Bearing Capacity Of Pavement Research Articles

Impacts of Backcalculation Software Selection on Airport Flexible Pavements Using the Aircraft Classification Rating/Pavement Classification Rating Method

From November 2024, the aircraft classification rating/pavement classification rating (ACR/PCR) method will be accepted by civil aviation authorities to notify the bearing capacity of airport pavements. Structural characteristics are necessary to calculate the parameters relating to this method, such as the modulus of elasticity which, in the case of existing pavements, can be obtained by backcalculation. However, the results of this procedure may vary depending on the type of method and algorithms used to minimize adjustment errors between the deflection basins adopted in the software. Given the above, this article aims to evaluate whether the choice of backcalculation software affects the resistance classification and admissibility of aircraft on airport pavements using the ACR/PCR method based on the backcalculated elastic moduli. The elastic modulus values of the materials from two runways were backcalculated using BAKFAA, BackCAP, BackMedina, and ELMOD software, and then used to calculate the PCR. The results of the backcalculation showed differences in the elastic moduli obtained by the software, mainly in the subgrade. It was found that the backcalculation software used can limit the type of aircraft and the runway resistance. Therefore, the choice of software for backcalculation of deflection basins can influence the results of the ACR/PCR method because of divergences in determining the resistance of the pavement’s bearing capacity and the admissibility of aircraft operations in the analyzed structures.

Comparison between ACN–PCN and ACR–PCR for rigid airport pavement with case study

This technical note analyses the new Aircraft Classification Rating–Pavement Classification Rating (ACR–PCR) system with a case study. The literatures and case studies showed that anomalies exist between results of pavement structural evaluation of rigid airport pavements using the pavement thickness design (PTD) method and the Aircraft Classification Number–Pavement Classification Number (ACN–PCN) method. In some situations, the ACN–PCN system provides a conservative assessment of pavement damage which will likely overestimate the load impact of aircraft with complex gear configuration. The International Civil Aviation Organisation (ICAO) introduced a new system, the ACR-PCR, which applies layered elastic analysis to estimate pavement bearing capacity. Using a case study from an airport in Southeast Asia, the anomalies between the designed pavement bearing strength of the PTD method and the ACN–PCN method were discussed. The ACR–PCR system can provide pavement structural evaluation results that are consistent with the PTD results.

Indicative assessment of the load bearing capacity of artificial airfield pavements

The load bearing capacity of airfield pavements is currently determined with the ACN-PCN method. It should also be noted that existing studies in the discussed area refer only to assessment of the surface’s current technical condition. Due to the above, actions were taken to collect data from the selected airport facilities in order to analyze changes in its parameters over a longer period of time. The measurements were carried out over a period of several years, on the same airport facilities and on the same airport’s functional elements. The obtained results were used to develop a methodology for index airfield pavement assessment and to determine criteria for technical condition assessment. Knowledge of the above parameters allows to determine the APCI index describing the current, comprehensive technical condition of the surface, allowing for forecasting further activities related to its operation.

Integrating Tensometer Measurements, Elastic Half-Space Modeling, and Long-Term Pavement Performance Data into a Mechanistic–Empirical Pavement Performance Model

Pavement performance models (PPMs) are utilized to predict pavement network conditions which is an essential part of any sustainable pavement management system (PMS). The reliability of a PMS and its outputs is proportional to the reliability of the PPM used. This article describes a mechanistic–empirical pavement performance model based on pavement response parameters—strains calculated in the pavement layers measured by tensometers embedded in the pavement surface and verified by calculations in the elastic half-space model and supplemented by empirical data from long-term pavement performance monitoring and accelerated pavement testing. Hence, the herein described PPM combines pavement serviceability evaluation, pavement bearing capacity, and the physico-mechanistic properties of paving materials. The analytical methods which were used to ascertain the physico-mechanistic characteristics, the material fatigue degradation model, and the surface degradation, unevenness in particular, are described. A comparison of the empirical PPM created in the last century used by the national road administrator to this day and the newly created PPM is presented. The comparison shows the difference in the calculated socio-economic benefits and subsequent cost–benefit analysis results. The comparison shows that the use of the old PPM may have produced false economic evaluation results that have led to poor decision making, partially explaining the unsustainable trend of road network management in our country.

