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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=PHNlYXJjaD48cGFyYW1zPjxwYXJhbSBuYW1lPSJkYXRlaW4iIHZhbHVlPSJhbGwiIC8+PHBhcmFtIG5hbWU9InN1YmplY3Rsb2dpYyIgdmFsdWU9Im9yIiAvPjxwYXJhbSBuYW1lPSJ0ZXJtc2xvZ2ljIiB2YWx1ZT0ib3IiIC8+PHBhcmFtIG5hbWU9ImxvY2F0aW9uIiB2YWx1ZT0iMTYiIC8+PC9wYXJhbXM+PGZpbHRlcnM+PGZpbHRlciBmaWVsZD0iaW5kZXh0ZXJtcyIgdmFsdWU9IiZxdW90O1NpbGljYSZxdW90OyIgb3JpZ2luYWxfdmFsdWU9IiZxdW90O1NpbGljYSZxdW90OyIgLz48L2ZpbHRlcnM+PHJhbmdlcyAvPjxzb3J0cz48c29ydCBmaWVsZD0icHVibGlzaGVkIiBvcmRlcj0iZGVzYyIgLz48L3NvcnRzPjxwZXJzaXN0cz48cGVyc2lzdCBuYW1lPSJyYW5nZXR5cGUiIHZhbHVlPSJwdWJsaXNoZWRkYXRlIiAvPjwvcGVyc2lzdHM+PC9zZWFyY2g+" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <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>Field Implementations for Concrete with Nontraditional and Natural Pozzolans</title>
      <link>https://rip.trb.org/View/2752286</link>
      <description><![CDATA[The objective of this project is to systematically evaluate how varying limestone content in Type IL cement influences the performance of concretes incorporating natural and nontraditional pozzolans (NNPs), and to identify the optimal nanosilica (nS) dosage for enhancing hydration kinetics, mechanical properties, and long-term durability. The project advances durable and high-performance concrete for transportation infrastructure through the development of optimized cementitious systems incorporating Type IL cement, nontraditional and natural pozzolans, and nanosilica(nS). By quantifying the synergistic effects among limestone content, NNPs, and nS, the study aims to reduce the clinker content of concrete while enhancing fresh properties, mechanical performance and durability. These improvements are expected to extend the service life of concrete structures and lower lifecycle costs.  ]]></description>
      <pubDate>Thu, 13 Aug 2026 15:31:30 GMT</pubDate>
      <guid>https://rip.trb.org/View/2752286</guid>
    </item>
    <item>
      <title>Determination of Test Methods to Quantify the Effects of Organic and Inorganic Constituents in Silica Sand Used for Construction</title>
      <link>https://rip.trb.org/View/2698276</link>
      <description><![CDATA[Quality control of sand and fine aggregate is of paramount importance to ensure the structural adequacy, long-term durability and sustainability of structures owned by the 
Florida Department of Transportation (FDOT). To ensure the organic components within sand do not exceed minimum threshold values, an evaluation of the materials as well as the test methods themselves will be performed as part of this research project. The results from the research project BEB28 suggest that there is a good correlation between the results obtained from the Modified Walkley Black (MWB) method and elemental analysis via combustion (EA) method. The two methods yield similar or consistent measurements of organic carbon content in soil samples. Such correlation is valuable because it indicates that both methods can be used interchangeably or in conjunction to assess soil organic carbon levels. This correlation strengthens the reliability and applicability of both techniques in soil research and management.]]></description>
      <pubDate>Fri, 01 May 2026 07:34:22 GMT</pubDate>
      <guid>https://rip.trb.org/View/2698276</guid>
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    <item>
      <title>State of Practice of Pozzolanic Concrete in Infrastructure Projects



