Toward the Development of Load Transfer Efficiency Evaluation of Rigid Pavements by a Rolling Wheel Deflectometer (original) (raw)
Related papers
Transportation Research Procedia, 2020
Rigid pavements have widespread use, e.g, in motorways and airports, due to their excellent properties such as high bearing capacity and long lifetime. However, when rigid pavements fail it is often due to bad load transfer efficiency (LTE) at its joints. Traditional methods of measuring LTE can be time consuming. Here, we study the possibility of measuring LTE using a moving load with the aim of achieving higher productivity. An experiment simulating Rolling Weight Deflectometer (RWD) measurements on a joint was carried out to gain understanding and confidence that can guide the analysis of real RWD data. Continuous data from measurements across a joint allows for determination of not only the LTE but also additional parameters characterizing the pavement and the joint. A semi-analytical model was implemented for simulating the pavement response next to a joint and used for interpretation and verification of the experimental data. The results show promise for the use of moving loads for rapid evaluation of joints.
EVALUATION OF RIGID PAVEMENTS BY DEFLECTION APPROACH
Since 1951 there has been a sevenfold increase in the Indian road network while the traffic has increased 120 times. This leads to the deterioration of the surface of the pavements. Deterioration of pavements may be functional or structural in nature. Evaluation and timely assessment of pavement condition will help to judge the necessary steps to be taken to improve pavement conditions. Pavement surface deflection measurements are one of the primary means of evaluating a flexible pavement structure. 'Benkelman Beam Deflection (BBD) Technique is used to find out the characteristic deflection for flexible pavement. The testing and analysis by BBD technique finally provides us with overlay thickness in terms of Bituminous Macadam. The use of BBD technique may not be only limited to evaluate flexible pavements. Evaluation of newly constructed rigid pavements on the basis of Load Transfer Efficiency of dowel bars gives an idea of the overall performance. The accuracy of evaluating load transfer efficiency (LTE) of joint is important to estimate whether the dowel is disabled or not. The ratio of the edge deflection of unloaded slab to the edge deflection of loaded slab is used as index to evaluate LTE of joint. The objective of this paper is to find out the utility of Benkelman Beam Deflection Test on rigid pavements. In this paper based on the known deflection relationship between loaded and unloaded slab calculated with the help of two Benkelman beams which is a technique generally used to determine the overlay thickness for flexible pavements. A rigid pavement road stretch (Swami Vivekanand Road) constructed 2 years ago in Pune city was evaluated using BBD technique. Deflections measured on slabs (loaded slab and unloaded slab) across the dowel bars would give a measure of the load transfer efficiency of the dowel bars.
Analytical-Empirical Pavement Evaluation Using the Falling Weight Deflectometer
Transportation Research Record, 1985
Because of the rapid development of hardware and software during the past 10 years, it is now possible to use an analytical-empirical (or mechanistic) method of structural pavement evaluation on a routine basis. The Dynatest 8000 falling weight deflectometer that, when used with the ELMOn program, determines the modulus of each structural layer in a pavement system is described. The moduli are determined nondestructively and in situ under conditions that closely resemble those under the influence of heavy traffic. Some practical examples illustrating the use of the method are presented, and its empirical components are discussed. These empirical components are also programmed into the ELMOD program so an overlay design may be carried out concurrently with the analytical determination of layered elastic moduli. The method may be used for both flexible and rigid pavements, where joint evaluation is not needed. The evaluation of joint or corner conditions in jointed portland cement con...
Procedia Engineering, 2017
Within the the National Sustainability Programme I, project of Transport R&D Centre (LO1610), the determination of measured jointed plain concrete pavements deflections to load was monitored. Impacts of climate and other effects upon resulting concrete pavement deflections were studied in the first place. The main issue for FWD measurements is the selection of suitable climatic conditions. In addition, loading transfer efficiency (LTE) at slab joints, which is a specific feature of concrete road pavements, was studied.