Mathematical Modeling of a Corrugated Geogrid and Geocell Reinforced Flexible Pavement Base with Interlayer Shear Performance Analysis

To combat permanent deformation in flexible road pavements and extend lifespan while reducing maintenance costs, an investigated solution "Corrugated Geogrid and Geocell Reinforced Flexible Pavement Base Design" is proposed. It enhances durability by improving inter-layer bonding and increasing the friction coefficient with a Corrugated Imminent Hexagonal Composite Geogrid, boosting pavement bearing capacity. The necessity of this research is the integration of corrugated geogrids and geocells into the design of flexible pavement, in conjunction with a comprehensive evaluation of interlayer shear performance, effectively tackles a range of engineering obstacles and enhances the pavement system's durability, stability, and affordability. Geogrid's corrugated structure resists shoving, offers stabilization, and, combined with Fusion Geoblanket and Perforated Geocell, prevents potholes. Typically, geocellular brace parts are utilized in civil engineering and technical applications, and they are frequently connected to geocellular systems or geocells. These systems are frequently employed in the building of retaining walls, slope protection, erosion control, and soil stabilization. The intended use and product design influence the installation procedures and specific functioning approach. The proposed model prevents permanent pavement failures, ensuring durability, low maintenance, and improved lifespan, assessed through Finite Element Analysis. Thus, the proposed method develops a layout for flexible pavement that's going to prolong its life expectancy and prevent long-term deformation failure.

Reporting the Bearing Capacity of Airfield Pavements Using PCR Index

Airfield pavements are important assets that have to secure the safe operation of an airport. On this basis, assessing and reporting the bearing capacity of an airfield runway pavement is a critical task. Recently, the Aircraft Classification Rating-Pavement Classification Rating (ACR-PCR) system has been introduced, which uses the PCR index for expressing the bearing capacity of an airfield pavement. In order to accurately determine PCR, the mechanical characteristics and the thicknesses of the individual layers of a pavement are required. For this purpose, it is not seldom that in the absence of resources dedicated to detailed pavement evaluation procedures, assumptions for the material characteristics of the pavement considering typical materials may be made, while pavement thicknesses may be derived by pavement design records. The present paper highlights the importance of using Non-Destructive Testing (NDT) for accurately assessing the in-situ condition of a flexible runway pavement and determining the PCR index. In order to achieve the goal of the investigation, measurements were performed along the flexible pavement of an airport runway. In addition, the paper focuses on the impact of the variation of the thickness and of the mechanical characteristics of the asphalt concrete layers on the PCR index and on the interpretation of the results considering the acceptance of aircraft operations by airport authorities.

Load-Bearing Capacity Assessment of Traffic Superstructures for Roads and Tramways

The load-bearing capacity of traffic superstructures is usually assessed based on deformation measurements. The bearing capacity is defined as the superstructure’s resistance to short-term deformations. However, different measurement concepts and evaluation methods are required for different superstructures to assess the bearing capacity. Therefore, this paper will present various methods for road and tramway superstructures and illustrate them with practical examples.The bearing capacity of road pavements is typically assessed by deflection measurements using the falling weight deflectometer (FWD). This dynamic measurement method applies a falling weight to the road surface, and the resulting deflection basin is recorded briefly. This can then be evaluated. Evaluations of various measurements in Germany are presented.The assessment of load-bearing capacity in the tramway sector is not currently established in German regulations. An individual measurement concept was developed and applied to assess the load-bearing capacity in urban transportation. The measurements aimed to determine the in-situ deformations of the grooved rail with a selected type of fastening during the passing of trams. In addition, the serviceability during operation was checked. The measurements were carried out on an open construction (grass track) and a closed construction (asphalt), as well as in tight curves and on straight track sections. Based on the deformations determined, conclusions can also be drawn about the service life.

Rigid layer depth setting method based on the uniformity of the backcalculated subgrade modulus

Modulus backcalculation using falling weight deflectomer (FWD) non-destructive testing data is an important technique for evaluating the structural bearing capacity of pavements. During the backcalculation process, the rigid layer setting depth has a great influence on the results. Hence, the rigid layer depth should be accurately set. In this study, a new rigid layer depth setting model was established by layer-by-layer detected deflections from a full-scale testing road. First, the reason for the inconsistency in the backcalculated subgrade modulus based on the detected deflections was determined by analyzing the surface deflections of the subgrade layer under different load levels. Then, a new rigid layer depth setting model named equivalent thickness method was established on this basis. Finally, a comparative analysis with other rigid layer depth setting methods was carried out. It was found that the inconsistency of the backcalculated subgrade modulus was due to the unreasonable rigid layer setting depth, and the rigid layer depth could be determined by setting the total equivalent thickness of the pavement as a certain value. The comparative analysis revealed that the equivalent thickness method significantly reduced the variability and improved the conformance of the backcalculated subgrade modulus rely on the layer-by-layer deflections.

