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    <title>Transport Research International Documentation (TRID)</title>
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    <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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <title>Validating Inverse Stereology Methods to Generate Two Dimensional Area Gradations for Computational Modeling</title>
      <link>https://trid.trb.org/View/1495187</link>
      <description><![CDATA[During the past few years, several researchers have employed computational methods to model and investigate the influence of several different factors on the overall behavior of asphalt mixture composites.  Two-dimensional models, particularly those with computationally generated geometries, are commonly used on account of their computational efficiency.  A critical input in such exercises is the two-dimensional distribution of aggregates in a given cross section, which needs to be generated from a representative three-dimensional volumetric gradation.  This can be typically achieved using some form of transformation such as inverse stereology.  The goal of this study was to determine the effectiveness of the inverse stereology approach when compared with the true two-dimensional area gradation observed in laboratory compacted hot mix asphalt (HMA) specimens.  The results from this study show that an inverse stereology approach based on a polyhedron shape was effective in replicating the two-dimensional area gradation created by cutting a laboratory specimen.]]></description>
      <pubDate>Fri, 23 Feb 2018 16:28:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/1495187</guid>
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    <item>
      <title>Estimating the gradation of asphalt mixtures using x-ray computerized tomography and stereology method</title>
      <link>https://trid.trb.org/View/1119670</link>
      <description><![CDATA[This paper presents an attempt at using X-ray computerized tomography (CT) and stereology method to estimate the gradation of asphalt mixtures. The three-dimensional (3-D) volumetric gradation of coarse aggregate under the assumption of spherical aggregate can be estimated from two-dimensional (2-D) area gradation using X-ray CT, which is a nondestructive test technique to obtain batch of slice images, analyzing these 2-D slice images, and applying stereology method, which is a probability statistical theory. Between the gradations of spherical aggregate assumption and mechanical sieving there is error, and it is proposed to employ a simple method of converting the gradation of spherical aggregate assumption to that of mechanical sieving. Furthermore, so that comparison between these two gradations can be made, a correction factor C is used to convert the gradation of spherical aggregate assumption to that of mechanical sieving.]]></description>
      <pubDate>Tue, 25 Oct 2011 11:45:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1119670</guid>
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      <title>Stereology- and Morphology-Based Pore Structure Descriptors of Enhanced Porosity (Pervious) Concretes</title>
      <link>https://trid.trb.org/View/902385</link>
      <description><![CDATA[In the structural and functional performance of enhanced porosity concrete (EPC) (or pervious concrete) and other macroporous materials, porosity, pore sizes and their distribution, connectivity, and specific surface area and other pore structure features play dominant roles. Analysis of such EPC features is dealt with in this paper using mathematical morphology and stereological techniques. Similar porosity values for the studied mixtures were provided by a morphological method based on two-point correlation and stereological methods based on area and line fractions. Lower porosity was shown by single-sized aggregate EPC mixtures than blended aggregate mixtures. Smaller pore sizes are found to result from higher proportions of smaller sized aggregates in the mixture. There is definition of an effective pore diameter based on a critical size based on opening granulometric density function, a two-point correlation based characteristic size, and pore size distribution of equivalent diameters. The pore sizes of the blended aggregate mixtures lie in between those of mixtures in which single-sized aggregates make up the blend. Good correspondence is seen between the inverse of the specific surface areas of pores and the effective pore diameter and correlation lengths, whereas there is linear relation of the mean free spacing between pores and these quantities. There is comparison of stereology-based three-dimensional pore distribution density indicating preconnectivity and a hydraulic connectivity factor for permeability, and the latter is shown to be a more sensitive parameter through which EPC specimens made with different size aggregates can be distinguished.]]></description>
      <pubDate>Fri, 30 Oct 2009 09:25:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/902385</guid>
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      <title>Stereological Principles of Spatial Modeling Applied to Steel Fiber-Reinforced Concrete in Tension</title>
      <link>https://trid.trb.org/View/890396</link>
