<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
    <description></description>
    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
    </image>
    <item>
      <title>Evaluation of long-term performance of recycled aggregate base (RAB) layers and optimization of their design thicknesses</title>
      <link>https://trid.trb.org/View/2144235</link>
      <description><![CDATA[To reduce the use of natural aggregates commonly used in base layers, constructing recycled aggregate base (RAB) layers has gained popularity. However, in the literature, there is limited information about the engineering properties of recycled concrete aggregate (RCA) materials with different gradations and the blends of RCA and recycled asphalt pavement (RAP) materials. There is also a lack of practice in using a mechanistic-empirical (ME) design method to optimize RAB layer thicknesses. In this study, several full-scale test cells were built with RAB and natural aggregate base layers, and the physical and engineering properties of the base layer aggregates were determined in the laboratory. For long-term performance evaluation of the cells built in the field, falling weight deflectometer (FWD) tests were performed, rutting measurements were taken, and soil temperature was monitored over a period of two years. An ME design procedure was used to optimize RAB layer thicknesses.]]></description>
      <pubDate>Wed, 31 May 2023 10:58:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2144235</guid>
    </item>
    <item>
      <title>Study on Binder Film Thickness Distribution of Recycled Asphalt Pavements</title>
      <link>https://trid.trb.org/View/2126507</link>
      <description><![CDATA[Binder film thickness (BFT) plays a vital role during the design of asphalt mixture and fine aggregate matrix because BFT can exert a significant effect on the performance of asphalt materials. However, the surface area factors are affected by the different specific gravities of the aggregates, which are always ignored during the calculation of BFT. Moreover, whether the BFT is uniformly distributed in asphalt mixture is controversial. Hence, it is necessary to further study the distribution of asphalt film thickness in asphalt materials and its influence factor. This study analyzed the distribution of BFT in coarse and fine parts of recycled asphalt pavements (RAPs). Firstly, a part of four types of RAP (Teichert, Syar, Vulcan coarse, and Vulcan fine) were sieved by #8 sieve (2.36 mm) to achieve coarse and fine parts of RAP. Secondly, the binder content and aggregate gradation were investigated through the ignition and extraction method. Thirdly, surface area ratio was used to evaluate the influence of the ignition and extraction method on the surface area of aggregate sieved from RAP. Finally, the BFT of different types of RAP were calculated through two different methods to evaluate the effect of specific gravities of the aggregates on BFT. The results indicate that for the coefficient of variation, 30 out of 32 data were less than 15.0 %, which implies the BFT was almost evenly distributed in coarse and fine parts of RAP. In addition, the difference of surface area factors caused by the different specific gravities of the aggregates exerts negligible influence on the surface area and the calculation of BFT.]]></description>
      <pubDate>Mon, 24 Apr 2023 16:19:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2126507</guid>
    </item>
    <item>
      <title>Advances in FAA Pavement Thickness Design Software: FAARFIELD 1.41</title>
      <link>https://trid.trb.org/View/1558726</link>
      <description><![CDATA[The Federal Aviation Administration (FAA) has introduced the first major changes to its FAARFIELD standard pavement design software since the last version was released in 2010. These program upgrades accompanied a thorough revision of Advisory Circular (AC) 150/5320-6 covering airport pavement design and evaluation. The newly released program, designated FAARFIELD 1.4, includes significant modifications to both rigid pavement and flexible pavement design models, and adds new features to improve the user experience. This paper summarizes the principal technical changes to structural models, failure models and design logic that affect thickness design using FAARFIELD. It is shown by examples that designs performed using FAARFIELD 1.4 typically are less conservative than in the previous version (FAARFIELD 1.3); however, exceptions to this general statement may be found. This paper also includes discussion of programming changes implemented in the FAARFIELD overlay design procedures that improve both speed and accuracy.]]></description>
      <pubDate>Mon, 31 Dec 2018 22:00:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1558726</guid>
    </item>
    <item>
      <title>Incorporation of Reliability into Airport Pavement Design Using Backcalculated Pavement Layer Moduli</title>
