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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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      <title>Numerical analysis of fatigue performance of steel fiber reinforced concrete pavement based on microscopic crack growth theory</title>
      <link>https://trid.trb.org/View/2606328</link>
      <description><![CDATA[The fatigue performance of rigid pavements on steel bridge decks remains an underexplored area, with most existing research focusing on flexible pavement systems and simplified macroscopic models. This study presents a refined mesoscale numerical framework for analyzing fatigue crack propagation in steel fiber reinforced concrete (SFRC) pavements using fracture mechanics and the extended finite element method (XFEM). A three-dimensional local model of an SFRC-orthotropic steel deck system was developed, incorporating moving load simulations to determine critical stress locations. Parameters such as steel fiber volume content, yield strength, and aspect ratio were systematically varied to evaluate their effects on crack propagation behavior and fatigue life. Model predictions were validated against experimental fatigue test results, showing strong agreement in crack path and fatigue life estimates. The findings indicate that increasing steel fiber content from 0.5% to 2.0% progressively enhances fatigue resistance, with simulated fatigue life improvements of 51%, 28%, and 20% over the 0.5%-1.0%, 1.0%-1.5%, and 1.5%-2.0% intervals, respectively, while higher fiber strength and optimized aspect ratios further improve performance. The proposed methodology provides a reliable tool for optimizing SFRC pavement design and offers practical guidance for extending the fatigue life of steel bridge decks.]]></description>
      <pubDate>Mon, 29 Dec 2025 09:35:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2606328</guid>
    </item>
    <item>
      <title>Viscoelastic damage equivalence for asphalt mastics under cyclic temperature variations: Towards Climate-Resilient-Pavements</title>
      <link>https://trid.trb.org/View/2640770</link>
      <description><![CDATA[Escalating climate change with pronounced diurnal temperature variations impacts asphalt pavement performance and environmental sustainability. This accelerates fatigue damage through repeated thermal cycling. Unlike traditional simplified thermal models, our approach integrates rheological characterization with accelerated thermal cycling for asphalt mastics to develop a comprehensive viscoelastic damage equivalence method. The innovation establishes time–temperature-cyclic thermal stress equivalence through stress relaxation analysis. It also introduces a time–temperature-cyclic thermal stress shift factor that incorporates Williams-Landel-Ferry (WLF) parameters with cyclic temperature factors. Master curve analysis establishes the crossover frequency as the governing parameter for the shift factor, due to its physical and statistical merits. The modified Coffin-Manson model yielded viscoelastic damage equivalence factors, validated within ± 20 % relative error. The method yields a preliminary adaptability zoning map, identifying northwestern regions (Xinjiang, Tibet, and Qinghai) and the northeastern provinces as high-priority zones for fatigue-resistant materials. This provides a framework for material selection and development in temperature-fluctuation-prone regions.]]></description>
      <pubDate>Mon, 22 Dec 2025 10:59:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2640770</guid>
    </item>
    <item>
      <title>Viscoelastic Computational Fracture Mechanics Approach for the Analysis of Thermal Reflective Cracking in Asphalt Overlaid Jointed Concrete Airfield Pavements</title>
      <link>https://trid.trb.org/View/2596604</link>
      <description><![CDATA[Predicting crack propagation in a composite airfield pavement is a computationally challenging task. This study presents the development of a fracture-based modeling approach to capture crack propagation in an asphalt concrete (AC) overlay on jointed Portland cement concrete (PCC) pavement structure. A four-stage numerical framework was developed to predict thermal induced joint reflective cracking. The framework leverages a combination of finite difference methods, finite element (FE) thermo-mechanical modeling, and the Generalized Finite Element Method (GFEM) coupled with the elastic-viscoelastic correspondence principle (EVCP). FE thermo-mechanical and GFEM fracture simulations were solved in 3-D. Performing the simulations in 3-D domain shows the non-uniformity of PCC joint movement through the depth and width of the concrete slabs. The results show that this non-uniformity is mainly influenced by AC stiffness and thermal expansion/contraction. Simplified design models were prepared for joint opening under different cooling cycles. GFEM s adaptive meshing and global-local analysis enable accurate calculation of stress intensity factors from the elastic solution. Application of EVCP provided the ability to address the critical challenges of incorporating 3-D viscoelastic analysis within the framework. Using EVCP viscoelastic ERR can be calculated for various AC mixtures and cooling cycles using a limited set of elastic solutions. The framework was validated using FAA outdoor test section for joint reflective cracking at the National Airport Pavement Test Facility. Thermal reflective cracking performance for different overlay scenarios was simulated in four different climatic regions, highlighting the framework s ability of capturing the effect of pavement structure and climate on overlay fatigue life.]]></description>
