<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>A Discrete Element Model of Ice Ridge Interaction with a Conical Structure</title>
      <link>https://trid.trb.org/View/1722756</link>
      <description><![CDATA[A numerical model of ice ridge interaction with narrow sloped structure is being developed to examine possible failure scenarios and loads it may impart on the structure. In reality there is no dominant interaction scenario and the roles of the consolidated layer, keel rubble and rubble pile accumulation on the slope still remain uncertain. Bonded-particle discrete element models are capable of simulating both the failure of continuous layers of ice and the granular behaviour of ice rubble. The computational complexity of the model is high; therefore, the simulations are run on high-performance computers. Ice ridge interactions with a Confederation Bridge pier have been simulated and the results compared with analytical estimates. The results show that the rubble pile heights and load levels obtained in the simulations are in agreement with observations indicating that the model performs well. The model will be used to further study ridge-structure interactions and hopefully help reduce uncertainties related to ridge properties and load determinations.]]></description>
      <pubDate>Thu, 30 Jul 2020 16:19:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1722756</guid>
    </item>
    <item>
      <title>Study on Application Effect of Sand Consolidating Agent for the Slope of Highway Subgrade in Season Frozen Zone</title>
      <link>https://trid.trb.org/View/1671086</link>
      <description><![CDATA[In deep season frozen areas, the solidified layer is easy to be destroyed due to the influence of freeze-thaw cycles after the surface layer of the sandy slope is solidified by chemical methods. In order to study the application effect of the new sand consolidating agent after solidifying sand body, the mechanism of strength formation was analyzed by scanning electron microscopy (SEM). The freeze-thaw cycle tests were carried out on sand consolidating samples. The direct shear tests and unconfined compressive strength tests were carried out before and after freeze-thaw cycles to analyze the freeze-thaw resistance of sand consolidating samples. The sand consolidation agent was tested on-site, and its strength was tested to observe its effect. The results showed that the adhesive membranes on the surface of sand particles were formed by the sand consolidating agent, which increased the cohesion and strength of sand particles. After freeze-thaw cycle tests, the cohesion, internal friction angle, and compressive strength of the solidified sand gradually decreased with increasing freeze-thaw cycles. The decreasing rate reduced from fast to slow and then tends to be stable. The failure mode of samples changed from brittle failure to plastic failure. The sand consolidating layer can effectively prevent collapse of the sandy slope. Combining with the external-soil spray seeding, the sand consolidation layer is beneficial to the growth of plants.]]></description>
      <pubDate>Fri, 20 Dec 2019 16:25:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/1671086</guid>
    </item>
    <item>
      <title>Highway Construction Materials from the Consolidated Rocks of Southwestern Iowa</title>
      <link>https://trid.trb.org/View/1601566</link>
      <description><![CDATA[Southwestern Iowa, unlike other parts of the State, does not have plentiful near-surface supplies of stone available for highway construction purposes. The long and intensive search for such road material by quarrymen, highway engineers, geologists, and others interested in all phases of stone use resulted in a growing conviction that the only hope of locating new and significant deposits lay in a regional geological survey. Further, such a survey would result in the delineation of areas where exploration should be economically feasible as well as those areas where exploration would have little or no chance of success. These views formed the foundation for developing the project covered by this report under a cooperative agreement with the Iowa Highway Research Board of the Iowa State Highway Commission. The aims of the project were (1) to locate and describe all consolidated rocks found in place at the surface, or penetrated by drilling or other means; (2) to correlate these rocks geologically; (3) to assemble this information and the valid geological inferences from it into cross sections and maps showing the type of bedrock, thickness of overburden and rock structure; and (4) to write appropriate commends so that the potential usefulness and the most promising sites for future exploration or expansion for stone quarries can be readily seen and be of maximum value. The report was prepared with the knowledge that its chief immediate use would be by highway engineers and geologists, county engineers, materials producers, and prospectors. To facilitate their use of the report, certain phases were stressed and some standard methods of presentation and arrangement were not rigidly followed. The scientific integrity of the report is not compromised by these deviations from the formal scientific writing practices, nor is the value of the report for other uses thereby lessened.]]></description>
      <pubDate>Wed, 15 May 2019 18:40:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1601566</guid>
