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    <title>Research in Progress (RIP)</title>
    <link>https://rip.trb.org/</link>
    <atom:link href="https://rip.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>
    <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>Research in Progress (RIP)</title>
      <url>https://rip.trb.org/Images/PageHeader-wTitle-RIP.jpg</url>
      <link>https://rip.trb.org/</link>
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    <item>
      <title>Advancing Slope Stability in Roadway Embankments: The Role of Innovative Geosynthetics and Numerical Modeling Under Dynamic Traffic Load and Extreme Rainfall Conditions</title>
      <link>https://rip.trb.org/View/2691527</link>
      <description><![CDATA[Slope stability in roadway embankments remains a critical concern in geotechnical engineering. The slopes are often mechanically stabilized by using conventional geosynthetics such as geotextiles, geogrids, and geomembranes for separation, reinforcement, filtration, drainage, and erosion control under static conditions. However, evolving infrastructure demands and increasing exposure to extreme weather and dynamic loading necessitate the adoption of advanced geosynthetics. New materials such as wicking geotextiles, which combine mechanical reinforcement with moisture regulation via capillary action, and geocomposites, which integrate multiple geosynthetic components for enhanced drainage and barrier performance, offer promising solutions. Numerical modeling techniques, including finite element and finite difference methods, are essential for evaluating the behavior of these materials under various environmental loading scenarios, capturing critical parameters such as rainfall infiltration, matric suction variations, and pore water pressure fluctuations. Furthermore, modeling under dynamic traffic loading enables the assessment of cyclic stress response, shear deformation, and stress redistribution in reinforced embankment systems. Despite these advances, research remains limited regarding the coupled effects of environmental and traffic-induced loading on advanced geosynthetic systems. This study proposes a comprehensive numerical modeling framework for advancing slope stability in roadway embankments by incorporating comprehensive laboratory test results, with a focus on evaluating the performance of advanced geosynthetics under combined environmental and traffic loading conditions. The outcomes are expected to support the development of resilient and sustainable transportation infrastructure systems. ]]></description>
      <pubDate>Thu, 10 Sep 2026 08:54:26 GMT</pubDate>
      <guid>https://rip.trb.org/View/2691527</guid>
    </item>
    <item>
      <title>Improving Life-Cycle Cost Analysis (LCCA) of Pavements with Geosynthetics Used as Separators with Real Life-Cycle Cost Data</title>
      <link>https://rip.trb.org/View/2712204</link>
      <description><![CDATA[Life-Cycle Cost Analysis (LCCA) is widely used to compare pavement design alternatives and evaluate long-term economic efficiency. Geosynthetics have been widely used in flexible pavements as separator layers between the base, subbase, and subgrade to improve long-term pavement performance and extend service life. LCCA is routinely used as an important asset management tool for evaluating agency and user costs over the life of a pavement. However, the accuracy of current LCCA approaches for pavements with geosynthetic separators remains uncertain because pavement performance prediction models are often based on limited laboratory testing or short-term field monitoring data. Variations in model assumptions, design inputs, maintenance activities, and user cost estimates can significantly affect LCCA results and may obscure the benefits of geosynthetics.

Since many pavements constructed during the early implementation of LCCA have now experienced major rehabilitation activities or reached a substantial portion of their service life, state departments of transportation (DOTs) have accumulated significant field performance, maintenance, and cost data. These data provide an opportunity to compare actual life-cycle costs with the original LCCA predictions and to improve future analyses.

