<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>Nonlinear unsaturated shear strength behaviour of compacted crushed rock class IV material: implications for corrugation in unsealed roads</title>
      <link>https://trid.trb.org/View/2647975</link>
      <description><![CDATA[Unsealed roads make up over 65% of Australia’s transport network and are prone to surface deterioration, such as corrugation, especially under dry climatic conditions. Corrugation formation is closely associated with progressive shear failure in the surface layer, often exacerbated by moisture loss. Crushed rock class IV material is widely used for unsealed road construction in Australia. The unsaturated shear strength behaviour of this material has not been characterised properly. This study presents a systematic experimental investigation into the unsaturated properties of compacted crushed rock class IV, focusing on the role of degree of saturation and fines content. Laboratory indirect tensile and direct shear tests were conducted on specimens compacted at optimum moisture content and subsequently dried back to a wide range of saturation levels. Results demonstrate a strongly nonlinear relationship between shear strength and degree of saturation, with cohesion peaking at intermediate saturation (around 40%–50%) and diminishing under both very dry and near-saturated states. The apparent friction angle increased with drying, reaching a peak at fully dry conditions. Comparison of fines-included and fines-removed specimens highlights the critical role of fines in generating suction-related cohesion and maintaining structural stability, as the specimens containing fines exhibited higher unsaturated cohesion. Nonlinear failure envelopes and an empirical Gaussian-based cohesion model are proposed to capture saturation-dependent behaviour, addressing limitations of conventional linear Mohr–Coulomb analyses. Practically, the results suggest that maintaining moisture within intermediate ranges and preserving fines during grading are essential strategies for improving the durability and performance of unsealed roads.]]></description>
      <pubDate>Tue, 24 Mar 2026 09:09:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2647975</guid>
    </item>
    <item>
      <title>A wind-driven device can improve the cooling efficiency of clogged crushed-rock embankments in permafrost regions</title>
      <link>https://trid.trb.org/View/2643938</link>
      <description><![CDATA[To improve the poor cooling efficiency of crushed-rock embankments (CREs) clogged by snow or sand, a novel fully automatic wind-driven air pumping device is developed to enhance convective heat transfer. Numerical simulations demonstrate that this device can increase the internal airflow by several orders of magnitude, thereby significantly strengthening forced convection and improving the overall cooling performance. The embankment and underlying permafrost experience notable temperature reductions, with the cooling effect gradually diminishing with depth. Even for deep permafrost layers, the device still exhibits a remarkable cooling effect. Among the tested configurations, the U-shaped crushed-rock layer embankment equipped with the wind-driven device exhibits the most pronounced cooling performance, outperforming the crushed-rock interlayer embankment with the device due to its higher overall convective efficiency from the revetment crushed-rock layers. Both equipped CREs effectively enhance the ground heat release capacity and substantially mitigate long-term settlement deformation, demonstrating a significant improvement in the thermal stability and structural safety of embankments. Furthermore, the proposed device shows strong adaptability to snow accumulation and sand clogging, ensuring reliable operation under severe environmental conditions. This study provides an innovative and practical approach for improving the cooling performance of CREs in snowy and sandy permafrost regions.]]></description>
      <pubDate>Thu, 26 Feb 2026 09:21:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2643938</guid>
    </item>
    <item>
      <title>Optimisation of gradation based on fractal dimension for large-size graded crushed stone</title>
      <link>https://trid.trb.org/View/2618001</link>
      <description><![CDATA[To improve the mechanical properties of large particle size graded crushed stone mixture and obtain the optimal grading. By using different design methods to obtain the grading of large particle size graded crushed stone, the maximum dry density test, CBR penetration test, static pressure test, and cyclic repeated compaction test were conducted on the large particle size graded crushed stone samples. Finally, fractal theory was introduced to quantitatively calculate the grading of large particle size graded crushed stone, and the fractal dimension of large particle size graded crushed stone was obtained. The relationship between the fractal dimension of large particle size graded crushed stone and density, CBR value, compressive strength, and deformation resistance was analyzed through grey correlation analysis. The experimental results show that large particle size graded crushed stone has better skeleton performance than conventional graded crushed stone; The density, CBR value, compressive strength, and deformation resistance of large-sized graded crushed stone are related to the grading. The skeleton dense grading ratio has stronger mechanical properties compared to the suspended dense grading and skeleton interlocking grading. And the optimal fractal dimension for the optimal configuration should be between 2.59−2.61.]]></description>
