<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <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" />
    <description></description>
    <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>
    </image>
    <item>
      <title>Low-Temperature and Microscopic Properties of Warm-Mix Recycled Styrene–Butadiene–Styrene-Modified Asphalt Binder</title>
      <link>https://trid.trb.org/View/2683100</link>
      <description><![CDATA[In this study, the warm-mix regeneration mechanism of an asphalt binder modified with styrene–butadiene–styrene (SBS) copolymers under simulated complex aging conditions, along with the performance of the recycled binder, were investigated. Bending beam rheometer tests were conducted to assess the low-temperature properties of the asphalt binder, and Fourier transform infrared spectroscopy and atomic force microscopy were employed for mechanistic analysis. The asphalt binder with the same degree of aging and warm-mix recycled binder recovered their low-temperature performance indicators and microscopic morphologies more efficiently than the hot-mix recycled binder. The addition of the regenerant and warm-mix agents to aged and original binders was a physical blending process that did not produce new functional groups. The regenerant was critical in adjusting the component proportions, whereas the warm-mix agent dispersed asphaltene clusters. However, neither additive restored the original molecular structure of SBS. An exponential function model was utilized to quantitatively characterize the relationship between the nanoscale microstructural properties and macroscopic rheological performance of the recycled binder. Furthermore, the butadiene index confirmed that the aged SBS-modified asphalt binder did not recover and that the performance of the recycled binder was inferior to that of the original binder.]]></description>
      <pubDate>Tue, 23 Jun 2026 17:00:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2683100</guid>
    </item>
    <item>
      <title>Lightweight Magnesium Nanocomposites with Enhanced Wear Resistance for Landing Gear Application</title>
      <link>https://trid.trb.org/View/2712139</link>
      <description><![CDATA[This study systematically evaluated the wear resilient performance of AZ61 magnesium alloy reinforced with 15 wt.% SiC and diverse amounts of multi-walled carbon nanotubes (MWCNTs) under dry sliding circumstances adopting pin-on-disc apparatus (ASTM G99). To identify the influence of factors like sliding speed (SS) (1-3 m/s), axial load (AL) (10-30 N), and MWCNT concentration (0-3 wt.%) that affect tribological performance, experiments were developed using a Central Composite Design (CCD) under Response Surface Methodology (RSM). SEM micrographs revealed a dispersion optimum near 2 wt.% MWCNT, where CNTs anchor to SiC and bridge the α-Mg matrix, while 3 wt.% shows agglomerates and micro-voids. Findings showed that wear loss (WL) and friction coefficient (CoF) was greatly amplified by increasing AL owing to localized heating and contact stresses. A compacted tribolayer was formed by increasing SS, which decreased WL but marginally raised the CoF. At low AL (10 N), SS (2.09 m/s), and 2.12 wt.% MWCNT, the wear resistance was significantly improved by improving load transfer and creating a lubricating carbon-rich coating, resulting in a decreased WL of 0.006 g. The CoF persisted within the range of 0.19 to 0.28. Agglomeration of MWCNTs caused increased WL and CoF when the MWCNT content is increased above 2 wt.%. Worn-surface microscopy at the optimum showed fine wear tracks and a continuous carbon/oxide glaze, evidencing a lubricious CNT-rich third-body film, whereas high AL/low MWCNT produced deep grooves and delamination.]]></description>
      <pubDate>Tue, 23 Jun 2026 13:36:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712139</guid>
    </item>
    <item>
      <title>Development of Graphene Filled Polypropylene Nanocomposite for Aerospace Application</title>
      <link>https://trid.trb.org/View/2712117</link>
      <description><![CDATA[Polypropylene, a commodity plastic, is the semi-crystalline thermoplastics widely used in high volume for general purpose application. Polypropylene is the macro molecules of soft and weak backbone, which by reinforcement of fillers in different forms such as fiber, spheroids, nanotubes, flakes, etc., can influence its mechanical, thermal, electrical, creep resistance, and flame resistance properties for use in aerospace applications. Currently, polycarbonate and nylon plastics are used in aerospace applications, however, they are expensive compared with polypropylene. In this thesis, efforts are put to study the effect of reinforcement fillers in the properties of polypropylene composite, primarily the mechanical and flammability properties. The matrix element, polypropylene co polymer and reprocessed polypropylene blended in equal ratio, are coupled with the dispersing phases such as graphene, mica, fumed silica, and polydimethylsiloxane polymer. Effect of graphene as reinforcing filler at different weight % to polypropylene composite’s properties are studied and compared with that of the neat polypropylene. Effect of coupling agent, Aminopropyltriethoxysilane (APTES), on mineral fillers and Polydimethylsiloxane polymer (PDMS) used for crosslinking with the polypropylene matrix is also studied and compared using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) techniques.]]></description>