      <link>https://trid.trb.org/View/1558719</link>
      <description><![CDATA[Currently, several variations of Falling or Heavy Weight Deflectometer (F/HWD) equipment exist on the market. The Federal Aviation Administration (FAA) National Airport Pavement Test Facility (NAPTF) Round-Up project provided an opportunity to examine different market available F/HWD equipment. This paper presents a case study of how the uncertainty of backcalculated in-situ moduli can be assessed and incorporated in the FAA Rigid and Flexible Iterative Elastic Layer Design (FAARFIELD) design procedure to determine appropriate pavement thicknesses. The mean values and standard deviations of backcalculated layer moduli were computed and then input into FAARFIELD using Rosenblueth’s procedure to predict the reliability of a 20-year pavement design performance. The research shows that the proposed procedure can be used as an alternative decision-making tool for airport engineers to more realistically predict pavement life using F/HWD data.]]></description>
      <pubDate>Mon, 31 Dec 2018 22:00:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1558719</guid>
    </item>
    <item>
      <title>Laboratory Performance of Superpave Mixes for Perpetual Pavements</title>
      <link>https://trid.trb.org/View/1558664</link>
      <description><![CDATA[Long life asphalt pavement, also known as “Perpetual Pavement”, is a pavement with design life more than 50 years and needs only periodic surface renewal. It works on the concept of controlling horizontal tensile strain at the bottom of the asphalt layer and vertical compressive strain at the top of the subgrade to a particular limit. This can be achieved by increasing the binder content of the mix over the optimum binder content (OBC) and by increasing the overall pavement thickness. In the present study two Superpave mixes were prepared using conventional binder at OBC [optimum binder mixture (OBM)] and also at 0.5% extra binder over OBC [rich binder mixture (RBM)] which can be used in Perpetual Pavements. The mixes were tested for indirect tensile (IDT) strength, moisture susceptibility, fatigue and rutting resistance. From the results it was observed that, OBM performed well as compared to RBM. However the fatigue life of RBM was more compared to the OBM and this helps in reducing the horizontal tensile strain at the bottom of the asphalt layer which in turn increases the life of the pavement.]]></description>
      <pubDate>Sun, 16 Dec 2018 21:39:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/1558664</guid>
    </item>
    <item>
      <title>Aging–Depth Relationship of Asphalt Binders in Hot-Mix Asphalt Pavements</title>
      <link>https://trid.trb.org/View/1496903</link>
      <description><![CDATA[Asphalt binder in hot-mix asphalt (HMA) pavement is subject to oxidative aging. Upon aging, the chemical changes of asphalt binder transfer to its physical changes, and the physical changes transfer to the behavioral and performance changes of HMA mixture. Therefore, understanding binder aging variations in asphalt pavement structures is critically important for mechanistic-based pavement design and analysis. Using test data on extracted asphalt binders from 21 roads in different climate conditions, this study examined the relationship between asphalt binder aging state and pavement depth. The study found that binder aging severity does not necessarily continuously decrease with pavement depth. Data from different climate conditions even show opposite trends. Therefore, one uniform empirical equation is inadequate to characterize the aging-depth relationship for all the asphalt pavements. It is recommended that a mechanistic-based binder aging model be developed in the future that takes the following fundamental influencing factors into consideration: aging susceptibility of the asphalt binder, temperature, and binder oxygen exposure.]]></description>
      <pubDate>Tue, 06 Mar 2018 16:22:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496903</guid>
    </item>
    <item>
      <title>Evaluation of Precut Technique to Control Thermal Cracking in Alaskan Asphalt Concrete Pavements</title>
      <link>https://trid.trb.org/View/1496445</link>
