitated pavements rather than in newly constructed pavements. Finally, using multi parametric linear fitting analysis, a new model was developed to accurately predict the temperature of asphalt layers in new pavements.

scholarly journals Development of a methodology to backcalculate pavement layer moduli using the traffic speed deflectometer

2018 ◽  
Vol 45 (5) ◽  
pp. 377-385 ◽  
Author(s):  
Omar Elbagalati ◽  
Momen Mousa ◽  
Mostafa A. Elseifi ◽  
Kevin Gaspard ◽  
Zhongjie Zhang
Keyword(s):  
Traffic Control ◽  
Coefficient Of Determination ◽  
Falling Weight Deflectometer ◽  
Ann Model ◽  
Acceptable Accuracy ◽  
Traffic Speed ◽  
Artificial Neural Network Ann ◽  
Falling Weight ◽  
Good Agreement

Backcalculation analysis of pavement layer moduli is typically conducted based on falling weight deflectometer (FWD) measurements; however, the stationary nature of FWD requires lane closure and traffic control. To overcome these limitations, a number of continuous deflection devices were introduced in recent years. The objective of this study was to develop a methodology to incorporate traffic speed deflectometer (TSD) measurements in the backcalculation analysis. To achieve this objective, TSD and FWD measurements were used to train and to validate an artificial neural network (ANN) model that would convert TSD deflection measurements to FWD deflection measurements. The ANN model showed acceptable accuracy with a coefficient of determination of 0.81 and a good agreement between the backcalculated moduli from FWD and TSD measurements. Evaluation of the model showed that the backcalculated layer moduli from TSD could be used in pavement analysis and in structural health monitoring with a reasonable level of accuracy.

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.

Fast Nondestructive Field Test Method to Determine Stiffness of Subsurface Layer in Thin Surface Hot-Mix Asphalt Pavement

2005 ◽  
Vol 1905 (1) ◽  
pp. 82-89
Author(s):  
Rajib B. Mallick ◽  
Animesh Das ◽  
S. Nazarian
Keyword(s):  
Hot Mix Asphalt ◽  
Subsurface Layer ◽  
Test Method ◽  
Effect Of Temperature ◽  
Falling Weight Deflectometer ◽  
Foamed Asphalt ◽  
Subsurface Layers ◽  
Seismic Property ◽  
Falling Weight

The determination of the moduli of subsurface stabilized layers in pavements with unknown and variable layers and thin asphalt layers is a challenging problem. Reliable estimation of moduli cannot be obtained from backcalculation of falling weight deflectometer data. In addition, for many stabilized layers, full-depth intact cores cannot be obtained from the field, and hence, laboratory determination of the moduli is not possible. Analysis of the seismic property of a pavement is a well-known method for estimation of the surface modulus of the pavement. This paper proposes a simple methodology on how seismic data acquired on the pavement surface can be effectively used to estimate the modulus of the surface layer as well as those of the subsequent subsurface layers of a flexible pavement. A research study was conducted on three hot-mix asphalt pavements with a foamed asphalt (FA) stabilized base in Maine. These three pavements were tested with both portable seismic and falling weight deflectometer equipment. Cores were taken from the same locations and tested in the laboratory for their resilient moduli. The modulus values obtained from different tests were compared, the effect of temperature on the modulus of the FA was evaluated, and the deflections computed from layered elastic analysis by use of the predicted modulus of the FA layer were compared with the observed deflections. It is concluded that the portable seismic equipment can be used to determine accurate moduli of subsurface stabilized layers. The practical advantages of using such equipment warrant further study for refinement of the method.

scholarly journals Temperature Correction of Deflections and Backcalculated Elasticity Moduli Determined from Falling Weight Deflectometer Measurements on Asphalt Pavements

2022 ◽  
Vol 24 (1) ◽  
pp. D1-D8
Author(s):  
Ilja Březina ◽  
Ondřej Machel ◽  
Tomáš Zavřel
Keyword(s):  
Bearing Capacity ◽  
Thermal Gradient ◽  
Temperature Correction ◽  
Asphalt Pavements ◽  
Falling Weight Deflectometer ◽  
Elasticity Moduli ◽  
Similar Comparison ◽  
Pavement Temperature ◽  
Falling Weight