      <pubDate>Wed, 10 Jun 2026 17:08:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712117</guid>
    </item>
    <item>
      <title>Optimized Laboratory Fabrication of Small-Specimen Geometry for Streamlining Dynamic Modulus and Cyclic Fatigue Testing of Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/2709230</link>
      <description><![CDATA[The asphalt community is focused on the paradigm shift in mixture design from the volumetrics to an optimization procedure based on performance testing called balanced mixture design. Streamlining performance testing to obtain index properties quickly and using a smaller quantity of materials is critical for the successful implementation. This paper aims to streamline dynamic modulus (|E*|) and cyclic fatigue testing by optimizing the number of 38 mm diameter specimens extracted from a single 150 mm diameter Superpave gyratory-compacted (SGC) specimen. The current provisional standard methods require vertical coring of four small specimens from a single SGC specimen. In this study, two sets of testing specimens were fabricated by coring four and five small specimens from each SGC specimen. The success rate in meeting target air voids, the |E*| analysis, and the cyclic fatigue results including cyclic fatigue index parameter (Sₐₚₚ) values were compared between the two sets of specimens. No significant or consistent differences were observed in performance testing results. Furthermore, innovative image analysis and microscopy techniques were used to study air voids distribution and aggregate structure within each specimen and to further validate the proposed coring pattern. Based on these findings, coring five 38 mm diameter testing specimens from one SGC sample is suggested to run |E*| and cyclic fatigue tests. This proposed modification to AASHTO TP 132 and TP 133 may save technicians’ time and allows for the optimal use of materials. The latter may become a significant saving when integrating these methods with laboratory long-term aging protocols and forensic studies.]]></description>
      <pubDate>Tue, 02 Jun 2026 11:01:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2709230</guid>
    </item>
    <item>
      <title>Microscale deterioration of polyethylene-modified asphalt under water-induced damage using atomic force microscopy</title>
      <link>https://trid.trb.org/View/2666232</link>
      <description><![CDATA[This study investigated the microscale degradation mechanisms of neat asphalt (NA) and polyethylene-modified asphalt (PE-NA) under various water-induced conditions by using atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The results indicate that PE modification increases the bee structure density by 23 % and improves surface roughness, adhesion, and modulus. Water-induced damage resulted in coarsening of the bee structure, increased roughness, loss of adhesion, and embrittlement in both asphalts, with the severity of degradation following the order: salt erosion > freeze-thaw > immersion. After salt erosion, the Ra value of NA increased significantly by 86.0 %, compared to only 26.0 % for PE-NA. PE-NA demonstrated superior structural retention, maintaining over 60 % more bee structures and preserving approximately 47.8 % of its adhesion force after salt erosion, whereas NA retained only about 38.4 %. FTIR analysis showed that water erosion intensified carbonyl oxidation (at 1700 cm⁻¹) in NA, whereas the PE modifier acted as a physical barrier, effectively suppressing oxidation and preserving morphological integrity. These findings highlight the effectiveness of PE modification in significantly enhancing asphalt durability in aggressive aqueous environments through microstructural stabilization and oxidation resistance.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666232</guid>
    </item>
    <item>
      <title>Investigation on the fatigue behavior of marine EH690 ultra-high-strength steel in load-carrying cruciform welded joints</title>
      <link>https://trid.trb.org/View/2634104</link>