</title>
      <link>https://rip.trb.org/View/2600544</link>
      <description><![CDATA[With the understanding of the advancements in the use of pozzolanic concrete to reduce carbon dioxide emissions, the Senate Committee on Environment and Public Works has requested reports on the use of low-carbon materials, including pozzolanic concrete, in federally funded projects. The request noted that the report should include steps taken to assess the durability, strength, cost, and environmental impacts of pozzolanic concrete compared with existing concrete products. The U.S. Department of Transportation Office of the Assistant Secretary for Research and Technology (US DOT OST-R), in coordination with the Federal Highway Administration (FHWA), will submit to the Committee a report on the use of pozzolanic concrete in federally funded infrastructure projects. The US DOT OST-R requested the TRB Cooperative Research Programs (CRP) to facilitate the conduct of this work and the preparation of the requested report. Research is needed to document the use of pozzolanic materials in concrete used in infrastructure projects and prepare the requested report.

The objective of this project is to document the use of pozzolanic materials in concrete used in infrastructure projects and prepare reports on the state of practice of pozzolanic concrete in infrastructure projects and in federally funded infrastructure projects. The latter report shall be prepared in a format appropriate for submission to the U.S. Congress. The research shall consider the use of fly ash, silica fume, and other pozzolans, both singularly and in combination. The documentation shall include the criteria and methods used to assess suitability of these materials for use in concrete structures, e.g., concrete properties such as durability and strength, estimated service life, economic considerations, and environmental impacts. For this project, pozzolanic concrete is defined as concrete containing pozzolanic materials. The research shall consider FHWA funded projects, projects located on federal lands, and projects using the formula and discretionary grants funds.]]></description>
      <pubDate>Thu, 18 Sep 2025 16:08:41 GMT</pubDate>
      <guid>https://rip.trb.org/View/2600544</guid>
    </item>
    <item>
      <title>Aggregate Alkali-Silica-Reactivity and Mitigative Measures</title>
      <link>https://rip.trb.org/View/2582928</link>
      <description><![CDATA[Alkali-Silica-Reactivity (ASR) is a well-documented issue with aggregate used in concrete throughout New Mexico. Historically, inexpensive coal fly ash (FA), a waste byproduct of power generation with pozzolanic properties, has been relied on as an effective means of mitigating ASR. As more and more coal-fired power plants are retired and replaced by natural gas power plants and renewable energy sources, FA is no longer a reliable and readily available source of material for mitigating ASR. Natural pozzolans currently used for ASR mitigation, such as pumicite and metakaolin, are available but are costly. New Mexico has many undeveloped sources of alternative natural pozzolans which could be utilized with proper characterization and become a significant economic contribute to the state’s economy. Establishing a statewide alkali-aggregate reaction (AAR) database based on detailed ASR testing is required to provide high quality concrete with excellent long-term performance necessary for the construction of highly safe and durable concrete transportation structures. It is expected future changes to concrete specifications will reduce supply burdens and costs for quality concrete, while at the establishing local sources for alternative pozzolans, benefiting local economies, as well as concrete suppliers and customers.]]></description>
      <pubDate>Tue, 05 Aug 2025 13:32:55 GMT</pubDate>
      <guid>https://rip.trb.org/View/2582928</guid>
    </item>
    <item>
      <title>Identification, Monitoring and Treatment of Pavements Damaged by Alkali-Silica Reaction: Guidelines for Engineers</title>
      <link>https://rip.trb.org/View/2582446</link>
      <description><![CDATA[The objectives of this research effort to review of state-of-the-art practice and guidance, including existing state and federal department of transportation (DOT) manuals, surrounding the identification, monitoring, treatment and re-use of alkali-silica reaciton (ASR) damage in pavements.]]></description>
      <pubDate>Wed, 30 Jul 2025 11:36:35 GMT</pubDate>
      <guid>https://rip.trb.org/View/2582446</guid>
    </item>
    <item>
      <title>Use of Colloidal Silica as a Finishing Aid for Concrete Pavement</title>
      <link>https://rip.trb.org/View/2577018</link>
      <description><![CDATA[To determine the feasibility of utilizing colloidal silica as a finishing aid to achieve a smooth pavement surface without negatively impacting the concrete surface. A few years ago, the cement manufacturers located in Missouri all switched to producing Type IL cement.  The limestone is introduced to the clinker during the grinding process.  For Type IL cements to have similar strength gain properties as Type I cements, the Type IL cements are ground finer than Type I cements.  This has resulted in less bleed water occurring along the concrete surface, making it more difficult to finish. To improve the finishing properties, finishers are adding water to the surface increasing the water-to-cementitious ratio at the surface.  This results in the concrete being more permeable, having reduced strength, and lower abrasion resistance. Utilizing a colloidal silica as a finishing aid could allow the finishers to achieve a smooth concrete surface without negatively impacting the surface. If the use of colloidal silica does not negatively impact the concrete, the department could develop a Qualified List (QL) of concrete finishing aids for contractors to utilize on Missouri Department of Transportation (MoDOT) projects.
]]></description>
      <pubDate>Thu, 17 Jul 2025 09:02:28 GMT</pubDate>
      <guid>https://rip.trb.org/View/2577018</guid>
    </item>
    <item>
      <title>Innovations Deserving Exploratory Analysis--The Transit IDEA Program. IDEA 106. Sustainable Tire Tread Nanotechnology for Battery Electric Buses</title>
      <link>https://rip.trb.org/View/2572330</link>
      <description><![CDATA[Battery Electric Buses (BEBs) place severe mechanical stress on tires. A long-term study of BEB fleets by the National Renewable Energy Laboratory (NREL) has shown a 45% reduction that the average BEB tire life. Excessive tire wear has been reported to contribute over 140% increase in tire costs in BEB maintenance budgets. Further, tire maintenance costs have been estimated to be almost 143% higher than for compressed natural gas (CNG) bus fleets.