      <pubDate>Thu, 11 Sep 2025 09:12:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2596604</guid>
    </item>
    <item>
      <title>Development of Balanced Mixture Design Index Parameters and the Flex Suite of Performance Analysis Tools for Asphalt Pavements—Volume I</title>
      <link>https://trid.trb.org/View/2406626</link>
      <description><![CDATA[This report documents research to advance mechanistic models, performance analysis and evaluation, and design methodologies to aid agency efforts to understand asphalt pavement performance. The research team developed FlexMAT™ version 2.1 and FlexPAVE™ version 2.0 as the material-level and pavement-level analysis tools, respectively. FlexPAVE 2.0 includes the simplified viscoelastic continuum damage model for fatigue and thermal cracking, the permanent strain shift model for rutting, and the NCHRP 09-54 aging models. FlexMAT 2.1 develops the input material properties for FlexPAVE 2.0 seamlessly. Sapp and the Rutting Strain Index are the cracking and rutting indexes, respectively, which aid balanced mix design (BMD) and improve performance analysis. These two indexes’ threshold values are a function of traffic level, using more than 100 different asphalt mixtures. The team used the four corners concept to develop performance-volumetrics and index-volumetrics relationships to use as the foundation for BMD methods. The team employed Bayesian inference-based Markov Chain Monte Carlo technique uncertainty analysis to develop a reliability framework for distress predictions using FlexPAVE 2.0 and also developed PASSFlex™ to support the steps of a performance evaluation on a project. One of the performance protocols the TFRS-01 project recommended was implemented into PASSFlex. The research team performed three shadow projects in concert with the Western Federal Lands Highway Division, Maine Department of Transportation, and Missouri Department of Transportation to introduce the asphalt mixture performance tester suite of performance tests and performance models. This volume is the first in a series. The other volume in the series is FHWA-HRT-24-111: Development of Balanced Mixture Design Index Parameters and the Flex Suite of Performance Analysis Tools for Asphalt Pavements—Volume Ⅱ.]]></description>
      <pubDate>Fri, 09 Aug 2024 08:41:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2406626</guid>
    </item>
    <item>
      <title>Development of Balanced Mixture Design Index Parameters and the Flex Suite of Performance Analysis Tools for Asphalt Pavements—Volume Ⅱ</title>
      <link>https://trid.trb.org/View/2406625</link>
      <description><![CDATA[This report documents research efforts to advance mechanistic models, performance analysis and evaluation, and design methodologies to aid agency efforts to understand asphalt pavement performance. The research team developed FlexMAT™ version 2.1 and FlexPAVE™ version 2.0 as the material-level and pavement-level analysis tools, respectively. FlexPAVE 2.0 includes the simplified viscoelastic continuum damage model for fatigue and thermal cracking, the permanent strain shift model for rutting, and the NCHRP 09-54 aging models. FlexMAT 2.1 is designed to develop the input material properties for FlexPAVE 2.0 in a seamless manner. The team developed Sapp and the Rutting Strain Index as the cracking and rutting indexes, respectively, to aid balanced mixture design (BMD) and facilitate improved performance analysis. The threshold values for these two indexes were determined as a function of traffic level using more than 100 different asphalt mixtures. The team also developed a performance-volumetrics relationship and index-volumetrics relationship using the four corners concept and used these relationships as the foundation for BMD and performance-related specifications. The developed BMD methods optimize the mixture for both aggregate gradation and binder content for a given set of aggregate stockpiles and binder. The team employed uncertainty analysis based on the Bayesian inference-based Markov Chain Monte Carlo technique to develop a reliability framework for distress predictions using FlexPAVE 2.0. The team also developed PASSFlex™ to support the user in the different steps of a performance evaluation on a project. One of the performance protocols recommended by the TFRS-01 project is implemented into PASSFlex. All the analysis tools developed in this research are based on Microsoft® Excel® and are seamlessly integrated. Finally, the research team performed three shadow projects in concert with the Western Federal Lands Highway Division, Maine Department of Transportation, and Missouri Department of Transportation to introduce the asphalt mixture performance tester suite of performance tests and performance models to State departments of transportation.]]></description>