    </item>
    <item>
      <title>Degradation-Related Changes in Ballast Gradation and Aggregate Particle Morphology</title>
      <link>https://trid.trb.org/View/1460880</link>
      <description><![CDATA[Ballast degradation or fouling often associated with deteriorating railroad track performance refers to the condition of a new ballast layer changing its aggregate particle size and shape properties with usage. Fouling is mainly due to degradation or breakage of ballast aggregates under traffic loading, although other fine materials intruding can also contaminate a clean and uniformly graded ballast layer. Previous research efforts have focused on studying the degraded ballast behavior of clean ballast aggregates mixed with finer materials such as sand, mineral filler, subgrade clay, and coal dust. However, this approach cannot fully represent the cases where fouled ballast composition is made up of aggregate particle breakdown or intrusion of foreign materials. In the field, over two-thirds of the ballast fouling cases are due to ballast aggregate particle abrasion and breakage, which necessitates a better basic understanding of the field degradation trends and the related changes in ballast gradation and aggregate particle morphology. This paper describes an experimental approach to quantify ballast gradation and aggregate morphological properties at different stages of degradation studied through Los Angeles (LA) abrasion testing and aggregate image analysis technique in the laboratory. The results from this experimental study were intended to quantify changes in ballast gradation and aggregate morphological properties due to the LA abrasion–based degradation process and link different physical properties of the ballast material to the previously defined fouling index (FI) as a practical indicator of fouling conditions. A good correlation was found between percent changes in aggregate shape properties quantified by image analysis of ballast particles larger than 9.5 mm (3/8  in.) and the number of turns of the LA abrasion drum. Further, the study findings are also linked to the field degradation trends reported in the literature, which necessitates ballast gradation and aggregate shape property changes also be tracked in the field and better documented to the FI when studying fouled ballast behavior.]]></description>
      <pubDate>Tue, 28 Mar 2017 17:08:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1460880</guid>
    </item>
    <item>
      <title>Dynamic Modelling of High Speed Ballasted Railway Tracks: Analysis of the Behaviour</title>
      <link>https://trid.trb.org/View/1447119</link>
      <description><![CDATA[The aim of the paper is to present a numerical model for a ballasted railway track that includes the dynamic effect of a moving train load and predicts the values of the vertical stiffness of the infrastructure. This model is therefore deemed to be a tool for the evaluation of the state of the track during service situations as well as a predictive model of the behaviour of the system. Consequently, it will be very useful when sizing the cross section of a new railway line is required.  The main modelling tool is the finite element method. In regard to this, the application of damping elements to avoid the elastic wave reflection on the boundaries of the numerical domain will be studied. The proposed dynamic analysis consider the change in time of the value of the train load, but not the change in position along the tracks.  In the end, a set of suggestions for the numerical model with moving loads will be summarize aiming for the mitigation of the unusual behaviour of the contact surface between the ballast and the sleepers.]]></description>
      <pubDate>Mon, 27 Feb 2017 09:38:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1447119</guid>
    </item>
    <item>
      <title>PFC2D Simulation Research on Vibrating Compaction Test of Soil and Rock Aggregate Mixture</title>
      <link>https://trid.trb.org/View/1104852</link>
      <description><![CDATA[In this study, the Particle Flow Code in 2 Dimensions (PFC2D) discrete element modeling program is applied to simulate the vibrating compaction process of soil and rock aggregate mixtures. Different gradations of soil and rock aggregate mixtures are considered; and the porosity and dry density values of the soil and rock aggregate mixtures are tracked during the simulation. The compaction curve is consistent to the physical test. The particle motion pattern and density formation mechanism are investigated during the vibrating compaction simulation. The particle flow behavior and the structural properties of the particles of different gradations are discussed.]]></description>
      <pubDate>Tue, 28 Jun 2011 14:00:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1104852</guid>
    </item>
    <item>
      <title>Laboratory Validation of Coal Dust Fouled Ballast Discrete Element Model</title>
      <link>https://trid.trb.org/View/935430</link>
