<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <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" />
    <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>Research in Progress (RIP)</title>
      <url>https://rip.trb.org/Images/PageHeader-wTitle-RIP.jpg</url>
      <link>https://rip.trb.org/</link>
    </image>
    <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>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>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>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[Study objectives are 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 alkali-silica reaction (ASR) gel formation in concrete.
The formation of 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.
Partners in this pooled fund study will select concrete mix designs with known ASR field performance either positive or negative.  They will supply samples of concrete mixtures components including aggregates, cements, and SCMs along with the corresponding mix designs to TFHRC where the chemistry laboratory will use the T-FAST and ATT methods to evaluate their ASR reactivity and the alkali threshold of the aggregate combination. This information will be compared against the alkali loading of the provided mixes to ensure that the T-FAST/ATT combination would have predicted field performance. Further, these results will be used to design an ASR mitigation test like T-FAST.]]></description>
      <pubDate>Thu, 20 Jul 2023 16:32:44 GMT</pubDate>
      <guid>https://rip.trb.org/View/2215649</guid>
    </item>
    <item>
      <title>Examining chemical and physical methods and relationships for Detection and Mitigation of ASR</title>
      <link>https://rip.trb.org/View/2085731</link>
      <description><![CDATA[This research involves advance ASR mitigation strategies using the chemical ASR test.  The Federal Aviation Administration (FAA) and several state agencies are assisting in this effort.]]></description>
      <pubDate>Fri, 16 Dec 2022 14:15:27 GMT</pubDate>
      <guid>https://rip.trb.org/View/2085731</guid>
    </item>
    <item>
      <title>Utilization of XRF for ASR</title>
      <link>https://rip.trb.org/View/2085719</link>
      <description><![CDATA[This research will investigate the applicability of wavelength dispersive XRF and handheld versions for use in conduct of chemical ASR test.]]></description>
      <pubDate>Fri, 16 Dec 2022 14:15:15 GMT</pubDate>
      <guid>https://rip.trb.org/View/2085719</guid>
    </item>
    <item>
      <title>Alkali-Silica Reaction Mitigation Strategies for ITD Concrete Mixes</title>
      <link>https://rip.trb.org/View/2083794</link>
      <description><![CDATA[Every year, Idaho Transportation Department (ITD) spends millions of dollars to repair deteriorated concrete structures around Idaho. One of the leading causes for deterioration of concrete is Alkali-Silica Reaction (ASR), a chemical reaction that develops between the reactive silica in the aggregates and the alkalis within the cement paste, causing expansion and cracking to the structure over a number of years. ASR will eventually compromise the durability and structural integrity of structures and pavements.
ITD is currently experiencing problems with secondary cementitious materials (SCMs) test results in terms of consistency and quality of materials. SCMs are critical for concrete durability, longevity, cost, workability, strength, and as a mitigation method to reduce ASR reactions that lead to premature concrete failure. Fly ash is typically used as an SCM by Contractors and Concrete Suppliers. Recently, fly ash production has been decreasing on a national scale, while demand has been increasing. This results in shortages, cost increases, and the need for agencies to accept lower quality materials. Fly ash supplies will become increasingly scarce as coal is replaced by cleaner energy sources in the U.S. Therefore, the supply chain for ITD concrete SCMs is in jeopardy.
There are various mineral admixtures commercially available in the United States and Idaho. However, the effectiveness of these admixtures in reducing ASR has not been independently verified in Idaho. The two mineral admixtures that ITD would like to investigate are diatomaceous earth (DE) and natural pozzolans (NP). These two products can be produced locally within the state or in adjacent states. Currently, fly ash used for mitigating ASR is being shipped in from the Midwest or Canada. Given the lack of independently verified data and observations to evaluate the performance of these two mineral admixtures in Idaho, ITD would like to better understand the costs and performance benefits of these admixtures that ITD contractors can obtain locally.
Another mitigation approach is the use of nano-silica (NS) admixtures when combined with Idaho aggregates. These tend to be liquid admixtures that are added to the concrete when batched. Very little information is available as to the effectiveness of NS on ASR mitigation. NS admixtures are very consistent and can be easily implemented into existing concrete batch plants.
