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    <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" />
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Laboratory Investigations on Lateritic Soil Stabilized with RBI Grade 81, Coconut Fiber and Aggregates</title>
      <link>https://trid.trb.org/View/2408010</link>
      <description><![CDATA[Soil stabilization is an excellent old technique adopted to improve the properties of any weak soil. In the recent past, many chemical stabilizers came to the market. In this study, a commercial stabilizer-RBI Grade 81’s (dosage 2–8%) potential to improve lateritic soil properties was investigated. At 6% RBI Grade 81 dosage, the effect of reinforcement was evaluated by using 0.5 and 1.0% coconut fibers. Strength improvement of 6% RBI Grade 81 stabilized soil admixed with <12.5 mm size aggregates (5, 10, and 15%) was studied to know the effect of granular layer demolition waste incorporation. CBR and UCS tests were used for strength evaluation. Considerable improvement in mix strength was observed above 6% RBI Grade 81 dosage on 28 curing days for the soil incorporated with fibers and aggregates. A linear fit was established between UCS and soaked CBR, which shows a high correlation (>0.9), and Prob > F is <0.06 depicting high reliability for the estimation of soaked CBR from UCS. Further, fatigue and durability tests were carried out to understand stabilized soil’s behavior under dynamic load application and performance during monsoon to simulate the submerged condition of the pavement in dense rainfall areas (>3500 mm). Stabilized lateritic soil mixes sustained freeze–thaw cycles effectively with weight loss of <14%. However, even at an 8% RBI Grade 81 dosage, the mix has not satisfied the wetting–drying test requirement. Stabilized soil blends showed excellent fatigue performance under repeated loads. The 6% RBI Grade 81 treated soil mixes can be used for modified subgrade.]]></description>
      <pubDate>Wed, 24 Sep 2025 15:24:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2408010</guid>
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    <item>
      <title>Novel Test to Assess Moisture-Induced Durability of Stabilized Soils Under Cyclic Loading</title>
      <link>https://trid.trb.org/View/2567049</link>
      <description><![CDATA[This study presents a new experimental procedure for evaluating the durability of stabilized soils subjected to multiple wetting and drying (W-D) cycles. An integrated experimental program combining dynamic shear rheometer (DSR) testing with W-D cycles was designed and implemented to assess moisture-induced performance degradation in natural sand stabilized with two types of rapid-setting cementitious stabilizers. Small cylindrical specimens (10.5?mm in diameter and 35.0?mm in height) of stabilized sand mixes were compacted, cured, and subjected to up to seven W-D cycles. Each W-D cycle was meticulously controlled to gauge its impact on the material’s durability. The mechanical properties of the stabilized samples were evaluated at different stages of the W-D cycles using the strain-sweep DSR testing based on a methodology developed from preliminary work. The proposed test method focuses on the shear properties of the material, measuring its mechanical response under the torsional loading of a cylindrical sample and providing dynamic mechanical properties and fatigue-resistance characteristics of the stabilized soils under cyclic loading. Test results demonstrate water-induced deterioration of stiffness and reduced resistance to cyclic loading with good testing repeatability, efficiency, and material-specific sensitivity. By combining dynamic mechanical characterization with durability assessment, the new testing method provides a high potential as a simple, scientific, and efficient method for assessing, engineering, and developing stabilized soils, which will enable more resilient transportation infrastructure systems.]]></description>
      <pubDate>Mon, 23 Jun 2025 08:44:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2567049</guid>
    </item>
    <item>
      <title>Experimental Investigation of the Engineering Properties of Stabilized Black Cotton Soil Using Industrial Waste Materials</title>
      <link>https://trid.trb.org/View/2452629</link>
      <description><![CDATA[In this study, the potential use of industrial waste materials, namely, copper slag (CS), iron ore tailings (IOT), and red mud (RM), as stabilizing agents for black cotton (BC) soil in pavement construction applications was evaluated. Laboratory tests were conducted to assess the performance of the stabilized BC soil, including Atterberg limits, compaction characteristics, California bearing ratio (CBR), unconfined compressive strength (UCS), permeability, and fatigue tests. Additionally, microstructural analysis was performed to further investigate the changes in the soil properties. The results indicated that BC soil mixed with CS, IOT, and RM exhibited enhanced plasticity, strength (UCS and CBR), permeability, and fatigue properties compared to untreated BC soil, regardless of the mix percentage. Notably, BC soil with 30% CS demonstrated comparable results to BC soil stabilized with 5% cement, significantly improving its properties. This study addressed a gap in pavement engineering research by evaluating the fatigue behavior of stabilized subgrade soils. It was concluded that incorporating 30% CS into BC soil not only enhanced its performance but also provided a sustainable alternative to traditional stabilizers such as cement and lime.]]></description>