      <description><![CDATA[EH690 ultra-high-strength steel (UHSS), due to its excellent mechanical properties and corrosion resistance, is widely employed in the construction of critical structures for ships and offshore platforms. Using digital image correlation (DIC) and scanning electron microscopy (SEM) techniques, the fatigue failure mechanisms of EH690 UHSS load-carrying cruciform welded joints (LCWJs) are investigated, revealing that fatigue failure primarily originates from stress concentrations induced by geometric discontinuities and porosity at the weld root. Fatigue strength of EH690 UHSS LCWJs is evaluated using the nominal stress method, notch stress method, and strain energy density method. S-N, ΔW-N, and Δσc-N curves for EH690 UHSS LCWJs are plotted and compared with prevailing fatigue design recommendation curves. Additionally, the influence of the weld leg thickness-to-plate thickness ratio (l/t1) on fatigue failure location is analyzed using the strain energy density method, revealing a transition from weld root to weld toe failure when l/t1 reaches 1.18. A comprehensive analysis of key factors, including weld geometry, plate thickness, fictitious radius, and misalignment, on the stress concentration factor (SCF) at the weld root is conducted. An empirical formula for calculating SCF at the weld root is proposed to enhance the efficiency of fatigue strength assessment using the notch stress method.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2634104</guid>
    </item>
    <item>
      <title>Investigation on Microstructure and Mechanical Properties in the Dissimilar Joining of WE43 to AA7075 Alloy using FSW</title>
      <link>https://trid.trb.org/View/2691958</link>
      <description><![CDATA[This research investigates the alterations in microstructure, microhardness, and joint strength resulting from the dissimilar friction stir welding (FSW) of WE43 magnesium alloy to AA7075 aluminium alloy. The study specifically analyses the role of FSW process parameters in the formation of intermetallic compounds (IMCs), the evolution of grain structure, the resultant microhardness distribution across the weld zone, and the joint tensile strength. A comprehensive microstructural characterization was performed utilizing optical microscopy (OM), field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDS), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD). These analyses confirmed significant grain refinement in the stir zone and the identification of various IMCs at the weld interface. Microhardness mapping indicated a gradient profile, with the weld nugget exhibiting superior hardness attributed to its dynamically recrystallized, fine-grained microstructure. Crucially, the low-heat-input FSW (LFSW) variant yielded a substantial increase in average microhardness, reaching 126 HV in the stir zone (SZ), due to grain refinement induced by severe plastic deformation. This configuration achieved a joint efficiency of approximately 68.7% relative to the WE43 base material. The enhancement in mechanical performance is directly linked to a modified joint preparation strategy that successfully suppressed the formation of brittle AlMg IMCs, instead fostering the formation of harder MgZn, Al2CuMg, and AlMgZn compounds. These findings underscore the efficacy of the LFSW technique in fabricating dissimilar WE43-AA7075 joints with favourable mechanical properties and a consistent microhardness profile. The process parameters are strategically selected to achieve better joint properties and form defect-free joints.]]></description>
      <pubDate>Tue, 14 Apr 2026 15:11:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2691958</guid>
    </item>
    <item>
      <title>Study on recycled LLDPE modified asphalt using fluorescence microscopy and entropy-weight evaluation for process selection</title>
      <link>https://trid.trb.org/View/2645682</link>
      <description><![CDATA[Road engineering is critical for large-scale waste plastic recycling. Agricultural mulch films have huge annual consumption but extremely low recycling rates. Unrecycled ones degrade slowly (over 400 years) and release microplastics, harming ecosystems. This study used linear low-density polyethylene (LLDPE) from these films as an asphalt modifier to boost recycling and improve properties of virgin asphalt. The study prepared LLDPE modified asphalt with 4 % LLDPE content adjusting shear temperatures (160 ℃, 180 ℃, 200 ℃), shear rates (2000 rpm, 3000 rpm, 4000 rpm), and feeding methods (direct blending, pre-melting blending). The mechanical tests were used to assess LLDPE’s effects on asphalt’s road performance and storage stability. Based on combined fluorescence microscopy with image processing, the indicators such as average particle size (Aps), roundness (Rs), nearest neighbor distance (NND) and coefficient of variation (CV) for quantitative evaluation of LLDPE’s melting and dispersion in asphalt were proposed. Finally, a 100-point evaluation system for modification effects via the entropy weight method was established. LLDPE improved asphalt’s high temperature deformation resistance but reduced low temperature ductility. The optimal process was 180℃, 3000 rpm and direct blending, which achieved the only full score.]]></description>