This project proposes a new material modification and processing in the manufacture of BEB tires. The method involves preparation of siloxane oligomers, adding a compatibilizer to avoid premature coagulation and phase separation, mixing the compatibilized siloxane oligomer to the natural rubber (NR) latex, followed by controlled shear blending and drying. The process creates a reinforced network of silica and NR within the tire tread and is essentially a drop-in technology to the current tire tread material  manufacturing process. By controlling silica dispersion, the process breaks the tradeoffs between high tire wear and low rolling resistance, allowing for performance gains not attainable with current methods and materials.

The work plan will involve preparing a new tire formulation of NR and compatibilized siloxane  to make prototype tires. The prepared material will be characterized using standard test methods for rubber materials. Prototype tires will be manufactured, and their performance compared with EPA SmartWay low rolling resistance tires and the tires of the collaborating transit partners. A fleet test plan and data collection strategy will be developed in collaboration with the transit partners. A transit impact analysis will also be conducted to evaluate the impact and adoption strategy. The material and tire manufacturing process will be scaled beyond laboratory to the pilot production stage along with the compound manufacturing process. Two transit agencies have agreed to run the tests on their fleets. 

Benefits to the transit agencies of this new BEB tire technology will include lower maintenance costs, increased vehicle range and energy efficiency, increased use of low rolling resistance tires, less frequent tire replacements, and reduced labor for tire maintenance. Taking into account their longer life, these tires are also estimated to reduces the total BEB tire costs by 44%.]]></description>
      <pubDate>Tue, 08 Jul 2025 16:59:59 GMT</pubDate>
      <guid>https://rip.trb.org/View/2572330</guid>
    </item>
    <item>
      <title>Advancing Forensic Investigation of Concrete Distresses at VTRC with Focus on Alkali-Silica Reaction (ASR)</title>
      <link>https://rip.trb.org/View/2567104</link>
      <description><![CDATA[The Virginia Transportation Research Council (VTRC) plays a pivotal role in supporting Virginia Department of Transportation (VDOT) by providing technical assistance to districts in addressing field-related issues. Traditionally, forensic investigations conducted by VTRC have relied on petrography, primarily utilizing light microscopy techniques such as stereo and polarizing light microscopy. While effective, this approach has inherent limitations, including labor-intensive sample preparation, reliance on visual assessments, and subjectivity in interpretation. Moreover, the current dependency on external consultants for forensic evaluations results in significant costs and delays, impacting timely decision-making. To address these challenges, VTRC is modernizing its forensic investigation capabilities by integrating advanced analytical instruments, including Raman spectroscopy and Scanning Electron Microscopy (SEM).These techniques not only reduce subjectivity but also improve the accuracy, efficiency, and reliability of forensic assessments.
The adoption of these technologies will significantly enhance VTRC’s ability to investigate key durability concerns such as alkali-silica reaction (ASR), delayed ettringite formation (DEF), and sulfate attack. Furthermore, future expansions of this research will explore applications in chloride diffusion, freeze-thaw resistance, air content analysis, and thermal distress assessments. Additionally, the development of a comprehensive database and algorithm for data interpretation will further refine forensic evaluations, ensuring consistency 
]]></description>
      <pubDate>Sun, 22 Jun 2025 09:50:47 GMT</pubDate>
      <guid>https://rip.trb.org/View/2567104</guid>
    </item>
    <item>
      <title>Development of Novel and Affordable Chip Seals for Maintenance and Pavement Preservation using Sustainable Materials</title>
      <link>https://rip.trb.org/View/2480349</link>
