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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>
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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>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Crystallization-induced clogging in tunnel drainage systems: Mechanisms, prevention, treatment, and case studies</title>
      <link>https://trid.trb.org/View/2686852</link>
      <description><![CDATA[Extensive studies have been conducted worldwide on crystallization clogging in tunnel drainage systems, yielding a series of important findings. This paper systematically reviews the research progress on the formation mechanisms, prevention, and treatment technologies of crystallization clogging in tunnel drainage systems. By integrating the innovative achievements of our team in this field with a representative engineering case from the Dongtianshan Tunnel Project in Xinjiang, the current research progress and engineering application prospects of this issue are discussed. Based on the spatial distribution characteristics and temporal evolution patterns of crystallization deposition in tunnel drainage systems, a three-level system framework is established to explain the influencing factors and evolutionary features of crystallization clogging. On this basis, a dual-path prevention concept involving front-end source control and back-end process regulation is summarized. Existing prevention and treatment measures are further reviewed from multiple aspects, including shotcrete composition optimization, drainage system design and construction improvement, pipeline coating, the application of physical fields, and the use of scale inhibitors. Meanwhile, the existing technical bottlenecks and engineering challenges are analyzed from five perspectives, namely crystallization clogging mechanisms, design and construction, materials, detection and monitoring, and treatment methods. The review shows that major challenges remain in the long-term evolution of calcium leaching from shotcrete, microscopic crystal nucleation mechanisms, the durability of preventive materials, intelligent detection and monitoring technologies, and the development of efficient and environmentally friendly treatment methods. These findings provide valuable references for mechanistic studies, technological innovation, and engineering practice related to crystallization clogging in tunnel drainage systems.]]></description>
      <pubDate>Tue, 07 Apr 2026 09:16:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2686852</guid>
    </item>
    <item>
      <title>Physicochemical Properties Evaluation of Asphalt-Coated Aggregates and Its Influence on Cement Hydration</title>
      <link>https://trid.trb.org/View/2646050</link>
      <description><![CDATA[The detrimental effect of asphalt-coated (reclaimed asphalt pavement or RAP) aggregates on the mechanical strength of portland cement concrete is well documented; however, the aggregates influence on the cement hydration process and subsequent effect on the concrete’s performance is not well established. This study investigates the effect of asphalt-coated RAP aggregates on the cement hydration process and its effect on mechanical strength. Asphalt-coated RAP aggregates were characterized by their physical, chemical, and mineralogical properties. The aging index and asphalt content were also investigated. A total of 13 mixes were formulated at different RAP replacement levels (volume replacement of coarser fraction) of 0%, 20%, 40%, 60%, and 80%. Based on test results, the addition of RAP reduced compressive strength and flexural strength by 8.16%–43.22% and 0.19%–24.95%. Fourier transform infrared (FTIR) analysis indicated an increase in the peaks associated with the clinker phase while peaks associated with the ─ OH stretch of calcium hydroxide disappeared in the RAP-concrete samples. In addition, the reduction in the nonevaporable water content in the RAP-concrete was observed. Thermogravimetric analysis (TGA) also revealed a reduction in the consumption of calcium hydroxide, indicating its impact on cement hydration. This study demonstrates that the mechanical strength of asphalt-coated RAP-concrete is closely linked to changes in cement hydration.]]></description>
      <pubDate>Fri, 20 Mar 2026 08:41:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2646050</guid>
    </item>
    <item>
      <title>A time-dependent hydration-driven bonded-particle model for simulating strength evolution in cement-stabilised granular soils: Experimental and DEM insights</title>
      <link>https://trid.trb.org/View/2640846</link>