      <pubDate>Fri, 09 Aug 2024 08:41:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2406625</guid>
    </item>
    <item>
      <title>Mechanistic Pavement Modeling of Typical Brazilian Pavements: Cohesive Zone Fracture Modeling and Continuum Damage Modeling</title>
      <link>https://trid.trb.org/View/2408306</link>
      <description><![CDATA[Pavement performance evaluation with respect to fatigue cracking has seen a major shift toward more rigorous mechanistic models that can capture the complex damage response of the mixtures more accurately. This study utilized two mechanistic methods (cohesive zone [CZ]-based fracture modeling and continuum damage [CD] modeling) to study the cracking behavior of asphalt mixtures and subsequently predict the damage-associated performance of pavements. A Superpave mixture designed for Brazilian highway conditions was selected to evaluate the two modeling approaches for the performance of the mixture when utilized as a surface course within typical Brazilian highway pavements. The mixture was first evaluated for its linear viscoelastic properties, and then the damage characteristics of the mixture were obtained through two different experiments: the semi-circular bending (SCB) beam test and the cyclic fatigue (CF) test. The SCB tests performed at different loading rates were used to obtain the model parameters of the nonlinear viscoelastic CZ model with a Gaussian damage evolution criterion, while the CF tests were performed at different strain amplitudes, and the mixture-specific damage characteristic curve and the fatigue failure criterion were obtained using the simplified-viscoelastic continuum damage model. From a design perspective, three pavement structures that varied in geometry (pavement layer thickness) and underlying layer properties were selected while retaining the same asphalt mixture. The three pavement scenarios were evaluated for the fatigue cracking performance from each of the mechanistic modeling methods. The results indicate that both methods rank the performance of the pavement structures in a similar manner, while the damage initiation and progression were seen to be different because of the different mechanics in modeling cracks.]]></description>
      <pubDate>Mon, 29 Jul 2024 20:13:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2408306</guid>
    </item>
    <item>
      <title>A fast method for solving conformal rolling contact problems</title>
      <link>https://trid.trb.org/View/2399783</link>
      <description><![CDATA[For conformal contact situations, some of the assumptions employed in classical contact theories, such as the flatness of the contact area, lose their validity. Existing conformal contact models are challenged by either accuracy or computational efficiency. With the aim of achieving a balanced trade-off between these contrasting requirements, this paper proposes a new simplified method to solve conformal rolling contact problems, which is based on fast non-Hertzian contact model INFCON and FaStrip. Numerical experiments are performed for two typical wheel/rail conformal contact scenarios to assess the performance of the proposed method, taking as the reference the CONTACT method for conformal contacts. The comparative analyses show that the proposed method is in good agreement with the reference method in terms of the determination of the contact stresses, total forces, and the prediction of wear, whereas the traditional half-space approach fails to capture the main features of the conformal contacts. In addition, the high computational efficiency of the proposed method shows the potential for application in vehicle dynamic simulation and damage analysis.]]></description>
      <pubDate>Mon, 29 Jul 2024 13:41:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2399783</guid>
    </item>
    <item>
      <title>Pavement Health Track (PHT), Remaining Service Life (RSL) Forecasting Models, Technical Information</title>
      <link>https://trid.trb.org/View/2398040</link>
      <description><![CDATA[The objective of this study was to develop for the Federal Highway Administration (FHWA), using an off-the-shelf engineering analysis software interface tool architecture, the Pavement Health Track (PHT) Analysis Tool. The PHT Analysis Tool is an engineering software application for determining and reporting the health of pavement networks in terms of the pavement’s remaining service life (RSL). The PHT Analysis Tool uses performance models recently developed by FHWA for the Highway Economic Requirements System (HERS) and the National Pavement Cost Model (NAPCOM). These pavement models are based on concepts developed under National Cooperative Highway Research Program (NCHRP) Projects 1-37A and 1-40D and included in the Interim American Association of State Highway and Transportation Officials (AASHTO) Mechanistic-Empirical Pavement Design Guide (MEPDG), making them a simplified version of the more complex mechanistic-empirical (ME) set of models and procedures used in the Interim AASHTO MEPDG. This report presents an overview of the simplified MEPDG models incorporated into the PHT Analysis Tool along with a detailed description of PHT Analysis Tool approaches to determining pavement RSL, guidance on setting up the PHT analysis tool input database from HPMS and other databases, and guidance on setting key parameters for determining overall RSL.]]></description>