Impact of remolded soil fabric on the volumetric deformation behavior of clayey soils

The volumetric deformation of clayey soils, leading to a reduction in the bearing capacity and serviceability of pavements and building structures, is a major concern during their design, construction, and maintenance. Several approaches are often followed to mitigate the volume expansion and concomitant damage, including removal and replacement, moisture treatment with appropriate compaction protocols, and chemical treatment. During these treatment processes, the in-situ fabric is altered as the natural undisturbed soils are remolded and compacted. Hence, it is crucial to understand the effect of remolding on the volumetric characteristics of clayey soils. To investigate this effect, coefficient of linear extensibility (COLE) tests were conducted on both natural and remolded soil samples. The objective was to evaluate the impact of soil fabric modification on volumetric characteristics such as suction compressibility index (γh) and soil water-retention characteristics, i.e., the soil–water characteristic curve (SWCC) of clayey soils. Our findings indicated that remolded soils had approximately 10% to 30 % higher γh-values than those of unaltered soils, which can be attributed to changes in porosity. Two distinct mechanistic models were developed using the packing theory concept to link the γh-value and SWCC of remolded and natural soils. Finally, an analysis was conducted to compare the potential vertical movement (PVM) of natural and remolded clay soils. This analysis revealed that the remolded soil fabric substantially increased the PVM values, particularly for high-plasticity clay soils. This effect should be considered when assessing the impact of treatment that requires remolding, which substantially alters the soil structure and fabric.

Influence of Spring Stiffness on the Loading Speed of the Falling Weight Deflectometer (FWD) in Bearing Capacity Evaluation of Cement Concrete Pavement

Introduction: The bearing capacity evaluation of cement concrete runway pavement is one of the most important contents in the airfield operation. Among the methods for estimating bearing capacity, the Falling Weight Deflectometer (FWD) is the most widely used method because it does not damage the pavement structure and spends so much time. The equipment for evaluation should have suitable parameters, such as. magnitude and loading speed, to the actual operating loads. Aims and Objectives: Currently, the equipment to assess the bearing capacity of cement concrete pavements of highways and airports by falling weight has been widely used in the world and is being applied in Vietnam. The loading system consists of a falling block through a spring system acting on the pressure plate under the pavement with a certain falling height. In particular, the spring system plays an important role in controlling the speed of the load on the pavement. In Vietnam, the test standards (Industry Standard 22TCN335-06, Vietnamese Standard TCVN 11365-2016) for assessing the pavement bearing capacity by FWD equipment do not specify the selection of spring stiffness corresponding to different operating speeds of the vehicle. Therefore, it is difficult to use the equipment for pavements with operating speeds different from the standard. In this paper, we study the effect of spring stiffness on the loading speed when considering different loading speeds corresponding to different speeds of vehicles moving in reality. This research is only limited to laboratory experiments. This study aims to determine the dependence of the loading magnitude and loading time on the damping spring stiffness of the dynamic loading equipment, that is, used as a basis for choosing the appropriate damping stiffness of FWD corresponding to actual vehicles. Methods: Among the methods for estimating the bearing capacity, the Falling Weight Deflectometer (FWD) is the most widely used method as it does not cause any damage to the pavement structure and spends much time. The equipment for evaluation should have suitable parameters, such as magnitude and loading speed, to the actual operating loads. Results: This paper presents the results of experimental research that determines the influence of the damping spring stiffness on the loading speed of the dynamic loading equipment on the model of the concrete slab in the laboratory. Conclusion: Based on the comparison of the FWD loading speed when using 02 damping springs with different stiffness, we propose the basis for choosing the damping system that conforms to the evaluation needs of different types of vehicles.