The objective of this research is to (a) use real life-cycle cost data from flexible pavements with geosynthetics used as a separator between the base/subbase and subgrade to validate the LCCA performed at the project design phase, (b) quantify the differences between LCCA results and real life-cycle costs and identify the factors that contribute to any discrepancies, and (c) make recommendations for future LCCA models for other geosynthetic functions. ]]></description>
      <pubDate>Wed, 10 Jun 2026 11:16:58 GMT</pubDate>
      <guid>https://rip.trb.org/View/2712204</guid>
    </item>
    <item>
      <title>Coastal and river bridge scour mitigation using hybrid solutions (TAMU)</title>
      <link>https://rip.trb.org/View/2663228</link>
      <description><![CDATA[Bridge piers, foundations, and abutments in coastal areas or across rivers often face heightened risk of detrimental scour development under wave and/or current loading. Along  coastlines bridges are part of essential evacuation routes, saving lives ahead of predicted storm impacts with life-threatening consequences if compromised. Further inland, many bridges across creeks and rivers that are part of rural transportation systems and low-volume road networks afford equally important transportation connections. When disaster strikes and these structures are compromised – as was painfully demonstrated in the recent Central Texas flash flood disaster – entire communities are cut-off from relief help or means to recover quickly. In most instances, bridge failure is initiated through hydraulically-induced scour formation and growth at the interface of the structural components and the surrounding sediment. If scour issues can be predicted and mitigated early, catastrophic failure can be avoided. The problem is that traditional mitigation techniques are costly or, in the case of rural bridges, may not even be included in the design. Here, the research team plans to test low-cost hybrid mitigation techniques that can help reduce scour impact to bridges caused by wave or current impact by using bio-cementation (such as Microbially-Induced Calcium Carbonate Precipitation - MICP) and/or geosynthetics in combination with the in-situ sediment.

Proposed Research: The team plans the following tasks to address the efficacy of these solutions to reduce scour: Task 1: Assess existing technological options for coastal and riverine bridge scour protection. This will be done via an in-depth literature review on scour protection with the goal of identifying various options, their advantages and limitations. 
Task 2: Conduct physical model wave flume scour tests with wave and/or current loading for different low-cost, hybrid scour protection combinations including MICP and geosynthetics in tandem with the in-situ sediments.
Task 3: Develop scour prediction equations based on the conducted physical model tests that can be used to assess the efficacy of the hybrid solutions for use in coastal and riverine bridge systems.
]]></description>
      <pubDate>Sat, 31 Jan 2026 11:25:04 GMT</pubDate>
      <guid>https://rip.trb.org/View/2663228</guid>
    </item>
    <item>
      <title>COLLABORATIVE: Quantifying erosion and load transfer mechanisms of geosynthetic reinforced coastal pavement subgrades and embankments during inundation events (TAMU/TXST)</title>
      <link>https://rip.trb.org/View/2663227</link>
      <description><![CDATA[Project Description: Transportation infrastructure in coastal regions is highly susceptible to soil erosion and subgrade degradation under frequent inundation events caused by storm surges. Fines within the subgrade are washed out due to flood-induced subsurface flow, while overflowing water along embankments results in overtopping and eventually leads to surficial erosion and complete collapse. These processes result in embankment and pavement failures; addressing these issues requires novel and innovative infrastructure durability solutions. One approach that combines hydraulic protection of subsoils with reduced soil erosion and provides drainage to recede floodwaters from infrastructure is geosynthetics. Geosynthetics, like geocomposites and turf-reinforced mats (TRMs), are often used to control erosion in slopes and levees from overtopping and rainfall. Also, the use of geosynthetics is increasingly growing for pavement reinforcement applications. These well-established benefits of geosynthetics can be combined and effectively applied for coastal transportation infrastructure that often sees failures following inundation events. Hence, this research study focuses on evaluating geosynthetics to solve both embankment erosion and maintain drainable and resilient subgrade foundations to support coastal transportation infrastructure. 
Geosynthetic Reinforcement of Coastal Embankment Slopes: TRMs and geocomposites will be studied for this application. Texas State University (TXST) will measure the erosion characteristics of the test materials using the erosion function apparatus (EFA). The EFA will quantify the erosion rates of the soil with and without the protection of these geosynthetic layers under varying hydraulic stresses, providing insights into soil erodibility and material performance. Texas A&M (TAMU) will conduct small-scale flume erosion studies on model embankment slopes using a coastal, sandy soil. Flume studies on embankment slopes built with and without geosynthetic reinforcements will be subjected to overtopping and inundation flow conditions for various time periods. Erosion patterns will be studied via laser and digital image scans. These data will also assess the role of geocomposites and TRMs on mitigating soil erosion and enhancing slope stability.  