      <description><![CDATA[This study presents a time-dependent bonded-particle Discrete Element Method (DEM) model for simulating the mechanical behaviour of cement-stabilised granular soils, incorporating the coupled effects of cement content, water-to-cement (w/c) ratio, and curing duration. A comprehensive micromechanical experimental program was conducted to quantify the evolution of bond strength—including tensile, compressive, and shear components—under varying mix designs and curing ages. The experimentally derived bond strength functions (closed-form) were implemented into a custom-developed DEM contact model to represent particle bonding behaviour realistically under different curing times. The model was validated through a series of 90 unconfined compressive strength (UCS) tests on cemented soil samples with varying cement contents (1 %, 2 %, and 3 %), w/c ratios ranging from 0.3 to 1.5, and curing periods of 3 to 90 days. The results revealed that bond strength increased exponentially with curing time, with the majority of strength gain occurring within the first 3–21 days. Numerical simulations closely matched experimental results, demonstrating agreement in peak strength, stress–strain behaviour, and failure modes. DEM simulations show 2.4× higher contact force and 48 % less particle displacement from curing (3–90 days) with increasing cement content. Coordination number rose with longer curing time and higher cement content, then dropped 8–13 % near peak and 3.3–4.5 post-peak, indicating bond breakage and cracking. Bond breakage ratio decreases with curing time due to cement hydration; a lower w/c ratio shows faster bond strength improvement over time. The proposed model reliably predicts cemented soil strength evolution, improving early-age and long-term analysis for geotechnical design.]]></description>
      <pubDate>Tue, 17 Feb 2026 13:12:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2640846</guid>
    </item>
    <item>
      <title>Moisture availability and hydration kinetics in roller compacted concrete pavement mixtures due to internal curing – A multiscale approach using Power’s model</title>
      <link>https://trid.trb.org/View/2619830</link>
      <description><![CDATA[This study investigates the influence of varying w/c ratios (0.30, 0.35, and 0.40), different environmental conditions (50 % RH at 36 °C and 95 % RH at 24 °C), and different curing regimes (air curing, curing compound, and water curing) on the moisture availability and hydration kinetics of internally cured roller-compacted concrete (RCC) pavement mixtures utilizing expanded clay aggregates. A total of 18 mixtures were cast which were characterized for evaporation rate, compressive strength, TGA, XRD, and FTIR tests to fundamentally understand the internal curing’s effectiveness on hydration, bound water, and compressive strength. Test results reveal that internal curing can reduce the evaporation rate, improve degree of hydration, and enhance the compressive strength particularly at lower w/c ratio, irrespective of environmental condition and curing regimes. From Power’s model, volume phase distribution analysis indicates that the cement hydration at low w/c ratio is water-constrained (reduced capillary water) while high w/c ratio mixtures approached space-constrained conditions (gel-space ratio). Power’s model can be modified to established critical contours plots to determine the optimal entrained water for predicting maximum achievable hydration potential without inducing excess porosity. This study concludes that external water curing can be negated at high w/c ratios and vice-versa in internally cured RCC pavement mixtures.]]></description>
      <pubDate>Wed, 31 Dec 2025 10:56:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2619830</guid>
    </item>
    <item>
      <title>Multi-physics modeling of early-age hygro-thermal-chemical (HTC) fields in the base plate of double-block ballastless track structures considering different curing strategies</title>
      <link>https://trid.trb.org/View/2602333</link>
      <description><![CDATA[Cast-in-situ ballastless track structures are prone to early-age cracking, which seriously affects their durability. Therefore, this paper focuses on investigating the complex multi-physical field distribution of double-block ballastless track structures at early ages. Currently, hygro-thermal-chemical (referred to as HTC model) coupled modeling has not been implemented in large-scale commercial software. This paper demonstrates the application of a recently proposed framework to study the early-age behavior of cast-in-situ double-block ballastless track structures via hygro-thermal-hydration analysis. To investigate the influence of curing methods on multi-physical fields, an additional layer with adjustable thickness was incorporated into the actual model to precisely simulate solar radiation absorption, convective heat transfer, and net thermal radiation at the actual boundary interfaces. The parametric analysis