      <description><![CDATA[Steel fiber-reinforced concrete's (SFRC's) mechanical properties partly depend on microreinforcement's dispersion characteristics. A straightforward approach to spatial modeling of concrete leading crack fiber reinforcement is offered through the established geometrical probability theory (integral geometry, stereology). There is introduction, discussion, and application of these theoretical principles to SFRC in tension, yielding fiber contribution general expressions to stress transfer over the leading crack for both the post-ultimate and ultimate domains. Fiber anisotropy resulting from fiber reorientation that comes from filling the mold and compaction, and from specimen slenderness, is involved. The same methodological approach used for specific cases of fiber geometry and type, as well as stress transfer mechanics, can be used to elaborate the expressions. Quantitative image analysis should be used to obtain global three-dimensional actual fiber structure information. Necessary analytical framework elaboration that uses the same stereological principles to form the basis on sampling and data collection strategies demonstrates this. And finally, there is discussion of economic and reliable approaches based only on vertical slice X-ray projects or only on vertical sections.]]></description>
      <pubDate>Tue, 30 Jun 2009 08:32:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/890396</guid>
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    <item>
      <title>Workability of SCC: Roles of Its Constituents and Measurement Techniques</title>
      <link>https://trid.trb.org/View/811074</link>
      <description><![CDATA[This book describes how self-consolidating concrete (SCC) is a highly flowable, yet stable concrete that can spread readily into place, fill the formwork, and encapsulate the reinforcement without any mechanical consolidation and without undergoing any significant separation of material constituents. It describes how SCC has many advantages over conventional concrete, such as: eliminating the need for vibration; decreasing the construction time and labor cost; reducing noise pollution; improving the filling capacity of highly congested structural members; improving the interfacial transitional zone between cement paste and  aggregate or reinforcement; decreasing the permeability and improving durability of concrete; and facilitating constructability and ensuring good structural performance. SCC has been attracting more and more attention worldwide since its introduction in the late 1980s. New applications for SCC are being explored in the book. In order to promote and encourage the use of SCC, ACI Committee 236, Material Science of Concrete, and ACI Committee 237, Self-Consolidating Concrete, organized two technical sessions on the “Workability of SCC: Roles of Its Constituents and Measurement Techniques” at the ACI Spring 2005 Convention in New York City, New York.  This publication contains 10 of the papers presented at the sessions. Six of the papers deal with the mixture proportions and the effects of raw materials on workability; two of them deal with the rheometer testing of SCC; one deals with form pressure; and one deals with the structural response of SCC frames under earthquake loading.]]></description>
      <pubDate>Fri, 22 Jun 2007 09:17:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/811074</guid>
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    <item>
      <title>A New, Portable Rheometer for Fresh Self-Consolidating Concrete</title>
      <link>https://trid.trb.org/View/811088</link>
      <description><![CDATA[This paper describes how the accurate determination of fresh concrete rheology is key in ensuring the production of self-consolidating concrete (SCC) is successful. However, rheometers are used infrequently in the field and empirical test methods are most commonly used to determine SCC workability despite measuring quantities that are related to rheological parameters only in an indirect way, if at all. Instead of using multiple empirical test methods to measure the workability of SCC, it is desirable to use a rheometer in both the laboratory and field to determine the flow properties of SCC quickly. Existing rheometers are generally unsuitable for routine field use because of their large size, high cost, or both. This paper describes the use of the International Center for Aggregates Research (ICAR) rheometer, a low-cost, fully portable device that can measure concrete mixtures ranging in workability from approximately 50 mm in slump to SCC. Laboratory test results of SCC mixtures and field testing experience are presented to demonstrate the validity and practicality of the ICAR rheometer.]]></description>
      <pubDate>Fri, 22 Jun 2007 09:17:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/811088</guid>
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    <item>
      <title>Coarse Aggregate and Self-Consolidating Concrete Passing Ability</title>
      <link>https://trid.trb.org/View/811087</link>
      <description><![CDATA[This paper examines the effect of aggregate content and gradation on self consolidating concrete (SCC) passing ability. Passing ability is defined as an SCC mixture’s ability to flow through narrow spaces without segregating or blocking. The mixtures tested ranged over two uniform aggregate sizes, two aggregate contents, two different mixture design philosophies, and a gradated aggregate mixture. Passing ability tests, slump flow tests, horizontal flow tests, and stereology tests were performed on these mixtures. Stereology is a statistical counting technique used primarily by natural scientists and concrete researchers have used sterolog to describe bubble size and distribution in concrete. A vertical flow box was developed by McBride to determine the passing ability of the various mixtures. Various bar spacings are tested. From the results of this study, it seems that two stereology parameters can be correlated to the minimum bar spacing that will allow SCC to pass. These parameters are the ratio of maximum aggregate size to mean aggregate free distance and the ratio of maximum aggregate size to mean aggregate random spacing.]]></description>
