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    <title>Transport Research International Documentation (TRID)</title>
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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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Laboratory Assessment of Warm Mix Asphalt Mixes When Prepared with Varying Packing Characteristics and Inclusion of Fibre</title>
      <link>https://trid.trb.org/View/1633197</link>
      <description><![CDATA[Aggregate gradation selection process plays a vital role in designing the Hot Mix Asphalt (HMA) layer. In India  mid-point blending of aggregate is adopted as outlined in Ministry of Road Transport and Highways (MoRTH). Bailey’s method of aggregate packing has significant effect in improving the structural skeleton of the aggregate in bituminous concrete mixes. During the preparation of HMA harmful gases are released which pollutes the environment. Numerous techniques are in practice, a few are at developing stage for reducing the effect of harmful gases. One among the technique for reducing the mixing temperature is with the use of Warm Mix Asphalt (WMA). The current experimental study attempts in the efficacy of bituminous concrete mixes prepared with MoRTH midpoint gradation and varied packing characteristics vis-à-vis of Bailey’s method. Both mixes were modified with sasobit and reinforced with fibre for judging the efficacy in Marshall Parameters, tensile strength, resilient and rutting characteristics. A total of six different mix combinations were prepared, out of which the first three mixes were prepared using MoRTH mid-point gradation and remaining three mix combinations were prepared with varied packing characteristics vis-à-vis of Bailey’s method. The results explains that reinforced WMA mixes prepared with Bailey method provides better efficacy towards stiffness value, moisture sensitivity and rutting resistance when compared with modified bituminous concrete mixes when prepared with MoRTH midpoint gradation.]]></description>
      <pubDate>Fri, 28 Jun 2019 11:38:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1633197</guid>
    </item>
    <item>
      <title>Effect of Polypropylene Granules in Asphalt Mix Prepared with Varying Packing Characteristics</title>
      <link>https://trid.trb.org/View/1567402</link>
      <description><![CDATA[Bituminous concrete pavements are subjected to failures/damages during the design period. One among the causes for damage is due to commercial vehicles carrying heavy loads with high frequencies. Predominately failures in the pavement structure are in the form of rutting and fatigue and are termed as structural failure. In order to improve the structural characteristics of hot mix asphalt layer, additives are used as bitumen alone cannot cope up with structural characteristics of bituminous mix. This study aimed to investigate the performance of Hot Mix Asphalt (HMA) mixtures designed using Bailey method of gradation and compared with conventional method of gradation. Bailey method allows aggregate interlocking which acts as backbone to the structure and develop strong aggregate skeleton for durability and rut resistance. Marshall Parameters are used to compare the packing characteristics of bituminous mix prepared through Bailey method and Conventional method (MoRTH Specifications). Indirect Tensile Strength, resilient modulus and rutting properties were used for comparing the packing characteristics of bituminous concrete mix when added with Polypropylene. Polypropylene (PP) granules exhibited good resistance towards rutting. The results infer that conventional mix prepared using mid-point gradation exhibit less resistance towards rutting when compared with Bailey gradation and addition of PP. Bituminous Concrete mix prepared with Bailey approach and when added with PP granules has good stiffness value when compared with above mix combinations.]]></description>
      <pubDate>Tue, 20 Nov 2018 10:11:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1567402</guid>
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    <item>
      <title>Improving quality control through chance constrained programming: A case study using Bailey method</title>
      <link>https://trid.trb.org/View/1502616</link>
      <description><![CDATA[Worldwide it is an accepted practice that guidelines regarding aggregate gradation to be adopted for any asphalt concrete mixture are recommended by transportation agencies. In general, these specifications are based on past experience and knowledge about local conditions. Alternatively, Bailey method of mixture design considers actual aggregate properties (like shape, density, packing characteristics) while deciding aggregate gradation. Such a mechanistic approach guarantees better mixture performance. As a single source of aggregate cannot meet requirements at all sieve sizes, aggregates from different sources have to be combined to achieve target gradation. Currently used deterministic optimization approaches for aggregate blending use mean values. This leads to a situation where resultant gradation is beyond specification limits occasionally. Alternatively, stochastic optimization approaches consider inherent gradation variability while arriving at final blending proportions. The present work describes a novel chance constrained programming approach that minimizes overall cost of mixture while considering quality control issues. The proposed chance constrained programming approach offers flexibility of introducing various gradation limits as well as Bailey ratio constraints simultaneously. The proposed methodology is validated using Monte Carlo’s simulation approach. The simulation results indicated that mixtures blended using chance constrained approach produce less number of failures when compared to deterministic approach. This is due to the fact that inherent material variability is considered during blend optimization. The proposed work offers advantages of producing asphalt concrete mixtures at lower cost while having better quality control.]]></description>
