Pavement Test Research Articles

The application of tuned mass dampers to the Tire Pavement Test Apparatus to minimize the impact of rig resonance

The 'Tire Pavement Test Apparatus (TPTA)' at Purdue University is a device that was originally developed to study a tire's air-borne noise radiation in the frequency range 300 Hz to 2 kHz. However, in recent years, the device has mainly been used to quantify a tire's contribution to structure-borne noise by measuring the force and acceleration at the hub. Hence, the frequency range of interest has shifted to frequencies below 300 Hz. By comparing measurements and FE simulations, undesired vibration was observed around 160 Hz in the measurement data. It was speculated that the rig supporting the tire exhibits resonant vibration in a frequency range that hinders the measurement of tire force in that range. To identify the cause and mechanism of the rig resonance, Experimental Modal Analysis (EMA) was performed. In addition, to mitigate the influence of rig resonance, tuned mass dampers commonly used in vehicle suspension systems were applied to the connecting arms of the TPTA. Careful adjustments of their mass and stiffness were performed to maximize vibration suppression performance by matching the major natural frequency of the TPTA support arms. As a result, significant vibration attenuation could be achieved, which has made it possible to highlight the pure tire effects in the measurement data.

Accelerated Pavement Testing Validation of a Pavement Response Model Using Three-Dimensional Finite Element Analysis Software: Two Case Studies

Accelerated pavement testing (APT) provides valuable information concerning the short- and long-term performance and life expectancy of pavement structures in a very short period as compared to full-scale field tests. Pavement modeling can produce early, reliable, and beneficial guidance that can be used to design and implement future APT experiments or extend the experimental results to similar materials and structures. Combining actual APT experimental data with well-calibrated models can provide complete and thorough investigations while saving agencies time and resources. The main objective of this study is to evaluate the effectiveness and accuracy of the 3D-Move Analysis Software (three-dimensional finite element software [3D FE]) in calculating pavement responses through a comparison with measured pavement responses and distresses from previous APT experiments using the Florida Department of Transportation heavy vehicle simulator (HVS). 3D-Move uses a continuum-based finite-layer approach to calculate pavement responses under various loading conditions. Results indicated that pavement responses, specifically longitudinal horizontal (tensile) strains at the bottom of the asphalt layer and transverse horizontal (tensile) strains at the surface of the asphalt layer, calculated by 3D FE are relatively similar to those measured in APT experiments. The calculated impact of the asphalt mixture properties, loading level, loading temperature, and the distance (offset) from the tire edge on pavement responses was consistent with those measured in HVS testing. Therefore, 3D FE analysis can be effectively used to compare the relative cracking performance of asphalt mixtures and aid in designing practical APT experiments and extending the results to similar asphalt mixtures and pavement structures.

Dynamic Strain Response of Hot-Recycled Asphalt Pavement under Dual-Axle Accelerated Loading Conditions

Accelerated pavement testing (APT) is an effective method to study the long-term performance of pavement. Therefore, the dynamic strain behavior analysis of asphalt pavement has important guiding significance in the study of pavement failure modes. To explore the dynamic response of a high-content plant-mixed hot-reclaimed asphalt mixture under a dynamic load of vehicles, a full-scale test road was paved, and ALT biaxial accelerated loading test equipment was used to simulate the dynamic loads of vehicles. Based on parameters such as axle load, temperature, speed, and loading times, the development law for the bottom strain of the three pavement structures was analyzed. The test results show that the most unfavorable position of the asphalt pavement load is located just below the centerline of the wheel track on one side, and the damage effect of a single double-axle wheel load is far greater than that of two single-axle wheel loads. Then, the longitudinal tensile strain of the pavement bottom always maintains the alternating state of compression-tension and compression. The longitudinal tensile strain of the pavement bottom is larger than the transverse tensile strain, and transverse fatigue cracks appear first. Under normal temperature conditions, the bottom tensile strains of the three composite pavement structures under different axial loads are close, and the pavement performance of the hot-recycled asphalt pavement of structure A and structure B can meet the specification requirements. The relationship between the bottom strain and axle load is nonlinear and is directly related to the tire ground pressure, and the difference in the tensile and compressive strain values of the bottom of the three composite pavement structures is small. Under high temperature conditions, the bottom layer temperature of structure A and structure B is lower than that of structure C, and the thermal heat transfer efficiency of hot-recycled asphalt pavement is lower than that of ordinary asphalt pavement. Additionally, the longitudinal tensile strain is about 1–1.5 times that of the transverse tensile strain. Based on the Boltzmann function, the accumulative tensile strain prediction model was established to reflect the relationship between the cumulative strain at the bottom and the number of loads.