Geosynthetic Reinforcement of Coastal Pavement Subgrade Foundations: TAMU flume study results will yield erosion patterns, more specifically void patterns, that will be used to create an  “eroded” pavement structure. These artificial voids will be created inside a large box setup, with 12 to 18 in. of subgrade supporting a flexbase aggregate base layer. These box samples will be instrumented with moisture probes, pressure cells, and MEMS deformation sensors. Each model pavement will be subjected to cyclic plate load tests to study and evaluate the load-bearing capacity and load transfer mechanism from repeated loads to the underlying subgrades. The same tests will be performed on the samples after they are inundated. The role of geocomposites both before and after exposure to moisture inundation, as well as load transfer mechanisms on subgrades with erosion-simulated voids, will be evaluated.
This is a collaborative project between Texas A&M University (TAMU) and Texas State University (TXST). Flume and large-scale box studies will be performed at TAMU Galveston campus and Center for Infrastructure Research (CIR) laboratories, respectively. TXST will perform the EFA with geosynthetic layers experiments. EFA studies focus on evaluating the critical shear stresses (i.e., hydraulic shear stresses at which soil erosion initiates) of the reinforced/unreinforced subsoils. Changes in critical shear stress at discontinuities such as gravel/sand interfaces will be of particular interest.  These combined results will generate a comprehensive understanding of the potential improvements of embankment and foundation reinforcement using advanced geosynthetic materials in providing resilient support to transportation infrastructure in coastal corridors. The results of this project will be used to design Phase II with coastal railroad track embankments.
]]></description>
      <pubDate>Sat, 31 Jan 2026 11:12:55 GMT</pubDate>
      <guid>https://rip.trb.org/View/2663227</guid>
    </item>
    <item>
      <title>Smart Geosynthetics for Performance Monitoring and Life Cycle Assessment of Transportation Infrastructure </title>
      <link>https://rip.trb.org/View/2646950</link>
      <description><![CDATA[Sensor-Enabled Geosynthetics (SEG) products are polymer composites that include networks of conducting fillers such as carbon black, carbon nanotubes, and graphene in their polymer formulation, enabling them to exhibit tensoresistive properties (i.e. strain sensing as a result of tension in the material). SEG technology provides a rapid and economical means to measure mechanical strain in geosynthetic products without the need for much costlier conventional instruments such as strain gauges and extensometers, and data acquisition systems. Therefore, it offers convenient and cost-effective performance monitoring technology for various transportation applications including roads and highways, reinforced soil walls, embankments, and bridge abutments. 

Previous work by the research team examined the in-isolation performance of GCG when subjected to different loading regimes. Therefore, the primary objective of the proposed project is to investigate the in-soil performance of SEG when subjected to different confining pressures, before they can be incorporated in field projects. This objective will be accomplished through a series of large-scale cyclic plate loading tests and additional ancillary tests that will be added to the similar tests that are currently carried out by the PI’s research team in two ongoing Oklahoma Department of Transportation (ODOT) projects as an expanded and unified research study. Example benefits of SEG technology include: improving the safety and performance of transportation infrastructure (i.e. roadways, retaining walls, bridge abutments, and reinforced slopes and embankments) by incorporating a monitoring and warning system, which will result in faster construction and any adjustments necessary in the construction process using real-time response data, leading to significant safety improvements, time and cost savings in the project, and the prevention of costly problems, failures and repairs during service or extreme events.  ]]></description>
      <pubDate>Tue, 06 Jan 2026 09:05:38 GMT</pubDate>
      <guid>https://rip.trb.org/View/2646950</guid>
    </item>
    <item>
      <title>Reinforcement Mechanism of Articulating Concrete Mats (ACMs) and Geosynthetic Fabric for the Design of Highway Embankment in Coastal Louisiana </title>
      <link>https://rip.trb.org/View/2646938</link>
      <description><![CDATA[Coastal highway embankments differ significantly from conventional highway embankments or levees due to their exposure to hurricanes and tropical storms. These events generate substantial hydrodynamic wave pressures that must be considered in design. Reinforcing soil fills at different elevations with geosynthetics is a common approach, but doing so effectively requires research that enhances existing design methods and clarifies their underlying rationale. Design elements such as tensile forces, reinforcement length, and vertical spacing depend on understanding the mechanical behavior of these materials under extreme loading.  

