Evaluation of the effects of transverse cracking on the falling weight deflectometer data of asphalt pavements

2021 ◽  
pp. 1-14
Author(s):  
Guozhi Fu ◽  
Yanqing Zhao ◽  
Guozhong Wang ◽  
Jincheng Wei
Keyword(s):  
Asphalt Pavements ◽  
Falling Weight Deflectometer ◽  
Transverse Cracking ◽  
Falling Weight

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.

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.

scholarly journals Application of FWD data in developing dynamic modulus master curves of in-service asphalt layers

2017 ◽  
Vol 23 (5) ◽  
pp. 661-671 ◽  
Author(s):  
Nader SOLATIFAR ◽  
Amir KAVUSSI ◽  
Mojtaba ABBASGHORBANI ◽  
Henrikas SIVILEVIČIUS
Keyword(s):  
Dynamic Modulus ◽  
Master Curve ◽  
Asphalt Pavements ◽  
Falling Weight Deflectometer ◽  
Master Curves ◽  
Simple Method ◽  
High Frequencies ◽  
Design Guide ◽  
Falling Weight

This paper presents a simple method to determine dynamic modulus master curve of asphalt layers by con­ducting Falling Weight Deflectometer (FWD) for use in mechanistic-empirical rehabilitation. Ten new and rehabilitated in-service asphalt pavements with different physical characteristics were selected in Khuzestan and Kerman provinces in south of Iran. FWD testing was conducted on these pavements and core samples were taken. Witczak prediction model was used to predict dynamic modulus master curves from mix volumetric properties as well as the bitumen viscosity characteristics. Adjustments were made using FWD results and the in-situ dynamic modulus master curves were ob­tained. In order to evaluate the efficiency of the proposed method, the results were compared with those obtained by us­ing the developed procedure of the state-of-the-practice, Mechanistic-Empirical Pavement Design Guide (MEPDG). Re­sults showed the proposed method has several advantages over MEPDG including: (1) simplicity in directly constructing in-situ dynamic modulus master curve; (2) developing in-situ master curve in the same trend with the main predicted one; (3) covering the large differences between in-situ and predicted master curve in high frequencies; and (4) the value obtained for the in-situ dynamic modulus is the same as the value measured by the FWD for a corresponding frequency.

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.

Structural Layer Coefficients of Crumb Rubber–Modified Asphalt Concrete Mixtures

1997 ◽  
Vol 1583 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Mustaque Hossain ◽  
Affan Habib ◽  
Todd M. Latorella
Keyword(s):  
Asphalt Concrete ◽  
Crumb Rubber ◽  
Asphalt Pavements ◽  
Falling Weight Deflectometer ◽  
Average Value ◽  
Concrete Mixtures ◽  
Mechanistic Approach ◽  
Asphalt Mix ◽  
Falling Weight ◽  
Structural Layer

Structural layer coefficients for crumb rubber–modified (CRM) asphalt concrete mixtures were developed from the backcalculated moduli values using the falling weight deflectometer (FWD) test results on in situ pavements. Several test sections of recently built crumb rubber–modified pavements on three routes in Kansas (I-135, K-32 and US-56) were selected for this study. I-135 is a newly built asphalt pavement and the other two are gap-graded CRM overlays. Deflection data were collected with a Dynatest 8000 FWD at 21 locations at 7.5-m intervals on each test section on I-135, 22 locations on K-32, and 11 locations on US-56. For CRM asphalt mix overlays, the average surface layer coefficients from the equal mechanistic approach of analysis were found to vary between 0.11 and 0.46 with most values falling around 0.30. This indicates a lower structural layer coefficient value for the asphalt-rubber mix compared with the conventional asphalt concrete. For newly constructed CRM asphalt pavements, the structural layer coefficients varied from 0.25 to 0.48, with the average value around 0.35. These values are close to the design layer coefficient values used for conventional asphalt concrete layers. Large variabilities in computed structural layer coefficients for the rubblized jointed reinforced concrete pavement were observed. The structural layer coefficients computed for this layer varied from 0.10 to 0.35.

