Field Characterization of Pavement Materials using Falling Weight Deflectometer and Sensor Data from an Instrumented Pavement Section

2020 ◽  
Vol 2674 (4) ◽  
pp. 205-221
Author(s):  
Zafrul H. Khan ◽  
Rafiqul A. Tarefder ◽  
Md Amanul Hasan
Keyword(s):  
Material Properties ◽  
Embedded Sensors ◽  
Sensor Data ◽  
Maximum Magnitude ◽  
Falling Weight Deflectometer ◽  
Response Signal ◽  
Error Norm ◽  
Material Response ◽  
Cross Anisotropy ◽  
Falling Weight

This study deals with the backcalculation of the mechanical properties of pavement layers using not only the falling weight deflectometer (FWD) sensor data but also pavement response under that FWD load from the embedded sensors in an instrumentation section. To perform the backcalculation, a layered viscoelastic pavement model incorporating asphalt concrete (AC) cross-anisotropy is developed as the forward model. Field degree of cross-anisotropy in AC is determined at the maximum magnitude frequency obtained through continuous wavelet transform of the material response signal. The material response signal is obtained from the deconvolution between the loading signal and the signal registered at the embedded sensors. An inverse analysis methodology is also developed to calculate the gross vehicle weight (GVW) of any vehicle passing through the instrumentation section using only the backcalculated material properties and pavement responses. From the results, it is observed that inclusion of the AC cross-anisotropy reduces the error norm, and a good agreement is observed with the laboratory dynamic modulus in both horizontal and vertical directions. It is also observed that the maximum magnitude frequency of material response and degree of cross-anisotropy in AC both decrease with an increase in average AC temperature. Furthermore, using the backcalculated material properties and pavement responses, it is possible to determine the GVW with 95% accuracy.

Rolling Weight Deflectometer with Thermal and Vibrational Bending Compensation

1996 ◽  
Vol 1540 (1) ◽  
pp. 77-82 ◽  
Author(s):  
R. F. Johnson ◽  
J. W. Rish
Keyword(s):  
Data Acquisition ◽  
Measurement Errors ◽  
Essential Elements ◽  
Sensor Data ◽  
Falling Weight Deflectometer ◽  
Straight Line ◽  
History Of ◽  
Beam Bending ◽  
Rolling Load ◽  
Falling Weight

A pavement deflectometer has been developed for continuous measurement of airfield pavements under a rolling load wheel. The rolling weight deflectometer (RWD) measures pavement deflection using a new method of laser triangulation. It also compensates for bending of the beam on which the sensors are mounted. This compensation allows accurate measurement of deflection in the presence of motion and thermal effects. The deflection measurement incorporates data from four equally spaced pavement sensors mounted on a beam. The method requires the sensors to remain in a straight line at all times. This method was previously plagued with measurement errors caused by thermal and vibrational effects. The RWD uses a laser beam to monitor the state of bending of the physical beam in real time. The bending data are used with pavement sensor data to produce accurate deflection measurements in the presence of any amount of beam bending. The bending-compensated RWD produces deflection measurements on 0.3-m (1-ft) intervals with an accuracy of 40 microns (0.0015 in.) while moving at 10 km/hr (6 mph). The RWD is composed of a towed trailer, a networked data-acquisition system, and a load platform. Its essential elements consist of a horizontally transported beam, strategically placed pavement sensors, sensors to measure beam bending, an odometer, and a data-acquisition computer. A brief history of pavement deflection methods is presented along with a description of the RWD. Preliminary field results include a comparison between data obtained by a falling weight deflectometer and the RWD.

Design on Falling Weight Impact Test Rig

2011 ◽  
Vol 148-149 ◽  
pp. 388-392
Author(s):  
Jie Du ◽  
Chun Ting Ma
Keyword(s):  
Impact Test ◽  
Particle Diameter ◽  
Test System ◽  
Computer Hardware ◽  
Sensor Data ◽  
Test Rig ◽  
High Shock ◽  
Data Acquisition Card ◽  
Weight Impact ◽  
Falling Weight

Based on Interaction energy of solid ball, the new particle damper is designed which can be used in a high temperature and high shock energy. To verify the design of the damper, a falling weight Impact test rig is designed, a sensor, data acquisition card and computer hardware constitutes a signal test system. Experimental results show that the particle diameter is the biggest impact for the role of the particle damper , the characteristics of the displacement curves are increased at first and then decreased, the opposite effect of the time. At the same time filled with particles and the degree of damping rod embedment also have an impact on energy consumption.

DIPLOBACK: Neural-Network-Based Backcalculation Program for Composite Pavements

1997 ◽  
Vol 1570 (1) ◽  
pp. 143-150 ◽  
Author(s):  
Lev Khazanovich ◽  
Jeffery Roesler
Keyword(s):  
Neural Network ◽  
Winkler Foundation ◽  
Multilayer Composite ◽  
Falling Weight Deflectometer ◽  
Subgrade Reaction ◽  
Elastic Parameters ◽  
The Neural Networks ◽  
Elastic Layers ◽  
Falling Weight ◽  
Moduli Of Elasticity

A neural-network-based backcalculation procedure is developed for multilayer composite pavement systems. The constructed layers are modeled as compressible elastic layers, whereas the subgrade is modeled as a Winkler foundation. The neural networks are trained to find moduli of elasticity of the constructed layers and a coefficient of subgrade reaction to accurately match a measured deflection profile. The method was verified by theoretically generated deflection profiles and falling weight deflectometer data measurements conducted at Edmonton Municipal Airport, Canada. For the theoretical deflection basins, the results of backcalculation were compared with actual elastic parameters, and excellent agreement was observed. The results of backcalculation using field test data were compared with the results obtained using WESDEF. Similar trends were observed for elastic parameters of all the pavement layers. The backcalculation procedure is implemented in a computer program called DIPLOBACK.

scholarly journals Propagation of Surface Waves in Asphalt Pavements Generated by Different Load Impulse of Falling Weight Deflectometer

2019 ◽  
Vol 15 (1) ◽  
pp. 29-35
Author(s):  
Jozef Komačka ◽  
IIja Březina
Keyword(s):  
Surface Waves ◽  
Travel Time ◽  
Time History ◽  
Asphalt Pavements ◽  
Load Force ◽  
Falling Weight Deflectometer ◽  
Waves Propagation ◽  
Propagation Of Waves ◽  
Falling Weight ◽  
The Waves

Abstract The propagation of waves generated by load impulse of two FWD types was assessed using test outputs in the form of time history data. The calculated travel time of wave between the receiver in the centre of load and others receivers showed the contradiction with the theory as for the receivers up to 600 (900) mm from the centre of load. Therefore, data collected by the sensors positioned at the distance of 1200 and 1500 mm were used. The influence of load magnitude on the waves propagation was investigated via the different load force with approximately the same load time and vice versa. Expectations relating to the travel time of waves, depending on the differences of load impulse, were not met. The shorter travel time of waves was detected in the case of the lower frequencies. The use of load impulse magnitude as a possible explanation was not successful because opposite tendencies in travel time were noticed.

Sign in / Sign up

Export Citation Format

Share Document