      <description><![CDATA[Thermal cracking is one of the most prevalent pavement distresses found in Alaska and cold areas of other northern states. Previous studies indicated that precutting of thermal cracks in asphalt concrete (AC) pavements has provided promising results in controlling pavement degradation associated with natural thermal cracking. However, a systematic approach has not been developed to implement optimum application of this technique in AC pavements. This paper summarizes national knowledge about the application of precut technique in pavements, and presents three case studies in controlling thermal cracking in AC pavements in Interior Alaska. These three case studies included 1) Phillips Field Road precut in 1984, 2) Richardson Highway precut in 2012, and 3) Parks Highway precut in 2014. Precut variables were introduced including three precut spacing intervals, five precut depths, and five pavement structures. It was found based on yearly road surveys that precutting treatment appeared promising to control thermal cracks. Shorter precut spacing along with stronger and/or thicker pavement structures look promising with respect to crack control. Results also suggested that there may be an optimum precut depth that produces the best crack reduction effect. Preliminary cost analysis of precutting treatments indicated precutting to be an economically promising way of controlling natural thermal cracks. Continuing evaluation and monitoring of these test sections are needed to recommend (with increased confidence) the best design methodology and construction practice for Alaska and cold areas of other northern states.]]></description>
      <pubDate>Wed, 28 Feb 2018 13:25:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496445</guid>
    </item>
    <item>
      <title>Large-Scale Deployment of Performance-Related Specifications for Jointed Plain Concrete Pavement: Results and Lessons Learned</title>
      <link>https://trid.trb.org/View/1439123</link>
      <description><![CDATA[On May 18, 2015, jointed plain concrete (JPC) paving began on one of nine performance-related specification (PRS) contracts along the Jane Addams Tollway (I-90) west of Chicago. The nine contracts consisted of reconstruction and widening projects for the pavement and bridges that carry between 40,000 and 80,000 vehicles per day into and out of the City of Chicago. While the contracts included a host of activities and pay items, the JPC pavements that will make up the mainline lanes of I-90 were all built according to the Illinois Tollway PRS Special Provision. Overall, approximately 750,000 square yards of JPC were placed in 2015 using PRS pay factor adjustments based on how the contractors performed relative to the target values in five performance categories: plastic air content, thickness, dowel alignment, 28-day compressive strength, and pavement surface smoothness. To manage all of the data collected for the PRS projects, a summary spreadsheet was established for each contract. All data are stored and reported by sublot, and the data are used to calculate the individual pay factors specific to each quality characteristic, as well as the overall pay factor for the contract.]]></description>
      <pubDate>Sun, 12 Feb 2017 20:02:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1439123</guid>
    </item>
    <item>
      <title>Developing Rigid Airport Pavement Multiple-Slab Response Models for Top-Down Cracking Mode using Artificial Neural Networks</title>
      <link>https://trid.trb.org/View/1439117</link>
      <description><![CDATA[The Federal Aviation Administration (FAA) has recognized for some time that its current rigid pavement design model, involving a single slab loaded at one edge by a single aircraft gear, is inadequate to account for top-down cracking. Thus, one of the major observed failure modes for rigid pavements is poorly represented in the FAA Rigid and Flexible Iterative Elastic Layer Design (FAARFIELD) program. A research version of the FAARFIELD design software has been developed (FAARFIELD 2.0), in which the single-slab three-dimensional finite element (3D-FE) response model is replaced by a 4-slab 3D-FE model with initial temperature curling to produce reasonable thickness designs accounting for top-down cracking behavior. However, the long and unpredictable run times associated with the 4-slab model and curled slabs make routine design with this model impractical. In this paper, use of artificial intelligence (AI)-based alternatives such as artificial neural networks (ANNs) with potential for producing accurate stress predictions in a fraction of the time needed to perform a full 3D-FE computation has been investigated. In the development of ANN models, a synthetic database of FAARFIELD input-output pairs representing a number of realistic scenarios were developed. Moreover, ANN models for only mechanical and simultaneous mechanical and thermal loading cases were developed and accuracy predictions of these models were documented. It was observed that very high accuracies were achieved in predicting pavement responses for all cases investigated.]]></description>
      <pubDate>Sun, 12 Feb 2017 20:02:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1439117</guid>
    </item>
    <item>
      <title>Development and HVS Validation of Design Tables for Permeable Interlocking Concrete Pavement: Final Report</title>
      <link>https://trid.trb.org/View/1359163</link>