      <pubDate>Thu, 08 Mar 2018 10:46:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1502616</guid>
    </item>
    <item>
      <title>Recommended combination of the Bailey parameters in Superpave gradation design for Japanese airfield pavements</title>
      <link>https://trid.trb.org/View/1279745</link>
      <description><![CDATA[The objective of this study is to investigate the necessary Bailey parameters to obtain satisfactory performance of Superpave mixtures for Tokyo International Airport (HND) pavements. The experimental work, which included 22 designed blends, was divided into three parts. Part 1 and Part 2 examined the effect of the Bailey parameters on voids in mineral aggregate (VMA) and rutting resistance. Based on the Part 1 and Part 2 findings, an optimization task was conducted in Part 3. Three performance related tests, namely the asphalt pavement analyzer (APA) test, wheel tracking test (WTT) and fatigue bending test were carried out to evaluate the performance of mixtures in Part 3. The test results indicated the Superpave coarse graded mixture with mid values of all Bailey ratios met the Superpave criteria and had higher resistance to rutting and cracking. The Superpave fine graded mixtures have to be designed with a lower coarse aggregate (CA) ratio and with the mid values of fine aggregate (FA) ratios to ensure adequate volumetric properties and high resistance to rutting and cracking. A comparison was made between the blends designed with and without the Bailey method. The results indicate that the blends designed with the Bailey method have provided significant improvement over those designed by the conventional Superpave method. It is recommended that the Bailey method be directly applied in a mixture design to save design time and effort.]]></description>
      <pubDate>Mon, 27 Jan 2014 11:03:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1279745</guid>
    </item>
    <item>
      <title>An Application to the European Practice of the Bailey Method for HMA Aggregate Grading Design</title>
      <link>https://trid.trb.org/View/1253956</link>
      <description><![CDATA[The Bailey Method provides a set of tools for the design and the evaluation of aggregate packing and voids of asphalt concrete grading while maintaining appropriate mixture workability and durability. In this study, concepts, procedures and parameters of the Bailey Method, that is strongly based on sieves and aggregate sizes adopted in the United States of America (USA), were applied in the European perspective. To this aim, two sets of asphalt mixtures were designed applying the Bailey Method. The study shows that the European practice for aggregate grading design allows the application of the Bailey Method criteria confirming the validity of its basic principles.]]></description>
      <pubDate>Thu, 18 Jul 2013 13:59:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/1253956</guid>
    </item>
    <item>
      <title>Application of the Bailey Method to New Hampshire Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/1107381</link>
      <description><![CDATA[The Superpave mix design system provides guidance in selecting the appropriate component materials for asphalt concrete mixtures.  However, the selection of the design aggregate structure is left to the experience of the mix designer.  This necessarily results in a trial and error process for selecting an aggregate gradation to meet specified volumetric parameters.  Also, the mix designer has no means to evaluate how the mix will work in the field during placement or how it will perform.  It is important to understand the influence of the aggregate structure on the volumetric properties, construction and performance of the asphalt mixture to achieve the desired properties and performance.  The Bailey Method was originally developed by Robert D. Bailey, an Illinois Department of Transportation engineer, as a means to prevent rutting while maintaining durability of mixtures and was based on his experience in the design of asphalt mixtures.  Bailey’s methods have been refined by several researchers to provide a systematic approach to blending aggregates to meet the volumetric criteria for any method of mix design, including Superpave, Marshall and Hveem.  The Bailey Method is based on the concepts of aggregate interlock and aggregate packing.  In addition, the Bailey Method provides tools for evaluating the effect of aggregate structure on mixture properties, constructibility, and performance.  The primary objective of this project was to determine if the Bailey Method can be a useful tool to design mixtures with improved performance using New Hampshire aggregate.  The mode of improvement given attention in this project is resistance to rutting under loading by the Third Scale Model Mobile Load Simulator (MMLS3) in hot, dry conditions.  A secondary objective was to evaluate the use of the MMLS3 as a tool to evaluate rutting.  Six mix designs commonly used throughout New Hampshire were chosen for evaluation.  Half of the designs used gravel stone with rounded, smooth faces and the other half used fractured rock with rough, angular faces.  