      <pubDate>Tue, 19 Nov 2024 14:38:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2452629</guid>
    </item>
    <item>
      <title>Engineering and Mineralogical Evaluation of a Rapid-Strength Stabilizer for Expansive Clays</title>
      <link>https://trid.trb.org/View/1929161</link>
      <description><![CDATA[Rapid stabilization of expansive soils has significant potential to support infrastructure development, particularly highway pavements. Historically, several studies have attempted to develop a stabilizer that can rapidly convert weak soils to strong soils with little manipulation and straightforward construction protocol. Often, such studies have recommended the use of non-traditional stabilizers that have not been widely implemented. This study aimed to develop and evaluate the use of a mixture composed of conventional stabilizers such as lime, metakaolin, and sodium silicate for rapid strength gain of expansive soils. A simulant soil composed of smectite, kaolinite, and quartz was used to evaluate the stabilizer. The optimum mix design for rapid strength gain was determined by varying the amount of lime, metakaolin, and sodium silicate. The proposed mixture was composed of 4% lime, 3% metakaolin, and 3% sodium silicate by weight of soil, respectively. Engineering characterization results showed a 170% increase in strength within 24 h of treatment. The durability of the treated soil was also evaluated by recording the strength after 3, 7, and 9 cycles of wetting and drying, respectively. The results indicate that the stabilizer performance is on par with the simulant soil treated with the optimal amount of lime and cement. Microscale characterization using scanning electron microscopy-energy dispersive spectroscopy and nanoindentation provided insights into the stabilization mechanism of the treated soil. Scanning electron microscopy demonstrated the formation of pozzolanic products such as (C,N)-A-S-H, which is attributed to the soil’s rapid stabilization.]]></description>
      <pubDate>Wed, 13 Jul 2022 10:56:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1929161</guid>
    </item>
    <item>
      <title>Numerical study on stability of lignosulphonate-based stabilized surficial layer of unsaturated expansive soil slope considering hydro-mechanical effect</title>
      <link>https://trid.trb.org/View/1895395</link>
      <description><![CDATA[Numerous laboratory-based solutions have been proposed in the recent literature for the stabilization of unsaturated expansive soil by recycling lignosulphonate (LS). However, the practical assessments of these proposals for the treatment of the rainfall-induced surficial failure in unsaturated expansive soil slopes are required, considering the frequency of this failure and associated economic loss. Moreover, in conventional geotechnical practice, the slope stability is generally evaluated only with consideration of the hydraulic response of the soil, ignoring the hydro-mechanical coupling effect associated with the swelling behavior of soil. Since LS-based stabilizers mainly impart the reduction of the swelling potential of expansive soils, the assessment of the stability of the LS-treated surficial layer of unsaturated expansive soil slopes requires consideration of the hydro-mechanical effect. For this purpose, the uncoupled and hydro-mechanical coupled analyses were conducted for dealing with the hydraulic and hydro-mechanical responses of the surficial layer of soil slopes, respectively. Specialized experimentations and pertinent literature review were performed to acquire the required input data for these analyses. It is observed that the LS-based surficial layer treatment affects the pore water pressure (PWP) profiles as well as wetting front depth (WFD), which are the critical aspects for influencing the stability of unsaturated expansive soil slopes. Among all LS-based stabilizers, only the stabilizer named composite cementing admixture (CCA) reasonably ameliorated the PWP profiles and WFD of the slope considering disastrous environmental impacts (i.e., wetting–drying cycles). Moreover, the heave problem of expansive soil slopes was observed to be mitigated by LS-based treatment among which the CCA performed the most efficiently. Furthermore, the critical factor of safety (FS) required for slope stability was also affected by the LS-based treatment, whereas the CCA was observed to provide the safest critical FS for slope stability.]]></description>
      <pubDate>Thu, 16 Dec 2021 16:07:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1895395</guid>
    </item>
    <item>
