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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>
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    <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>Application of Maturity to Estimate the Strength Development of High-Early-Strength Concrete Mixtures Using Isothermal Calorimetry</title>
      <link>https://trid.trb.org/View/2344676</link>
      <description><![CDATA[Repair materials for concrete infrastructure applications are designed to minimize closure time and subsequent effect on traffic. Available material choices are typically limited to expensive prepackaged materials or high-early-strength (HES) concrete mixtures. HES concrete mixtures are often designed with high paste content and limited inclusion of supplementary cementitious materials so to promote higher early-age strengths. The traditional approval for HES concrete mixtures has relied on testing the strength of concrete cylinders cured at room temperature. This practice has often resulted in the overdesign of these HES mixtures, primarily because it fails to consider the higher temperatures that typically develop during the in situ curing. Moreover, as highlighted in several reports by state agencies, the high cement content and the near absence of proper curing practices have likely contributed to the premature failure of some of these mixtures. In this study, isothermal calorimetry was explored as a potential tool to quickly evaluate HES concrete formulations in terms of early-age mechanical performance. It was found that this test method, when combined with maturity, can provide reasonable estimations of the concrete strength development for isothermal and nonisothermal curing conditions up to 8 h after the initial mix. The proposed test method can be used as a first step in the optimization of HES concrete mixtures and can help predicting the time to reopening for in situ conditions.]]></description>
      <pubDate>Fri, 29 Mar 2024 16:58:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2344676</guid>
    </item>
    <item>
      <title>Passive Deicing Technology</title>
      <link>https://trid.trb.org/View/1739031</link>
      <description><![CDATA[This report describes results from applying a proprietary passive snow melting/deicing technology which uses natural geothermal energy. It draws low temperature heat from the underground constant temperature layer with a minimum temperature loss to heat up a surface pavement, such as highways, airport runways, taxi ways and aprons, parking lots and sidewalks. It does not require any external supplemental energy, such as electrical power. or heated fluid. It avoids requirements for manpower and machinery to plow snow or distribute chemicals. It prevents the formation of black ice. Currently the snow melting agents commonly used are alcohols, chemicals, and/or salts, which corrode and destroy the pavement structure and cause pollution of the soil, water and atmosphere. In addition, mechanical snow removal has the following disadvantages: • Need to use professional snow removal machinery. • Large investment. • Energy consumption, high operating costs. The main feature of the GX technology is that a closed vessel partially filled (small percentage) with the proprietary isothermal heat transfer medium (the Medium) becomes a very high heat conductivity device. The Medium consists of organic and inorganic chemical compounds that impart high heat flux and high thermal conductivity to the vessel. There are no toxic or radioactive materials used. The operating temperature range is -40 deg. C to +70 deg. C. In use, the size of the device (for paving usually a tube) can be based on the actual size of the pavement. The number and spacing of the installation arrangement of the tubes has the following characteristics: 1. One-time installation, without post-maintenance, can maintain long-term operation. 2. Continuously heated surface from the underground constant temperature layer. 3. Immediate snowmelt without external energy source and no ice formation. 4. The construction method is simple. 5. No environmental impact. 6. Since GX tube is not liquid filled, there will be no road surface cracking or damage due to thermal expansion of the tubes such as in the case of a thermal pump system. 7. The passive GX heating system provides an even temperature distribution on the pavement surface and will have slowly changing temperature difference between the mean ground temperature and the surface temperature, and between seasonal ambient temperature changes.]]></description>
      <pubDate>Tue, 29 Sep 2020 11:19:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1739031</guid>
    </item>
    <item>
      <title>Effect of Admixed and External Chlorides on Transport of Chlorides in Concrete</title>
      <link>https://trid.trb.org/View/1663205</link>