Investigation of Performance of Asphalt Pavement with Fly-Ash Stabilized Cold In-Place Recycled Base Course

2003 ◽  
Vol 1819 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Haifang Wen ◽  
Mathew P. Tharaniyil ◽  
Bruce Ramme
Keyword(s):  
Fly Ash ◽  
Asphalt Pavement ◽  
Asphalt Pavements ◽  
Generation Process ◽  
Falling Weight Deflectometer ◽  
Structural Capacity ◽  
Base Course ◽  
Pavement Base ◽  
Granular Base ◽  
Falling Weight

Class C fly ash is a coal combustion product from lignite or subbituminous coal obtained as a result of the power generation process. In recent years, efforts have been made to incorporate self-cementing fly ash into cold in-place recycled (CIR) asphalt material to improve the structural capacity of asphalt pavement base layers. In this study, asphalt pavements in County Trunk Highway JK in Waukesha County, Wisconsin, were pulverized in place and mixed with fly ash and water to function as a base course. To evaluate the contribution of fly ash to the pavement’s structural performance, nondestructive deflection tests were performed with a KUAB 2m-FWD falling weight deflectometer (FWD) on the outer wheelpath right after construction. The MICHBACK program was used to backcalculate the material properties of pavement layers from FWD measurements of deflection. The average moduli of the materials in the hot-mix asphalt layer, fly ash–stabilized base course, and subgrade were backcalculated. The structural capacity and structural number were also obtained from FWD test data. The structural coefficient of 0.16 was obtained for the fly ash–stabilized base course in the highway. The results of FWD testing indicate that CIR stabilization with self-cementing fly ash is an economical method of recycling flexible pavements and eliminates the need for expensive new granular base courses for road reconstruction.

Prediction of critical responses in full-depth asphalt pavements using the falling weight deflectometer deflection basin parameters

2022 ◽  
Vol 318 ◽  
pp. 126019
Author(s):  
Bongsuk Park ◽  
Seonghwan Cho ◽  
Reyhaneh Rahbar-Rastegar ◽  
Tommy E. Nantung ◽  
John E. Haddock
Keyword(s):  
Asphalt Pavements ◽  
Falling Weight Deflectometer ◽  
Critical Responses ◽  
Falling Weight

Accuracy evaluation of statically backcalculated layer properties of asphalt pavements from falling weight deflectometer data

2020 ◽  
Vol 47 (3) ◽  
pp. 317-325
Author(s):  
Guozhi Fu ◽  
Cheng Xue ◽  
Yanqing Zhao ◽  
Dandan Cao ◽  
Mohsen Alae
Keyword(s):  
Spectral Element Method ◽  
Spectral Element ◽  
Asphalt Pavements ◽  
Accuracy Evaluation ◽  
Falling Weight Deflectometer ◽  
Static Deflection ◽  
Dynamic Effects ◽  
Surface Deflection ◽  
Pavement Structures ◽  
Falling Weight

This study is to evaluate the dynamic effects of falling weight deflectometer (FWD) loading on the surface deflection of asphalt pavement and the accuracy of statically backcalculated layer moduli from FWD data. The dynamic and static deflections were computed using the spectral element method and the layer elastic theory, respectively, for various pavement structures. The static deflection is considerably larger than the dynamic deflection for typical FWD loading and the normalized difference between static and dynamic deflections increases with increasing distance from the load center and decreases with increasing loading duration. The dynamic deflections were utilized to backcalculate the layer moduli using two static backcalculation procedures, MODULUS and EVERCALC. The backcalculated moduli can be significantly different from the actual moduli. The results indicate that the static backcalculation procedure can lead to significant errors in the backcalculated layer moduli by ignoring the dynamic effects of FWD loading.

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