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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>
    <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>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Feasibility of one side 3-D scanning for characterizing aggregate shape</title>
      <link>https://trid.trb.org/View/1628155</link>
      <description><![CDATA[The objective of this paper is to investigate the feasibility of one side 3-D scanning (OSS) method for the shape characterization of aggregate particles in 3-D. Seventy-two typical crushed stone particles and 77 typical gravel particles were selected for the investigation. Each selected particle was tested 3 times by the OSS method using a handheld 3-D laser scanner with randomly resting it on a flat plane. The size and shape indicators were calculated for each OSS test and the optimized results were also obtained by a proposed optimizing procedure in accordance with the results of the 3 times of OSS tests. The whole digital particle (WDP) data of each selected particle was acquired at the same time and the WDP based size and shape indicators were calculated as the references of the feasibility investigation. The statistical tests of all sizes and shape indicators between each OSS based result set and WDP based result set were performed. The OSS based length (L) and thickness (T) show good reliability for each test. Not every OSS test can obtain reliable results of width (W). However, the optimized results of all the 3 OSS based size indicators have enough reliability. All the shape indicators derived from the optimized OSS based size indicators also have enough reliability. The OSS method with employing the optimized results based on multiple (3 or more) tests is statistically feasible. And it is a time-saving way which is suitable for extensive testing in engineering application.]]></description>
      <pubDate>Wed, 14 Aug 2019 14:31:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1628155</guid>
    </item>
    <item>
      <title>Discrete Element Modeling for the Superpave Gyratory Compactor Test of Asphalt Mixture: Analysis of Contact Model Parameters</title>
      <link>https://trid.trb.org/View/1572335</link>
      <description><![CDATA[This study established the ball-based and the clump-based Discrete Element Method (DEM) simulation of the Superpave Gyratory Compactor (SGC) tests. The Burger’s model and the contact bond model were employed to simulate the compaction behavior of asphalt mixture. The influence of the contact model parameters, such as the friction coefficient (f sub s) and viscosity parameters (E sub k, E sub m, η sub k, and η sub m) and bond strength (T sub s), upon the compatibility of asphalt mixture were simulated through the established ball-based SGC DEM models. Based on the sensitivity analysis of the contact parameters and the lab test results, a micro-parameters calibration method was proposed. This method produced a simulation that displayed good congruity. The influence of aggregates shapes was also investigated through lab tests and the clump-based DEM simulation of three groups of samples with rounded, fractured, and original coarse aggregates shapes. The friction coefficient was found to have significant influence on the initial and final void ratio; bond strength was critical to the changes in trend of void ratio. In contrast, viscosity parameters in the Burger’s model were found to have limited influence on the compatibility. With respect to aggregates shape, the clump-based SGC DEM models, except during the unstable early stage of compaction, were found to have good congruity with lab tests. Furthermore, fractured and rounded coarse aggregates produced a negative trend with respect to void ratio when compared with the original specimens in both lab tests and DEM simulation.]]></description>
      <pubDate>Sat, 02 Mar 2019 15:41:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/1572335</guid>
    </item>
    <item>
      <title>A digital image analysis of gravel aggregate using CT scanning technique</title>
      <link>https://trid.trb.org/View/1502620</link>
      <description><![CDATA[Particle shape is one of the most important factors which affects the gravel aggregate’s properties. It is also one of the important factors that directly affects the performance of asphalt pavements. In this paper, the gravel aggregate of quartzite was studied by using the industrial computed tomography (CT) instrument. MATLAB was used to capture the aggregate slice properties including reverse color, median filtering, noise reduction, binarization and so on. The three-dimensional (3D) aggregate model was reconstructed by using the software of MIMICS. The 3D model of the aggregate was further optimized. The best fitting cuboid, cylinder, cone and sphere information of the aggregate were obtained by using the characteristics analysis function.]]></description>