      <pubDate>Fri, 22 Jun 2007 09:17:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/811087</guid>
    </item>
    <item>
      <title>Size Characterisation of Pore Structure for Estimating Transport Properties of Cement Paste</title>
      <link>https://trid.trb.org/View/766939</link>
      <description><![CDATA[The conventional experimental approaches to assessing pore structure characteristics (e.g. mercury intrusion porosimetry) in cement paste have difficulties in providing reliable results. This problem can be approached by geometrical statistical and mathematical methods, e.g. stereological analysis and mathematical morphological measurements. This paper deals with the application of these methods to section images of cement paste specimens and presents a representative set of results of size characterization of pore structure in cement pastes with various water cement ratios and degrees of maturity. The size characterization of pore space allows direct prediction of paste permeability with empirical relationships. However, only porosity, pore size, and eventually porosity connectivity (i.e. connected fraction of porosity) are taken into account in the conventional models for estimating permeability of cement pastes, such as the Kozeny-Carman equation and the Katz-Thompson equation. These simplified models cannot provide accurate estimation of paste permeability without significant improvements. Accurate predictions of cement paste permeability and of other transport properties require incorporating information on how the pores are interconnected, i.e., on topology characteristics of pore structure. This requirement can be fulfilled by pore network modeling, which reflects pore size distribution and the complex situation of connectivity in pore space. Potential applications of mathematical morphology methods for constructing the pore network model and thereby estimating transport properties of cement paste are also discussed in this contribution.]]></description>
      <pubDate>Fri, 02 Dec 2005 11:18:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/766939</guid>
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    <item>
      <title>QUANTITATIVE DESCRIPTION OF COARSE AGGREGATE VOLUME FRACTION GRADIENTS</title>
      <link>https://trid.trb.org/View/675191</link>
      <description><![CDATA[Within any cast cylinder of concrete, the coarse aggregate will tend to be inhomogeneously distributed.  This variability may arise as a result of segregation caused by gravity or as a result of the wall effect that is caused by the inability of the aggregate to penetrate the walls of the mold.  Using methods from image analysis, stereology, and statistics, this study defined local estimates of aggregate inhomogeneity that quantify phenomena that have been qualitatively described in the past. The methods involved modification of the two-dimensional images to prepare them for analysis, as well as simple diagnostic statistics for determining the presence of a wall effect.  While the techniques were developed specifically for cast cylinders, they can be generalized to other cast or cored concrete specimens.  Details of the image analysis procedures are appended.]]></description>
      <pubDate>Sun, 25 Feb 2001 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/675191</guid>
    </item>
    <item>
      <title>ANALYSIS OF COMPRESSIVE STRESS-INDUCED CRACKS IN CONCRETE</title>
      <link>https://trid.trb.org/View/542158</link>
      <description><![CDATA[This paper presents the results of experimental studies of the micromechanical behavior of concrete under different loading conditions.  Cylindrical specimens of normal- and high-strength concrete were tested under uniaxial and confined compression. Cracks and pores in the concrete specimens were impregnated with an alloy that has a low melting point.  At the stress of interest, this alloy was solidified to preserve the stress-induced microcracks as they exist under load and images from the cross sections of the concrete specimens obtained using scanning electron microscopy.  Stereological analysis that interprets three-dimensional structures by means of two-dimensional sections was used on the computerized images to determine the density, orientation, and branching of the compressive stress-induced microcracks and the effect of confinement on microcrack behavior.  The density and branching of the microcracks decreased as the confining stress increased.  The confining stress had a pronounced influence on microcracks in the interfacial transition zone between the cement paste and aggregate.  The amount of interfacial cracking decreased significantly as the confining stress was increased.  Under uniaxial compression there were significant differences in the crack patterns observed in normal- and high-strength concretes. Under confined conditions, the two types of concrete had similar microcrack patterns.]]></description>
      <pubDate>Sun, 27 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/542158</guid>
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