Mechanical Properties of Slag-Based Geopolymer Grouting Material for Homogenized Micro-Crack Crushing Technology

Homogenized micro-crack crushing can fully retain the bearing capacity of concrete pavement, but local weak road base needs to be reinforced before being directly overlaid with hot-mixed asphalt. Therefore, indoor tests were conducted to study the mechanical properties of slag-based geopolymer as a grouting material for weak road base, and the morphology and influence of polymerization reactants were observed. Concurrently, on-site grouting tests were conducted to study the grouting effect. The results show that the compressive strength, flexural strength and bonding strength of slag-based geopolymer all increase with age. The maximum compressive strength and flexural strength of the geopolymer at 28 d were 18.88 MPa and 6.50 MPa, respectively. The maximum flexural bonding strength at 14 d was 4.58 MPa. As the ratio between water and slag powder increased, the compressive strength and flexural strength gradually decreased, while the bonding strength first increased and then decreased. In the range of ratios of water to slag powder from 0.26 to 0.28, the above three strengths were relatively high, and the compressive shear bonding strength was the highest when the ratio of water to slag powder was 0.28. The shrinkage of the slag-based geopolymer increases with the increase in ratio of water to slag powder, and the porosity also increases, resulting in a decrease in compactness after consolidation. When the ratio of water to slag powder was 0.28, the reactant was mainly a gel-phase material, and the shrinkage crack of the consolidated geopolymer was relatively small. After grouting the weak road base of the concrete pavement, the voids at the bottom of the concrete pavement slab were effectively filled, and the deflection of the pavement slab was significantly reduced. The average deflections of monitoring line I, monitoring line II and monitoring line III decreased by 49%, 41% and 54%, respectively, after grouting. After solidification, the slag-based geopolymer was distributed in layers, which further compacted the road structure layer and improved the bearing capacity.

ANALYSIS OF THEORETICAL BASIS FOR ASSESSING THE BEARING CAPACITY OF AIRPORT CEMENT CONCRETE PAVEMENT IN VIETNAM BY THE DYNAMIC DEFLECTION EQUIPMENT

This article presents the theoretical basis of the backcalculation method for determining the bearing capacity of the airport cement concrete pavement on the basis of the deflection data obtained in the field and the calculation results according to specialized software of the dynamic deflection equipment. Through experimental data of measuring actual deflection at taxiway S in Tan Son Nhat airport, compare the calculated bearing capacity according to the backcalculation theory and outputted value from the software has an error of 4% to 7%. It can be seen that, the backcalculation method of bearing capacity in cement concrete pavement according to the theory of multi-layer system structure gives similar results with the results calculated according to the specialized software of dynamic deflection equipment. The research results serve as the basis for evaluating the ability to use the existing dynamic deflection equipment in the world, for assessing the bearing capacity of the airport cement concrete pavement in the conditions of Vietnam.

On the variants of SVM method for the estimation of soil elastic modulus from TSD model: Numerical parametric study

The accurate estimation of the subgrade resilient modulus MR is a crucial element in designing durable and resilient pavements as it quantifies the soil’s bearing capacity to withstand traffic loads without excessive deformation or failure. Conventional methods and devices that are used to estimate MR, such as the Falling Weight Deflectometer (FWD) have several limitations due to operational and security constraints when measuring at the network level. To overcome these limitations, Traffic Speed Deflectometer (TSD) has been developed, which can continuously assess the pavement bearing capacity without requiring traffic control. However, processing the massive amounts of data generated by TSD requires specialized processing techniques such as Machine Learning (ML). Therefore, the primary objective of this paper is to develop an efficient and effective model that can accurately estimate MR by combining two techniques: (TSD + ML). The study uses numerical simulations of deflection velocity slope SV under TSD as the forward model. The research employs Support Vector Machine (SVM) algorithm for ML to classify and estimate MR modulus values from a synthetic and controlled dataset. SVM model exhibits robust performance in both classification and regression analysis, whereas, 95% of the discrepancies between estimated and tested values did not exceed ±15MPa. Advanced numerical validation, sensitivity analysis and parameter estimation methods were also conducted to optimize the model’s performance. Overall, the approach proposed in this paper has the potential to make a significant impact in the field of subgrade evaluation and can facilitate the development of better road infrastructure.

Evaluating the use of machine learning for moisture content prediction in base and subgrade layers

Subgrade moisture content significantly influences soil strength and pavement bearing capacity. Pavement moisture content varies greatly throughout the year, especially in cold regions. Thus, having a better understanding of seasonal variation in moisture content in the pavement is needed to be developed. This research aims to apply machine learning models to predict the moisture content of unbound materials in the pavement. Unfrozen volumetric moisture content measurements recorded at the Integrated Road Research Facility test road in Edmonton, Alberta were used to train machine learning models to predict moisture content at depths within 2.7 m of the road surface. Machine learning models were implemented based on three parameters of pavement temperature, day of the year and depth. The results from the machine learning model were compared with a statistical model and showed higher accuracy than the existing model, indicating that machine learning models could enhance moisture content prediction in the pavement.