      <description><![CDATA[This report details the research undertaken to develop revised design tables for permeable interlocking concrete pavement using a mechanistic-empirical design approach. The study included a literature review, field testing of existing projects and test sections, estimation of the effective stiffness of each layer in permeable interlocking concrete pavement structures, mechanistic analysis and structural design of a test track incorporating three different subbase thicknesses (low, medium, and higher risk), tests on the track with a Heavy Vehicle Simulator to collect performance data to validate the design approach using accelerated loading, refinement and calibration of the design procedure using the test track data, development of a spreadsheet based design tool, and development of revised design tables using the design tool. A new example design table, based on the number of days with standing water in the subbase (zero, 10, 30, 50, 90, and 120) has been developed. The table uses a similar format to that currently used in the ICPI Permeable Interlocking Concrete Pavements guideline. The minimum design thicknesses required to prevent subgrade rutting that are proposed in the new table do not differ significantly from those in the current ICPI guide, and are mostly less conservative. Designs for a specific set of project circumstances can be undertaken using the same spreadsheet-based design tool used to develop the tables in conjunction with the hydrological design procedures provided in the ICPI guide.]]></description>
      <pubDate>Fri, 07 Aug 2015 10:12:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1359163</guid>
    </item>
    <item>
      <title>Improving the Foundation Layers for Concrete Pavements</title>
      <link>https://trid.trb.org/View/1362144</link>
      <description><![CDATA[Quality pavement foundation layers are essential to achieving excellent pavement performance. In recent years as truck traffic has greatly increased, the foundation layers have become even more critical to successful pavement performance. Unfortunately, there are still many pavement failures in the U.S. related to inadequate subbase, natural subgrade, and embankment (commonly referred to as foundation layers or roadbed). Factors that contribute to pavement foundation problems are believed to be poor construction practices, ineffective quality control/quality assurance (QC/QA) testing methods and sampling plans, material variability and unpredictable long-term material behavior, poor verification of material properties during construction, insufficient development of performance-related specifications, and low capital investment in the foundation layers. The objective of this research is to improve the construction methods, economic analysis and selection of materials, in-situ testing and evaluation, and development of performance-related specifications for the pavement foundation layers.  The outcome of this study will be conclusive findings that make pavement foundations more durable, uniform, constructible, and economical.  Although the focus of this research will be portland cement concrete (PCC) concrete pavement foundations, the results will likely have applicability to asphalt cement concrete (ACC) pavement foundations and, potentially, unpaved roads.  All aspects of the foundation layers will be investigated including thickness, material properties, permeability, modulus/stiffness, strength, volumetric stability and durability.]]></description>
      <pubDate>Wed, 22 Jul 2015 01:02:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/1362144</guid>
    </item>
    <item>
      <title>Ordinal Logistic Regression Model for Predicting AC Overlay Cracking</title>
      <link>https://trid.trb.org/View/1250645</link>
      <description><![CDATA[Predicting performance of asphalt concrete (AC) overlay is important for both pavement design and management. Based on 328 AC overlay sections from the long-term pavement performance (LTPP) program, ordinal logistic regression models were developed in this study to predict the probability of severity levels for alligator cracking. It was found that the alligator cracking is significantly affected by alligator cracking of the existing pavement, thickness of overlay, thickness of the existing AC, age of pavements after resurfacing, truck volume, freeze-thaw cycles, and the amount of precipitation per wet day. In addition, it was found that the use of recycled asphalt pavement in the amount specified in the SPS 3 experiment and preoverlay treatment significantly affect overlay cracking. Both statistical conformance tests and empirical verification using independent data indicate that the developed models are reasonably accurate. The model can generate the probability of a pavement staying at a certain distress level and the odds ratio, which enables highway agencies not only predict probability of cracking but also assess the confidence of making such predictions.]]></description>