      <description><![CDATA[The binding of chlorides by the hydration products of cement in concrete is one of the factors that affects the rate of chloride ingress, which in turn can influence the time to corrosion initiation of reinforcing steel in concrete. Theoretical assessments of the influence of chloride binding on the chloride ingress and service life estimates are often based on empirically developed chloride binding isotherms to account for the interaction between the concrete matrix and external chlorides. While being useful, these assessments disregard the binding influence of admixed chlorides that may be present in the concrete from the early stages of hydration. It is suspected that the presence of free admixed chlorides can influence the diffusivity of chlorides in concrete. This work focuses on determining the binding behavior of admixed chlorides and proposes a modified diffusion model that takes chloride binding from admixed and external chlorides into consideration.]]></description>
      <pubDate>Thu, 14 Nov 2019 09:32:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1663205</guid>
    </item>
    <item>
      <title>Influence of temperature on water vapour sorption isotherms and kinetics of hardened cement paste and concrete</title>
      <link>https://trid.trb.org/View/1440999</link>
      <description><![CDATA[Water vapour sorption isotherms (WVSIs) have contributed significantly towards current knowledge of the porous nanostructure of cementitious materials and are an important component in modern durability calculations. In this paper, two newly developed multi-chamber testing apparatuses for determining WVSIs of hardened cementitious materials are described. The adsorption, desorption and scanning behaviour of hardened cement paste and concrete are studied in detail over temperatures of 23°C to 80°C. Experiments provide confirmation of a monotonic reduction in sorption hysteresis with increasing temperature and show a disappearance of low humidity hysteresis by 60°C. Time and history dependence of apparent isosteric enthalpy of adsorption is demonstrated. Typically overlooked anomalous (non-Fickian) sorption kinetics are observed to significantly influence the equilibrium process. The magnitude and effect of temperature and humidity on kinetics is examined. Evidence supporting the role of microstructural change in observed size-independent kinetics and WVSI changes with temperature are discussed.]]></description>
      <pubDate>Sat, 14 Jan 2017 17:18:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/1440999</guid>
    </item>
    <item>
      <title>Indirect assessment of hydraulic diffusivity and permeability for unsaturated cement-based material from sorptivity</title>
      <link>https://trid.trb.org/View/1400970</link>
      <description><![CDATA[The hydraulic diffusivity, water permeability and relative gas permeability for cement-based materials are indirectly evaluated from measured sorptivity and water vapor sorption isotherms (WVSIs). The dependence of sorptivity on initial saturation degree is first established to help calculate hydraulic diffusivity and other transport properties. An experimental program with a self-scaled preconditioning strategy is also carefully designed and conducted on three concretes to measure their sorptivity, WVSIs as well as permeability to various fluids. It's found that hydraulic diffusivity of ambiguous physical significance may be not a good durability indicator. The predicted water permeability is larger than measured value but at the same order of magnitude. This overestimation is attributed to the required drying preconditioning. The predicted relative water permeability agrees well with reported data. However, the predicted relative gas permeability agrees with the measured data from classical CEMBUREAU method better than that from tri-axial permeameter with higher inlet gas pressure.]]></description>
      <pubDate>Mon, 18 Apr 2016 12:31:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/1400970</guid>
    </item>
    <item>
      <title>Prediction of water vapour sorption isotherms and microstructure of hardened Portland cement pastes</title>
      <link>https://trid.trb.org/View/1396170</link>
      <description><![CDATA[Water vapour sorption isotherms of cementitious materials reflect the multi-scale physical microstructure through its interaction with moisture. Our ability to understand and predict adsorption and desorption behaviour is essential in the application of modern performance-based approaches to durability analysis, along with many other areas of hygro-mechanical and hygro-chemo-mechanical behaviour. In this paper, a new physically based model for predicting water vapour sorption isotherms of arbitrary hardened Portland cement pastes is presented. Established thermodynamic principles, applied to a microstructure model that develops with hydration, provide a rational basis for predictions. Closed-form differentiable equations, along with a rational consideration of hysteresis and scanning phenomena, makes the model suitable for use in numerical moisture simulations. The microstructure model is reconciled with recently published ¹H nuclear magnetic resonance (NMR) and mercury intrusion porosimetry results.]]></description>