      <pubDate>Mon, 01 Jul 2024 16:20:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2398040</guid>
    </item>
    <item>
      <title>Updates to Mechanistic-Empirical Design Inputs for Illinois Flexible Pavements</title>
      <link>https://trid.trb.org/View/2379594</link>
      <description><![CDATA[This study reviews the Illinois Department of Transportation’s (IDOT's) full-depth asphalt, limiting strain criterion, and asphalt over rubblized concrete design procedures, considering technological advancements in hot-mix asphalt—namely, the increased use of recycled materials and modified asphalt binders. The researchers evaluated the current |E*| algorithm by conducting laboratory tests with four mix designs and seven asphalt binders of different Superpave performance grades. They compared predictive models, including the current Illinois modulus algorithm as well as the Witczak, Hirsch, and newly developed Illinois Center for Transportation (ICT) Bayesian neural network (BNN) models. The ultrasonic pulse velocity (UPV) nondestructive test for modulus and field modulus measurements was evaluated as well. Subsequent tasks involved reviewing current fatigue endurance limit (FEL) criteria from an adapted protocol for the four-point bending beam fatigue test. This study found that typical hot-mix asphalt modulus values in Illinois are underestimated compared to modern mixes, suggesting potential savings by allowing an increased modulus value to be used, reducing layer thickness design. Low-temperature performance grades significantly influenced modulus, and the developed ICT BNN predictive model outperformed traditional ones. While UPV was promising for modulus screening, challenges related to material properties assumptions were identified. The current stage of research on assessing modern mixes’ FEL reveals the complexity of observing FEL using simplified methods. To advance this objective, a concept of acceptable stiffness ratio (SR) is introduced. In these cases, exceptionally long fatigue life would be obtained for mixes that demonstrate an acceptable drop in SR within 10,000 cycles, with no apparent evolution of the damage state. The most conservative estimation of strain level that would result in acceptable SR aligned with IDOT’s current 70 microstrain FEL criteria. On the less conservative side, allowing a 10% drop in SR within 10,000 loading cycles could increase the acceptable SR < 1 strain level as high as approximately 180 microstrain, with caution needed regarding evolving mobility trends and environmental stressors including the changing climate.]]></description>
      <pubDate>Tue, 28 May 2024 09:14:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2379594</guid>
    </item>
    <item>
      <title>A study of the relationship between rear-of-wheel particle emissions and close-proximity tire/road noise of a passenger car</title>
      <link>https://trid.trb.org/View/2335830</link>
      <description><![CDATA[Non-exhaust particulate emissions and road traffic noise will continue to constitute significant threats to the environment and human health during the 21st century. In the EU alone, >60 million adults are subjected to unhealthy levels of vehicle noise, while over 200,000 premature deaths are caused by chronic exposure to excessive concentrations of fine particles, with road traffic being a key source. Although these pollutants share common sources and can affect the same targets, studies have often treated their emissions separately. This study establishes both the phenomenological and mathematical relationships between tire/road noise (TRN) and rear-of-wheel particle (RoWP) emissions. Information from test track measurements, coupled with correlation-based models, enables linking TRN with RoWP emissions through variables such as vehicle speed and pavement properties, including macro-texture scales. A careful examination of the data reveals that pavement macro-texture acts as a crucible in which TRN and RoWP emissions are generated in an interrelated manner. However, at speeds over 70–80 km/h, the depletion of readily mobilizable RoWP fractions, followed by the emergence of refractory (hard-to-mobilize) circum-/super-micron RoWP fractions from resuspension (which accompanies the intensification of air-pumping TRN generation mechanisms), marks a collapse of this interdependence. These results, supplemented by valuable insights into the particulate emission performance of pavements, serve to outline future air quality challenges and provide a basis for the simplified monitoring and control (e.g. through acoustic measurements) of RoWP emissions.]]></description>
      <pubDate>Mon, 08 Apr 2024 09:16:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2335830</guid>
    </item>
    <item>
      <title>Short-Term Predictions of Asphalt Pavement Rutting Using Deep-Learning Models</title>
      <link>https://trid.trb.org/View/2329202</link>