Assessment of pavement deflection under vehicle loads using a 3D-DIC system in the field.

This study aims to introduce the use of 3D-digital image correlation (DIC) to the in situ testing of pavements and to support the development of techniques for a rapid evaluation of the conservation status of existing roads. Little research was found on this topic. The passage of a car wheel on an asphalt pavement was adopted as a case study. The DIC measurements were compared to those gathered by contact sensors. From a qualitative point of view, the DIC measurements captured the realistic shape of a deflection basin. From a quantitative point of view, the deflection values provided by the DIC system had a mean error of 0.015 mm and a standard deviation of 0.011 mm. At the moment of highest load, these errors had a mean value and standard deviation of − 0.016 mm and 0.021 mm, respectively. Thus, to improve the accuracy of the system, we propose modifying the camera support, speckle pattern, and control of natural light.

Accelerated evaluation of membranes for pavement structures on orthotropic steel bridge decks

ABSTRACT Membranes of sufficient bonding characteristics could improve the integrity of the multi-layer structures on orthotropic steel deck bridges (OSBDs), enhancing thus the structural response of these systems and, ultimately, their service life. In this research, full-scale experiments were performed at the LINTRACK accelerated pavement testing facility of the Delft University of Technology to evaluate the performance of two surfacing systems commonly used in the Netherlands, giving emphasis on assessing the interface response of membranes with the surrounding materials. Results indicated that the tensile strains remain almost uniform at the top of porous asphalt, in both transverse and longitudinal directions, as no appreciable loss in stress-carrying capabilities was seen even at the end of the testing program. The sections exhibited similar behaviour in terms of strains, with some differences in strains indicating the impacts of membranes at interfaces. The importance of membranes of the desired bonding characteristics was also reflected by the relative displacement measurements. The relative interlayer slip had been higher in the transverse direction than the longitudinal one, with slightly higher displacements in one of the test sections. Overall, no cracking was observed on either section, and the current findings support the use of membranes between surfacing layers on OSBDs.

A study of artificial debond pavement under controlled traffic by Ground Penetrating Radar

This study utilized high-frequency Ground Penetrating Radar (GPR) with a center frequency of 2600 MHz to monitor the critical geometric changes of debonding in a road pavement. The pavement was under repetitive traffic loadings up to 80,000 cycles tested in the accelerated pavement testing (APT) facility inUniversité. Gustave Eiffel, Nantes, France. The debond zones (i.e. loss of contract between layers) were artificially made of sand infill, geotextiles and absence of tack coat between bitumen layers. GPR amplitude ratio test (ART) and time-frequency analysis (TFA) were adopted to study changes of each debond zone under an increment of loading cycles. The results show that an increase of the loading cycles leads to an increase of the normalized amplitude and the shift of the center frequency of the reflection to a lower regime. The analysis appears to be a good indicator to monitor the geometrical changes of debond zones undergoing various traffic loadings, and can be turned to be a useful tool for diagnosis of pavement debond behavior, and maintenance of the pavement before any damages become visual.