      <pubDate>Thu, 08 Mar 2018 10:46:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/1502620</guid>
    </item>
    <item>
      <title>Prediction Models for Skid Resistance of Asphalt Pavements and Seal Coat</title>
      <link>https://trid.trb.org/View/1496823</link>
      <description><![CDATA[Maintaining adequate level of skid resistance is essential for road safety. As part of their regular maintenance program, many departments of transportation collect skid data on roads to ensure sufficient traction between road surface and vehicle tires. This study developed models for skid resistance of asphalt mix and seal coat surfaces. These models express the skid number over time as a function of aggregate gradation, aggregate resistance to abrasion and polishing, and traffic level. The researchers examined 70 test sections in this study, half of which had an asphalt mix surface while the other half had seal coat surfaces. Skid data were collected using a skid trailer while surface friction characteristics of the test sections were evaluated using a dynamic friction tester and circular texture meter. In addition, the change in aggregate shape properties due to abrasion and polishing was studied using the Micro-Deval test and Aggregate Image Measurement System (AIMS). The results demonstrated that the developed models provide good correlation with the skid measurements in the field. This study produced a revised version of a utility called skid analysis of asphalt pavement (SAAP) that incorporates the new models for skid resistance of both asphalt mixes and seal coat. The SAAP can be used by pavement management agencies and contractors to estimate the skid resistance over time.]]></description>
      <pubDate>Tue, 06 Mar 2018 16:22:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496823</guid>
    </item>
    <item>
      <title>Evaluation of the AIMS2 and Micro-Deval to Characterize Aggregate Friction Properties</title>
      <link>https://trid.trb.org/View/1465433</link>
      <description><![CDATA[This National Center for Asphalt Technology (NCAT) report is a summary of a study performed at NCAT by Auburn University Civil Engineering graduate student Mary Greer. Details of the study are reported in her Master's Thesis as part of her qualifications for a Master of Science Degree in May 2015. There is a need for a laboratory protocol to rapidly evaluate the quality of aggregate friction properties for use in an asphalt surface. Aggregates with good friction resist polishing and retain their shape characteristics. An asphalt surface needs to maintain adequate friction as it is polished by traffic to ensure motorists' safety on the roadway. Some current laboratory procedures used to evaluate the friction properties of aggregates are time consuming and subjective. The purpose of this research study was to evaluate the correlation of aggregate field friction performance to aggregate properties using a laboratory protocol consisting of the second generation Aggregate Imaging Measurement System Model AFA2A (AIMS2) and Micro-Deval. The test protocol used the AIMS2 device to quantify aggregate shape characteristics (angularity, texture, and form) before and after polishing in the Micro-Deval. The aggregates were selected for their friction performance in asphalt surfaces at the NCAT Test Track. Field friction performance was measured with the locked-wheel skid trailer. Aggregate angularity and texture indexes were compared with the skid trailer field measurements to determine if a correlation could be established. The AIMS2 device detected changes in aggregate shape after conditioning in the Micro-Deval. However, the analysis did not establish good correlation between the AIMS2 indexes and the field friction data using the test protocol developed in this research study. Additional studies are needed to expand the aggregate types and enhance the laboratory test protocol to verify these conclusions or improve the ability of the test to correlate to field friction performance.]]></description>
      <pubDate>Mon, 22 May 2017 17:06:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/1465433</guid>
    </item>
    <item>
      <title>Characterisation of unbound aggregate materials considering physical and morphological properties</title>
      <link>https://trid.trb.org/View/1448393</link>
