Comparative studies of lightweight deflectometer and Benkelman beam deflectometer in low volume roads

Guzzarlapudi, Sunny Deol; Adigopula, Vinod Kumar; Kumar, Rakesh

doi:10.1016/j.jtte.2016.09.005

Cited by 22 publications

(13 citation statements)

References 12 publications

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“…The studies from 2016 [35,36] examining three soft-grained clay materials and one sandy provided the following occurrence intervals of resilient modulus M r : 20-134 MPa for Cl, 90-150 MPa for siCl, and 11-84 MPa for csaCl. The occurrence intervals of M r,CBR from cyclic CBR ranged from 37 to 66 MPa for Cl, from 15 to 28 MPa for siCl, and from 44 to 80 MPa for csaCl.…”

Section: Discussionmentioning

confidence: 99%

Using Resilient Modulus to Determine the Subgrade Suitability for Forest Road Construction

Ševelová

Florian

Hrůza

2020

Forests

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Forest roads are often constructed in environments with low bearing capacity of the subgrade. The subgrade then has an effect on their service life and damage. According to the methodology of the American Association of State Higway and Transportation Officiales AASHTO, the design of pavement is divided into three levels according to the intensity of the traffic load. For pavements with the highest load intensity, preparing the resilient modulus from a cyclic triaxial test is required. For other traffic load classes, including forest roads, the methodology allows the use of the estimate of resilient modulus value determined from other tests. In the laboratory at the Faculty of Forestry, Mendel University of Brno, the method from the Delft University 2009 was tested and subsequently modified, using a standard CBR machine for repeated loading. A total of 276 samples from various types of forest road subgrade from the Czech Republic were tested by the method of repeated loading on the CBR machine, from which the values of the Resilient Modulus were newly labelled Mr,CBR. The results of the statistical analysis showed a large variability of Mr,CBR values and wide intervals of its occurrence for individual types of subgrade. The variability was subjected to analysis and the influence of basic geotechnical parameters on the values of Mr,CBR was analyzed. A fundamental correlation was found between the value of Mr,CBR and the value of the plunger stress, which reached values exceeding the bearing capacity of the soil types using the Delft University method. It is necessary to limit the plunger stress during cyclic loading up to the failure limit or even better to the expected traffic load. The modified procedure results show a more consistent behavior of the modulus.

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Section: Discussionmentioning

confidence: 99%

Using Resilient Modulus to Determine the Subgrade Suitability for Forest Road Construction

Ševelová

Florian

Hrůza

2020

Forests

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“…A hypothetical case study was performed to analyze the effect of soil modulus on the design life of a flexible pavement consisting of an asphalt layer, base layer, and subgrade (Figure 12). Rutting, fatigue, and low-temperature cracking are the principal types of diseases that should be considered for the design of flexible pavement [30]. Typical modulus values obtained from the literature were used for the asphalt and base layers.…”

Section: Case Studymentioning

confidence: 99%

Back‐Calculation of Soil Modulus from PFWD Based on a Viscoelastic Model

Zhang

Ren

Khan

et al. 2019

Advances in Civil Engineering

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To improve the accuracy of back-calculation of soil modulus using the portable falling weight deflectometer (PFWD), a viscoelastic method (VEM) overcoming the limitations of the conventional linear elastic method (LEM) was proposed. A quasi-static dynamic analysis technique of Laplace transformation and a modified Gauss–Newton optimization algorithm were adopted in the proposed method. The back-calculation program was compiled with MATLAB. The effectiveness of the proposed method was verified with the in situ plate load test (PLT) conducted on a highway embankment. In situ test results showed that a time lag existed between the peaks of deflection and load, and load-deflection curves were nonlinear, which indicated the viscoelastic nature of the soil. The back-calculated modulus using the LEM and VEM was higher than that using the PLT. In the case of low stiffness soil, the average error of back-calculation using the LEM and VEM was 53.1% and 14.8%, respectively. However, for stiffer soil, the average error of back-calculation using the LEM and VEM method was 12.4% and 4.3%, respectively. Moduli of back-calculation using LEM and VEM methods were used to perform flexible pavement analysis, which showed that with an 8% reduction of modulus, the pavement service life reduced by 25%. More accurate estimation of modulus can save maintenance cost in the future.

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“…Also, validation of static modulus with California bearing ratio (CBR) related subgrade modulus shows moderate correlation of 0.67 to 0.74 whereas dynamic modulus shows good correlation of 0.74 to 0.93 for different types of soils, respectively. Therefore, the comparative analysis shows that LWD provides reliable subgrade modulus values, and it can be used as a quick subgrade strength evaluating tool for low volume roads [24] Various researchers used FWD for elastic modulus estimation. LWD test were performed on the individual layers of the pavements independently like base course, subbase course and subgrade course.…”

Section: In-situ Testmentioning

confidence: 99%

Application of Ground Penetration Radar and Light Weight Deflectometer for Pavement Quality Control and Quality Assessment

Narnoli*,

Suman

2019

IJRTE

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Pavement evaluation requires the frequent assessment of structural and functional condition. Earlier functional assessment of pavement were rapid and non destructive whereas structural evaluation required destructive testing. With growth in technology the light weight deflectometer (LWD) and ground penetrating radar (GPR) replaced the destructive testing in most part of the world. This paper highlights the use of LWD and GPR as non destructive testing tool in pavement evaluation. LWD and GPR test were conducted on the granular material to investigate the composite modulus of layer for their quality assessment. LWD test results were found to be significantly affected by the base plate diameter, contact between plate and surface layer, whereas drop height does not show significant difference on composite modulus. GPR technology has showed its versatility in pavement layer thickness evaluation, void and crack detection, and sub surface exploration. Ground coupled GPR has been used for subsurface exploration. At project level pavement management system, the combined use of GPR and deflection testing device has resulted in effective monitoring of pavement structural capacity. Hence LWD and GPR had showed its effectiveness for quality control and quality assurance (QC/QA) in PMS.

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Comparative studies of lightweight deflectometer and Benkelman beam deflectometer in low volume roads

Cited by 22 publications

References 12 publications

Using Resilient Modulus to Determine the Subgrade Suitability for Forest Road Construction

Using Resilient Modulus to Determine the Subgrade Suitability for Forest Road Construction

Back‐Calculation of Soil Modulus from PFWD Based on a Viscoelastic Model

Application of Ground Penetration Radar and Light Weight Deflectometer for Pavement Quality Control and Quality Assessment

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