      <pubDate>Sun, 06 Mar 2016 16:49:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/1396170</guid>
    </item>
    <item>
      <title>Numerical Simulation of Sorption-Desorption Isotherme for Cement-Based Materials</title>
      <link>https://trid.trb.org/View/1369186</link>
      <description><![CDATA[One of the most important issues in civil engineering about structures is their durability. A structure during his lifetime faces different environmental situations, like different relative humidities, and different cycles of drying and saturation will be imposed on it, so it is very critical to characterize materials behavior against these changes. Some informations are needed to predict it, one of these informations is desorption and sorption isotherm. In cement based materials just as cement paste, there remain generally extremely fine pores, consequently obtaining isotherms experimentally is considered as a substantially time-consuming experience. Therefore, it is of interest to model the isotherm from a numerical point of view. This physical phenomenon has been a field of study of intense researches, however, there are not many models relying on true physical effects which take place during drying and saturation. In the present work, in order to model a porous media, a numerical morphology of the geometry of the porous media has been presented by means of a random field excursion through the selection of a random field and a threshold. Random field parameters are defined based on experimental values. Once the porous media has been reproduced, the morphological analysis must be done in order to model water transfers.]]></description>
      <pubDate>Wed, 30 Sep 2015 09:09:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/1369186</guid>
    </item>
    <item>
      <title>Experimental Study of Temperature Effects on Water Vapour Sorption and Moisture Transport Phenomena</title>
      <link>https://trid.trb.org/View/1369172</link>
      <description><![CDATA[Water vapour sorption isotherms (WVSIs) provide a relationship between the mass of adsorbed water within pores and the prevailing relative humidity; they are a reflection of the material microstructure. One aspect of cementitious material WVSIs that has not been firmly established is the effect of elevated temperatures. In this paper, two newly developed multi-chamber WVSI testing apparatus are described. These apparatus have been used to study the adsorption and desorption isotherms and kinetics of HCP and concrete at various temperatures. Results show a two-stage equilibrium process in desorption studies, where the initial stage is associated with diffusive moisture transport, and the second appears associated with a time-dependent loss of hysteresis moisture.]]></description>
      <pubDate>Mon, 28 Sep 2015 08:57:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/1369172</guid>
    </item>
    <item>
      <title>Quantitative discrimination of the nano-pore-structure of cement paste during drying: New insights from water sorption isotherms</title>
      <link>https://trid.trb.org/View/1363461</link>
      <description><![CDATA[A new ability to quantitatively evaluate the complex pore system of cement pastes, using water sorption isotherms, is used to illuminate: (a) evolutions of microstructure during drying, (b) the mechanisms that control drying shrinkage, and (c) a novel method to compute the original w/c (i.e., water-to-cement ratio, mass basis). Each of these points has significant implications on concrete performance and durability in engineering practice. The authors show that irreversible changes in the nanostructure during first drying are associated with changes in the pores that empty between ≈  85-and-45% relative humidity (RH). It is also shown that water in the interlayer space (e.g., similar to clays) of the binding calcium–silicate–hydrate (C–S–H) phase, does not empty until drying below ≈ 25% RH. However, this water, once removed, does not completely re-saturate the pore spaces even at nearly 100% RH — for time scales on the order of weeks. With the ability to specifically identify the volume of pores associated with the C–S–H gel, as opposed to the larger capillary pores and the smaller interlayer spaces, a method for computing the original w/c (and hence cement content), of cementitious material is proposed. These results suggest improved methods for evaluating and modeling the engineering behavior of cement-based materials.]]></description>
      <pubDate>Tue, 25 Aug 2015 21:44:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/1363461</guid>
    </item>
    <item>