demonstrates that a 3-mm-thick additional layer achieves optimal geotextile curing simulation, while thicknesses of 7 mm and 3 mm are required for plastic film curing and natural curing, respectively. Based on the HTC model, this study also investigates the effects of three methods used at the construction site on the early-age multi-physics fields of the base plate. The results revealed that: when geotextile covering and sprinkling water was implemented, the cement hydration reaction rate reaches its peak approximately 14 h after casting, coinciding with the highest temperature gradient along the vertical direction and the most significant relative humidity (RH) reduction rate in the base plate. The moisture diffusion depth of the base plate covered with geotextile and watered for 14 days is only 65 % of the base plate depth. To minimize shrinkage deformations, extending the water curing period is recommended. Additionally, the hydration rate of the base plate covered with plastic film is higher than those of the other two curing methods, resulting in greater temperature and humidity gradients, therefore, the construction process involving plastic film covering is not recommended.]]></description>
      <pubDate>Mon, 29 Sep 2025 11:06:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2602333</guid>
    </item>
    <item>
      <title>Non-uniform temperature fields and debonding of a long-span CFST arch bridge under coupled environmental actions</title>
      <link>https://trid.trb.org/View/2588072</link>
      <description><![CDATA[To investigate the temperature field distribution characteristics and delamination mechanisms in long-span concrete-filled steel tubular (CFST) arch bridges within mountainous regions, comprehensive in-situ measurements were performed on the Chongqing Shuangbao Bridge. A sophisticated temperature field model for CFST arch bridges under solar radiation, ambient temperature variations, and cement hydration thermal effects was developed. Furthermore, an innovative theoretical framework integrating engineering mechanics with the temperature field model was established to analyze interfacial delamination behaviors. Experimental and theoretical analyses yielded several significant findings: (1) During the hydration exothermic phase, the temperature field at concrete center exhibited a tri-linear distribution pattern (characterized by rapid initial rise, subsequent decline, and final stabilization), with the ascending rate significantly exceeding the descending rate; temperatures exceeded 50°C between 25 and 73 h post-placement. (2) The external steel tube temperature demonstrated sinusoidal diurnal variations during and post-hydration, closely correlating with ambient temperature fluctuations; after hydration, concrete temperatures also followed sinusoidal diurnal distributions, with amplitudes increasing proportionally to radial distance from the center. (3) A pronounced radial temperature gradient from center to surface manifested during hydration, reaching a maximum differential of 40°C; the temperature gradients substantially decreased to 7°C after hydration. (4) Longitudinal stress differentials between the interface steel tube and concrete measured 42.5 MPa (sun-exposed side) and 74.2 MPa (shadowed side), while radial stress differentials were −1.37 MPa and −0.34 MPa, respectively. (5) The temperature field model demonstrated a tri-linear distribution pattern with an effective influence depth of D/8 to D/4 (where D represents steel tube diameter); the temperature constant exhibited significant temporal dependency on environmental conditions and hydration heat evolution. (6) Although longitudinal relative slip occurred at the steel-concrete interface during placement, no void was detected.]]></description>
      <pubDate>Fri, 15 Aug 2025 16:32:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2588072</guid>
    </item>
    <item>
      <title>Evaluate, Modify, and Adapt the ConcreteWorks Software for Iowa’s Use, Phase II</title>
      <link>https://trid.trb.org/View/2576286</link>
      <description><![CDATA[This Phase II project contained two parts. Part A focused on the investigation of the characteristics and thermal properties of commonly used slags in Iowa cementitious materials and their effects on adiabatic temperature rise (ATR) in Iowa mass concrete structures. A new hydration model for slag-containing cementitious materials and a three-parameter ATR prediction model were developed and validated. These models were incorporated into the ConcreteWorks software, significantly improving its thermal predictions for mass concrete with slag. Part B focused on the development of a new seal slab component in the ConcreteWorks software. This new component is simple, user friendly, and well-integrated into the existing ConcreteWorks software