      <pubDate>Fri, 20 Mar 2026 08:41:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2645682</guid>
    </item>
    <item>
      <title>Revealing the Thermal-Gas Stability of Lithium Ion Batteries under Low-Temperature Cyclic Aging</title>
      <link>https://trid.trb.org/View/2681218</link>
      <description><![CDATA[With high energy density and long cycle life, lithium-ion batteries (LIBs) are currently the most promising electrochemical devices for electric vehicles and energy storage. However, the safety and reliability of LIBs can be significantly compromised in low-temperature cyclic due to anode lithium plating and other factors which are still unclear. Therefore, it is essential to reveal the thermal-gas stability of LIBs under low-temperature cyclic. This study investigates the thermal runaway (TR) characteristics and gas production characteristics after TR of 18650-type NCA LIBs across four states of health (SOH), from 100% to 70%. Using Glove box, Electrochemical impedance spectroscopy, Scanning electron microscope, X-ray photoelectron spectroscopy, Accelerating rate calorimetry, and Gas chromatography, the research identifies critical trends in temperature rate, gas composition and explosion risk. After around 150 cycles, there is a significant and rapid decline in capacity. The internal resistance of batteries continues to increase, lithium is precipitated on the anode, and the cathode experiences particle fragmentation. Comparing the 70% SOH batteries with the 100% SOH, it is observed that more Li2O, Li2CO3 and LiF appeared on the anode. The triggering time of TR was 41.38% earlier, and the maximum temperature during TR decreased by 7.89%. The mass loss of the 70% SOH batteries were 11.85% higher than that of the 100% SOH. The gas production volume of the 80% SOH is the lowest, while that of the 70% SOH is the highest. Compared with the 100% SOH batteries, the upper limit (UEL) of gas production explosion for 70% SOH decreases by 3.67%, while the lower limit (LEL) increases by 24.46%. This indicates that the gas production of fresh batteries has a wider range of explosion limits. These research findings provide crucial insights for enhancing the safety and reliability of LIBs during operation, storage, and recycling processes.]]></description>
      <pubDate>Wed, 18 Mar 2026 11:20:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2681218</guid>
    </item>
    <item>
      <title>Investigation of Salt-Releasing Behaviors of Salt-Storing Lignin Fiber and the Performance of Asphalt Mixture</title>
      <link>https://trid.trb.org/View/2639349</link>
      <description><![CDATA[This study investigated a self-developed salt-storing lignin fiber as an anti-icing additive for asphalt pavements. The sustained- salt-release capability and road performance of this material were systematically evaluated. Salt-release kinetics were quantified through conductivity measurements, while morphological changes and salt distribution within the asphalt mortar following freeze–thaw cycles were characterized using scanning electron microscopy with energy-dispersive X-ray spectroscopy. Performance assessments included rutting tests to evaluate high-temperature stability and semicircular bend tests to determine cracking resistance at low and intermediate temperatures, as well as postmoisture damage. Key findings revealed that incorporating a hydrophobic agent enabled the salt-storing fiber to achieve sustained salt release. Freeze–thaw cycling significantly altered the mortar surface morphology, inducing pits, pores, and salt aggregation. Correspondingly, single-cycle conductivity gradually decreased with increasing freeze–thaw cycles. However, by the sixth cycle, the mixture containing 100% salt-storing fiber exhibited an 88.9% higher cumulative conductivity, and the mixture with 100% commercial product (SG) showed a 94.1% higher cumulative conductivity, compared to the mixture with 50% replacement. Increased incorporation of anti-icing material reduced high-temperature performance; dynamic stability declined from 13,676 cycles/mm (0% replacement) to 9,773 cycles/mm (100% salt-storing fiber) and 8,690 cycles/mm (100% commercial product). Low- and intermediate-temperature cracking resistance exhibited nonlinear variation with higher replacement ratios. Following moisture damage, fracture toughness at low temperatures decreased notably with greater anti-icing material content, while fracture energy increased marginally.]]></description>
      <pubDate>Thu, 12 Mar 2026 08:49:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2639349</guid>
    </item>
    <item>
      <title>A 2D image analysis framework for quantifying interfacial and synergistic homogenization in virgin-RAP asphalt blends</title>