      <pubDate>Mon, 09 Feb 2026 13:55:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2618001</guid>
    </item>
    <item>
      <title>Stabilisation of demolition materials for pavement base layer applications using bagasse ash geopolymer</title>
      <link>https://trid.trb.org/View/2643582</link>
      <description><![CDATA[This study examined the stabilisation of recycled construction and demolition waste, specifically recycled crushed rock (RCR) and recycled asphalt pavement (RAP), using bagasse ash (BA) geopolymer for pavement base materials. The research aimed to improve the mechanical properties of these materials while addressing waste disposal and reducing cement consumption. The study developed RAP and RCR stabilised with BA geopolymer according to the Department of Highways, Thailand standard for cement-modified crushed rock (DH-S. 203/2556), with a minimum unconfined compressive strength (UCS) of 2,413 kPa. The results show that using 5% BA was the most effective for stabilisation. Higher BA content reduced the material density and increased the alkaline solution requirement. Sodium hydroxide (NaOH) concentrations of 8, 10, and 12M significantly improved the UCS and elastic modulus by enhancing geopolymerization. While RAP-BA geopolymer exhibited lower strength than RCR-BA because the asphalt coating weakened the bond, it improved energy absorption by 60–129% due to increased flexibility – vital for road structures under dynamic loads. A 50:50 RCR:RAP mix with 5% BA, 10M NaOH, and sodium silicate, compacted in dry conditions and cured at ambient temperature, offers a sustainable alternative to conventional material by reducing greenhouse gas emissions while maintaining comparable UCS and costs.]]></description>
      <pubDate>Sat, 10 Jan 2026 18:02:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2643582</guid>
    </item>
    <item>
      <title>Drainage characteristics of a graded crushed stone layer in a sandwich-structured red clay highway subgrade</title>
      <link>https://trid.trb.org/View/2627509</link>
      <description><![CDATA[This study evaluates the drainage behavior of a sandwich-structured red clay subgrade incorporating a graded crushed stone layer to improve moisture stability during infiltration. The analysis combines theoretical modeling and physical model tests with fluorescent tracer experiments to monitor water migration. The second soil layer (T2) exhibits significant fluctuations in volumetric water content, peaking at approximately 50 % before stabilizing at roughly 35 %. In contrast, the first soil layer (T1) peaks at approximately 32 % (36 % lower than T2) and eventually stabilizes at approximately 27 % (22.8 % lower than T1's peak). Initially, water migrates laterally in the gravel layer with rapid discharge, followed by vertical infiltration into the underlying soil. Further, the influence zone exhibits a fan-shaped distribution. In contrast, water movement within red clay is predominantly vertical, with minimal lateral flow. These findings provide a technical reference for moisture control in red clay subgrades and support the application of composite sandwich structures in highway construction, particularly in humid and high-rainfall regions.]]></description>
      <pubDate>Fri, 09 Jan 2026 08:44:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2627509</guid>
    </item>
    <item>
      <title>Cement-treated crushed stones: influence of cement type on mixture porosity</title>
      <link>https://trid.trb.org/View/2598416</link>
      <description><![CDATA[The study analysed the absorption and void content of CTCS mixtures with two cement types (CP II-F 32 and CP IV 32 RS) and binder levels (3% and 5%) to evaluate the impact of cement type on porosity. The results indicated that replacing CP II-F 32 cement with CP IV 32 RS cement leads to mixtures that are less porous, more compact, and with stronger bonds between mortar and aggregate. The macro and microstructure images corroborated the results obtained. Complementary analyses of the mechanical behavior of the mixtures showed that mixtures with CP IV had higher strengths and stiffnesses compared to mixtures with the same CP II cement content, indicating a better performance of mixtures with cement containing a high content of pozzolanic material. Factorial models highlighted a strong correlation between porosity and mechanical properties, demonstrating that reduced absorption and void indices result in higher performance.]]></description>
      <pubDate>Mon, 24 Nov 2025 15:30:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2598416</guid>
    </item>
    <item>
      <title>Comparative study on embankment slope cooling technologies in the permafrost region of Central Yakutia (Russia)</title>