Можливості стандартних методів випробування дорожніх одягів навантаженням

The standard methods for testing road pavements by loading have been widely applied to assess the road pavements maintenance during design, construction and survey stages and especially for the Pavement Management System purposes. These test methods were classified by the type of an applied load as static loading, cyclic loading or impulse loading tests. The paper reviews the above mentioned test methods from the aspects of their scopes, advantages, and general requirements for testing in accordance with the world-wide experience in road building industry. Static loading shall be positioned as the simplest and low-cost test method that permits the testing of relatively thick pavement constructions but does not allow the measurements of deflection bowl. Cyclic loading is more convenient for thinner pavements testing and, together with surface moduli, permits the measurements of deflection bowl. Impulse loading is the most representative test method that simulates traffic loading most adequately and permits the deflection bowl measurements as well. Impulse load can be applied using “high-weigh” device such as falling weight deflectometer, or light weight deflectometer thus given the possibility for testing road pavements with a monolithic upper layer or an unbound layer (base layer, sub-base, sub-grade layer). Standard methods for testing road pavements by loading were widely implemented to measure the surface moduli, the deflection bowl values and also, for rigid pavements, the load transfer efficiency in an area of joint or crack. Surface moduli and deflection bowl values are effectively used, mainly through the back-calculation processes, to assess the stiffness of pavement layers, the life span of road pavements and also for the project or network level testing of road pavements. These tasks rise as high actual for Ukraine intended to be integrated in the EU transport system, where trucks weighing up to 40 tonnes are permitted for international hauling. Considering the necessity for expansion of network level testing to assess the bearing capacity of road pavements and to set restrictions for trafficking at some critical conditions especially seasonal those, the conclusions state the need to process related national standards as national normative documents aiming on: – implementation of standard international classification of methods for testing the road pavements by loading considering the type of loading; – widening the requirements for proceeding of tests; – improvement the pavement management system. Keywords: road pavement; non-destructive testing; static loading; cyclic loading; dynamic loading.

Prediction of Primary Deformation Modulus Based on Bearing Capacity: A Case on Forest Road with a Light Falling Weight Deflectometer Zorn ZFG 3000 GPS

Bearing capacity and compaction are among the most important and frequently used geotechnical parameters in road construction. The aim of this study was to determine the possibility of predicting the value of the primary deformation modulus E1 (obtained from measurements using a static plate load test—PLT) based on measurements with a Zorn light falling weight deflectometer (LFWD), type ZFG 3000 GPS, with a drop weight of 10 kg. A regression analysis was performed on 245 bearing capacity measurements that were taken on 46 forest road sections with various road surfaces. Different regression models were tested, from linear to logarithmic, polynomial, exponential and power models, but excluding polynomials of fourth and higher degree. The results showed that the prediction of E1 values (PLT) from the dynamic deformation modulus values Evd (LFWD) was possible. However, the reported unsatisfactory strength of the relationship between the two parameters was associated with a high risk of error (r = 0.64, R2 = 0.41, Se = 49.78). Neither the use of more complex non-linear regression models, nor the use of multiple regression by introducing an additional estimator in the form of the s/v ratio, significantly improved estimation results. The quality of the prediction of the E1 value was not constant. It varied, depending on the type of forest road, the use of geosynthetic reinforcement and the type of road subgrade. During the study, it was also found that the quality of the prediction of the E1 value could be improved by limiting the range of Evd values tested from above. It is advisable to continue this type of research, as the obtained results could form the basis for future development of national standards for the use of LFWDs to control the bearing capacity and compaction of forest road pavements.