      <link>https://trid.trb.org/View/2667346</link>
      <description><![CDATA[Characterization of blending condition between the aged asphalt on reclaimed asphalt pavement (RAP) and the virgin asphalt are critical for advancing asphalt pavement recycling technologies. This study proposes a novel quantitative methodology for assessing the homogenization rates of virgin-RAP asphalt blends through 2D image analysis. Pre- and post-blending RAP asphalt-aggregate morphologies were precisely identified via field emission scanning electron microscopy-backscattered electron (FESEM-BSE) combined with energy-dispersive X-ray spectroscopy (EDS) elemental mapping, and the synergistic homogenization rate and the interfacial homogenization rate were modeled mathematically. 20 % TiO₂ was identified as the optimal tracer content (Δa variation ratio = 0.007, G* variation ratio = 0.037) due to enhanced EDS detectability and minimal rheological impact. Atomic force microscopy (AFM) analysis revealed a strong positive linear correlation between Derjaguin-Muller-Toporov (DMT) modulus and DSR-derived G*, and significant negative correlations between G* and adhesion force, and between G* and energy dissipation. The RAP asphalt content synergistically influenced microstructural evolution and nanomechanical properties of virgin-RAP asphalt blends. Elevated RAP preheating temperature (200°C) maximized the synergistic homogenization rate (0.798), while extended residence time optimized interfacial homogenization (0.521); mixing time showed comparatively minor influence.]]></description>
      <pubDate>Mon, 23 Feb 2026 11:24:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2667346</guid>
    </item>
    <item>
      <title>A solvent-free AFM approach for high-resolution aging assessment in reclaimed asphalt binders</title>
      <link>https://trid.trb.org/View/2639991</link>
      <description><![CDATA[The accurate characterization of reclaimed asphalt binder (RAB) properties is critical for sustainable pavement rehabilitation, yet conventional extraction and recovery methods involve hazardous solvents, posing environmental and efficiency challenges. To advance cleaner production in asphalt recycling, this study introduces a novel solvent-free approach using atomic force microscopy (AFM) to directly assess the nanomechanical properties of RAB within mixtures, eliminating the need for extraction. Two specimen preparation techniques—hot asphalt pouring and frozen-storage/low-temperature cutting—were developed to enable AFM observation of binder and mixture samples. The derived nanoscale Derjaguin-Muller-Toporov (DMT) modulus and adhesion force demonstrated high sensitivity to asphalt aging and strong correlations with macroscale performance indicators. Regression models were established to predict the macroscopic properties of RAB based on nanomechanical data, enabling reliable estimation without solvent use. Furthermore, a three-tier aging classification system for RAB was proposed based on DMT modulus thresholds. The method’s validity was confirmed using reclaimed asphalt pavement (RAP) materials from three field sources, demonstrating its effectiveness in characterizing RAB aging and properties in situ. This research provides a sustainable, efficient alternative to traditional practices, aligning with the principles of cleaner production by reducing chemical waste, energy consumption, and procedural complexity in pavement recycling.]]></description>
      <pubDate>Thu, 12 Feb 2026 08:53:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2639991</guid>
    </item>
    <item>
      <title>Niobium Alloyed Brake Disc for reduced NVH and Emission Control</title>
      <link>https://trid.trb.org/View/2663529</link>
      <description><![CDATA[:Recent regulations limiting brake dust emissions have presented many challenges to the brake engineering community. The objective of this paper is to provide a low cost, mass production solution utilizing well known existing technologies to meet brake emissions requirements. The proposed process is to alloy the Gray Cast Iron with Niobium and subsequently Ferritic Nitrocarburize (FNC) the disc. The Niobium addition will improve the wear resistance of the FNC case, reducing wear debris.The test methodology included: 1. Manufacture of disc samples alloyed with Niobium, 2. Finish machining and ferritic nitrocarburizing and 3. Evaluation of airborne wear debris utilizing a pin-on-disc tribometer equipped with emission collection capability. The airborne emission and wear surfaces were further analyzed by Scanning Electron Microscopy, Energy Dispersive techniques (SEM-EDS), X-Ray Diffraction and Optical Microscopy. The cast iron test matrix included four groups; Unalloyed eutectic 4.3% Carbon Equivalent (CE), Unalloyed hypereutectic >4.3% CE, Niobium alloyed Eutectic and Niobium alloyed hypereutectic gray cast iron. The results demonstrate the advantages of Niobium alloyed FNC treated discs in reduced wear and meeting Euro7 airborne emission requirements. The Niobium alloyed eutectic Gray Cast Iron plus FNC treatment exhibited the best wear debris performance for both the Non-Asbestos organic (NAO) and Low Metallic (Low Met) friction materials. The Niobium alloyed hypereutectic Gray Iron plus FNC treatment also performed well with both NAO and Low Metallic friction materials.]]></description>