Long-Term Performance of Flexible Pavements Constructed on Recycled Base Layers

There has been an increased interest in using reclaimed asphalt pavement (RAP) aggregates as a base course in Wisconsin for the offered economic and environmental benefits. Laboratory studies showed that RAP can have resilient modulus values higher than typical natural aggregates, and can also have higher durability, especially in freeze–thaw cycles. However, it is also recognized that RAP exhibits temperature sensitivity and larger permanent deformations than natural aggregates. How these characteristics manifest themselves in the northern U.S. climates can only be assessed by long-term observation of field performance. Wisconsin Department of Transportation (WisDOT) has been using RAP as a base course for over 30 years. The qualitative assessment of WisDOT roads constructed with RAP showed they are performing adequately. However, this impression has not yet been verified quantitatively. This paper presents a quantitative assessment and comparisons for field performance of pavement test sections constructed with RAP and natural crushed aggregate (CA) base course layers in Wisconsin. The performance was evaluated using pavement distress surveys of roadways containing RAP and CA, falling weight deflectometer (FWD), dynamic cone penetrometer (DCP) tests, and analysis of WisDOT’s available data. Based on the field evaluation, the performance of the hot mix asphalt (HMA) pavements with RAP was found adequate and comparable to those with CA base course layers. A recommendation was given that WisDOT shall continue the practice of using RAP in base course layers of HMA pavements, given proper quality checks for materials, and proper quality control/quality assurance measures being applied during construction.

Three-dimensional finite element analysis for structural parameters of asphalt pavement: A combined laboratory and field accelerated testing approach

To solve the issues that material parameters measured under specific laboratory conditions are extremely different from the actual pavement, a method of structural parameters correction in semi-rigid base asphalt pavement combining numerical simulations, laboratory tests, and accelerated pavement testing (APT) was proposed. The dynamic modulus and the uniaxial static compression creep tests were conducted to explore the effect of temperature, size, and fatigue. Then, these factors were coupled to the modified Burgers model that can reflect the creep law of the whole process. A constitutive model reflecting the real parameters of the pavement was subsequently constructed with the ABAQUS user-defined material (UMAT) subroutine. Experimental results illustrated it was verified that the modified subroutine has good feasibility both in single-layer and multi-layer materials from the actual pavement. Furthermore, simulated results also showed excellent agreement with field-tested findings. Finally, the rutting deformation curves and the demarcation points of each stage were obtained, which could guide the rutting prediction and maintenance decision of semi-rigid asphalt pavement.

Comparison of Relative Structural Characterization Methods for Additive-Modified Asphalt Mixtures

The evaluation, adoption, and efficient deployment of asphalt additives in flexible pavements has historically been a relatively slow process, requiring years of testing and evaluation before a new product may be fully and readily used in pavement cross-sections. However, the fast-paced and innovative nature of the additive marketplace produces numerous products that have the potential to improve performance, reduce costs, or both, but have been hindered by slow deployment. To address the need for a more rapid set of evaluation tools, the National Center for Asphalt Technology Test Track initiated an Additive Group experiment in 2021 to build full-scale pavement test sections modified with several asphalt additives, including recycled tire rubber, recycled plastics, reactive polymers, and aramid fibers. Data will be collected from these test sections to develop a framework for evaluating asphalt additives in the future. Phase 1 of the investigation was to conduct limited laboratory testing and structural analysis from which a group of additives would be selected for full-scale construction and evaluation. Focused on fatigue cracking, this paper details the laboratory testing conducted for Phase 1 and two different structural pavement analysis methods using FlexPAVE™ and WESLEA. Even though the two structural pavement analysis methods are very different, the FlexPAVE and WESLEA analyses provided strongly correlated predicted cracking performance, remarkably similar predictions of equivalent pavement thicknesses, and nearly identical structural layer coefficients. It is recommended that these two approaches be further evaluated against laboratory and field performance data that will be collected from the Additive Group experiment.