      <description><![CDATA[The objective of this paper is to evaluate the factors affecting resilient and permanent deformation behaviour of unbound granular materials, with a focus on the aggregate physical and morphological characteristics. To evaluate the behaviour of base course, repeated load triaxial testing is commonly used to establish the stress-dependent resilient modulus properties of unbound aggregate base and subbase materials. Although resilient modulus of aggregates is a critical input into mechanistic-empirical pavement design methods, the resilient modulus of unbound base material is often estimated from empirical correlations with index properties in the AASHTOWare Pavement ME design procedure for its simplicity. Since actual field stress conditions and resilient modulus stress states are generally quite different from those generated in the empirical test methods, use of an empirical correlation could lead to an unreliable prediction of resilient modulus and permanent deformation. In order to properly assess the stability of an unbound aggregate layer, it is necessary to establish a proper process to understand the factors affecting fundamental and performance-related properties of unbound granular materials. In this study, aggregate samples from four different sources were tested for resilient modulus and Poisson’s ratio measurements using the Precision Unbound Material Analyzer equipment. Morphological or shape properties of aggregate samples were also measured using an image analysis device. The results demonstrate that aggregate physical and morphological properties affect aggregate resilient modulus and permanent deformation. Further, it is suggested that the resilient modulus of the aggregate should not be used as the sole indicator of rutting performance of aggregate base.]]></description>
      <pubDate>Sun, 19 Mar 2017 18:01:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1448393</guid>
    </item>
    <item>
      <title>Aggregates for Thin Maintenance Surfaces</title>
      <link>https://trid.trb.org/View/1392138</link>
      <description><![CDATA[Important qualities of aggregates used for thin maintenance surface (TMS) include aggregates wear and skid resistance, shape, gradation, and size. The wear and skid resistance of an aggregate influences the lifetime of the individual aggregate particles, and thus the lifetime of the TMS. A TMS’s effectiveness is impacted by the shape, gradation, and size of the aggregate used for the surfacing material along with the lifetime of the aggregate.]]></description>
      <pubDate>Mon, 11 Jan 2016 17:23:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/1392138</guid>
    </item>
    <item>
      <title>Investigation of the effect of aggregates' morphology on concrete creep properties by numerical simulations</title>
      <link>https://trid.trb.org/View/1362018</link>
      <description><![CDATA[Prestress losses due to creep of concrete is a matter of interest for long-term operations of nuclear power plants containment buildings. Experimental studies by Granger (1995) have shown that concretes with similar formulations have different creep behaviors. The aim of this paper is to numerically investigate the effect of size distribution and shape of elastic inclusions on the long-term creep of concrete. Several microstructures with prescribed size distribution and spherical or polyhedral shape of inclusions are generated. By using the 3D numerical homogenization procedure for viscoelastic microstructures proposed by Šmilauer and Bažant (2010), it is shown that the size distribution and shape of inclusions have no measurable influence on the overall creep behavior. Moreover, a mean-field estimate provides close predictions. An Interfacial Transition Zone was introduced according to the model of Nadeau (2003). It is shown that this feature of concrete's microstructure can explain differences between creep behaviors.]]></description>
      <pubDate>Tue, 25 Aug 2015 21:43:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1362018</guid>
    </item>
    <item>
      <title>Study of Cost-Effective Methods for Recovery of Skid Resistance on Concrete Pavement</title>
      <link>https://trid.trb.org/View/1337439</link>
      <description><![CDATA[Rapid reduction in skid resistance on concrete pavements inside tunnels has long been suffered all over Japan. As a result of comprehensive research and study on the expressways operated by NEXCO, it became clear that the decrease in skid resistance in tunnel sections is caused by the polishing action by vehicles’ tires passing without water. It was also speculated that higher skid resistance can be sustained as with larger macro-texture, even after the texture is polished by vehicles passing. It was further confirmed that the shape of macro-texture also affects skid resistance; angular-shaped positive macro-texture assures higher resistance. Finally judging from the experiments on surface roughening methods for the skid resistance recovery on the concrete road surface, shot-blast with bigger steel balls was proved to be the most cost-effective way.]]></description>
      <pubDate>Mon, 26 Jan 2015 13:23:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1337439</guid>
    </item>
    <item>
      <title>Experimental and Stress-Dilatancy Investigation of Mechanical Behavior for Asphalt Mixture</title>
      <link>https://trid.trb.org/View/1316789</link>
