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    <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" />
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    <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>
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    <item>
      <title>Predicting Dynamic Shear Modulus of Asphalt Mastics using Discretized-Element Simulation and Reinforcement Mechanisms</title>
      <link>https://trid.trb.org/View/1630627</link>
      <description><![CDATA[Dynamic shear modulus of an asphalt mastic has a remarkable effect on the mechanical performance of an asphalt pavement, and particulate composite micromechanical models are proven to be suitable for the prediction of modulus of asphalt mastics. However, the prediction accuracy of the current micromechanical models decreases sharply at a high filler concentration and high temperature (or low frequency). This study aims to develop a modified micromechanical model that can be applied to predict modulus of asphalt mastics at a wide range of frequencies and filler concentrations. Dynamic shear rheometer (DSR) tests are performed using asphalt mastics with four filler concentrations, and three-dimensional discrete-element method (DEM) is implemented to validate the DSR tests and obtain additional master curves of asphalt mastics with different filler concentrations. The reinforcement mechanisms are introduced into the micromechanical models to predict the laboratory test results with an increase of the prediction accuracy. The numerical results show that the test data is repeated by the DEM simulation, which is believed to be a promising tool to present the rheological behavior of asphalt matrix and asphalt mastics. The modified micromechanical viscoelastic model can predict the dynamic shear modulus of asphalt mastics successfully at high filler concentration and low frequency.]]></description>
      <pubDate>Wed, 21 Aug 2019 09:35:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1630627</guid>
    </item>
    <item>
      <title>Asphalt pavement rutting simulated using granular micromechanics-based rate-dependent damage-plasticity model</title>
      <link>https://trid.trb.org/View/1639930</link>
      <description><![CDATA[Repeated application of vehicle loads on the asphalt pavement creates permanent deformations and surface cracks. Simulation of this pavement distress has posed severe challenges due to the granular nature of the pavement materials. In this paper, the granular micromechanics approach is used in a thermo-mechanical framework to obtain the constitutive relationships for the non-linear rate-dependent granular materials with damage and plasticity. The developed constitutive relationships were validated and verified with experimental data and implemented into a non-standard finite-element (FE) framework to simulate asphalt pavement performance under the repeated traffic load. The FE model was subjected to different repeated load levels to demonstrate response nonlinearity. The applied load was subsequently removed and pavement was allowed to recover to a stress free condition to obtain the permanent deformation. The simulations results demonstrated that 30% increase in the applied load causes approximately 127% increase in the rutting depth at the centre of the applied load. Critically horizontal tensile plastic strains were observed near tire edge, indicating top-down cracking of pavement under the applied load. The presented approach provides an alternative for simulating asphalt pavement rutting by incorporating the effects of micro-scale mechanisms on the macro-scale rutting response in an FE framework. The advantage of the granular micromechanical approach is that the damage, plastic potential and flow rule are defined using simple 1d functions at micro-scale, in contrast to tensorial formulation of complex plastic potentials, damage functions and rules for their evolution in conventional approaches.]]></description>
      <pubDate>Tue, 30 Jul 2019 15:56:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/1639930</guid>
    </item>
    <item>
      <title>Investigation of the Mechanical Properties of Engineered Cementitious Composites with Low Fiber Content and with Crumb Rubber and High Fly Ash Content</title>
      <link>https://trid.trb.org/View/1589161</link>
      <description><![CDATA[Engineered cementitious composites (ECCs) are a type of micromechanically-designed cementitious composite reinforced with a moderate volume fraction of short fiber, typically 2% by volume. ECCs form steady-state multiple cracking that considerably improves the tensile strength and ductility of traditional concrete. In this study, the properties of matrix and the interface of ECCs were tailored through the use of crumb rubber, different types of sand, and different replacement levels of cement with fly ash. The study examined the effect of sand replacement with crumb rubber (20% by volume), two types of river sands (coarse and fine), increasing the content of class F fly ash (up to 75% cement replacement), and low fiber content (1.75%) on the mechanical properties of ECCs. Compressive strength, uniaxial tensile, and third-point bending tests were performed to characterize the properties of ECC mixes. Experimental results demonstrated that increasing fly ash content and using crumb rubber favored ductility of the composites. However, higher fly ash contents and a low water-to-binder (W/B) ratio produced lower strengths as these limited the pozzolanic reaction of fly ash making it act partially as a filler. While incorporation of crumb rubber showed adverse effects on the tensile strength of ECC materials (up to 26% decrease), the tensile ductility of ECC materials improved significantly (up to 434% improvement). Moreover, the implementation of different types of sand produced minor effects on the mechanical properties of ECCs. Overall, a tradeoff between the strength and ductility of the composites was detected, which highlights the implications of matrix/interface tailoring in the overall performance of ECC.]]></description>