Integrating Deterministic and Fuzzy Concepts into the Benefit–Cost Analysis of Wyoming’s Proposed Pavement Testing Track Facility

Integrating Deterministic and Fuzzy Concepts into the Benefit–Cost Analysis of Wyoming’s Proposed Pavement Testing Track Facility

Investigating the Influence of Joint Reinforcements of Portland Cement Concrete Slabs Under Asphalt Concrete Overlays on Vertical Deflections Using Accelerated Pavement Testing

Joint gaps between slabs in underlying Portland cement concrete (PCC) pavements are critical factors in the life span of asphalt concrete (AC) overlays. Therefore, being informed about the vertical deflections that may occur around the joints is important. In this study the joints were reinforced with three different materials: ethylene propylene diene monomer (i.e., rubber joint filler [RJF] reinforcement), bitumen-based sealant (i.e., rubber plate [RP] reinforcement), and steel plate (SP) (i.e., SP reinforcement), to limit the vertical movement of the underlying PCC. Tests were conducted at the accelerated pavement testing facility for two different AC overlay thicknesses, 50 mm and 100 mm, during 100,000 passages to investigate the influence of AC overlay thickness variations on slab vertical deflections and to also evaluate types of joint reinforcement on slab vertical deflections. For 50-mm thick AC overlay, the most effective joint reinforcements to prevent deformations caused by loading were RP, RJF, and SP; for a 100-mm thickness, this was determined to be RJF, SP, and RP, respectively.

Plastic strain rate in granular materials as a function of stress history: a probabilistic approach for the PBD model

ABSTRACT The permanent deformation of granular materials is an important indicator in making decisions associated with the traffic of superheavy vehicles on pavements. The PBD model, a recently developed mechanistic-empirical model, analyzes the effect of superheavy load vehicles using the plastic strain rate as an indicator. The plastic strain rates of materials subjected to repeated cyclic stresses are defined by two states: (1) the post-compaction phase and (2) the shakedown state, with a probable range of permanent deformation being defined from each of these states. This paper explores the limits of applicability of the PBD model at different times in the stress history of granular materials. An accelerated pavement test with typical pavement structures from Quebec (Canada) is used as a reference. The changes in the plastic strain rate to variables related to the stress history in the granular material were studied, and a probabilistic relationship is proposed to improve the analytical predictions of the PBD model.

Evaluating the potential of using foamed concrete as the insulation layer for pavements in cold regions

Insulated pavement structures help prevent frost penetration and its negative impacts on roadways and airfields in cold regions. The most commonly used insulating material in pavements is extruded polystyrene (XPS) boards. However, the utilization of XPS boards has several unavoidable drawbacks such as degradation due to long-term moisture infiltration. For this reason, there is an increasing interest to explore alternative materials such as tire chips, bottom ash, and foamed glass aggregates as the insulation layer. This paper aims to evaluate the potential of using foamed concrete as an insulation layer. To achieve this goal, a thermo-mechanical (TM) coupled model was developed to simulate the responses of insulated pavement with a foamed concrete insulation layer. In addition, the compressive strength and thermal conductivity of different densities of foamed concrete were tested to provide the material parameters for the developed model. The model was then calibrated by a large-scale insulated pavement test. The calibrated model was used for a parametric study to reveal the influence of the thickness, depth, and density of the foamed concrete layer on the thermal and mechanical performance. Simulation results show that the developed model can accurately predict the thermal performance of insulated pavements. Compared with the performance of uninsulated pavements, the foamed concrete -insulated pavement has better performance in resisting frost effect and traffic loading. The parametric study also found that a minimum thickness exists for a foamed concrete insulation layer to ensure the subgrade layer is unfrozen. Increasing the thickness, depth, and density of a foamed concrete layer enhances its mechanical performance.