and enables the prediction of the temperature profile of a bridge footing placed on a seal slab. In Part A, the research included the following: (1) characterizing physical and chemical properties of slags and concrete materials, (2) studying slag’s effect on cement hydration using isothermal calorimetry, (3) evaluating temperature rise in mass concrete with various slag types and dosages using semi-adiabatic calorimetry, (4) testing large concrete blocks with various slag replacements, (5) developing and validating the ATR prediction model for slag concrete, and (6) integrating the models into the ConcreteWorks software. In Part B, the research included the following: (1) developing a new seal slab component in the ConcreteWorks software and (2) conducting trial analyses to investigate the effects of the time of footing placement, the sizes of the footing and seal slab, and environmental conditions on the temperature profile of a bridge footing placed on a seal slab. The updated ConcreteWorks software now features enhanced input parameters and equations for better heat prediction, confirmed through thermal and sensitivity analyses. The improved slag hydration model, which accurately incorporates slag’s chemical properties, enhances temperature prediction accuracy for concrete containing slag. The maximum core temperature of a footing placed on a seal slab was generally found to be higher than that of a footing with no seal slab. In addition, it was found that a seal slab generally enhances the capacity for heat retention in the footing, keeping the core temperature of the footing high for a longer period.]]></description>
      <pubDate>Wed, 06 Aug 2025 15:00:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2576286</guid>
    </item>
    <item>
      <title>Multi-scale insights into the adhesion of steel slag-asphalt interface influenced by hydration process</title>
      <link>https://trid.trb.org/View/2545098</link>
      <description><![CDATA[Steel slag, a byproduct of the steelmaking process, exhibits poor volumetric stability in its freshly produced or untreated state, which significantly restricts its application in pavement engineering. Currently, weathering is the predominant process for treating steel slag. A multi-scale approach was employed to investigate the mechanism of hydration reactions on the adhesion properties of the steel slag-asphalt interface during the weathering process in this study. The effects of hydration on adhesion properties were evaluated through modified boiling tests and surface free energy (SFE). The surface morphology of unhydrated and hydrated steel slag was compared using scanning electron microscopy (SEM) and optical profilometry. The adhesion properties of asphalt at the interfaces with unhydrated steel slag (C₃S and C₂S), hydrated steel slag (CaCO₃), and basalt (SiO₂) were systematically analyzed using molecular dynamics (MD) simulations, incorporating static, pull-off, and novel dynamic water scouring models to simulate diverse environmental conditions. The results indicated that the mass loss rate (MLR) and peeling rate (PR) of hydrated steel slag after a 10-minute boiling test were 1.3 and 2.2 times higher than those of unhydrated steel slag, respectively. Meanwhile, hydration treatment reduced the adhesion work between steel slag and asphalt by 2.0% and increased the peeling work by 33.5%. SEM images and 3D surface topography analyses showed that hydration transformed the rough-textured structure on the steel slag surface into a loose honeycomb structure, resulting in an increase of 6.42% in arithmetic average roughness (Ra) and 8.84% in root mean square roughness (Rq). MD simulations demonstrated that the mean square displacement (MSD), diffusion coefficient (DC), and z-value of relative concentration (RC) peaks of asphalt on the CaCO₃ surface were greater than those on C₃S and C₂S, while the interface interaction energy, adhesion work, and cohesion ratio (CR) were lower. Under water molecule scouring, the simulated peeling rate (SPR) of asphalt on the CaCO₃ surface increased by 34.5% compared to C₃S but decreased by 7.7% compared to C₂S. Furthermore, there was a strong correlation (r>0.8) between the experimental and simulation data.]]></description>
      <pubDate>Wed, 21 May 2025 16:54:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2545098</guid>
    </item>
    <item>
      <title>Hydration Kinetics and Performance of MgO-Activated Slag Binder with Available Carbonate and Silicate</title>
      <link>https://trid.trb.org/View/2526332</link>