      <title>Evaluation of Sustainable and Environmentally Friendly Stabilization of Cohesionless Sandy Soil for Transportation Infrastructure </title>
      <link>https://trid.trb.org/View/1751144</link>
      <description><![CDATA[The stabilization of cohesionless soils with cementitious materials is essential for local materials to be used for construction activities, due to the lack of strength of such geomaterials in their native state. Generally, such stabilization results in enhanced mechanical properties due to formation of pozzolanic compounds which may satisfy the design requirements. However, there is a high carbon-footprint when traditional stabilizers are used. During natural disasters, such as flooding and hurricanes, pavements built using cohesionless soils may undergo significant damages. Recently, researchers have started exploring other alternative form of chemical additives that will be effective in stabilization yet will have low carbon footprint with high sustainable benefits. A new class of alumino-silicate-polymers, commonly known as Geopolymers have emerged due to its eco-friendly and sustainable nature and its cementitious properties. Geopolymer has received significant attention as an alternative to Ordinary Portland Cement (OPC) and lime for soil stabilization, and other applications for pavements, bridges, and other transportation structures. However, most of the previous studies on using Geopolymers for soil stabilization focused on stabilization of clay-rich soils. Some preliminary results also suggest that stabilization of sandy soils with Geopolymers might even results in more durable solution when compared to clay-rich soils, or use of OPC stabilizers, due to the excellent adhesion of the Geopolymers to the send particles. However, very limited studies were reported in the literature in this area and the proposed research plan aims at evaluating the performance of Geopolymers in effectively stabilizing cohesionless soils typical for coastal region of Region 6. A collaborative research study is formulated by teams from Department of Civil and Environmental Engineering and Department of Material Science and Engineering in Texas A & M University, College Station to investigate the feasibility of stabilizing cohesionless soils using Geopolymers and combination of Cement and Geopolymer for transportation infrastructure in Region 6. The effects of Geopolymer, dosage rates, and curing condition on overall performance and structural and mechanical properties of Geopolymer-stabilized soils have to be studied in order to optimize the use of Geopolymer derived from local waste and natural materials for transportation infrastructure in Region 6. As part of the proposed study, shrinkage, strength and stiffness tests in the form of unconfined compressive strength and repeated load triaxial tests will be conducted to evaluate the performance of stabilized soil. Both material characterization studies related to micro to macro behavioral changes of native soils and Geopolymer-and Cement-Geopolymer-treated soils will be carried out as a part of this research. During implementation phase, sustainable, resiliency, and life cycle analysis of Geopolymer-stabilized cohesionless soils will be evaluated. The proposed research should provide major benefits in the design of resilient, and ecofriendly infrastructure in Texas and other regional states in Region 6 where cohesionless soils are in abundance. The proposed research with Geopolymers, should provide sustainable greener alternative for transportation infrastructure that will be resilient with low distress problems. Therefore, proposed collaborative study focuses on these Tran-SET’s areas: Area 4: Improving durability and extending the life of the infrastructure (Sub-area: Application of new materials and technologies); Area 5: Preserving the environment; Area 6: Preserving the existing transportation system. Two doctoral students will work with PIs (Dr. Radovic, Dr. Puppala, and Dr. Chakraborty) to execute the proposed research tasks. The expected deliverable from this project is a technical report summarizing all tasks from both institutes including necessary design guidelines of resilient Geopolymer-stabilized cohesionless soils. The team also anticipates to publish several high impact research publications including journal and conference articles. Results of this project will be also disseminated in transportation related workshops and committee talks at TRB annual meetings and presented to the potential industry partners.]]></description>
      <pubDate>Tue, 10 Nov 2020 19:54:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/1751144</guid>
    </item>
    <item>
      <title>Effect of Low-Quality Recycled Concrete Aggregate on Stabilized Clay Properties</title>
      <link>https://trid.trb.org/View/1714562</link>