      <pubDate>Mon, 22 Apr 2019 16:06:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1589161</guid>
    </item>
    <item>
      <title>Micromechanical Particle Interactions in Railway Ballast through DEM Simulations of Direct Shear Tests</title>
      <link>https://trid.trb.org/View/1590755</link>
      <description><![CDATA[Particle shape properties can significantly affect the load response behavior and field performance of the uniformly graded ballast layer in railway track structures. Particle contact and the related micromechanical behavior of the unbound aggregate ballast layer assembly influenced by the particle shape properties have not yet been thoroughly investigated. In this study, an aggregate imaging and particle shape-analysis approach based on computer vision technology was introduced to calculate aggregate morphological indices and construct polyhedral discrete elements with shapes close to realistic ballast aggregate particles. A model of direct shear test on railway ballast based on the discrete-element method (DEM) was developed using generated nonbreakable discrete elements as individual ballast particles and validated by closely matching the predicted shear stress–strain behavior with laboratory test results. The DEM model simulation predictions were then used to investigate the relations between microscale interactions of individual ballast particles, particle size effects in relation to shear box test equipment dimensions, and macroscale behavior trends of the aggregate assemblies. Stronger particle interactions and higher coordination numbers were observed as the imaging-based angularity index (AI) and flat and elongated (F&E) ratio increased. Furthermore, limiting individual particle movement was shown to increase strength and provide greater resistance to failure and deformation.]]></description>
      <pubDate>Thu, 18 Apr 2019 11:04:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/1590755</guid>
    </item>
    <item>
      <title>Micromechanics-based investigation of fatigue deterioration of engineered cementitious composite (ECC)</title>
      <link>https://trid.trb.org/View/1464209</link>
      <description><![CDATA[This paper reports fatigue deterioration of engineered cementitious composite (ECC), a unique high-performance fiber-reinforced concrete featuring high ductility. Sources of fatigue dependency in ECC microscopic constituent properties were discovered experimentally. These fatigue-dependent fiber and fiber/matrix interface properties were incorporated into a novel multi-scale mechanics-based analytical model to reveal the influences of fatigue dependency on the fiber-bridging and fatigue crack propagation in ECC. The flexural stress-fatigue life (S-N) of ECC were predicted and compared with experimental results. It was found that several fatigue-induced changes of microscopic constituent properties contribute to the fatigue deterioration of fiber bridging of ECC. As a result, saturation of multiple cracks (and thus strain capacity) of ECC was much reduced under fatigue. The flexural fatigue model incorporating the fatigue-dependent fiber-bridging constitutive model developed in this study could be used to predict the flexural stress-fatigue life of ECC and the resulting S-N curve agreed well with experimental results.]]></description>
      <pubDate>Mon, 15 May 2017 15:16:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1464209</guid>
    </item>
    <item>
      <title>Research of the micromechanics of composite materials with polymer matrix failure under static loading using the acoustic emission method</title>
      <link>https://trid.trb.org/View/1461181</link>
      <description><![CDATA[Micromechanics of composite materials’ failure has been investigated under static loading by means of acoustic emission (AE) method. The results showed that for samples made of fiberglass with transverse fibers with respect to the applied load, the process of destruction both in the deformation parameters and in the parameters of total AE has two stages of damage accumulation. At the same time the parameter of total AE shows that the process of destruction begins 5–6% earlier than it is shown by the deformation parameter. Also the nature of the total AE change was analysed.]]></description>
      <pubDate>Mon, 01 May 2017 09:45:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1461181</guid>
    </item>
    <item>
      <title>Characterization of Asphalt Material Moisture Susceptibility Using Multiple-Scale Methods</title>
      <link>https://trid.trb.org/View/1438053</link>
      <description><![CDATA[Moisture damage, a common disease of asphalt pavements, seriously deteriorates pavement’s performance and durability. Currently, researchers pay most attention to macro investigation of moisture damage in asphalt materials. However, moisture damage in asphalt materials can be attributed to the complex interactions between water, asphalt and aggregates occurring at the micro level so that macro tests cannot provide precise insight into this process and its mechanisms. To this end, two promising micromechanical tests, atomic force microscopy (AFM) and nanoindentation, were used in this paper to capture the micromechanical properties of asphalt binder and mixture samples before and after moisture damage. For data comparison and systematic evaluation, surface energy method and freeze-thaw splitting test were also performed. Results show that AFM and nanoindentation are promising methods in investigation of asphalt materials’ moisture damage because they can quantitatively determine the loss of asphalt samples’ strength and also differentiate their damage types (adhesion or cohesion failure). Surface energy method and freeze-thaw splitting test correlate well with AFM and nanoindentation in characterization of moisture susceptibility of asphalt binder and mixture samples. It is concluded that these four testing methods can achieve a systematic and accurate evaluation of asphalt materials’ moisture resistance.]]></description>