      <link>https://trid.trb.org/View/2590282</link>
      <description><![CDATA[In recent decades, the world has observed an active development of northern regions around the globe. Climate change is increasing the availability of hard-to-extract natural resources mining. Railways are one of the best options for the progress of transport infrastructure in these regions due to the low cost of cargo and passenger transportation. Embankments are the most common design solution of the roadbed in areas with permanent frozen soils. However, they significantly change the conditions of heat exchange between the atmosphere and permafrost. The slope surface of the embankment increases the warming effect due to increased snow accumulation in winter and insolation in summer. Climate change accelerates permafrost degradation processes. Based on computer simulation different methods of slope surface cooling were compared for the site of the Amur-Yakutsk Mainline on ice-rich permafrost. The following cooling technologies were considered in the article: crushed stone revetment, ventilation ducts and thermal insulation material. As a result of the study, it was determined that crushed stone was most effective in neutralizing the warming effect of the slope when the air temperature rises. The results obtained for the railway section in Central Yakutia will help to select the right parameters for cooling measures when designing the railway route and reconstructing the highway in the northeastern part of Russia. Especially in areas with near-surface underground ice and ice-rich frozen soils.]]></description>
      <pubDate>Thu, 16 Oct 2025 17:02:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2590282</guid>
    </item>
    <item>
      <title>Thermal effects analysis of separated crushed-rock embankment configurations on underlying permafrost</title>
      <link>https://trid.trb.org/View/2589264</link>
      <description><![CDATA[The thermal stability of embankments in permafrost regions is significantly influenced by rising temperatures resulting from climate change and engineering activities. This study examines the thermal interactions and cooling performance of various separated embankment types—including ordinary embankments (SOE), crushed rock-based embankments (SCE), and two hybrid configurations (SCFE and SCRE)—through a combination of field monitoring data and numerical simulations conducted along the Gonghe–Yushu high-grade highway (GYHH). A comprehensive numerical model encompassing air, porous media, and soil domains was developed to simulate convective and conductive heat transfer processes under complex permafrost conditions. Results show that the SCE effectively raises the permafrost table and reduces the maximum thawing depth due to enhanced ventilation and heat dissipation. Hybrid embankments exhibit asymmetric thermal behavior influenced by the placement of the crushed-rock structure; notably, the SCFE configuration (crushed-rock in the front) demonstrates superior cooling performance compared to SCRE. These findings offer theoretical support for optimizing embankment design to enhance the long-term stability of road infrastructure in permafrost regions.]]></description>
      <pubDate>Thu, 25 Sep 2025 09:30:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2589264</guid>
    </item>
    <item>
      <title>Laboratory Characterization of Cement-Treated Rock Rubble as Airfield Pavement Base Layer</title>
      <link>https://trid.trb.org/View/2407394</link>
      <description><![CDATA[As a means to ensure economic and environmental sustainability in pavement works, the use of locally obtained waste materials (rocks) in base layer design as well as exploring energy-efficient construction methods is highly encouraged. This study explores the use of cement-treated recycled rocks of up to 1.5 in. (37 mm) in size as an alternative base layer material for the construction of airfield pavements. The Preplaced Aggregate Concreting Method (PAC) was implemented to construct the base layer without any vibration or compaction effort. This is an unconventional airfield pavement base construction method, which solely relies on the flowability of the grout mix to ensure the voids between rocks are filled up by means of gravity. The experimental program explores the compressive strength, modulus of elasticity and tensile strength of the material. The preliminary results demonstrate the potential of CTRR as a viable base layer alternative to existing stabilized bases.]]></description>
      <pubDate>Mon, 22 Sep 2025 17:13:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407394</guid>
    </item>
    <item>
      <title>Tyre derived aggregates and waste rock blends: Resilient moduli characteristics</title>
      <link>https://trid.trb.org/View/2516055</link>