Toward Asphalt Pavement Health Monitoring With Built-In Sensors: A Novel Application to Real-Time Modulus Evaluation

Modulus is a critical parameter for evaluating the bearing capacity and remaining life of pavements. The prevalent modulus back-calculation method by using the pavement surface deflections captured from falling weight deflectometer (FWD) could characterize the overall bearing capacity of pavements. However, a non-uniqueness issue may occur when identifying the modulus of each layer from the perspective of mathematics. Alternatively, this paper presents a novel application to real-time modulus evaluation based on asphalt pavement health monitoring with built-in sensors. First, the sensor layout is optimized on the basis of the theoretical relationship between modulus and mechanical response inside the pavement. The proposed sensor layout, including input (random loads), output (mechanical responses), and environmental sensing modules, is illustrated in detail. Then, the procedure for real-time modulus evaluation is proposed, and the convergence and uniqueness of modulus evaluation results are investigated. Lastly, a case study of the realistic asphalt pavement health-monitoring system is conducted to demonstrate the effectiveness of the application to real-time modulus evaluation. The results indicate that the proposed modulus evaluation method has a potential to identify the modulus of each pavement structural layer in real time with a convergent and unique solution under a realistic traffic load. The evaluation process has the advantage of not interfering with traffic compared with the prevalent FWD-based modulus evaluation method. The pavement health monitoring with built-in sensors is recommended for newly built roads to facilitate long-term real-time performance assessment and maintenance decision making.

Preliminary evaluation of the ACR-PCR system for reporting the bearing capacity of flexible airfield pavements

Assessing and reporting the bearing capacity of airfield pavements have always been significant tasks in airport engineering, since they support the decision making procedure, which is a core element of Airport Pavement Management Systems (APMS). The official reporting system utilized worldwide during the last four decades is the Aircraft Classification Number – Pavement Classification Number (ACN-PCN) system. However, recently an updated system has been introduced, aiming to overcome the defects of the ACN-PCN system that have been observed during its implementation. This system, referred as the Aircraft Classification Rating – Pavement Classification Rating (ACR-PCR), aims to incorporate the latest advances in airfield pavement design and evaluation and is expected to be fully applicable about 2024. Since this is a transfer period, the current investigation aims to identify any critical aspects arising from the application of the updated system, based on recent Federal Aviation Administration (FAA) airfield pavement evaluation techniques. On this basis, the transferability between the two system is examined, providing useful commentary and remarks for airport authorities, who would like to implement the ACR-PCR method to its full extent. The analysis shows that the transferability between the two systems seems not to be feasible and the implementation of the updated ACR-PCR may present several issues, such as the modification of the existing reported bearing capacity.

Stiffness identification method for asphalt pavement layers and interfaces using monitoring data from built-in sensors

The bearing capacity of asphalt pavement gradually deteriorates due to repeated traffic loads. As the crucial mechanical index to evaluate the bearing capacity, the evolution of the stiffness of pavement layers and interfaces is necessary to be mastered. This paper proposes a stiffness identification method for the asphalt pavement layers and interfaces by using monitoring data from built-in sensors. First, the analytical solution of multi-layered elastic/viscoelastic medium with imperfect interlayer subjected to moving load is derived, and the theoretical relationship between stiffness and mechanical response can be obtained. The sensor layout is optimized on the basis of the theoretical relationship. Then, the stiffness identification method is developed, and its feasibility is theoretically explored through an example of three-layered elastic/viscoelastic medium. Finally, the proposed stiffness identification method is applied to a realistic asphalt pavement to validate its reliability. Results show that the proposed method can evaluate the stiffness of pavement layers (including elastic and viscoelastic properties) and interfaces. It is noteworthy that the stiffness identification method by using monitoring data from built-in sensors can be performed in real-time under each passing vehicle load, and is helpful to understand the damage behavior of pavement and guide maintenance decision-making.

Orthogonal Set of Indicators for the Assessment of Flexible Pavement Stiffness from Deflection Monitoring: Theoretical Formalism and Numerical Study

The monitoring of pavements along roads is generally based on the use of indicators directly derived from measurements. More specifically, the bearing capacity of pavements is often simply deduced from either the maximum deflection value measured or the difference between two measured values along the deflection basin. This paper proposes a methodology to define a set of orthogonal indicators adapted to the structure being evaluated. This methodology is presented for deflection measurements recorded on a flexible pavement simulated by the Burmister model and consists of searching the weighting functions to calculate different indicators as linear forms of the deflection bowl. Weighting functions are defined for each indicator in order to maximize its sensitivity to a given structural parameter without being sensitive to the other structural parameters. The paper presents the various steps involved in constructing the indicators. A numerical example of an application shows that variations of each indicator follow the Young’s modulus variations specific to this indicator. Several extensions of this method are also introduced for other mechanical models or instrumented pavements.