      <description><![CDATA[It is important to understand the mechanism of dilation for asphalt pavement design. In this paper dilatancy theories are discussed including Rowe's and Roscoe's stress-dilatancy, and so on. The uniaxial compressive test is employed to measure dilation of asphalt mixtures under various test temperatures. Radial and volume changes of asphalt mixture specimens are obtained by UTM-25 multifunctional material system and special radial displacement transducers. The test result is illustrated through Reynolds' dilatancy theory. The experimental result shows that the test temperature and time were found to play an important role on the dilation behavior of asphalt mixtures. The dilation characteristics are affected by the aggregate properties such as density, friction coefficient, shape, and angular size. Thus, the constitutive of dilation of asphalt mixture should be considered according to the aforementioned points. Analysis using Reynolds' dilatancy theory suggests that the dilation is governed by the kinematic constraints imposed by the aggregate skeleton.]]></description>
      <pubDate>Wed, 03 Sep 2014 10:32:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1316789</guid>
    </item>
    <item>
      <title>Comparison of Surface Energy Values of Limestone with Respect to Different 3D Surface Roughness Measurements</title>
      <link>https://trid.trb.org/View/1310174</link>
      <description><![CDATA[Moisture damage is one of the most important factors affecting durability of asphalt pavements. Selection of appropriate aggregates with optimum properties will help to improve the quality and durability of pavements. Recent studies showed that contact angle measurement using sessile drop instrument is an economical and convenient method for determining the surface energy of solid aggregates. However, there are few studies which compared contact angle measured on aggregate surface with varying surface roughness. Therefore, the present study is intended to compare contact angles measured on limestone which is polished with different grade Silicon carbide grits to reduce surface roughness. Contact angles were measured at selected points using probe liquids such as water, ethylene glycol and diiodomethane. In addition, measurements of surface roughness were made using three-dimensional optical profilometer. Also, using the contact angle measured, surface energy components were calculated. Energy ratio and compatibility ratio parameter of limestone with PG 64-22 were determined using the surface energy components. From the present study, it was observed that surface roughness could cause variations in contact angle measurements which could be minimized by appropriate polishing of aggregate surface.]]></description>
      <pubDate>Wed, 04 Jun 2014 08:57:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/1310174</guid>
    </item>
    <item>
      <title>Mechanistic Modeling of Unbound Granular Materials</title>
      <link>https://trid.trb.org/View/892757</link>
      <description><![CDATA[Several tests are used for characterizing unbound granular materials for pavement applications. The California Bearing Ratio (CBR), resilient modulus (MR), Dynamic Cone Penetrometer (DCP) tests are three of the most common tests used for this purpose. The objective of this research is twofold. The first is to develop numerical models for these three tests. The second is to investigate the relationship between basic material properties, boundary conditions, and test results, ultimately, to develop a physics-based correlation between these tests. A 3-D discrete element method (DEM) based model is adapted to simulate these tests. Good agreement is observed between the results of the simulations and sample numerical and experimental studies on granular materials. The DEM code is used to determine effects of aggregate shape, coefficient of friction, gradation, stiffness and other details on test results. The model is also used to investigate statistics of inter-particle interaction between the granular particles.]]></description>
      <pubDate>Wed, 08 Jul 2009 16:32:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/892757</guid>
    </item>
    <item>
      <title>Determining Representative Volume Elements of Asphalt Concrete Mixtures Without Damage</title>
      <link>https://trid.trb.org/View/881218</link>