Past studies have shown that a majority of the aggregate sources in Idaho will react with alkalis in cement and thus, do not qualify under the AASHTO T 380 test (expansion ≤ 0.04% is passing). Additionally, using a non-reactive aggregate in concrete for all ITD projects is unrealistic. Therefore, to reduce ASR and provide durability to Idaho’s infrastructure, identification of effective ASR mitigation methods is critical. 
While there are many manufacturers of mineral admixtures who claim that their product is the best solution, independent testing and verification is required to assure durability of concrete structures in Idaho as well as building confidence for ITD contractors to select the right solutions that would work in Idaho. To accomplish this, ITD seeks researchers to conduct the testing, verification, and cost analysis as well providing recommendations and guidance for implementing the research outcomes.
]]></description>
      <pubDate>Wed, 14 Dec 2022 17:01:07 GMT</pubDate>
      <guid>https://rip.trb.org/View/2083794</guid>
    </item>
    <item>
      <title>Alkali-Silica Reaction (ASR) Mitigation in High Alkali Content Cements</title>
      <link>https://rip.trb.org/View/2059153</link>
      <description><![CDATA[VDOT has been requested to approve the use of locally produced cement with alkali
content exceeding 1%. However, to prevent deleterious alkali-silica reaction (ASR),
current VDOT specifications limit the alkali content of cement to 1%. A rational
approach to allow for the use of cement with alkali content above 1% while preventing
ASR is to consider the alkali loading in concrete (instead of solely focusing on the alkalis
in the cement). Nonetheless, this approach is not presently considered in VDOT
specifications. In addition, the performance-based ASR mitigation approach of the 2020
Virginia Road and Bridge Specifications relies on a withdrawn test procedure (ASTM
C227). As a response, the main purpose of this study is to update ASR provisions in the
Virginia Road and Bridge Specifications to: (1) consider the alkali loading in concrete;
and (2) incorporate a currently acceptable ASR evaluation test method. In turn, this will
help to more effectively mitigate the ASR distress and therefore increase the service life
of concrete infrastructure in Virginia. Specifically, this study will evaluate the effect of
cement alkali content, concrete alkali loading, and supplementary cementitious materials
(SCMs) type and dosage on ASR in routine concrete mix designs used in VDOT projects.]]></description>
      <pubDate>Thu, 10 Nov 2022 11:20:56 GMT</pubDate>
      <guid>https://rip.trb.org/View/2059153</guid>
    </item>
    <item>
      <title>Alkali-Silica Reaction Mitigation using Alternative Supplementary Cementitious Materials</title>
      <link>https://rip.trb.org/View/1948643</link>
      <description><![CDATA[New Mexico contains several aggregate sources that are extremely susceptible to alkalisilica
reaction (ASR). To mediate ASR, the New Mexico Department of Transportation
(NMDOT) requires a minimum of 20% class F fly ash (by mass of cement) in nearly all
concrete produced for their projects. Since class F fly ash has become difficult to procure
and future availability is uncertain, NMDOT is considering alternative supplementary
cementitious materials (SCMs) that could be used in place of class F fly ash.
This project will assess two SCMs being considered for widespread acceptance by
NMDOT and builds on work performed during a Year 3 Tran-SET project to investigate a
natural pozzolan mined near Espanola, NM for use with extremely reactive fine
aggregates. This new project will focus on utilizing the natural pozzolan (pumicite) as well
as a metakaolin product with a broad range of reactive aggregates. NMDOT has limited
data for mixture proportions and durability properties (such as ASR mitigation) of concrete
produced with these SCMs. Therefore, they are unable to confidently accept the materials
for use in concrete produced for NMDOT projects, even if class F fly ash is not available.
The specific focus of this project is to assess ASR mitigation capabilities of the alternative
SCMs when used in combinations with several crushed coarse aggregate sources so that
general guidelines that can be developed to minimize the use of the SCMs (based on
aggregate reactivity) to prolong availability of SCM sources and improve sustainability.
This project will begin with a comprehensive literature review to identify the most
important properties and characteristics of SCMs, especially metakaolin and natural
pozzolans, in terms of their influence on ASR and concrete durability. For the
experimental work, a suite of mortar mixtures will be proportioned with cementitious
materials combinations that include the pumicite and metakaolin as well as control
mixtures that contain either fly ash or no SCMs. ASR mortar bar tests will be conducted
using eight aggregate sources and SCM contents that range from 0 to 30%. Effectiveness
of the SCMs will be assessed by comparing their performances with results from the
control mixtures. Cementitious materials combinations that produce acceptable ASR
results will be used to produce 10 concrete mixtures that will be tested for slump, air
content, compressive strength, and flexural strength to ensure that the mixtures provide
adequate workability and strength, and then subjected to durability tests to assess their
chloride permeability, resistance to freezing and thawing, and shrinkage characteristics.