      <description><![CDATA[Fouling refers to the condition of railroad ballast when voids in this unbound aggregate layer are filled with relatively finer materials or fouling agents commonly from the ballast aggregate breakdown, outside contamination, or from subgrade soil intrusion. When ballast gets fouled, this unbound layer may not adequately serve its primary functions to provide drainage and structural support under the repeated loading applied by trains. Coal dust fouling has been identified as one of the most critical fouling scenarios as it significantly decreases the strength and stability of railroad ballast. A Discrete Element Modeling (DEM) approach was adopted in this study to investigate the coal dust fouled ballast performances. A DEM program BLOKS3D was used to employ realistic three-dimensional polyhedrons as discrete elements generated through digital imaging of aggregate particles. An appropriate DEM model parameter calibration process was carried out to predict both the clean ballast condition and the partially to fully coal dust fouled ballast behavior as obtained from laboratory shear box tests, which properly validated the BLOKS3D DEM simulations.]]></description>
      <pubDate>Wed, 13 Oct 2010 14:53:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/935430</guid>
    </item>
    <item>
      <title>A Probabilistic Model for Predicting the Resistance of Aggregates in Asphalt Mixes to Fracture</title>
      <link>https://trid.trb.org/View/924991</link>
      <description><![CDATA[Increased loads on asphalt pavements have lead to the development of asphalt mixes that rely on stone-on-stone contacts in resisting applied loads. These mixtures tend to experience high forces at the contact points that could cause aggregate fracture and make the asphalt pavements more prone to distresses such as cracking and permanent deformation. This paper introduces an approach to express the probability of aggregate fracture in asphalt mixes as a function of the contact bond strength and internal force distribution at the contact points. The internal force distribution was obtained using a discrete element model of the internal structure of asphalt mixtures subjected to loading. The contact bond strength was determined using statistical analysis of the results of a single aggregate crushing test. The developed approach can be used to determine the asphalt mixture design and aggregate properties that minimize fracture and achieve desirable mixture performance.]]></description>
      <pubDate>Thu, 19 Aug 2010 11:16:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/924991</guid>
    </item>
    <item>
      <title>Field Assessment of the Performance of a Ballasted Rail Track with and without Geosynthetics</title>
      <link>https://trid.trb.org/View/923592</link>
      <description><![CDATA[Understanding the complex mechanisms of stress transfer and strain accumulation in layers of track substructure under repeated wheel loading is essential to predict the desirable track maintenance cycle as well as the design of the new track. Various finite element and analytical techniques have been developed in the past to understand the behavior of composite track layers subjected to repeated wheel loads. The mechanical behavior of ballast is influenced by several factors, including the track confining pressure, type of aggregates, and the number of loading cycles. A field trial was conducted on an instrumented track at Bulli, New South Wales, Australia, with the specific aims of studying the benefits of a geocomposite installed at the ballast-capping interface, and to evaluate the performance of moderately graded recycled ballast in comparison to traditionally very uniform fresh ballast. It was found that recycled ballast can be effectively reused if reinforced with a geocomposite. It was also found that geocomposite can effectively reduce vertical and lateral strains of the ballast with obvious implications for improved track stability and reduced maintenance costs.]]></description>
      <pubDate>Fri, 30 Jul 2010 08:28:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/923592</guid>
    </item>
    <item>
      <title>Pervious Concrete: Compaction and Aggregate Gradation</title>
      <link>https://trid.trb.org/View/913093</link>
      <description><![CDATA[Traditional portland cement concrete (PCC) and pervious concrete are very different. Open questions therefore exist regarding the suitability of applying current standard concrete testing protocols to pervious concrete. There are unique pervious concrete features that may require special testing considerations. Pervious concrete compaction and consolidation are examined in this paper. Cylindrical specimen preparation techniques are presented in this study that will produce laboratory specimens similar to those of field pervious concrete slab. Additionally the authors provide a simple correlation to allow concrete designers to estimate pervious concrete porosity based on its aggregate bulk density when crushed limestone is used. When designing pervious concrete mixtures, this practical tool saves time.]]></description>
      <pubDate>Fri, 19 Feb 2010 10:58:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/913093</guid>
    </item>
    <item>
      <title>Roadbase Reconsolidation</title>
      <link>https://trid.trb.org/View/794954</link>
      <description><![CDATA[This paper describes how roadbase reconsolidation retains old pavement and roadbed gravel and compacts both into consolidation with sublayer soil and requires less gravel to restore road surface. Crumbled pavement fragments are shielded from leaching into groundwater by the layer of new pavement.]]></description>
      <pubDate>Fri, 29 Dec 2006 11:07:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/794954</guid>
    </item>
    <item>