      <description><![CDATA[Recycled concrete aggregate (RCA) is the result of the demolition of concrete structures and pavements. Using RCA to replace quarried aggregates in paving projects is one way to utilize the millions of tons of concrete waste that is produced annually and landfilled. However, RCA may have inferior physical properties when compared to virgin aggregates, such as the presence of recycled mortar and preexisting deficiencies. This study evaluated the potential use of RCA from D-cracked pavement for soil stabilization. D-cracking is a type of pavement deterioration that originates in the coarse aggregate particles due to freezing and thawing. The engineering properties of low-plasticity clay with RCA and three common regional stabilizers (i.e., lime, Class C fly ash, and a combination of portland cement and fly ash) were investigated. Clay mixtures with varying proportions of chemical stabilizers and RCA from D-cracked pavements were evaluated by comparing measured unconfined compressive strength, linear shrinkage, and the California bearing ratio. Laboratory test results indicated that RCA, in conjunction with all cementitious materials, except lime, improved clay strength, stiffness, and shrinkage properties. The results from this study highlight that RCA from D-cracked pavements can be used for clay subgrade stabilization.]]></description>
      <pubDate>Fri, 19 Jun 2020 14:19:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1714562</guid>
    </item>
    <item>
      <title>Performance Evaluation of Cement and Slag Stabilized Expansive Soils</title>
      <link>https://trid.trb.org/View/1493107</link>
      <description><![CDATA[Swelling, shrinking, and subsequent low strength of expansive soil poses significant damage to structures if it is considered as foundation or fill material. Recently, the use of cement has become very prevalent in stabilizing these problematic soils owing to its effectiveness. However, the swelling potential of expansive soil is not always adequately resolved by cement. The presence of sulfate salts aggravates the situation impairing the effectiveness of cement, leading to the need to reassess its performance. In this study, the effectiveness of different stabilizers was investigated in stabilizing high-plasticity soil. Two types of soil with variable sulfate content were treated with slag, Type I/II, and Type V Portland cement, and their performances were evaluated based on Atterberg limits, pH, unconfined compression, and volumetric swell tests. A total of 312 samples were prepared for 18 different soil–stabilizer blends tested after 7, 28, and 90 days of curing period. Laboratory test results indicated that strength gain performance was attenuated and swelling potential increased due to the presence of sulfate salts. Adding stabilizers improved the strength of soils by a factor of 4–10 and decreased the swelling potential to < 1%. Atterberg limits decreased initially and then slightly increased with the increase of additive dosages. Additives increased the pH up to a maximum value of 11–12, which could be used as an indicator of target stabilizer addition rate. Finally, slag improved the performance of cement significantly and has proven to be a better option for treating high sulfate expansive soils.]]></description>
      <pubDate>Wed, 18 Apr 2018 12:12:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1493107</guid>
    </item>
    <item>
      <title>Performance Evaluation for Polymer-Stabilized Soils</title>
      <link>https://trid.trb.org/View/1439289</link>
      <description><![CDATA[A poorly graded natural sand was stabilized by using a liquid polymer soil stabilizer from the generic family of styrene acrylics. The stabilized specimens were tested for short-term performance and durability. Short-term performance was evaluated by testing the specimens for unconfined compressive strength shortly after specimen casting. Durability was assessed by testing the specimens that were aged under different scenarios, that is, 24 wet–dry cycles, 24 freeze–thaw cycles, and 8 months of outdoor exposure. In addition, the fatigue response of the stabilized specimens was evaluated by testing their fatigue resistance after 1,000,000 cycles of repetitive loading with 500 and 700 microstrains. The results of such evaluations suggest an acceptable performance of the aged specimens, with limited strength loss after aging. In the fatigue test, the specimens showed a perfectly elastic behavior with no sign of failure. However, because of the unique nature of the test results, further inspections should be conducted to have a better understanding of the potential for using liquid polymer soil stabilizers in pavements.]]></description>
      <pubDate>Tue, 07 Mar 2017 10:25:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1439289</guid>
    </item>
    <item>
      <title>Stabilization of Horseshoe Lake Road using Geofibers 
and Soil-Sement®</title>
      <link>https://trid.trb.org/View/1218220</link>