      <description><![CDATA[The combination of magnesium oxide (MgO) with various reactive aluminosilicates has recently been studied as an alternative binder, which bridges the chemistry of alkali-activated materials containing reactive MgO and hydrated magnesium silicate (M-S-H) binders containing reactive aluminates. This study is devoted to investigating the hydration kinetics and hydration products of the MgO-activated slag binder with available carbonate and silicate. The compressive strength results are used to assess the effect of the mechanism performance of the MgO-activated slag binder. A thorough investigation involving X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric-differential thermal analysis (TG-DTG), and Si²⁹ MAS-nuclear magnetic resonance (Si²⁹ MAS-NMR) was performed to investigate the evolution of carbonates and silicates. The precipitation of part of Mg²⁺ and Ca²⁺ from the solution as carbonate is beneficial to promote the hydration process, and it can reduce the Ca/Si ratio and Mg/Si ratio in C-(A-)S-H and M-S-H gel. The filling effect and nucleation effect of silicate formed by silica fume (SF) reduces the content of interlayer water, bound water, hydrotalcite, and the generation of exposed fibrous crystalline, which forms a dense microstructure. The improved hydration kinetics via the use of available carbonate and silicate led to samples with increased hydration and enhanced performance (51.6 versus 21.9 MPa at 28 days) when compared to the control sample.]]></description>
      <pubDate>Thu, 24 Apr 2025 09:07:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2526332</guid>
    </item>
    <item>
      <title>Red mud modified fly ash based road base materials: Mix design, hydration mechanism, and heavy metal migration behavior</title>
      <link>https://trid.trb.org/View/2510830</link>
      <description><![CDATA[Red mud (RM) and fly ash (FA) are solid wastes generated by the alumina industry and phosphate chemical enterprises during the production of alumina and phosphoric acid, respectively. Their large-scale harmless and resource utilization is of great significance. In this study, advanced scientific testing techniques and research methods were used to prepare cementitious materials and no-fire ceramic granules from solid wastes such as RM, FA and phosphogypsum (PG), which were used to prepare road base materials, and to investigate the mix design, hydration mechanism, and heavy metal migration behavior.The results showed that the optimum mix proportion for red mud-fly ash cementitious materials (RFCM) was determined as follows: RM 40.79 %, FA 36.89 %, PG 17.47 %, PC 4.85 %, and superplasticizer dosage at 1.7 % of the binder material. Under a water-to-binder ratio of 0.18, after 28 days of curing, the flexural strength was 3.6 MPa, and the compressive strength was 26.9 MPa. Based on soil environmental and human health risk assessment results, Cr had carcinogenic risks, while more attention was needed on the risks of Hg, Cd, and Pb. Thus, this study identified Cr, Cd, Hg, and Pb as characteristic heavy metals (HMs). Using the optimal mix proportion of the RFCM as a basis, the optimal mix proportion of unburned ceramsite was determined as follows: RM 22.74 %, FA 20.56 %, PG 9.74 %, PC 2.7 %, and river sand 44.26 %. The density grade of the unburned ceramsite was 600, meeting the requirements of "Lightweight aggregates and its test methods-Part 1: Lightweight aggregates" (GB/T 17431.1–2010) for bulk density, cylinder compressive strength, and water absorption. Substituting aggregates with equal particle sizes for red mud-fly ash based road base materials (RFRBM) and designing the mix proportion for RFRBM, the mix ratio of base course aggregates was 20–30 mm: 10–20 mm: 5–10 mm (unburned ceramsite): 0–5 mm = 17.3: 34.8: 24.5: 23.5, with an optimal dosage of binder material at 12 %. The specimens could meet the requirements of "Technical guidelines for construction of highway roadbases" (JTG/T F20–2015) for unconfined compressive strength and splitting tensile strength. At the same time, the durability of RFGFM was tested and analysed with reference to the standard. Utilizing leaching kinetic models analyzed the leaching behavior of characteristic HMs in the base course system and constructed a risk control system for HMs in RFRBM. Finally, reference limits for HMs were proposed according to the application scenarios of RFRBM.]]></description>
      <pubDate>Thu, 27 Mar 2025 11:35:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2510830</guid>
    </item>
    <item>
      <title>Performance regulation of desulfurized gypsum on solid waste-based road base materials: Hydration characteristics and environmental performance</title>
      <link>https://trid.trb.org/View/2507502</link>