      <title>GEOTECHNICAL CHARACTERIZATION OF THE STEEPLY DIPPING PIERRE SHALE</title>
      <link>https://trid.trb.org/View/754364</link>
      <description><![CDATA[This study compares alternative approaches for differentiating and characterizing the swelling potential of steeply dipping strata in the Pierre Shale along the Colorado Front Range Urban Corridor.  The hazard associated with this geologic setting is commonly referred to as heaving bedrock because adjacent strata expand to different degrees and may cause damaging differential deformation to residential and light commercial structures. This study is part of a larger investigation aimed at determining the feasibility of using reflectance spectroscopy, a remote sending technology, to identify and characterize the swelling potential of expansive soils and bedrock.  A trench in the Upper Pierre Shale was logged and 252 samples were taken horizontally with thin-walled brass tubes.  Grain size, Atterberg Limits, filter paper suction, and clod tests provided, for each of the samples, the swell potential indices and rankings according to schemes proposed by Seed, Chen, and McKeen.  Swell-consolidation tests provided percent swell pressure indices under in-situ surcharge pressures.  All the indices are consistent in that they suggest that trench wall can be differentiated into two zones of steeply dipping strata overlain by a horizontal and shallow overburden soil.  However, the schemes differ in that McKeen's indices vary over a significantly broader range of categories compared with the Seed and Chen indices.  McKeen's indices and also the swell-consolidation indices have two advantages compared with Seed's and Chen's indices.  They are obtained on relatively undisturbed materials and they are properties involved in quantitative heave prediction models.  These advantages suggest that McKeen's scheme is providing the most sensitive and useful basis for differentiating semi-quantitative categories of swelling potential at this site.]]></description>
      <pubDate>Mon, 28 Mar 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/754364</guid>
    </item>
    <item>
      <title>IMPORTANCE OF GROUND WATER STUDIES TO HIGHWAY ENGINEERING</title>
      <link>https://trid.trb.org/View/722900</link>
      <description><![CDATA[This paper describes how, reports on groundwater resources are destined to be of increasing value to the highway engineer.  As more information is learned about the occurrence and movement of groundwater and the importance of its control in highway construction and maintenance, reports describing groundwater conditions and the related geology in various parts of the country have been published.  These groundwater reports and the records on which they are based are a great resource for the highway engineer.  The chief contributors to the highway engineers' work are the geologic data and information relative to groundwater conditions, and descriptions of methods used to determine the hydraulic properties of earth materials.  In Ohio, as a result of the cooperative program between the Geological Survey and the Ohio Division of Water, water-resources reports covering all or parts of six counties have been published and reports on eight more are in progress.]]></description>
      <pubDate>Tue, 13 Aug 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/722900</guid>
    </item>
    <item>
      <title>A PRECISION TRIAXIAL APPARATUS USING SMALL SIZE SPECIMENS AND STRENGTH PROPERTIES OF SOFT CLAY</title>
      <link>https://trid.trb.org/View/638105</link>
      <description><![CDATA[A precision triaxial test apparatus (PTA) using small specimens 15 mm (0.6 in) in diameter and 35 mm (1.4 in) in height was developed recently and its applicability is examined for Mito clay deposits.  In this paper, the PTA is outlined, and the strength properties of undisturbed Mito clay, which is normally a consolidated natural deposit, and its remolded clay are examined through consolidated undrained triaxial compression and extension tests using the PTA.  The PTA was able to evaluate the strength properties of triaxial compression and extension such as the coefficient of earth pressure at rest, rate of strength increase, effective angle of friction and the effect of strain rate.]]></description>
      <pubDate>Sun, 31 Dec 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/638105</guid>
    </item>
    <item>
      <title>RE-ORGANIZATION OF US RAILWAY SYSTEMS</title>
      <link>https://trid.trb.org/View/656379</link>
      <description><![CDATA[As much as the railroad industry has improved its cost structure, its physical plant and its financial performance over the last 20 years, it continues to have significant shortcomings.  When looking at transportation in global terms, it's obvious that a railroad serving only one coast is handicapped because it may miss out on future changes in worldwide trading patterns.  The biggest problem for the rail industry is that it hasn't been able to earn its cost of capital.  This speech details that the next logical step in the evolution of the North American rail industry is the formation of railroads stretching from ocean to ocean and coast to coast. This will have economic consequences for the maritime industry in general and for ports in particular.]]></description>
      <pubDate>Fri, 02 Jun 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/656379</guid>
    </item>
  </channel>
</rss>