      <description><![CDATA[Waste management is an increasingly important topic in the growing economies of developed and developing countries. The environmental issues related to non-biodegradable tyre waste requires the need for innovative solution for the recycling and reuse of waste tyre derived products in sustainable infrastructure applications. The usage of tyre derived aggregates (TDA) has been of recent interest to the recycling and road construction industries, due to the vast quantities of waste tyres that are currently stockpiled or landfilled. Furthermore, in recent years there has been a high demand for alternative products to replace quarried aggregates, which are exceedingly costly from an environmental and economic point of view. TDA products, due to their relatively small sizes after processing need to be blended with larger sized granular products to obtain pavement materials with adequate physical and strength properties. The abundance of waste crushed rock (CR) from residential subdivision activities, make this material ideal for granular stabilization with TDA, and furthermore will result in a blended pavement product with reduced rigidity. In this research, extensive laboratory evaluation was undertaken to assess the mechanical suitability of the CR + TDA blends for pavement base/subbase applications. TDA samples were shredded, screened and split into three different sizes, small (TDA-S), medium (TDA-M) and large (TDA-L). In this research, TDA-S, TDA-M and TDA-L were blended with CR with contents of 1%, 2% and 3% (by weight). The inter-particular interaction of the soft TDA and rigid CR aggregates were also evaluated under repetitive loading, at two different moisture conditions. The CR + TDA blends showed an acceptable permanent strain behavior at low deviator stresses. The resilient modulus of the CR + TDA blends were found to conform to recommended models at low stress levels, whereas the CR + TDA blends in the elastic region, exhibited stress levels which were expected for base/subbase courses and which were reduced at higher stress levels. In this research, CR + TDA blends, with optimum contents of 2% TDA were found to be a viable for usage in pavement base/subbase applications.]]></description>
      <pubDate>Tue, 01 Apr 2025 09:50:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2516055</guid>
    </item>
    <item>
      <title>Study on the cooling effect of crushed rock-based embankment of high-grade highway in permafrost region under the influence of crushed-rock fragmentation and weathering</title>
      <link>https://trid.trb.org/View/2491373</link>
      <description><![CDATA[In road construction within permafrost regions, the crushed rock-based embankments(CRBEs) are commonly used as active cooling measures, particularly on the Qinghai-Tibet Plateau. The unique climatic conditions in this region can lead to fragmentation and weathering of the crushed-rock within these embankments, subsequently diminishing their cooling effectiveness. This study, drawing on field observations from the Gonghe-Yushu high-grade highway(GYHH) and supplemented by numerical simulations, investigates how such degradation affects the embankment's cooling performance. Results indicate that fragmentation and weathering increase soil temperatures underneath the CRBE, accelerate the degradation rate of the permafrost table, and significantly reduce the radius and area of the frozen zone. Additionally, the permafrost table descends more slowly on shady slopes compared to sunny ones. Consequently, the altered pore structure and reduced ventilation due to rock degradation impede internal heat dissipation within the CRBE, thus undermining its cooling capacity.]]></description>
      <pubDate>Thu, 27 Feb 2025 10:45:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491373</guid>
    </item>
    <item>
      <title>Mechanical response and damage evaluation of cement-stabilized crushed stone base roads under load and freeze-thaw coupling effects</title>
      <link>https://trid.trb.org/View/2484960</link>
      <description><![CDATA[Cement stabilized crushed stone base material is widely used in pavement structures, but it is prone to damage under complex loads and freeze-thaw cycles, which can lead to pavement failure. Due to insufficient consideration of the behavior of the material under the coupling conditions of freeze-thaw and dynamic loads in engineering, there are deficiencies in the assessment of its freeze-thaw damage mechanism and fatigue life. Based on this, this article constructs a fully controlled load freeze-thaw test system suitable for simulating structures of cement stabilized crushed stone base, and based on this test system, the mechanical response of small-sized pavement structures under load freeze-thaw action is measured. The results indicate that compared to a single load, freeze-thaw cycles and load coupling accelerate the deterioration of pavement structures and produce greater deformation in the crushed stone base. Finally, the load freeze-thaw damage factor was constructed and introduced into the fatigue equation. The life prediction equation for freeze-thaw damage of cement stabilized crushed stone base structure was derived and established, providing a theoretical basis for guiding the engineering application of cement stabilized crushed stone base materials in cold regions.]]></description>
      <pubDate>Tue, 18 Feb 2025 10:56:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2484960</guid>
    </item>
    <item>
      <title>Influence of initial state and residual stresses on the modulus-density relationship of geomaterials: insights from multiple experimental setups</title>