      <pubDate>Tue, 03 Sep 2013 12:32:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/1250645</guid>
    </item>
    <item>
      <title>Analyzing Influence Factors of Transverse Cracking on LTPP Resurfaced Asphalt Pavements through NB and ZINB Models</title>
      <link>https://trid.trb.org/View/1259542</link>
      <description><![CDATA[The negative binomial (NB) and zero-inflated negative binomial (ZINB) models were employed to simulate the development of pavement transverse cracks on asphalt overlays and to evaluate the influence of different designs of asphalt overlays on crack development. Pavement transverse crack data were collected from 15 long-term pavement performance (LTPP) SPS-5 test sites. Analyzed factors include traffic level, overlay thickness, mixture [using reclaimed asphalt pavement (RAP) or virgin], intensity of surface preparation (mill or no mill) before overlay, total thickness of pavement, and freeze index. Analysis results indicate that the NB and ZINB models were effective in simulating the development of pavement transverse cracks by addressing the overdispersion. In addition, the ZINB model outperformed the NB model by explaining the excess zeros in the cracking count data to capture both the initiation and propagation of cracking. The regression analysis indicates that mill before overlay is effective in retarding the initiation of cracks, but not the propagation of cracks. Thicker overlay appears to reduce transverse cracking. High traffic level or using RAP is likely to increase the number of transverse cracks. Total thickness of pavement and freeze index are not significant for the development of transverse cracks.]]></description>
      <pubDate>Tue, 03 Sep 2013 12:29:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/1259542</guid>
    </item>
    <item>
      <title>Using M-E PDG to Study the Effectiveness of Electronic Waste Materials Modification on Asphalt Pavements Design Thickness</title>
      <link>https://trid.trb.org/View/1259489</link>
      <description><![CDATA[The objective of this study was to use the Mechanistic-Empirical Pavement Design Guide (M-E PDG) to investigate the effectiveness of electronic waste (e-waste) modification on the minimum design thickness of asphalt pavements. Common e-waste plastic powders, acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS), were used to modify Hot Mix Asphalt (HMA) mixtures in this study. The HMA modifiers include e-waste plastics intended for end user applications along with chemically treated e-waste plastics. Chemical treatment of e-waste plastics involved using free radical initiators on e-waste plastics in an attempt to improve asphalt binder and plastic bonding capabilities within the mixture. The percentage of ABS and HIPS blended with asphalt mixtures was 2.5% and 5% by weight of binder. In this study, multiple design trial runs of nine different mixtures (including the control mixture) were conducted using the M-E PDG software version 1.1. From the M-E PDG results analysis, it was concluded that in general using e-waste materials as modifiers for asphalt mixtures would decrease the design thickness of the asphalt pavements. The design thickness of treated acrylonitrile butadiene styrene (T-ABS) with percentage of 2.5 by weight of asphalt binder resulted in the smallest pavement thickness among all studied mixtures. This methodology would help evaluate various sustainable materials within asphalt mixtures from the perspective of the pavement designer improving the decision making process constructing more economical pavement sections.]]></description>
      <pubDate>Tue, 20 Aug 2013 17:24:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1259489</guid>
    </item>
    <item>
      <title>Pavement thickness variability</title>
      <link>https://trid.trb.org/View/1205568</link>
      <description><![CDATA[An estimate of the target population standard deviation must be determined for the statistical quality control of pavement layer thickness. The formula used in the past to describe the variability of layer thickness is restrictive in its application.  This report suggests an alternative approximation for target population standard deviation which varies with pavement thickness. The proposed expression is based on a larger number of actual measurements and covers a wider range of pavement thicknesses.  This report concerns work undertaken as part of project wmr 74/8, "the development of quality control procedures for road building materials and road construction practices", financed under the transport, planning and research (financial assistance) act, 1977 (a).]]></description>
      <pubDate>Fri, 24 Aug 2012 21:10:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/1205568</guid>
    </item>
  </channel>
</rss>