      <description><![CDATA[Pavement infrastructure is vital for quality of life, the economy, and societal prosperity. With rising demands and limited resources, maintaining and preserving this infrastructure is increasingly crucial. Severe weather events heighten these needs. Chip seals, commonly used in Region 6 and nationwide, are essential for preserving pavements. They seal against water intrusion and improve safety by enhancing friction through better macro- and micro-texture. For effective chip sealing, high-quality cover aggregate and binder are essential. For projects involving High Friction Surface Courses, ODOT and other state DOTs in Region 6 currently use Bauxite as the cover aggregate. Although effective, use of this imported material increases cost and reduces affordability. Recent developments in pavement surfaces with high reflectivity, make engineered chip sealing a suitable tool for addressing the heat island effects, particularly in urban areas. 
To this end, the research team will develop an innovative chip sealing technology and test it in the field using local and sustainable materials. The team seeks to use Tar Creek mine chat from Oklahoma and silica sand from Texas as cover aggregates and a specialized asphalt binder with high reflectivity to develop this innovative and affordable chip sealing technology. This specialized binder is transparent in nature and can dissipate heat faster than conventional black asphalt binder. Moreover, chat materials are very hard and angular, making them (i.e., washed chat with desired gradation) a suitable cover aggregate. Similarly, silica sands, being mined in several quarries in Texas, possess cover aggregate qualities. In the proposed study, both of these cover aggregates will be used as a replacement of Bauxite. 
Conventional pavements absorb and retain heat, contributing to Urban Heat Islands (UHIs), particularly in urban environments where temperatures are significantly higher than in rural areas. Chip sealing with high reflectivity will not only enhance pavement life and functionality (i.e., adequate friction) but also reduce UHIs and help combat the effects of extreme weather. The specific objectives of this proposed project are: (1) develop chip sealing with Tar Creek mine chat and silica sand and the specialized asphalt binder and evaluate laboratory performance; (2) use the developed chip sealings in one of the maintenance projects and evaluate field performance; (3) investigate the economic and environmental impacts related to extreme heat on socio-demographic populations and develop correlations between pavement albedo, heat index, and network centrality measures.
The following tasks will be pursued in this study. Task 1: Collection of necessary materials; Task 2: Evaluation of binder properties; Task 3: Determination of cover aggregates properties; Task 4: Evaluation of compatibility between binder and aggregates; Task 5: Development of chip seal mixes; Task 6: Evaluation of laboratory performance; Task 7: Evaluation of field performance; Task 8: Assessment of socio-economic impact, and Task 9: Submission of quarterly progress reports and a final report.
]]></description>
      <pubDate>Wed, 01 Jan 2025 15:56:19 GMT</pubDate>
      <guid>https://rip.trb.org/View/2480349</guid>
    </item>
    <item>
      <title>Evaluation of T-FAST for Aggregate Acceptance</title>
      <link>https://rip.trb.org/View/2458792</link>
      <description><![CDATA[The purpose of this study is to investigate the feasibility of using the newly developed Turner-Fairbank Highway Research Center ASR Susceptibility Test (T-FAST) for aggregate acceptance on the Approved Materials List (AML). Results from Turner-Fairbank Highway Research Center showed T-FAST could produce accurate alkali-silica reaction (ASR) aggregate testing in as little as 21-days of age. Therefore, T-FAST may be very beneficial for the Louisiana Department of Transportation and Development (DOTD) to produce aggregate acceptance results in a short time frame. ]]></description>
      <pubDate>Tue, 19 Nov 2024 09:21:50 GMT</pubDate>
      <guid>https://rip.trb.org/View/2458792</guid>
    </item>
    <item>
      <title>Evaluation of T-Fast Test Method for Aggregate Acceptance</title>
      <link>https://rip.trb.org/View/2452562</link>
      <description><![CDATA[The objective of this study is to: (1) review the state of the practice for using T-FAST for alkali-silica reactivity (ASR) evaluation; (2) laboratory testing and evaluate the feasibility of using T-FAST and ASR testing; and (3) determine the level of implementation and/or continued research required for adopting T-FAST test method.