      <title>Bimodal behavior of C-S-H interpreted from short-term length change and water vapor sorption isotherms of hardened cement paste</title>
      <link>https://trid.trb.org/View/1362055</link>
      <description><![CDATA[Short-term length change isotherms (SLCIs) and water vapor sorption isotherms are useful to eliminate the effects of the colloidal features of calcium-silicate-hydrate (C-S-H). SLCIs of hardened cement pastes initially conditioned by drying to equilibrium at different relative humidities (RHs) were measured over a complete RH loop between 5% and 98%. Based on the correlation between incremental thickness of adsorption and incremental strain from 40% to 98% RH, the basal spacing of C-S-H above 40% RH appears to increase further with increasing water vapor sorption. However, no correlation of these values was found from 5% to 40% RH and the basal spacing is considered stable in this domain. These properties of C-S-H are directly related to its isothermal volume change as a function of RH. It can be concluded that the dominant shrinkage driver above 40% RH is disjoining or hydration pressure and that below 40% RH is change in surface energy.]]></description>
      <pubDate>Tue, 25 Aug 2015 21:44:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1362055</guid>
    </item>
    <item>
      <title>Representative volume element estimation for desorption isotherm of concrete with sliced samples</title>
      <link>https://trid.trb.org/View/1363458</link>
      <description><![CDATA[The aim of this study is to determine the Representative Volume Element (RVE) size related to the desorption isotherm on concrete. Slices of three thicknesses taken from cast cylinders of an ordinary portland cement (OPC) concrete were desorbed from fully saturated condition to the dry state. The slice thickness had no clear influence on the water content once mass stabilization was reached. A method is being proposed to determine the RVE based on a statistical analysis of the water contents (or water saturation degrees) of the slices. The results show that a sample with the volume 7d³ may be considered as the RVE of an OPC concrete (d is the maximum aggregate size).]]></description>
      <pubDate>Tue, 25 Aug 2015 21:43:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1363458</guid>
    </item>
    <item>
      <title>MODELING OF DRYING SHRINKAGE OF POROUS MATERIALS BASED ON INTERMOLECULAR FORCE</title>
      <link>https://trid.trb.org/View/1351617</link>
      <description><![CDATA[In enormous previous studies, researches assumed the geometry of pore is cylindrical, although they considered the effect of ink bottle pore. However, recent High-Resolution TEM studies shows the globule of C-S-H particle is plate-like or disk-like. According to this fact, the authors assume that the interlayer pore and small gel pore should be shaped slit-like pore. On the other hand, large gel pore which is existed between globule flocs in C-S-H gel has the two different type pore, one is slit-like pore, the other is cylindrical pore. Both adsorption/desorption isotherm and shrinkage/swelling change is determined by the change of Gibbs free energy Ω of such C-S-H gel system. Gibbs free energy Ω of C-S-H gel is formulated by considering of several interfacial force, in particular, disjoining pressure such as van der Waals force, effectrostatic force and hydration force. A local minimum of Ω determined the distance of plate for slit-like pore, the water content in cylindrical pore, which is corresponding the ambient relative humidity. Stress was obtained by differentiating Ω. Considering the variation of elasticity of paste with RH. The authors' model with thermodynamic approach provides a fairly good reproduction of the previous experimental data about both adsorption/desorption diagrams and shrinkage/swelling diagram.本研究はセメント硬化体の処女乾燥・再吸着時の乾燥収縮量を予測するために、従来用いられてきたセメント硬化体の細孔形状を円筒形と仮定されて構築された円筒形細孔モデルと、セメント内部の一部分を二つの平板が成すスリット状細孔と考え、熱力学的アプローチからスリット状細孔モデルを構築し、それらを組み合わせることで乾燥収縮のヒステリシスループを再現することが出来た。また乾燥収縮量の詳しい値に乖離が見られたためパラメータ等を吟味し、精度を上げることで改善されると考える。]]></description>
      <pubDate>Thu, 30 Apr 2015 09:23:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1351617</guid>
    </item>
    <item>
      <title>Modelling a Temperature Regime of a Railway Track Structure and its Comparison with the Results of Experimental Measurements</title>
      <link>https://trid.trb.org/View/1339918</link>