      <description><![CDATA[Pavement maintenance causes an instant change in the pavement’s material or structural properties and affects the subsequent development of pavement distresses and performance. The occurrence of maintenance action significantly limits the applicability of predictive models that rely heavily on the continuity of time and pavement exposure conditions. Using rutting of asphalt pavement as an example, this study treated the partitioned rutting development as short-term time series. The proposed average cosine similarity of pavement rutting development effectively integrated the data collected within a characteristic length in the longitudinal direction of the pavement. Integration of the raw data effectively mitigated the data inconsistency caused by measuring errors and simplified the model construction. The authors employed convolutional neural network (CNN) and long short-term memory (LSTM) as two typical deep-learning (DL) models to capture the characteristics of rutting development from limited data and make corresponding predictions. The effects of model hyperparameters and input type on the model performance (e.g., accuracy and stability) were investigated to identify the optimal setting for various modeling data. The comparisons with two statistical models—exponential smoothing (ES) model and autoregressive integrated moving average (ARIMA) model—indicated the potential of applied DL models in accurately predicting rutting development in field pavement. Finally, three strategies of improving model performance were explored and discussed for future applications, i.e., increasing the input length, input dimensionality, and model complexity.]]></description>
      <pubDate>Thu, 04 Apr 2024 16:59:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2329202</guid>
    </item>
    <item>
      <title>Evaluating the Fatigue-Cracking Resistance of North Dakota’s Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/2361859</link>
      <description><![CDATA[Fatigue cracking is a critical pavement distress caused by extreme environmental conditions and heavy repeated cyclic loading. Performance-based design methods that use mechanistic models focus on material performance properties, creating an opportunity to use engineered and recycled materials such as reclaimed asphalt pavement (RAP). The primary goal of this study was to use the simplified viscoelastic continuum damage (S-VECD) model to assess the fatigue behavior of North Dakota’s asphalt mixtures. Eight mixtures typically used in North Dakota were sampled and underwent |E*| testing to determine their linear viscoelastic (LVE) properties. The S-VECD tests were conducted on the same mixtures to determine their damage characteristics. The outputs from the two tests were exported to the FlexMATTM software to obtain their damage characteristic curves, DR failure criterion parameters, and Sapp-index values. CT-index values for the same mixtures were obtained from the North Dakota Department of Transportation (NDDOT). The results revealed that the mixture used for HWY 52, which does not contain RAP, was least susceptible to fatigue cracking. The mixture used for HWY 6, which contains the highest RAP content (25%), had the lowest fatigue resistance, revealing RAP’s stiffening effect on asphalt mixtures. The mixture used for HWY 1, which used the performance grade (PG) 58S-34 binder, had the second-highest fatigue-cracking resistance despite containing 15% RAP, indicating that binder grade affects an asphalt mixture’s fatigue behavior. A relatively low correlation was observed between the CT-index and Sapp-index.]]></description>
      <pubDate>Wed, 03 Apr 2024 12:23:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2361859</guid>
    </item>
    <item>
      <title>Evaluation of the Accuracy of Pavement ME Methodology in Calculating Equivalent Loading Frequency and Its Effect on Strain Response Predictions in Flexible Pavements</title>
      <link>https://trid.trb.org/View/2319692</link>
      <description><![CDATA[The prediction of strain responses under axle loadings is critical for flexible pavement design by the mechanistic-empirical approach. The mechanistic-empirical pavement design (pavement ME) method uses linear-elastic analysis to simulate the strain responses under axle loadings, and it relies on the concept of equivalent loading frequency to determine the elastic modulus of the asphalt concrete (AC) layer from the dynamic modulus master curve. The pavement ME method has a simplified procedure to calculate this frequency. The main goal of this study is to evaluate the accuracy of axle loading frequency calculated by the pavement ME method. This paper first introduces the concepts of predominant and equivalent frequencies, provides a brief explanation of the difference between them, and then proposes three predominant frequency methods for evaluation. The accuracy of the pavement ME method and the other methods of calculating the predominant frequency is evaluated in terms of frequency, modulus, and strain by comparing their results with those from dynamic viscoelastic analysis with moving loads. Results show that the time–frequency relationship for predominant frequency is closer to f=1/(2t) than f=1/t, assuming that the pulse duration t is accurate. Nevertheless, using f=1/t with the approximate pulse duration as calculated by the pavement ME method gives reasonable predictions of the maximum tensile strain. On the other hand, while it gives reasonable predictions of vertical strains with increasing depth, the pavement ME method can underestimate them near the surface by up to 55%. Overall, even though the procedure for pavement ME frequency calculation is highly simplified, its general performance appears to be acceptable.]]></description>