]]></description>
      <pubDate>Tue, 12 Nov 2024 15:21:42 GMT</pubDate>
      <guid>https://rip.trb.org/View/2452562</guid>
    </item>
    <item>
      <title>TRC2401: Evaluation of Alkali-Silica-Reaction (ASR) Potential for Aggregate Sources in Arkansas</title>
      <link>https://rip.trb.org/View/2422919</link>
      <description><![CDATA[New test methods have been developed to determine the susceptibility of aggregates to alkali-silica reactions (ASR) and the alkali threshold of aggregate combinations. This project will examine the ASR susceptibility of aggregates, determine the alkali threshold of common aggregate combinations, and develop a mix design analysis tool to evaluate the ASR susceptibility of concrete mix designs. Samples of every aggregate approved for concrete production on the Qualified Products List (QPL) will be collected and tested using the Turner-Fairbank Highway Research Center ASR Test (T-FAST) method. T-FAST results will be utilized to select common aggregate combinations for Alkali Threshold Test (ATT) testing. A program will be written to analyze the alkalinity load of concrete mix designs and compare it to the Alkalinity threshold of aggregate combinations.]]></description>
      <pubDate>Thu, 29 Aug 2024 12:16:36 GMT</pubDate>
      <guid>https://rip.trb.org/View/2422919</guid>
    </item>
    <item>
      <title>Change: A Resilient Approach for Enhancing Asphalt Pavement Performance under Natural Events</title>
      <link>https://rip.trb.org/View/2363912</link>
      <description><![CDATA[Pavements are strong structures but are subjected to large traffic loading and different atmospheric conditions. Asphalt pavements face problems related to their physical and mechanical characteristics. One of the biggest challenges that asphalt pavement must overcome is its high thermal susceptibility, the relatively low durability and not enough climate resiliency. These problems can result in problems such as permanent deformation at high temperatures, and the expansion-contraction phenomenon trigger the appearance of thermal cracking shortening the durability and resilience of the asphalt pavements. A new recycled-aerogel composite for construction materials, named “RaC”, was developed in the Advanced Pavement Laboratory at Arizona State University (ASU). This novel product includes recycled materials such as crumb rubber particles, oil, fibers, and/or material in the form of aerogel particles or fibers. The recycled-aerogel composite is combined with asphalt binder or asphalt mixtures to yield modified material with improved characteristics. RaC solves shortcomings of asphalt pavements such as high-temperature deformation and thermal cracking making longer-lasting transportation infrastructures. This technology decreases the consumption of raw materials and energy fitting the concept of circular economy. The objective of this project is to thrive in extending the life of asphalt by using recycled materials to make asphalt pavement more durable and provide guidelines for the proper utilization of this new technology.]]></description>
      <pubDate>Fri, 05 Apr 2024 12:15:58 GMT</pubDate>
      <guid>https://rip.trb.org/View/2363912</guid>
    </item>
    <item>
      <title>Extending the Lifespan of Concrete Superstructures via Alkali-Silica Reaction Mitigation</title>
      <link>https://rip.trb.org/View/2343323</link>
      <description><![CDATA[Mitigation of deleterious alkali-silica reaction (ASR) in concrete is one of the priorities of the Federal Highway Administration (FHWA) as sources of non-reactive aggregates have been significantly depleted across the U.S. Traditional methods for mitigating ASR involve the use of supplementary cementitious materials (SCMs). Recent research by FHWA (i.e., FHWA-PROJ-08-0078) has marked the need for new and more efficient materials in mitigating ASR in concrete pavements. Preliminary studies have shown that new types of SCMs, such as calcined clay-based materials, and nanomaterials, such as nanosilica, nano-metakaolin, nanotubes, and graphene can present a great potential to mitigate ASR. The effectiveness of ASR prevention depends on the threshold and optimum dosage of nanomaterials, as well as mixing and dispersion of the nano-additives. This project aims at establishing protocols and practices for the design of ASR-resistive concrete with calcined clay-based SCMs and nanomaterials, with application to superstructures (pavements, bridge decks, piers). Deliverables include the development and deployment of standard guidelines about mixture design, ASR resistance evaluation, and life cycle assessment of nanoengineered concrete.]]></description>
      <pubDate>Fri, 23 Feb 2024 16:12:54 GMT</pubDate>
      <guid>https://rip.trb.org/View/2343323</guid>
    </item>
    <item>
      <title>New Performance Approach to Evaluate ASR in Concrete</title>
      <link>https://rip.trb.org/View/2215649</link>
      <description><![CDATA[The formation of alkali-silica reaction (ASR) gels in concrete has been a major issue for the industry since they were first discovered in the 1930s. The gels are formed by the reaction of the alkalis from the cement with the silica in certain ASR susceptible aggregates. The gels can absorb water, swell, and cause the concrete to crack.