Because coastal embankments are subjected to wave pressures from storms with defined return periods, engineers must account for the maximum hydrodynamic loads these storms generate. In particular, the unique reinforcement roles of geosynthetics and articulating concrete mats (ACMs) must be thoroughly understood to optimize the design. Key factors include ACM layer thickness, the number and arrangement of non-woven geotextile separator layers, and failure modes such as tensile rupture and pull-out resistance in geogrids and woven geotextiles.  

Building on the results from Southern Plains Transportation Center (SPTC)-funded Cycles 1 and 2, this project will use experimental and numerical methods to evaluate the behavior of geosynthetic reinforcements placed at various elevations within embankment fills. Emphasis will be placed on understanding how these materials fail under load and how their performance changes with elevation and storm intensity. In addition to continuing the work from earlier phases, this project will also assess the seepage-reduction capabilities of non-woven geotextiles and the surface stabilization benefits of ACMs applied to embankment slopes.  

Large-scale direct shear testing will be conducted to analyze both tensile rupture and pull-out failure mechanisms in conditions representative of coastal environments. Seepage and slope stability analyses will complement this testing to evaluate the combined performance of ACMs and geotextile separators under storm loading.  

The findings from this research will help validate and refine current design guidelines for coastal highway embankments that incorporate geosynthetics and ACM armor. The study will also contribute to a deeper understanding of conventional geosynthetic failure mechanisms in coastal applications. Ultimately, the research will yield practical, implementable steps for assessing both internal and external stability in coastal embankment design.  ]]></description>
      <pubDate>Mon, 05 Jan 2026 22:35:37 GMT</pubDate>
      <guid>https://rip.trb.org/View/2646938</guid>
    </item>
    <item>
      <title>Synthesis of Information Related to Highway Practices. Topic 57-18. Practices Related to the Use of Geosynthetics and Pavement Foundations</title>
      <link>https://rip.trb.org/View/2630496</link>
      <description><![CDATA[BACKGROUND - In recent years, the geosynthetic industry has introduced new products and techniques, intended to improve pavement performance and longevity. However, it is unclear how geosynthetic solutions (emerging and established) are being implemented in practice by state departments of transportation (state DOTs). A synthesis documenting current practices in the use of geosynthetics for pavement foundations can help state DOTs achieve durable pavement foundations and improve asset performance.

OBJECTIVE - The objective of this synthesis is to document current state DOT practices for the use of geosynthetics (e.g., geotextiles, geogrids, geocells, and geocomposites) for pavement foundations. This synthesis will encompass practices throughout the planning, design, construction, and maintenance/rehabilitation stages.

Information to be gathered includes (but is not limited to): (1) Criteria, procedures, guidelines and manuals for selecting and using geosynthetics in different contexts; (2) 
Design tools (e.g., software or analytical models) and inputs (e.g., geosynthetic properties or soil-geosynthetic interaction properties) used to model pavement foundations with geosynthetics; (3) Uses of geosynthetics during construction, including when they are needed. Differences between evaluating geosynthetics for use in construction and in design. (4) Experience gained and lessons learned from incorporating geosynthetics in pavement foundations; (5) Define material characteristics of geosynthetics; (6) Workflow on development and maintenance of specifications related to geosynthetics; (7) Pilot projects for using geosynthetics; (8) Quality assurance (QA) processes of pavement foundations built with geosynthetics; (9) Methods and gaps in quantifying the benefits of geosynthetics; (10) Practices to track condition and performance of pavement foundations using geosynthetics; and (11) Maintenance, rehabilitation and reconstruction activities on pavement with geosynthetics, including recycling and reclamation of pavement foundations using geosynthetics.