      <description><![CDATA[One solution to reducing the cost of importing gravel in areas where available soils are predominately silts and sands is to stabilize the local soils with geofibers and synthetic fluids.  There have been several studies which have evaluated improvements in soil strength using geofibers.   Laboratory work at the Alaska University Transportation Center has shown that the use of geofibers in combination with synthetic fluids has the potential to stabilize silts and sands, making them usable for roadway and airport construction.  A 500 ft test section was constructed on Horseshoe Lake Road, near Wasilla, Alaska.  The test section was comprised of 250 ft using six inches of geofiber and Soil-Sement® and 250 ft using twelve inches of geofiber and Soil-Sement®.  The test section was monitored over 16 months for performance and soil strength.  Overall the test section has performed well.]]></description>
      <pubDate>Wed, 31 Oct 2012 17:06:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1218220</guid>
    </item>
    <item>
      <title>Evaluation of Sustainability of Low-Volume Roads Treated with Nontraditional Stabilizers</title>
      <link>https://trid.trb.org/View/1107703</link>
      <description><![CDATA[The use of nontraditional stabilizers to treat unpaved (mostly low-volume) roads has received attention over the past several years as various types of stabilizers have been developed and become available. Evaluation of the sustainability of various infrastructure actions, including the provision and maintenance of roads, is becoming more relevant as the effects of actions taken in the natural environment on itself and on the human environment are evaluated and understood in more detail. The Greenroads rating system offers a method for evaluation of the sustainability of the design, construction, and maintenance of roads. The system was developed with a focus on surfaced higher-volume roads. In this paper, the potential applicability of the Greenroads system for the evaluation of the sustainability of unsurfaced low-volume roads is investigated through two case studies of experiments in which unpaved low-volume test sections were treated with various types of traditional and nontraditional material stabilizers. Appropriate parameters were selected from the general Greenroads metric to ensure that those affecting unpaved low-volume roads would be evaluated (e.g., runoff quality and use of regional materials) while parameters such as paving emission reduction were excluded from the analysis. The assumption was made that all compulsory project requirements would be met by each of the options evaluated. It was concluded that the Greenroads metric can be used to evaluate the potential sustainability of unpaved low-volume roads treated with nontraditional stabilizers and that the metric can provide insight into the potential effect of various parameters on the sustainability of the various stabilization options.]]></description>
      <pubDate>Wed, 27 Jul 2011 13:43:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1107703</guid>
    </item>
    <item>
      <title>Recommended Practice for Stabilization of Sulfate Rich Subgrade Soils</title>
      <link>https://trid.trb.org/View/904504</link>
      <description><![CDATA[Calcium-based stabilizers (CaO-based stabilizers) develop a high pH environment when mixed with water during construction. This high pH condition and the presence of lime (CaO) introduce an environment favorable to the formation of two expansive minerals, ettringite and possibly thaumasite, when sulfate-bearing salts are present in soil. The success of a lime stabilization project depends heavily on the accuracy of predictions regarding the potential of the native soils to form these disruptive minerals. This report describes the nature of these minerals and the mechanism of their formation in soils stabilized with lime, cement, or fly ash. The key issue for the engineer in deciding how to properly stabilize sulfate-bearing soils is to quickly and efficiently determine: (1) the sulfate content of the soils and (2) the threshold quantity of sulfates likely to cause damage. This report addresses both issues but focuses on the methods used to quantify sulfate content. Quick and effective field techniques and more precise laboratory tests are compared and evaluated. Recommendations are presented regarding the appropriate testing protocol to use. Specific recommendations for changes to the American Association of State Highway and Transportation Officials (AASHTO) test method T-290-95 (methods A and B) are made. The report also outlines techniques for effective risk assessment including reconnaissance, topographical assessment, pedological and geological assessment, climatic assessment, and soil sampling plans. The report also outlines construction tests that can reduce risks for various levels of sulfate determined using a method such as AASHTO T-290-95 (revised) or equivalent.]]></description>
      <pubDate>Mon, 16 Nov 2009 15:38:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/904504</guid>
    </item>
    <item>
      <title>Influence of Chemical and Physical Characteristics of Cement Kiln Dusts (CKDs) on Their Hydration Behavior and Potential Suitability for Soil Stabilization</title>
      <link>https://trid.trb.org/View/862992</link>