      <description><![CDATA[This study presents a simple method to define the representative volume elements (RVEs) of asphalt concrete mixtures without damage. Three currently used asphalt concrete mixtures (two dense-graded Superpave® mixtures with different nominal maximum aggregate sizes of 9.5 and 12.5 mm and one stone matrix asphalt mixture with a nominal maximum aggregate size of 19.0 mm) were selected and evaluated. To address the significant heterogeneity of asphalt concrete mixtures properly in defining RVEs, several geometrical factors, such as area fraction, gradation, orientation, and the distribution of aggregate particles in asphalt concrete mixtures, were all considered together by using two-dimensional images of actual asphalt concrete inner structures produced by digital-image processing. Geometrically defined RVEs were then supported by finite element simulations to check whether effective nondamage material properties obtained from the RVEs, such as the linear viscoelastic dynamic modulus, were representative of the corresponding bulk asphalt concrete mixture. Analysis results indicated that typical dense-graded Superpave asphalt concrete mixtures can be characterized by their effective nondamage properties with an approximate RVE size of 50 mm. However, the properties of stone matrix asphalt mixtures, which contain larger aggregates, should be measured on a larger scale for improved accuracy. Findings from this study were generally consistent with results of other studies performed on the basis of extensive laboratory tests, which implies that the simple geometrical–numerical method here can be a potentially efficient approach to define the RVEs of asphalt mixtures with much less time and effort.]]></description>
      <pubDate>Mon, 23 Mar 2009 07:40:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/881218</guid>
    </item>
    <item>
      <title>Mixture Design and Performance-Based Specifications for Cold Patching Mixtures</title>
      <link>https://trid.trb.org/View/865194</link>
      <description><![CDATA[Cold patching asphalt mixtures constitute an essential element for the maintenance and rehabilitation of pavement infrastructure. Although this maintenance technique is both expensive and time consuming, it can minimize further damage and costly future repairs as well as increase user and vehicle safety. As a result, cold patching mixture performance is critical. Unfortunately, there is a lack of standard mixture design guidelines for homemade mixtures and performance-based mixture specifications for both homemade and containerized mixtures to ensure satisfactory field performance. This report presents a homemade mixture design for cold and wet weather areas by identifying the failure mechanisms of cold patching mixtures and analyzing the effects of gradation, aggregate shape, binder content and viscosity, curing time, temperature, and admixtures on the mixture workability and stability. Laboratory and accelerated pavement testing (APT) procedures are specifically defined for use with cold patching mixtures. Protocols and procedures are also defined for the field evaluations of these mixtures. Results from field evaluations are used as overall relative measures of field performance and as validation for those results obtained from laboratory and accelerated pavement tests. Furthermore, testing results, in conjunction with testing procedures developed as part of this project, are used to provide recommendations for performance-based specifications for homemade and containerized cold patching mixtures. Such recommendations provide interim guidelines for the rejection or approval of such mixtures. Overall, the protocols and testing procedures discussed in this report help ensure the material characteristics necessary for desired patch performance in the field, which in turn reduces the failure rate and makes cold patching a more cost-effective maintenance operation.]]></description>
      <pubDate>Fri, 01 Aug 2008 16:43:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/865194</guid>
    </item>
    <item>
      <title>Relationship of Aggregate Texture to Asphalt Pavement Skid Resistance Using Image Analysis of Aggregate Shape</title>
      <link>https://trid.trb.org/View/860353</link>
      <description><![CDATA[This Innovations Deserving Exploratory Analysis (IDEA) project conducted a detailed analysis of aggregate texture and its relationship to pavement skid resistance.  A new method was developed for the evaluation of aggregate resistance to polishing.  This method relies on the Micro-Deval test as the mechanism for polishing aggregates and the Aggregate Imaging System (AIMS) for quantifying the change in texture due to polishing.  Test results showed that the Micro-Deval test is an effective method for polishing aggregates within a short time.  Also, the AIMS texture analysis is able to rapidly and accurately quantify the influence of polishing on texture.  The verification of the new method was achieved through measuring the skid resistance of pavements constructed using three different aggregate sources and three different aggregate gradations.  The skid resistance was found to be related not only to average aggregate texture, but also to the texture distribution within an aggregate sample.  The developed method can be used in models for predicting the change in asphalt pavement skid resistance as a function of aggregate texture, mixture properties, and environmental conditions.]]></description>
      <pubDate>Wed, 04 Jun 2008 17:18:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/860353</guid>
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