      <pubDate>Tue, 20 Feb 2024 09:17:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2319692</guid>
    </item>
    <item>
      <title>A direct method for the extension of FastSim under non-Hertzian contact conditions</title>
      <link>https://trid.trb.org/View/2239634</link>
      <description><![CDATA[In wheel-rail contact mechanics, there coexist different models characterised by their ability to reproduce the real phenomenon and the time associated with computing the solution. In simulation of the vehicle dynamics, the increase in the computational performance places researchers close to a horizon in which it is possible to implement the most realistic theories (Variational Theory or finite elements), although at present the use of these models is mainly limited to offline calculations, far from real-time simulation. In this context, this work presents a tangential contact theory that is an intermediate point between simplified models (unable to model non-Hertzian contact) and more realistic models (whose complexity triggers simulation times). The tangential contact model proposed is based on the FastSim algorithm, whose precision comes from the algorithm convergence to the results of an exact adhesion theory (i.e. when creepages tend to zero). The impossibility of considering Kalker’s Linear Theory as an adjustment method when the hypotheses of the Hertzian model are not fulfilled leads to the adoption of the Kalker’s steady-state CONTACT version in adhesion conditions. The calculations presented through the proposed algorithm provide errors for creep forces lower than 4% with computational times one order lower than the Variational Theory.]]></description>
      <pubDate>Tue, 10 Oct 2023 11:40:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2239634</guid>
    </item>
    <item>
      <title>An improved regression model to predict fatigue life of asphalt mixes incorporating low to moderate RAP contents</title>
      <link>https://trid.trb.org/View/2135389</link>
      <description><![CDATA[The research on the fatigue performance of recycled asphalt mixture and the establishment of its fatigue life prediction model is the key to its large-scale engineering application. The four-point bending fatigue tests of the fresh and recycled asphalt mixtures under the strain control of cyclic loading were conducted to investigate influencing factors on their fatigue performance and establish a new fatigue prediction model for RAP (recycled asphalt pavement). The hot recycled asphalt mixture samples of AC-16C were prepared by a uniform test design method, with the RAP content of 0%, 20%, 30%, and 40%. Through the fatigue test data of 20 groups of fresh asphalt mixture with 0% RAP and 40 groups of recycled asphalt mixtures with the contents of 20%, 30%, and 40% RAP, the simplified applicability of the fatigue prediction model in the current Chinese specifications for the design of highway asphalt pavement (JTG D50-2017, JTG model) and its parameters modification were studied, thereby an improved regression fatigue prediction model of recycled asphalt mixture is established on consideration of strain level, asphalt content, void ratio, and RAP mixing amount. This fatigue prediction model for recycled asphalt mixtures was proposed by modifying the parameters of the fatigue equation for new asphalt mixtures in the Chinese Highway Asphalt Pavement Design Code. (JTG D50-2017) and comparing the fatigue test data of the recycled asphalt mixture. The research results show that: The simplified JTG fatigue prediction model can effectively predict the fatigue life of fresh asphalt mixture with the content of 0% RAP, and the model parameter a is a constant of the order of 1016; The correction coefficients α and β of the initial bending stiffness modulus S0 and the Voids Filled with Asphalt (VFA) in the improved JTG model of the hot recycled asphalt mixture considering the RAP content are 0.006 and 0.0136, respectively; The model can accurately predict the fatigue life of recycled asphalt mixtures with the range of RAP content of 0–40%, with an average deviation of only 0.106, and has higher prediction accuracy for fatigue life measured close to or higher than 106 times. The average deviation of the predicted life of 20%, 30%, and 40 %RAP fatigue is only 0.057, 0.079, and 0.125. This paper’s indoor fatigue prediction model has higher accuracy for recycled asphalt mixture than the well-known traditional models.]]></description>
      <pubDate>Wed, 29 Mar 2023 09:32:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2135389</guid>
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