      <description><![CDATA[Desulfurization gypsum (DG) is a solid waste byproduct from treating sulfur-containing flue gases in power plants. DG is subjected to long-term stockpiling due to its high sulfate content and the presence of harmful elements, which have caused significant environmental damage. To address the challenges of DG utilization, solid waste-based road base materials (SWB) were prepared by combining DG with red mud (RM), fly ash (FA), blast furnace slag (BFS), and coal gangue (CG), under the guidance of the multi-waste synergy theory. In contrast to previous studies, the SWB in this research is composed entirely of solid waste. Furthermore, a comparison was made between the hydration and harmful element solidification mechanisms of SWB and those of traditional road base materials. Finally, the regulatory patterns and mechanisms of DG on the mechanical performance, durability, and environmental properties of SWB are revealed in this paper. The results indicate that the hydration exothermic rate and cumulative hydration heat of SWB are enhanced by DG, and its heavy metal immobilization capacity is also improved. A higher degree of polymerization is exhibited by SWB, accompanied by a compressive strength of 7.1–9.1 MPa at 7 days and a heavy metal comprehensive solidification rate exceeding 80 % (leachate meeting China's drinking water standards-GB/T 5749–2022) when the SO₃ content is between 2.06 % and 2.93 %, the C/S (mass ratio of Ca to Si) is 0.72–0.75 and the S/A (mass ratio of Si to Al) ranges from 1.31 to 1.32. SWB’s application provides a novel approach for the sustainable development of industrial zones.]]></description>
      <pubDate>Thu, 20 Mar 2025 09:49:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2507502</guid>
    </item>
    <item>
      <title>Hydration, Hardening Properties, and Microstructure of Magnesium Phosphate Cement–Emulsified Asphalt Composites across Various Stoichiometries</title>
      <link>https://trid.trb.org/View/2431623</link>
      <description><![CDATA[To promote green and low-carbon development in the rehabilitation of damaged asphalt pavements, a cold patching material combining magnesium phosphate cement (MPC) with emulsified asphalt (EA) was developed. This study systematically examined the impact of each preparation parameter on the performance of the composite system, including the EA to MPC ratio (A/C), the mass ratio of dead-burned magnesium oxide (MgO) and phosphate (M/P), and the dosing ratio of borax, a retarder (B/M). It also investigated their effects on workability, hydration process, mechanical behavior, and microstructure of MPC-EA. Furthermore, it elucidated the mechanism behind the loss of strength in MPC-EA. The results demonstrate that each component of MPC-EA has interdependent influences on workability. When A/C<0.2 and M/P increased to 4, there was a 5.4% to 31.5% reduction in setting time and an increase in compressive strength as well. However, when A/C>0.2, M/P gradually lost its regulating effect. EA significantly prolonged the setting time of the MPC-EA system; for instance, when A/C=0.5 (compared with MPC), setting time more than doubled but fluidity was severely impaired due to EA incorporation into the system. Additionally, borax in the MPC-EA system exhibited significant delaying effects on setting time, while positively affecting fluidity as well. Moreover, borax modulated heat release rate and cumulative heat release in MPC-EA, which influenced mechanical properties and improved microstructure within this system too. Furthermore, when A/C is not greater than 0.2, the pore structure becomes refined; however, when A/C is greater than 0.2, the porosity increases along with an increase in harmful micropores proportion within MPC-EA. The scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) test clarified microscopic mechanisms behind strength loss in MPC-EA: inhibition of hydration product development, poor crystalline morphology, and encapsulation by asphaltene film leading to decreased mechanical strength due to incomplete reaction between hydration products and reactants.]]></description>
      <pubDate>Tue, 15 Oct 2024 09:17:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2431623</guid>
    </item>
    <item>
      <title>SPR-4908:  Potential Implications of Pore Solution Composition of Type IL Cement on the Curability of Concrete</title>
      <link>https://trid.trb.org/View/2434103</link>
      <description><![CDATA[The study will provide the Indiana Department of Transportation (INDOT) with information on how the alteration in pore solution composition due to the use of limestone cement can impact durability of concrete with respect to chemical stability of hydration products, corrosion resistance of reinforcement, sulfate resistance and performance in aggressive environment. The possible, practical deliverables of this study will include: (i) Possible changes to the current standard testing procedures, (ii) development of predictive model, based on the inter‐relationship between the chemistry of the pore solution of the Type IL cementitious system, and durability performance of the Type IL concrete.