      <pubDate>Thu, 26 Jan 2017 14:32:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/1438053</guid>
    </item>
    <item>
      <title>The micromechanical signature of high-volume natural pozzolan concrete by combined statistical nanoindentation and SEM-EDS analyses</title>
      <link>https://trid.trb.org/View/1436697</link>
      <description><![CDATA[Although concrete sustainability can be remarkably improved by replacing high amounts of Portland cement clinker with supplementary cementitious materials (SCMs), this approach is far from being fully exploited. To compete with conventional concrete, a better understanding of low-cement concrete is needed regarding both microstructural features responsible for mechanical performance and key parameters for robust mix design. In particular, this paper aims at disclosing the microstructure of cementitious systems in which up to 60% of Portland cement has been replaced with natural pozzolan (NP), without significantly affecting the 90-day mechanical strength and stiffness (using a fixed water-to-binder ratio of 0.35). The study carries out coupled nanoindentation/energy-dispersive X-ray spectroscopy analyses, micromechanics modelling and image analysis to disclose the mechanical effects of NP on the overall stiffness and strength (i.e., the formation of a micro-granular skeleton of hard anhydrous inclusions and the transformation of Portlandite into calcium-aluminum-silicate-hydrate [C-A-S-H]).]]></description>
      <pubDate>Mon, 19 Dec 2016 18:18:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1436697</guid>
    </item>
    <item>
      <title>A micromechanics-based fatigue dependent fiber-bridging constitutive model</title>
      <link>https://trid.trb.org/View/1428154</link>
      <description><![CDATA[Fiber-reinforced cementitious composites (FRCC) represent a large group of construction and building materials. While numerous experimental studies have been conducted on fatigue of FRCC, predicting FRCC fatigue performance remains difficult. This paper proposes a novel multi-scale analytical model to capture the fatigue dependency of fiber bridging constitutive law in FRCC. On the micro-scale, a new analytical model to predict the post-fatigue single-fiber pullout behavior (P-u curve) is established based on the understanding of the fatigue dependency of fiber and fiber-matrix interface. On the macro-scale, the fatigue-induced fiber strength reduction was considered and probabilistics is introduced to describe the randomness of fiber location and orientation so that the fatigue dependent fiber-bridging constitutive law can be predicted. The model proposed in this paper is the first analytical model that is able to capture the effects of fatigue cycle as well as the fatigue loading level on deterioration of fiber bridging in FRCC.]]></description>
      <pubDate>Sat, 19 Nov 2016 17:45:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/1428154</guid>
    </item>
    <item>
      <title>Numerical modelling of porous cement-based materials by superabsorbent polymers</title>
      <link>https://trid.trb.org/View/1428159</link>
      <description><![CDATA[The development of new cementitious materials raises new challenges with regard to structural design. One of the potential applications of superabsorbent polymers (SAP) is to deliver well-defined porosity to cement systems. This is particularly interesting for the development of porous cement-based materials with high technical performance. In this paper, a numerical approach to model the basic mechanical properties of the porous cement with SAP is developed. The modelling approach is based on computational micromechanics and uses a representative volume element that emulates the microstructure of the cement-based material to determine the overall material response and the local behaviour. Using this approach several sensitivity analyses are undertaken examining various parameters. The modelling approach is compared with experimental results showing reasonable correlation. The proposed approach provides faster and cheaper tool to design porous materials due to a reduction in the required experimental effort.]]></description>
      <pubDate>Sat, 19 Nov 2016 17:45:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1428159</guid>
    </item>
    <item>
      <title>Mechanical regains due to self-healing in cementitious materials: Experimental measurements and micro-mechanical model</title>
      <link>https://trid.trb.org/View/1397366</link>
      <description><![CDATA[This paper focuses on mechanical regains that can be obtained due to self-healing of cementitious materials. Experimentally, small cracks with a width of around 10 µm were healed by water immersion and corresponding regains were assessed by means of three-point-bending tests. A general discussion about stiffness and strength regains is provided with the help of newly introduced indices. Besides, the first comprehensive finite element model to characterise the micro-mechanical properties of the healing products is introduced, based on the coupling of the microstructural hydration model CEMHYD3D and the finite element code Cast3M. The main objective is to analyse the healing potential and rate, as well as the nature of the healing products. The nature of the simulated healing products is in agreement with observation conducted using SEM/EDX on artificial cracks created at early age.]]></description>
      <pubDate>Tue, 29 Mar 2016 11:33:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1397366</guid>
    </item>
    <item>
      <title>Micromechanics-Based Analysis of the Effect of Aggregate Homogeneity on the Uniaxial Penetration Test of Asphalt Mixes</title>
      <link>https://trid.trb.org/View/1392576</link>