Information will be gathered through a literature review, a survey of state DOTs, and follow-up interviews with selected DOTs for the development of case examples. Information gaps and suggestions for research to address those gaps will be identified.]]></description>
      <pubDate>Tue, 25 Nov 2025 16:37:41 GMT</pubDate>
      <guid>https://rip.trb.org/View/2630496</guid>
    </item>
    <item>
      <title>SPR-5032: Moisture Damage Control and Mitigation in Pavement Foundations Using Innovative Geosynthetics</title>
      <link>https://rip.trb.org/View/2577102</link>
      <description><![CDATA[This project is primarily about controlling water in pavement foundation layers for increased pavement performance. This study proposes to remove water out of the pavement systems via use of geotextile fabric (moisture management geotextile) as a separation layer in pavement foundation systems to mitigate the damage that occurs due to high moisture contents. The workplan consists of constructing sites with these innovative geosynthetics and conducting field tests and analyses. The field tests will include lightweight deflectometer, falling weight deflectometer, moisture and temperature monitoring through depth.]]></description>
      <pubDate>Thu, 17 Jul 2025 15:57:29 GMT</pubDate>
      <guid>https://rip.trb.org/View/2577102</guid>
    </item>
    <item>
      <title>SPR-5026: Evaluating the Effectiveness of Geosynthetics in Controlling the Detrimental Effects of Slow-Moving and Turning Traffic</title>
      <link>https://rip.trb.org/View/2553993</link>
      <description><![CDATA[This study presents a comprehensive evaluation of geosynthetics in slow-moving and turning traffic regions.  Phase 1 includes laboratory testing to assess geogrid effectiveness by quantifying lateral restraint, and stiffness enhancements under turning traffic stress conditions. Phase 2 focuses on field implementation with site selection, instrumentation, and in-situ performance monitoring. The study will develop optimized design strategies and construction practices, with findings disseminated through a final report and implementation guidance for effective integration into INDOT projects.]]></description>
      <pubDate>Thu, 15 May 2025 16:00:15 GMT</pubDate>
      <guid>https://rip.trb.org/View/2553993</guid>
    </item>
    <item>
      <title>Design Criteria for Highway Embankments Reinforced with Geosynthetic Material Exposed to Localized Wave Forces</title>
      <link>https://rip.trb.org/View/2474311</link>
      <description><![CDATA[Unlike the designs of regular highway embankments or levees, the crest level of a coastal highway embankment must be determined by seriously considering the anticipated coastal water levels and storm surge conditions. In the design of a coastal highway embankment, soil fills at different elevations are reinforced with geosynthetic reinforcement. To design effective and reliable geosynthetic reinforcement (tensile force calculation, determination of the reinforcement lengths and vertical spacings, etc.), it is imperative to modify the existing design methods. A coastal highway embankment is typically subjected to strong hydro-dynamic wave pressures. Therefore, during the design process, maximum hydro-dynamic wave pressures consistent with a storm/hurricane with a design return period must be applied to the embankment.
This research aims to develop geometrical and structural design criteria of highway embankment in coastal areas. The design should consider the varying hydrodynamics of the coastal area, including wave height, wave period, and tidal fluctuations. The research will be focused on: (1) Determinations of wave height, embankment crest elevation and freeboard; (2) Reinforcement design of the geosynthetic materials at the bottom of embankment and in the embankment fills of different layers.