The primary purpose of the concrete testing is to evaluate whether the mixtures have
workability, strength, and durability properties that are comparable to mixtures containing
only class F fly ash. The implementation phase of the project includes documenting and
disseminating the results of the research in a final report for the project, publication of
journal and conference papers, and presentations at conferences.
The New Mexico State University (NMSU) research team is led by the PI, Professor Craig
Newtson, who has more than 20 years of concrete related research experience, has had
projects totaling more than $2,400,000 in funding, and has published more than 85
research papers.]]></description>
      <pubDate>Fri, 06 May 2022 12:19:52 GMT</pubDate>
      <guid>https://rip.trb.org/View/1948643</guid>
    </item>
    <item>
      <title>Durability of Concrete Produced with an Alternative Supplementary Cementitious Material</title>
      <link>https://rip.trb.org/View/1751181</link>
      <description><![CDATA[New Mexico contains several aggregate sources that are extremely susceptible to alkali-silica reaction (ASR). To mediate ASR, the New Mexico Department of Transportation (NMDOT) requires a minimum of 20% class F fly ash (by mass of cement) in nearly all concrete produced for their projects. However, class F fly ash has become difficult for concrete producers to procure, and future availability is uncertain. Consequently, NMDOT is considering adopting alternative supplementary cementitious materials (SCMs) that could be used in place of class F fly ash. The purpose of this research project is to assess one of the alternative SCMs being considered for potential acceptance by NMDOT. The SCM to be studied is a natural pozzolan mined from a pumicite deposit near Espanola, NM. Natural pozzolans are a class of siliceous or siliceous and aluminous materials that possess little or no cementitious value by themselves, but can react chemically with calcium hydroxide and water at ordinary temperatures to form compounds possessing cementitious properties that can improve concrete strength and durability. NMDOT has little data for mixture proportions and durability properties of concrete produced with this material, so they are not able to confidently accept the material for use in concrete produced for NMDOT projects, even if class F fly ash is not available. This research project consists of a comprehensive literature review to identify the most important properties and characteristics of SCMs, and especially natural pozzolans, in terms of their influence on concrete durability. For the experimental work to be conducted in this study, a suite of concrete mixtures, similar to currently accepted NMDOT mixtures, will be proportioned using the natural pozzolan to replace different percentages of fly ash. Concrete produced from these mixtures will be tested for slump, air content, compressive strength, and flexural strength to ensure that the mixtures provide adequate workability and strength. Then, the durability of the concrete mixtures will be tested by assessing their chloride permeability, resistance to freezing and thawing, susceptibility to ASR, and their shrinkage characteristics. Results from mixtures containing the natural pozzolan will be compared to control mixtures produced using NMDOT concrete mixtures containing only class F fly ash. The implementation phase of the project includes documenting and disseminating the results of the research. Dissemination of the results will include the final report for the project, publication of journal papers, publication of conference papers, and presentations at conferences. The New Mexico State University (NMSU) research team is led by the PI, Professor Craig Newtson, who has over 20 years of concrete related research experience on projects totaling more than $2,300,000 in funding. The team also includes Associate Professor Brad Weldon as a Co-PI. Dr. Weldon has supervised more than $1,300,000 in funded research projects and has received national recognition for his research.]]></description>
      <pubDate>Wed, 11 Nov 2020 09:42:24 GMT</pubDate>
      <guid>https://rip.trb.org/View/1751181</guid>
    </item>
    <item>
      <title>Evaluation of the Miniature Concrete Prism Test (MCPT) for use in LADOTD</title>
      <link>https://rip.trb.org/View/1656143</link>
      <description><![CDATA[The objective of this study is to evaluate the suitability of the Miniature Concrete Prism Test (MCPT) method to assess alkali-silica reactivity, and to determine the level of implementation and/or continued research required for adopting this test method.]]></description>
      <pubDate>Wed, 02 Oct 2019 09:51:53 GMT</pubDate>
      <guid>https://rip.trb.org/View/1656143</guid>
    </item>
  </channel>
</rss>