      <description><![CDATA[This paper, based on microstructure-based discrete element method (DEM), is to investigate the effect of vertical aggregate homogeneity, i.e. aggregate homogeneity in vertical cross sections, on the uniaxial penetration test of asphalt mixes. An aggregate homogeneity index, used to evaluate the aggregate homogeneity in a two-dimensional (2D) cross section, was briefly introduced; the vertical aggregate distribution was evaluated by the index. Microstructure-based discrete element modeling of a uniaxial penetration test was accomplished by a discrete element program called Particle flow code in two dimensions (PFC2D). The effect of vertical aggregate homogeneity on the penetration strengths with regard to a uniaxial penetration test was simulated by the DEM; the obtained results were verified by uniaxial penetration testing. Results show that the effect of vertical aggregate homogeneity on the penetration strengths can be numerically simulated by the microstructure-based DEM. The penetration strengths in the uniaxial penetration test are anisotropic; further, the vertical aggregate homogeneity dominates the variations in the penetration strengths in the uniaxial penetration test. Furthermore, it is revealed that there is a good correlation between vertical aggregate homogeneity and variations in the penetration strengths.]]></description>
      <pubDate>Tue, 22 Mar 2016 22:15:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1392576</guid>
    </item>
    <item>
      <title>Microstructural Analysis of Porous Asphalt Concrete Mix Subjected to Rolling Truck Tire Loads</title>
      <link>https://trid.trb.org/View/1394389</link>
      <description><![CDATA[Porous asphalt concrete (PAC) course is best known for its noise reduction and improved wet skid resistance characteristics. Nevertheless, the use of PAC is associated with reduced lifetimes and high maintenance costs, mainly owing to various distress mechanisms such as raveling. Therefore, it is necessary to have a better understanding of the stress states associated at the micromechanical level, that is, at the mastic–aggregate interfacial zone and the mastic itself. For this purpose, it is necessary to develop micromechanical finite element (FE) models that are composed of realistic asphalt mix meshes with different phases that are subjected to rolling wheel loads. A framework is presented to develop a three-dimensional FE model capable of simulating a rolling wide-base truck tire over an asphalt pavement surface. From results of FE simulations, the stress states at the mastic and mastic–aggregate interfacial layer were studied. For the analyzed surface of the PAC mix, it was observed that the mastic phase registered high stress states compared with the mastic–aggregate interfacial phase, suggesting that the sample may experience a cohesive failure in the long run. The developed methodology also provides a tool to analyze the influence of tire operating conditions such as tire inflation pressures and loads on the stress states of asphalt mixes. Finally, the micromechanical stress response of PAC mix was compared with that of other conventional asphalt mix designs, and it was found that the magnitude of stresses developed in the mastic of PAC are higher compared with the conventional asphalt mix designs.]]></description>
      <pubDate>Mon, 07 Mar 2016 17:18:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1394389</guid>
    </item>
    <item>
      <title>A new model for the cracking process and tensile ductility of Strain Hardening Cementitious Composites (SHCC)</title>
      <link>https://trid.trb.org/View/1376359</link>
      <description><![CDATA[Strain Hardening Cementitious Composites (SHCC) are materials exhibiting tensile hardening behavior up to several percent strain accompanied by the formation of fine multiple cracks. Their tensile ductility is governed by the spacing and opening of cracks, which depend on the stress transfer between the fibers and the matrix. In this article, a new analytic model which takes into consideration the effects of non-uniform matrix strength, post-cracking increase in fiber bridging stress and fiber rupture on stress transfer and multiple cracking behavior of SHCC is developed. Using material parameters within the range reported in the literature, simulation results can reach reasonable agreement with test data on SHCC for two different fiber contents. The effect of fiber length on tensile behavior of SHCC is then simulated to illustrate the applicability of the model to material design. The new model should be helpful to the micromechanics-based design of SHCC for various ductility requirements.]]></description>
      <pubDate>Tue, 15 Dec 2015 11:07:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/1376359</guid>
    </item>
    <item>
      <title>Microporomechanics study of anisotropy of ASR under loading</title>
      <link>https://trid.trb.org/View/1373235</link>
      <description><![CDATA[In this article, the authors introduce a new micromechanical model for alkali–silica reaction. Their idea was to build a model with the following characteristics. First, the model has to be simple enough to be used to compute damage under loading and chemical attack at the level of each element in a structure code. Second, its parameters must be easy to identify on available alkali–silica reaction lab experiments. The authors have chosen to model the behavior of concrete containing aggregates such that most of the damage occurs in the cement paste. Using micromechanics and an energy criterion, the model remains analytical except for the minimization of the energy. The parameters were identified on Multon's triaxial experiments and good results were obtained for compressive loadings up to 10 MPa.]]></description>
      <pubDate>Tue, 17 Nov 2015 08:24:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/1373235</guid>
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