The first tests to determine the ASR susceptibility of aggregates came out in 1947. There have been many tests since then. They mostly rely on the measurement of engineering properties. Typically, a sample of mortar or aggregate is immersed in sodium hydroxide solution at elevated temperature and the physical expansion of the sample measured after a period. The T-FAST method is a more sensitive and accurate test which predicts ASR expansion using purely chemical measurements. The test is completed in 21 days.

Although these tests can detect ASR reactive sites in aggregates, they cannot determine whether gels will form in the resulting concrete. That depends on the alkali loading of the mix. The idea of measuring the alkali threshold of aggregates has been discussed for many years although no simple or reliable test has been available. A new test, (ATT) has been developed in the chemistry laboratory at the Turner Fairbank Highway Research Center (TFHRC). The test is simple and is completed in 21 days. With the ATT method it is possible to determine the likelihood of ASR formation in concrete.

While research at TFHRC supports this notion there is a need to verify the validity of this technique by evaluating many commonly used aggregates.

OBJECTIVES: To evaluate a wide selection of concrete mix designs to validate the use of the new AASHTO TP-144-21 (T-FAST) and alkali threshold test (ATT) methods in conjunction with mix design data, cement mill reports and SCM properties to determine the likelihood of ASR gel formation in concrete.

]]></description>
      <pubDate>Thu, 20 Jul 2023 16:32:44 GMT</pubDate>
      <guid>https://rip.trb.org/View/2215649</guid>
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