The evaluation of the bearing capacity of asphalt pavements is usually performed by analysing the deflections measured by a Falling Weight Deflectometer (FWD). The deflection changes with the pavement temperature. In evaluation is necessary to consider the thermal gradient of pavement and perform the temperature correction. The article contains an analysis of effects of the pavement temperature on FWD results on the long-term monitored sections. The temperature correction was performed on measured deflections or back-calculated elasticity moduli. The moduli recalculated to the temperature of 20 °C according to both procedures were similar. Comparison of moduli determined by recalculation to moduli backcalculated from the deflection bowls measured at the temperature of 20 °C, has proven smaller differences for the moduli determined from the deflection bowl corrected to the temperature of 20 °C.

scholarly journals Prototype of the Runway Monitoring Process at Smaller Airports: Edvard Rusjan Airport Maribor

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1689 ◽  
Author(s):  
Boštjan Kovačič ◽  
Damjan Želodec ◽  
Damjan Doler
Keyword(s):  
Process Model ◽  
Deformation Model ◽  
Falling Weight Deflectometer ◽  
Research Model ◽  
Reliable Determination ◽  
Time Period ◽  
Monitoring Process ◽  
Falling Weight ◽  
Short Time

The last 20-year announcement predicts a 3.5% increase in the number of yearly passengers which will result in the doubling of the number of passengers in air transport by 2037. Such anticipation indicates the need for efficient monitoring of airport infrastructure as the support of opportune and efficient maintenance works. The novelties of this article are a process model of maintenance and monitoring, suitable for smaller and less burdened airports, and the methodology of monitoring of runways by implementation of the geodetic and geomechanics falling weight deflectometer (FWD) method. In addition, the results confirm the assumption that a specific environment such as an airport allows for sufficiently reliable determination of deformation areas or areas of vertical deviations of runways in a relative short time period available for measurements by using geodetic methods only or by combining other methods; our research model includes the FWD method. With the research, we have also shown there is an interaction between deformations or areas of vertical deviations on the surface and anomalies in the runway lower constructure which will, hereinafter, allow the development of the prediction, creating a vertical deviations or deformation model.

Assessing the Precision of Falling Weight Deflectometer for Field Measurements

2006 ◽  
Vol 3 (3) ◽  
pp. 14205
Author(s):  
SW Dean ◽  
B Choubane ◽  
S Gokhale ◽  
N Mike Jackson ◽  
A Nazef
Keyword(s):  
Field Measurements ◽  
Falling Weight Deflectometer ◽  
Falling Weight

Correlation of Non-Destructive Pavement Test Devices

2014 ◽  
Vol 912-914 ◽  
pp. 613-616
Author(s):  
Sheng Chun Li
Keyword(s):  
Field Measurements ◽  
Falling Weight Deflectometer ◽  
Pavement Rehabilitation ◽  
Ningxia Hui Autonomous Region ◽  
Aashto 1993 ◽  
Falling Weight ◽  
Near Future ◽  
The Relationship ◽  
Non Destructive ◽  
Rehabilitation Strategy

This paper studies the correlation of non-destructive pavement test devices, the falling weight deflectometer (FWD) and Benkelman Beam (BB), in evaluation of pavement structure capacity. Field measurements were made at an expansion highwayG6 in Ningxia Hui Autonomous Region, China. Based on the deflection results measured with FWD and BB, the relationship between FWD and BB was established. The subgrade moduli of the test section were back-calculated. The results show that the ratio of E(sta) and MR(dyn) is consistent with the suggestion of AASHTO 1993. Due to the fact that the use of FWD test is convenient and the results are stable, it demonstrates that the falling weight deflectometer (FWD) is an appropriate device to evaluate the pavement structural and to select the optimal pavement rehabilitation strategy in the near future.

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