      <link>https://trid.trb.org/View/2487726</link>
      <description><![CDATA[Quality control in pavement construction traditionally relies on density measurements of geomaterials. With the introduction of modulus measurement methods, a shift has occurred due to the operational advantages of modulus-estimating devices over conventional density measurement techniques. Modulus-based methods also provide valuable information for the mechanistic-empirical (ME) design of pavement layers. However, a challenge emerges as a single modulus measurement does not directly correspond to a specific density measurement, leading to concerns about replacing density measurements in quality control processes. While it is generally accepted that a geomaterial's modulus primarily depends on its moisture content and density or void ratio, this study explores the complex relationship between modulus and density, particularly in field scenarios with consistent moisture content. Using three different laboratory-scale test set-ups, characterised by unique loading and boundary conditions, the research highlights the significant role of a geomaterial's initial state in obtaining accurate modulus estimates. The results reveal that identical densities can exhibit variations in modulus due to differences in initial densities and the development of residual lateral stresses. These variations in field conditions often stem from different paving or spreading techniques, emphasising the need for a comprehensive approach when establishing density-modulus correlations.]]></description>
      <pubDate>Mon, 20 Jan 2025 16:46:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2487726</guid>
    </item>
    <item>
      <title>Evaluation of the Long-Term Thermal–Mechanical Stability of an Embankment Replaced with Crushed Rocks in Cold Regions</title>
      <link>https://trid.trb.org/View/2431574</link>
      <description><![CDATA[Conventional measures of protecting permafrost cannot improve embankment stability in warm permafrost regions. Therefore, based on the principle of allowing permafrost to thaw, a method of replacing the 4.5?m underlying permafrost layer with 200–400?mm diameter crushed rocks was proposed to reduce embankment settlement. To evaluate the long-term stability of the embankment in question, a hydro-thermomechanical coupling model considering condensation is established for unsaturated frozen soil; the water, heat, and deformation conditions of the embankment in 20 service years are calculated; and its working mechanism is analyzed. In addition, the optimal replacement depth of the crushed rocks is discussed from thermodynamic and economic perspectives. The results show that: (1) an increase in replacement depth can increase the permafrost table under the embankment centerline, thus improving the thermal stability of the embankment; (2) the increase in replacement depth can reduce the unfrozen water content from the deep foundation to the embankment filling layer, thus reducing the cumulative settlement; (3) if only the embankment stability is considered, the embankment stability is better with the greater replacement depth. If both stability and economy are considered, a replacement depth of 4.0?m is the optimal solution. The maximum settlement, maximum horizontal deformation, maximum uneven settlement, and maximum horizontal deformation difference of this embankment are -0.693, -0.241, 0.306, and -0.358?cm. This study provides a reference for the settlement control of embankments and the optimal design of crushed-rock embankments in warm permafrost regions.]]></description>
      <pubDate>Wed, 18 Sep 2024 17:19:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2431574</guid>
    </item>
    <item>
      <title>Full-scale model testing of a graded crushed stone sandwich structure within the ballastless track subgrade</title>
      <link>https://trid.trb.org/View/2404071</link>
      <description><![CDATA[This paper aims to analyse the static and dynamic characteristics of the sandwich structure consisted of an upper ballastless track structure layer, middle graded crushed stone interlayer, and lower foamed concrete subgrade layer, and clarifies its long-term dynamic stability. A full-scale test model of the sandwich structure being optimized was established, and then the static and dynamic loading tests were carried out. The results show that the use of foamed concrete as the subgrade filler can make the sandwich structure subgrade have better static stress and vibration diffusion effect compared with the traditional ballastless track subgrade. Under the loading conditions of this model test, the sandwich structure does not produce a resonance phenomenon when the loading frequency increases from 1 Hz to 10 Hz. And the sandwich structure has good vibration characteristics and long-term dynamic stability under cyclic loading. All these indicate that the graded crushed stone sandwich structure of the ballastless track foamed concrete subgrade can provide a smooth and long-term stable foundation for the line.]]></description>
      <pubDate>Thu, 22 Aug 2024 15:09:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2404071</guid>
    </item>
  </channel>
</rss>