]]></description>
      <pubDate>Wed, 25 Sep 2024 09:26:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2434103</guid>
    </item>
    <item>
      <title>Influence of Nano-Activated CaCO3-Metakaolin on Early Strength and Microstructure of Cement</title>
      <link>https://trid.trb.org/View/2410526</link>
      <description><![CDATA[The early strength, microstructure, and structure of cement mortar under low-temperature curing conditions were investigated through compressive strength tests, scanning electron microscopy, x-ray diffraction, synchronous thermal analysis (thermogravimetric analysis coupled with differential scanning calorimetry), and nuclear magnetic resonance tests. The study focused on the impact of the single addition of nano-activated CaCO3 (NAC) and the simultaneous addition of metakaolin (MK) on cement mortar. The results indicate that the addition of NAC accelerated the early hydration of cement. At a 1% dosage, the compressive strength increased by 6.84%, 14.77%, and 18.58% at 1?day, 3?days, and 7?days, respectively. When 5% MK was co-added, the compressive strength increased by 15.16%, 27.85%, and 21.66% at 1?day, 3?days, and 7?days, respectively. The combination of NAC and MK accelerated the hydration of cement, refined the products, reduced the porosity, improved the microstructure, and enhanced the early compressive strength of cement-based materials.]]></description>
      <pubDate>Fri, 02 Aug 2024 08:43:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2410526</guid>
    </item>
    <item>
      <title>Optimal development of the new type of ultra-fine fly ash semi flexible pavement grouting material: Rheological, mechanical, pore distribution, and hydration characteristics</title>
      <link>https://trid.trb.org/View/2393397</link>
      <description><![CDATA[In order to solve the problems that the fluidity of semi-flexible pavement grouting materials (SFPGM) is not up to standard, the early strength is not enough, or the fluidity meets the requirements but the early strength is not up to standard, the power plant by-Product -ultra-fine fly ash (UFA) was used to optimized the performance of grouting materials (GM) in this study. The microstructure of hardened slurry was analyzed by XRD, FTIR, MIP and SEM. The findings indicate that when the UFA content increases, the fluidity of the GM initially increases and then declines, whereas the compressive strength initially reduces and then increases. The sample exhibits optimal fluidity performance when the content of UFA is 9 %. The flow cone fluidity of the initial and 20 min is 12.33 % and 17.63 % lower than that of the reference sample. When the amount of UFA is 12 %, the compressive strength of sample is the highest at each age. Additionally, that the fluidity of sample S12 is sub-optimal in all samples, only worse than that of sample S9. In the early stage of GM hydration, UFA with slow hydration rate produces a significant ‘ball-bearings effect’ between irregular cement particles. This is beneficial to the relative sliding between the slurry particles, reduces the yield stress and plastic viscosity of the fresh slurry, and improves the flow performance of the GM. The pozzolanic effects of UFA in GM primarily manifests during the later stages of hydration. The primary hydration products of UFA modified GM include ettringite, C-S-H gel, C-A-S-H gel, calcium carbonate, and aluminium glue (AH₃). During the progression of the hydration reaction, the quantity of ettringite (AFt) in the slurry steadily augments, causing the initial fine needle-like structure to evolve into a more fully formed needle-like structure. A complex three-dimensional network of interlocking spatial structures is formed by many hydration products that continually interlace and develop, improving strength. The higher the perfusion rate of the GM, the higher the compactness of the SFPGM, and the better the high temperature stability and low temperature crack resistance.]]></description>
      <pubDate>Thu, 11 Jul 2024 13:53:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2393397</guid>
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