      <description><![CDATA[Following the completed experimental monitoring of the temperature regime of the construction of a subgrade structure on the experimental stand of the Departments Railway Engineering and Track Management and measurement of thermal conductivity coefficients λ of building materials used in construction of a subgrade structure, there are constructed mathematical models, which are designed to not only verify the temperatures obtained in individual structural components of subgrade structure of experimental stand, but also the possibility to use appropriate software to model temperature regime of other types of constructions of subgrade structures. The paper presents mathematical models for the typical winter periods, which have been recorded since the beginning of the experimental measurements conducted from 2003 to the end of the winter period of 2013 using the software SV-HEAT SVOFFICE SoilVision and there are also comparisons presented in achieving the position of zero isotherm in the construction of a subgrade structure. At the end of this paper, some of the knowledge obtained from the mathematical modelling of the temperature regime of the construction of a subgrade structure and confrontations with the temperature regime of a monitored, real railway track are underlined.]]></description>
      <pubDate>Mon, 02 Feb 2015 10:27:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1339918</guid>
    </item>
    <item>
      <title>Analysis, Fabrication, and Testing of a Liquid Piston Compressor Prototype for an Ocean Compressed Air Energy Storage (OCAES) System</title>
      <link>https://trid.trb.org/View/1341467</link>
      <description><![CDATA[Previous work concerning ocean compressed air energy storage (OCAES) systems has revealed the need for an efficient means for compressing air that minimizes the energy lost to heat during the compression process. In this paper, the authors present analysis, simulation, and testing of a tabletop proof-of-concept experiment of a liquid piston compression system coupled with a simulated OCAES system, with special attention given to heat transfer issues. An experimental model of a liquid piston system was built and tested with two different materials, polycarbonate and aluminum alloy, used for the compression chamber. This tabletop liquid piston system was tested in conjunction with a simulated OCAES system, which consisted of a hydrostatic tank connected to a compressed-air source from the wall to mimic the constant hydrostatic pressure at ocean depth experienced by the air stored in an actual OCAES system. Good agreement was found between the experimental and numerical studies and demonstrated that the heat transfer characteristics of a liquid piston compression process are effective in reducing the increase in air temperature that occurs during the compression process. The results also suggest that it may be possible to achieve a near-isothermal process with a fully optimized liquid piston compression system.]]></description>
      <pubDate>Thu, 29 Jan 2015 09:17:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1341467</guid>
    </item>
    <item>
      <title>STUDY ON WATER VAPOR ADSORPTION ISOTHERMS OF HYDRATION PRODUCTS IN HARDENED CEMENT PASTE</title>
      <link>https://trid.trb.org/View/1283849</link>
      <description><![CDATA[The performances of concrete are influenced by the microstructure of hardened cement paste. The microstructure of hardened cement paste is affected by the hydration products. Therefore, in order to evaluate the characteristics of the microstructure of hardened cement paste, the physical properties of hydration product should be clarified accuracy.The purpose of this study is to evaluate the amount of adsorbed water in cement paste. The composition (C/S ratio, the H/S ratio) and the amount of adsorbed water of C-S-H were estimated by using synthesized C-S-H and C-S-H generated from synthesized alite paste. In addition, the amount of adsorbed water of calcium hydroxide and calcium aluminate hydrates were estimated by using synthesized hydration products. Furthermore, the amount of adsorbed water of hardened cement paste also was measured.From the experimental results, the H/S ratio of C-S-H under each relative humidity is proportional to the C/S ratio independent of the mix proportion and curing temperature. From these results, the relation equation between the C/S ratio and the amount of adsorbed water of C-S-H was proposed. The amount of adsorbed water calculated from the relation equation of C-S-H is good agreement with the amount of adsorbed water of the synthesized C-S-H. In addition, the amount of adsorbed water of calcium aluminate hydrates, such as ettringite, monosulfate and C4AH13 were higher than that of calcium hydroxide and hydrogarnet. Moreover, the amount of adsorbed water of hardened cement pastes can be calculated from the amount of hydration products and each amount adsorbed water of hydration products.本研究では、セメント系硬化体の水蒸気吸着量を評価するため、各種水和物およびセメント硬化体の相対湿度0％～97％の範囲の水蒸気吸着量について検討を行った。その結果、合成C-S-Hおよび合成エーライトから水和生成したC-S-Hは、任意の湿度環境下においてCaO/SiO<sub>2</sub>モル比とH<sub>2</sub>O/SiO<sub>2</sub>モル比が直線関係となることを明らかにし、C-S-Hの水蒸気吸着量をその組成に基づいて推定する式を提案した。また、C-S-H以外の水和物であるカルシウムアルミネート水和物の水蒸気吸着量を測定し、C-S-Hの水蒸気吸着量の推定式およびC-S-H以外の水和物の水蒸気吸着量を用いて、セメントペーストの相組成より硬化体全体の水蒸気吸着量を推定した。]]></description>
      <pubDate>Mon, 24 Feb 2014 08:43:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1283849</guid>
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