      <pubDate>Mon, 02 Feb 2026 16:36:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663529</guid>
    </item>
    <item>
      <title>Failure Analysis of Dissimilar Metal Weld Joint of an Air Spring Bracket within an Automotive Active Seat Suspension System</title>
      <link>https://trid.trb.org/View/2663473</link>
      <description><![CDATA[In modern four-wheelers, seat suspension systems play a crucial role in enhancing occupant comfort by mitigating the effects of road unevenness and vibrations. Among these systems, active suspension mechanisms offer advanced performance through complex assemblies involving welded, riveted, and bolted joints. This study investigates the failure of an air spring bracket - a critical component of a pneumatic active suspension system - manufactured by Gas Metal Arc Welding (GMAW) of two dissimilar ferrous materials which are likely to be SAPH440 and S355J2. These different materials were used based on mechanical properties required to perform by their particular part.System level validation tests were conducted to ensure the reliability of the seat suspension system. The one of the validation tests is continuous cyclic fatigue test which is carried out on the complete seat assembly. However, during vibration / cyclic endurance testing, premature failures were observed near the weld joints. Detailed failure analysis using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and optical microscopy revealed cracks and discontinuities at the weld interfaces. The microstructure in the heat-affected zone (HAZ) exhibited ferrite-Martensite structure with grain coarsening. The fractography reveals the cleavage type and river type fracture morphology which indicates the part failed due to brittle fracture. Inadequate welding of SAPH440 steel can lead to issues such as cracking, distortion, and poor fusion due to its high carbon content and inadequate heat control.The failure analysis study identified that less fusion control of welding parameters and associated thickness and carbon compositions variation which significantly contributed to the component’s fatigue failure. Preventive strategies, including the optimization of sectional thickness and design changes for uniform stress distribution are proposed to improve the reliability of welded assemblies.]]></description>
      <pubDate>Mon, 02 Feb 2026 16:36:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663473</guid>
    </item>
    <item>
      <title>In-situ study on asphalt blending of hot recycled asphalt mixtures using atomic force microscopy</title>
      <link>https://trid.trb.org/View/2627536</link>
      <description><![CDATA[The blending efficiency between virgin and aged asphalt has long been a study focus in the hot recycled asphalt mixtures (HRAM). To fulfill the in-situ investigation on the asphalt blending, atomic force microscopy (AFM) technology with quantitative nano-mechanical mapping (QNM) module was used in this study. White dolomite was used as virgin aggregate to be distinguished from RAP aggregate based on their color difference, which is beneficial of the selection of test region. A method named as ‘frozen storage and low-temperature cutting’ was proposed to prepare the AFM specimen of HRAM, avoiding altering the original asphalt state. Base on the results of AFM test, a quantitative indicator for the degree of blending (DOB) was proposed. The influencing factors of RAP contents, mixing method and the use of rejuvenator was considered in this study. The results show that under conventional mixing (CM) method, the asphalt within the HRAM exhibits a progressive blending process between virgin and RAP aggregates, forming three types: virgin asphalt, blending asphalt and aged asphalt. Mixtures with higher RAP content demonstrate a lower DOB. The recycled-mortar mixing (RMM) method enables a more uniform asphalt blending on fine RAP materials, thereby increasing the DOB by at least 44 %. Additionally, the use of rejuvenator contributes to enhance DOB, but its enhancement remains below 10 %. Therefore, it is recommended to adopt the CM method in conjunction with the use of rejuvenator to maximize the DOB in HRAM.]]></description>
      <pubDate>Fri, 09 Jan 2026 08:44:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2627536</guid>
    </item>
  </channel>
</rss>