REVIEW OF FALLING WEIGHT DEFLECTOMETER FOR ASSESSMENT OF FLEXIBLE PAVEMENT
ELK ASIA PACIFIC JOURNAL OF CIVIL ENGINEERING AND STRUCTURAL DEVELOPMENT , 2018
Fast development of road networks has become a trend in India and everywhere in the world. From the past couple of decades, it has been observed that numerous highways are in a phase of deteriorations. Identifying the reasons for deteriorations requires a pavement evaluation study. Many performances study have been made out by exploring flexible pavements, by the users of widely accepted falling weight deflectometer (FWD) as a non-destructive test (NDT) and considered it as a standard for structure assessment. The primary objective of this study is to a review of an FWD instrument and the also study of the empirically derived methods and a back calculation process for computing layer moduli and factors influencing it. The essential need of correction factors to get reliable layer moduli is an also discussed, in addition to the investigation of advancement of low-cost indigenous FWD models flexible pavements, by the users of widely accepted falling weight deflectometer (FWD) as a non-destructive test (NDT) and considered it as a standard for structure assessment. The primary objective of this study is to a review of an FWD instrument and the also study of the empirically derived methods and a back calculation process for computing layer moduli and factors influencing it. The essential need of correction factors to get reliable layer moduli is an also discussed, in addition to the investigation of advancement of low-cost indigenous FWD models
A Study of the Structural Performance of Flexible Pavements Using a Traffic Speed Deflectometer
Geo-China 2016, 2016
The falling weight deflectometer (FWD) is a non-destructive testing device that has been used by many road agencies worldwide since 1980 for structural evaluation of flexible pavements. In early 2000, the world first Doppler laser-based traffic speed deflectometer (TSD) was developed by Greenwood Engineering, and now eight TSD vehicles are in use worldwide. The two main advantages of the TSD technology are: (a) the ability to carry out continuous bearing capacity measurements instead of discrete points, (b) that testing can be carried out at traffic speeds without the need for lane closures with a stationary device such as FWD. The objective of this paper was to study the structural performance of flexible pavements using TSD deflection data. The study successfully established a correlation between maximum deflections TSD-D 0 and FWD-D 0 that are derived from the two devices. This study also drew some interesting conclusions in that deflection data collected by TSD could be transformed to FWD equivalent structural numbers with simple models as derived in the study. The outcome of this study was an established methodology for reporting structural performance at network level utilizing TSD deflection data.
A Study of the Structural Performance of Flexible Pavements Using Traffic Speed Deflectometer
Journal of Testing and Evaluation, 2017
The falling weight deflectometer (FWD) is a non-destructive testing device that has been used by many road agencies worldwide since 1980 for structural evaluation of flexible pavements. In early 2000, the world first Doppler laser-based traffic speed deflectometer (TSD) was developed by Greenwood Engineering, and now eight TSD vehicles are in use worldwide. The two main advantages of the TSD technology are: (a) the ability to carry out continuous bearing capacity measurements instead of discrete points, (b) that testing can be carried out at traffic speeds without the need for lane closures with a stationary device such as FWD. The objective of this paper was to study the structural performance of flexible pavements using TSD deflection data. The study successfully established a correlation between maximum deflections TSD-D 0 and FWD-D 0 that are derived from the two devices. This study also drew some interesting conclusions in that deflection data collected by TSD could be transformed to FWD equivalent structural numbers with simple models as derived in the study. The outcome of this study was an established methodology for reporting structural performance at network level utilizing TSD deflection data.
2013
It is currently believed that mechanistic evaluation of rigid pavements using full scale test data is the most appropriate way to study pavement behavior. Current methods outline a single and dual gage approach for evaluating stress-based load transfer efficiency (LTE (S)) at the transverse joints. The single gage method can be very useful for joints where only a single gage is located or where dual gages are located, but only one of the gages is producing accurate responses. Additionally, the installation and monitoring of gages is expensive; therefore, the ability to accurately calculate the stress-based load transfer efficiency based on a single gage will provide an impetus to several resource starved agencies to monitor the performance of the joint without the need to install two gages. Both methods have produced similar estimations of LTE (S) for single axle carriages; however, it is unknown if this approach yields similar results for multi axle carriages. The dual gage approach for measuring LTE(S) has been implemented successfully in prior studies at Rowan University for tandem axle configurations for testing conducted on Construction Cycle 2 (CC2) at the Federal Aviation Administration (FAA) National Airport Pavement Test Facility (NAPTF). In this study LTE(S) was determined based on a single gage for multi-axle carriages. The analysis was conducted on CC2 and CC6 test items. The LTE(S) calculated based on a single gage was then compared with those calculated with the dual gage. This analysis has shown mixed results and limitations regarding the accuracy of the stress-based LTE using a single gage.
Structural Responses of Flexible Pavement Subjected to Different Axle Group Loads
2020
This study presents the structural responses of flexible pavement which were subjected to different axle group loads. Three types of axle group loads, e.g. single axle-dual wheel, tandem axle-dual wheel, and tridem axle-dual wheel, were applied over the field for the instrumented trial section. The corresponding structural responses were measured using a series of embedded instrumentations e.g. pressure cells, asphalt strain gauges, strain gauges, thermocouples, moisture sensors etc. A 3-dimensional (3-D) finite-element analysis (FEA) model and the multi-layer linear-elastic analysis (LEA) were developed to estimate structural responses which were then compared with the field measurement data. Both FEA and LEA assumed the pavement layer materials to be homogeneous, isotropic, and linearelastic. The elastic moduli of pavement layers were determined from the falling weight deflectometer (FWD) based on the backcalculation procedure. Results from the analysis indicated that both FEA and...