Exploring lessons learned from partnerships to establish a regional accelerated pavement testing facility in Wyoming

ABSTRACT A foremost accelerated pavement testing (APT) test road facility is proposed along interstate 80 for the dry-freeze climate by the Wyoming Department of Transportation (WYDOT). A survey was undertaken among states and industries in the region as part of the feasibility study to identify research needs and interests in the test road project. This paper summarises the responses of the survey and lessons learned from the experiences of 3 APT test road facilities in the U.S. Respondents perceive the APT to be relevant and critical to the study and state-of-practice of pavement engineering. Respondents’ research needs include local calibration for the mechanistic-empirical (ME) pavement design, pavement preservations alternatives, and recycled materials for pavements. The presented information and the lessons learned will guide future APT programmes at the planning stage on nurturing partnerships and avoiding the mistakes of earlier APTs to minimise the wastage of scarce resources.

Development of a Fatigue Damage Model for Roller Compacted Concrete Pavement Based on In Situ Saw-Cut Beams and Accelerated Pavement Performance

As a durable, economical, and low-maintenance concrete material, roller compacted concrete (RCC) is steadily becoming the preferred choice for many pavement applications. However, the fatigue models in current pavement thickness design procedures have generally been found to over-predict the RCC pavement fatigue damage under in situ heavy truck loading. In this study, a comprehensive beam fatigue test experiment was performed using field saw-cut RCC slab samples from two full-scale accelerated pavement testing (APT) sections to investigate the fatigue behavior of in situ RCC pavements. This is the first research study to investigate the fatigue behavior of field RCC beam samples prepared and constructed with a high-density asphalt-type paver and a vibratory roller. The results indicate that a well-compacted RCC pavement can achieve higher flexural strength and exhibit better fatigue life than conventional concrete pavement. Based on the beam fatigue test results and in situ fatigue performance of APT test sections, an RCC fatigue-life model was developed, providing a more accurate solution for estimating the allowable number of load repetitions of RCC pavements subjected to vehicular fatigue loading. This model could be used in RCC thickness design procedures to determine the optimum RCC design thickness and long-term fatigue performance of RCC pavements for roadway application.

Validation of Compaction of Bituminous Mix in Roller Compactor cum Rut Analyser (RCRA) For Performance Based Pavement Testing and Mix Design

Abstract: Validation is one of the most important criteria in any research work. Any equipment needs to be validated with wellestablished and known methods. In this research work, an indigenously developed equipment called Roller Compactor cum Rut analyser (RCRA) is validated to ascertain that the required compaction is achieved. Keywords: Marshal Method, Bituminous mix, Roller Compactor cum Rut Analyser, Density

Towards a sustainable monitoring: A self-powered smart transportation infrastructure skin

Sustainable monitoring of traffic using clean energy supply has always been a significant problem for engineers. In this study, we proposed a self-powered smart transportation infrastructure skin (SSTIS) as an innovative and bionic system for the traffic classification of a smart city. This system incorporated the self-powered flexible sensors with net-zero power consumption based on the Triboelectric Nanogenerator (TENG) and an intelligent analysis system based on artificial intelligence (AI). The feasibility of the SSTIS was tested using the full-scale accelerated pavement tests (APT) and the long-short term memory (LSTM) deep learning model with a vehicle axle load classification accuracy up to 89.06%. This robust SSTIS was later tested on highway and collected around 869,600 pieces of signals data. The generative adversarial networks (GAN) WGAN-GP (Wasserstein GAN - Gradient Penalty) was used for data augmentation, due to the imbalanced data of different vehicle types in actual traffic. The overall accuracy for on-road vehicle type classification improved to 81.06% using the convolutional neural network ResNet. Finally, we developed a mobile traffic signal information monitoring system based on cloud platform and Android framework, which enabled engineers to obtain the vehicle axle-load information mobilely. This study is the emerging design and engineering application of the self-powered flexible sensors for smart traffic monitoring, which provides a significant advance for intelligent transportation and smart cities in future.