The proposed research will consist of the following tasks. Task 1 involves conducting a review of pertinent literature. Task 2 is the determination of the Design Water Level (DWL). Determination of DWL was an integral part of the Louisiana marsh creation project, which necessitated an extensive analysis of Water Surface Elevation (WSE) data. So far, the analytical procedure has selectively incorporated historical WSE readings from three strategic locations. In this current research, more station data would be investigated to cover more coastal areas in Louisiana. Determination of the embankment crest level is Task 3 of this project. Determination of an embankment crest level is important for ensuring that the embankment can withstand future condition when sea level is heightened. To calculate the embankment crest level, the design water level (the highest expected water level) and the safety margin called freeboard will be used. Unlike taking a one-foot-high tradition for the freeboard, the team will be following recommended formulations to complete the calculations. Task 4 is related to the development of an effective method for the designs of geosynthetic fabric as reinforcement in highway embankment fills. The traditional 'breaking' and 'pullout' failure mechanisms for the reinforcing geosynthetic materials in embankment fills will be followed for this purpose. Large-scale direct shear tests will be conducted to understand the frictional interaction mechanisms between the geosynthetics and embankment fills. 
]]></description>
      <pubDate>Tue, 10 Dec 2024 13:50:55 GMT</pubDate>
      <guid>https://rip.trb.org/View/2474311</guid>
    </item>
    <item>
      <title>Soil Stabilization Using One-Part Geopolymer: A Sustainable Approach for Enhanced Durability and Performance</title>
      <link>https://rip.trb.org/View/2474212</link>
      <description><![CDATA[Soil stabilization is a way of improving the physical properties of soil to ensure the stability and longevity of soil. Traditional soil stabilization methods commonly employ materials like Portland cement and lime. The exploration of additional options for stabilization agents has gained considerable interest. One such promising alternative is the use of geopolymers. Geopolymers are inorganic polymers formed through the activation of aluminosilicate materials with alkaline solutions. Unlike traditional cement, geopolymers utilize industrial by-products such as fly ash, slag, and metakaolin as their primary raw materials, which are abundantly available and often considered waste. The geopolymerization process involves the chemical reaction of these materials with an alkali activator, resulting in a hardened binder with superior mechanical and chemical properties. 
The goal of the present study is to use one-part ready-to-use solid geopolymer which needs only water to activate and eradicate the necessity for handling hazardous liquid alkaline activators. This research aims to evaluate one-part geopolymers as an innovative solution for soil stabilization. By addressing the technical, environmental, and economic aspects, this study seeks to establish a comprehensive understanding of the potential benefits and practical application of geopolymers in enhancing soil properties for construction purposes. 
Specific objectives of the project include the following: (1) Optimizing a one-part geopolymer formulation suitable for soil condition; (2) Evaluating the mechanical properties of geopolymer-stabilized soils including compressive strength, tensile strength, and durability; (3) Conducting life cycle assessment of the binders, and (4) Investigate the practical application methods and economic feasibility of one-part geopolymers in field conditions. 
The proposed research will consist of the following tasks. Task 1: Selecting sources of aluminosilicate raw materials, appropriate alkaline activators and soil samples. Task 2: Characterization of soil through laboratory tests, such as particle size analysis, Atterberg limits and specific gravity. Task 3: Optimize the design mix proportions and conduct mechanical tests, such as Proctor compaction tests, unconfined compressive strength, split tensile strength tests and durability tests (wetting-drying cycles, freeze-thaw cycles and chemical resistance). Task 4: Perform economic life cycle impact analysis along with leachate analysis to assess the potential for leaching harmful substances into soil. Task 5: Conduct small scale field trials with various types of soil collected from different locations of Louisiana and stabilized using the proposed one-part geopolymer formulations.