      <description><![CDATA[Interaction of cement kiln dusts (CKDs) with a given soil depends on the chemical and physical characteristics of the CKDs. Hence, characterization of CKDs and their hydration products may lead to better understanding of their suitability as soil stabilizers. In this paper, 4 different CKD powders are characterized and their hydration products evaluated. A detailed chemical (X-ray diffraction), thermogravimetric, and morphological (scanning electron microscope) analyses of the CKD powders and hydrated CKD pastes are presented. In general, high free-lime content (~14–29%) CKDs, when reacted with water produced significant amounts of calcium hydroxide, ettringite, and syngenite. These CKDs also showed higher unconfined compressive strength and higher temperature of hydration compared to CKDs with lower amounts of free-lime. An attempt was made to qualitatively correlate performance of CKD pastes with the chemical and physical characteristics of the original CKD powders and determine their potential suitability as soil stabilizers. To that effect, limited unconfined compressive strength testing of CKD-treated kaolinite clays was performed. Results suggest that both compressive strength and temperature of hydration of the CKD paste can give early indications of the suitability of particular CKD for soil stabilization.]]></description>
      <pubDate>Tue, 24 Jun 2008 07:42:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/862992</guid>
    </item>
    <item>
      <title>Sensitivity of Selected Colorado Soils to Form Ettringite/Thaumasite When Treated with Calcium-Based Stabilizers and When Soluble Sulfates Are Available</title>
      <link>https://trid.trb.org/View/843062</link>
      <description><![CDATA[The sensitivity of five Colorado soils, which were selected to represent the variety of soils likely to be treated with calcium-based chemical stabilizers such as hydrated lime or Portland cement, to the formation of potentially expansive minerals is evaluated using thermodynamic principles based on Gibb?s free energy and direct measurements. Phase diagrams are used to predict the threshold levels of soluble sulfates that favor the formation of the expansive mineral ettringite, which is most widely blamed for deleterious expansion in sulfate bearing soils treated with calcium-based stabilizers. The results of the thermodynamic, phase diagram evaluation are checked against direct measurement of ettringite using differential scanning calorimetry (DSC), and the results agree well. The conclusions derived from this research are that, as expected, mineralogical differences among the soils affect the threshold level of soluble sulfates that trigger the development of ettringite and that the presence of soluble silica and the form of alumina present have a dominant effect. The research validates previous research that a safe lower limit of soluble sulfates is approximately 3,000 ppm as long as additional soluble sulfates do not migrate into the soil. A methodology is presented for using the DSC to directly assess the threshold level of sulfates for a particular soil. However, refinement of the method is a key goal of on-going research. The DSC method to assess the potential of a specific soil to react deleteriously with a calcium based stabilizer when sulfate content in the soil is above a threshold level should be implemented by the Colorado Department of Transportation (CDOT). This will require the purchase of a Q-2000, TA Instruments or equivalent DSC by the CDOT Materials and Geotechnical Branch.]]></description>
      <pubDate>Mon, 07 Jan 2008 16:22:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/843062</guid>
    </item>
    <item>
      <title>Volume Change Behaviors of Expansive Soils Stabilized with Recycled Ashes and Fibers</title>
      <link>https://trid.trb.org/View/782365</link>
      <description><![CDATA[In this paper, class F fly ash, bottom ash, polypropylene fibers, and nylon fibers were evaluated as potential stabilizers in enhancing volume change properties of sulfate rich expansive soils. As a part of the research evaluation, a comprehensive laboratory experimental program was designed and conducted on two different subgrade soils from two locations in Texas. Four dosage levels of each stabilizer, two compaction moisture content levels, and 14 days curing period were investigated. Volume change behavioral tests including volumetric free swell, volumetric shrinkage strain, and vertical swell pressure tests were conducted on both isolated stabilizer treated and combined ash-fiber stabilized soils. Ash stabilizers showed improvements in reducing swelling, shrinkage, and plasticity characteristics by 20–80% whereas fibers treatments resulted in varied improvements. In combined treatments, class F fly ash mixed with nylon fibers was the most effective treatment on both Dallas and Arlington soils, where the soil property enhancements were considered average-to-moderate. Possible mechanisms that resulted in the soil property improvements are discussed along with the recommended stabilizers and their dosages for expansive soil treatments.]]></description>
      <pubDate>Wed, 31 May 2006 09:31:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/782365</guid>
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