Long-Term Performance of Recycled Asphalt Pavement with Recycled Engine Oil Bottom Based on Accelerated Loading Test

The practical performance of recycled asphalt obtained from recycled engine oil bottom (REOB) was evaluated by paving a test road of base asphalt and REOB-recycled asphalt mixture in a laboratory, where accelerated loading tests with 700,000 cycles were conducted. During accelerated loading, pavement temperature, layer bottom strain, pavement skid resistance, and rutting were monitored. The performance of pavement core material was tested after loading to analyze the index change of binder and the compaction degree of the mixture. The results show that the long-term anti-rutting ability of REOB-recycled asphalt pavement is approximately 10% higher than that of the base asphalt pavement, although the long-term anti-sliding force and anti-fatigue performance are poor. A developed model of rut with loading time can better predict the development trends of these parameters with loading cycles. The performance test of the pavement material after loading shows that 700,000 cycles can only degrade the performance of the test pavement, not damage it. The recycled asphalt pavement with 7% REOB has basically the same performance as the base asphalt under 700,000 cycles, indicating that REOB-recycled asphalt pavement can ensure basic road performance, while providing economic and environmental advantages. These results provide a reference for the application and form optimization of REOB-recycled asphalt pavement.

Airport Pavement Stiffness Monitoring and Assessment of Mechanical Stabilization using Bender Element Field Sensor

The bender element (BE) field sensor is a newly developed embedded pavement instrumentation that measures shear wave velocity to estimate constructed layer moduli of unbound aggregate bases and subbases. This paper presents findings related to monitoring stiffness characteristics of airport pavement base courses instrumented with BE field sensors and tested under full-scale accelerated pavement testing during Construction Cycle 9 (CC9) of the National Airport Pavement Test Facility (NAPTF) by the U.S. Federal Aviation Administration (FAA). The CC9 aggregate base courses were constructed following FAA’s P-209 specification for a geosynthetic experiment using a biaxial geogrid installed at the bottom of the 8-in. (203-mm) thick base in the north test section, while the control pavement in the south test section was built without a geogrid. Two BE field sensors were installed in the north and south test sections approximately 1 in. (25 mm) above the base–subbase interface. Multiple stages of aircraft gear loads, including static dual-gear, dynamic slow-roll (moving wheel), and dynamic proof-roll, were applied to the test sections. BE field sensor data collected throughout multiple loading stages were used to investigate the stiffness characteristics of the pavement base. These preliminary tests conducted at the NAPTF CC9 experiment revealed the effects of static and dynamic aircraft gear loads on the stiffness of the aggregate base layer and how confinement influenced the moduli of the geogrid-stabilized base. Further, previously observed anti-shakedown effects caused by vehicle load wander could be quantified through changing base course modulus and deformation behavior from the BE field sensor data analysis.

Asserting the Applicability of Copper Slag and Fly Ash as Cemented Base Materials in Flexible Pavement from a Full-Scale Field Study

This research made innovative use of copper slag and fly ash in the construction of a cemented base course of flexible pavement. A full-scale field study evaluated the structural and functional performance of flexible pavement test sections constructed using various combinations of copper slag and fly ash (Class F or Class C) with and without lime. Various performance parameters, namely deflection basin parameters, dissipated energy, back-calculated elastic modulus, service life ratio, and roughness index, were evaluated for flexible pavement test sections constructed with 250-mm-thick conventional granular base [wet-mix macadam (WMM)], 150-mm- and 250-mm-thick copper slag–Class F fly ash–lime (CFL) (70% copper slag +23% Class F fly ash +7% lime) and copper slag–Class C fly ash (CCF) (40% copper slag +60% Class C fly ash) base layers. Falling weight deflectometer tests and bump integrator tests were performed in situ; laboratory tests, namely unconfined compression and resilient modulus tests, were performed on core samples. The average elastic moduli, back-calculated from six FWD tests conducted over 15 months after construction, for CCF and CFL base were 430 and 602 MPa, which are more than 3 times that of WMM. Significant waste utilization up to 1,348 tons of copper slag and 945 tons of fly ash per kilometer length of road can be achieved by using CCF and CFL mixes in base layers of flexible pavement with a service life ratio as high as 1.78 and cost efficiency of 17.4%.