]]></description>
      <pubDate>Tue, 10 Dec 2024 13:47:34 GMT</pubDate>
      <guid>https://rip.trb.org/View/2474212</guid>
    </item>
    <item>
      <title>2319 Comparative Performance of Geotextile Products for Subgrade Stabilization through Plate Load Tests</title>
      <link>https://rip.trb.org/View/2434203</link>
      <description><![CDATA[Different geosynthetic manufacturers and suppliers continuously produce newer subgrade stabilization products and advocate for their use in the Oklahoma Department of Transportation (ODOT)-sponsored and other roadway projects in Oklahoma, which makes it essential for ODOT to have an objective and reliable set of guidelines and product evaluation program for the acceptance and use of such products based on their measured performance in conjunction with soils that would be representative of those encountered regularly across the state. This project aims to address this need for ODOT by testing different subgrade stabilization geotextile products using nominally identical aggregate base-subgrade models in the laboratory so that their performances can be quantified and compared consistently and reliably in terms of their corresponding Settlement Reduction Factors (SRF) and Traffic Benefit Ratios (TBR) for field applications (Mahmood 2013). These factors can help ODOT engineers quantify the benefit of individual geotextile products directly relative to unreinforced (i.e. control) conditions, especially to implement for the project conditions and requirements they encounter in Oklahoma. The research team will also search for any data available from other states to determine any specific trends and variations in the TBR and SRF values for different geotextile products on subgrade soils in Oklahoma as compared to those reported on other subgrades, which can also be beneficial for verification purposes relative to the results of the study. ASTM D 8462 (ASTM 2022) will be used to carry out the plate load tests. The products that will be included in this study are those which are most often used in Oklahoma, as well as those promoted by other manufacturers as equivalent alternatives at lower prices, and higher-end products to determine practical upper-bound values for the benefits expected from subgrade stabilization products for future cost benefit analysis.]]></description>
      <pubDate>Thu, 26 Sep 2024 15:59:24 GMT</pubDate>
      <guid>https://rip.trb.org/View/2434203</guid>
    </item>
    <item>
      <title>Laboratory Test Method for Estimating the Contribution of Geosynthetics to Pavement Performance



</title>
      <link>https://rip.trb.org/View/2352950</link>
      <description><![CDATA[Geosynthetics are available in a wide range of forms and materials and are used in many applications. Geosynthetics are often used by highway agencies in conjunction with unbound base layers as a means for enhancing the performance of pavements. Test methods are currently available to estimate the performance enhancement resulting from the use of geosynthetics in the pavement structure (e.g., ASTM D8462, Cyclic Plate Load Tests to Evaluate the Structural Performance of Roadway Test Sections with Geosynthetics). However, there is concern about the validation of the test methods and reliability of the resulting estimates. Research is needed to evaluate the merits of the tests currently used for estimating the benefits of geosynthetics and, if necessary, enhance these test methods or develop new methods that can reliably estimate the contribution of geosynthetics to pavement performance. Such test methods will help highway agencies and others in making decisions regarding use of geosynthetics in pavement structure.

The objective of this research is to develop a practical, validated laboratory test method for estimating the contribution of geosynthetics to pavement performance. The research shall be limited to asphalt pavements and use of geogrids and geotextiles in unbound base and subgrade.]]></description>
      <pubDate>Mon, 18 Mar 2024 19:23:51 GMT</pubDate>
      <guid>https://rip.trb.org/View/2352950</guid>
    </item>
    <item>
      <title>Improving Safety by Eliminating the Bump at End of the Bridge Using Lightweight Backfill and Geosynthetics</title>
      <link>https://rip.trb.org/View/2341567</link>
      <description><![CDATA[Seasonal temperature changes, traffic loading, and compressible foundation can induce bridge abutment movements, which result in differential settlement between bridge and abutment, i.e., bump. Bumps create a hazardous condition for vehicles, which increases motor vehicle fatalities and costs for maintenance and repair. The bump at the end of the bridge is a universe problem for transportation infrastructure around the world including the US. It has caused many motor vehicle fatalities and costed more than 100 million dollars annually to maintain and repair in the US alone. A laboratory study done by this research team has demonstrated the effectiveness of using geogrid reinforcement with geofoam to mitigate the bump problem when the abutment is on a firm foundation. Lightweight backfill is expected to reduce the settlement of bridge abutments on a compressible foundation; therefore, the combination of lightweight backfill with geosynthetics is expected to eliminate the bump even when the abutment is on a compressible foundation. This combined technology needs to be verified by a numerical study and then a field study in the future. The outcome of this project will lead to the development of innovative and sustainable technology for eliminating the bump at the end of the bridge. The successful development of this technology will improve the safety of the bridge approach and the economy of bridge maintenance and repair.]]></description>
      <pubDate>Mon, 19 Feb 2024 16:04:06 GMT</pubDate>
      <guid>https://rip.trb.org/View/2341567</guid>
    </item>
    <item>
      <title>Assessment of Wave Impacts on Highway Embankments due to Hurricanes/Tropical Storms in Coastal Louisiana</title>
      <link>https://rip.trb.org/View/2291284</link>
      <description><![CDATA[Geosynthetic-reinforced highway embankments are often built on expansive clays along the Louisiana shorelines. An embankment is often reinforced using articulating concrete mats and geosynthetic separator fabrics, consisting of planar reinforcements arranged in horizontal planes in the fill to resist outward movements of the fill. Facing treatments ranging from vegetation to flexible armor systems are applied to prevent unraveling and sloughing of the face. These embankments are different from regular levees or embankments in the sense that they are subjected to high current and large wave pressures, as well as pore water pressure conditions, especially under extreme weather events such as hurricanes and tropical storms. This one-year study will only focus on the analysis of wave pressure analyses and the development of wave pressure envelopes that can be used for the design of coastal embankments as well as for assessing the vulnerability of existing embankments to hurricanes. 
The PI and his graduate students have been collaborating with the Coastal Protection and Recovery Authorities of Louisiana (CPRA) on research projects funded by the Louisiana Sea Grant for more than ten years. In this project, long-term measurements provided by the CPRA on wave behavior and design parameters for containment dikes will be examined and applied to the present study on coastal highway embankments. The goal is to quantify the impact of wave pressure on highway embankments using innovative data analysis. The following commonly employed methods will be taken in these analyses: Goda Design Method, Minikin Design Method, and Blackmore and Hewson Design Method. Based on these analyses, a practical method for the distribution of wave pressure on embankments will be developed. These distributions will then be combined to produce wave pressure envelopes, which reflect the worst wave pressure conditions for selected hurricanes and tropical storms of different categories, experienced within the last 20 years. This research project will lead to a more accurate and reliable design approach for geosynthetic-reinforced embankments subjected to wave pressures from hurricanes or tropical storms.
 The following tasks will be carried out in the one-year duration of this project: (1) Collect and review the integrated field observations and modeling data from ADV and wave gauges (e.g., wind wave, velocity, and water levels, etc.) at the specific sites in coastal Louisiana experienced during specific hurricanes, such as Hurricanes Katrina, Rita, and Ida; (2) Compute the time-dependent dynamic wave/current pressure distributions on the faces of selected highway embankments based on the measured data from specific hurricanes, following the three methods noted above; (3) Find the maximum wave pressure at each point on the surface of the embankment based on the analyses in Task 2. Use these maximum wave pressure values to generate a wave envelope; (4) Develop two or three wave pressure envelopes corresponding to the hurricanes and tropical storms of different categories, which were recorded in coastal Louisiana during the past 20 years; (5) Recommend the developed wave pressure envelops to the Louisiana Department of Transportation and Development (LA DOTD) as standardized wave pressure loads for different categories of hurricanes, for future designs of coastal highway embankments as well as for vulnerability of existing embankments under future extreme events. 

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      <pubDate>Wed, 15 Nov 2023 18:05:49 GMT</pubDate>
      <guid>https://rip.trb.org/View/2291284</guid>
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