Two mixtures also contained 15% recycled asphalt pavement.  Nominal maximum size aggregate values of 19mm and 12.5mm were chosen as representative of most mixtures place in the state.  The MMLS3 laboratory testing resulted in expected trends in relative performance of the various mixtures.  Three of the mixtures were then chosen for redesign with the Bailey Method.  The Bailey parameters for the original mixtures were calculated and the gradations were redesigned to fall within the recommended ranges.  The predictions of changes in voids in the mineral aggregate based on the Bailey parameters were reasonable for the angular aggregate, but not for the smooth aggregate evaluated in this study.  The redesigned Bailey mixtures did show an increase in rutting performance.  Overall, this research project showed that the Bailey Method could be a useful tool in the evaluation and design of New Hampshire mixtures.  The Bailey Method should not be used exclusively, but can be used in combination with knowledge of the aggregate angularity, roughness and engineering judgment to provide guidance during the mix design procedure and improve mixture performance.  The study also showed that the MMLS3 is an appropriate method for evaluating the relative rutting performance of different mixtures in the laboratory.]]></description>
      <pubDate>Mon, 25 Jul 2011 07:10:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1107381</guid>
    </item>
    <item>
      <title>Analysis of Oklahoma Mix Designs for the National Center for Asphalt Technology Test Track Using the Bailey Method</title>
      <link>https://trid.trb.org/View/842206</link>
      <description><![CDATA[The Oklahoma Department of Transportation (ODOT) has designed hot-mix asphalt (HMA) mixtures to research perpetual pavement at the National Center for Asphalt Technology (NCAT) test track. The HMA types include a rich bottom layer mixture, a Superpave 19.0-mm mixture, and a 12.5-mm stone mastic asphalt mixture. Each mix design was analyzed using the Bailey method to gain familiarity with the method and examine the method’s projection of performance. This paper provides an explanation of the Bailey method analysis performed on mix designs created for ODOT’s perpetual pavement research at the NCAT test track and considerations regarding the local application of the method. It also includes a summary of the method. The Bailey method was developed by Robert Bailey of the Illinois DOT in the early 1980s. The method evaluates the way aggregate particles fit together by analyzing unit weight, aggregate bulk gravity, and aggregate gradation. This packing depends on gradation, type, and amount of compactive effort, particle shape, particle surface texture, and particle strength. The basic suppositions of the Bailey method correspond well with traditional HMA design assumptions. The specific parameters used in the analysis may need to be re-evaluated on a regional basis. A key concern resulting from an analysis of Oklahoma mix designs is permeability associated with coarse-graded HMA mixtures.]]></description>
      <pubDate>Thu, 20 Dec 2007 13:56:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/842206</guid>
    </item>
    <item>
      <title>A Look at the Bailey Method and Locking Point Concept in Superpave Mixture Design</title>
      <link>https://trid.trb.org/View/842202</link>
      <description><![CDATA[This study analyzes the physical and performance characteristics of asphalt concrete mixtures with aggregate structures designed using the Bailey method of aggregate gradation evaluation. Three aggregate types—limestone, sandstone, and granite—were considered in this study. Three different aggregate structures of 12.5-mm nominal maximum particle size were designed for each aggregate type. Mixtures were designed for high traffic levels. The binder type selected was performance grade 76-22M. The compaction characteristics of the mixtures were analyzed using data from the Superpave gyratory compactor. Locking points and compaction indices were defined and determined for all the mixtures in the study. Simulative (Hamburg wheel tracking test) and fundamental (semicircular fracture and IT strength) tests were conducted to determine laboratory performance properties and evaluate the mixtures under different loading and environmental conditions. The design number of gyrations (Ndesign) recommended by Superpave was compared to the locking points obtained from this study. The data indicate that the current Ndesign level recommended by Superpave is much higher than the locking points of the mixtures and may subject the mixtures to high compaction energy for an extended period of time. Selected mixtures were designed using the locking point as the design number of gyrations instead of the recommended Superpave Ndesign. The data presented in this paper suggest that mixes with dense aggregate structures can be designed using their locking point instead of the recommended Ndesign. The designed mixtures maintained good resistance to permanent deformation and maintained an adequate level of durability.]]></description>
      <pubDate>Thu, 20 Dec 2007 13:55:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/842202</guid>
    </item>
    <item>
      <title>Influence of Mineral Aggregates on Mechanical and Volumetric Properties of Asphalt Mixtures: Analysis of the Bailey Method</title>
      <link>https://trid.trb.org/View/813504</link>
      <description><![CDATA[This work presents an evaluation of the Bailey Method of gradation selection of aggregates for Hot Mix Asphalt.  The Bailey Method was developed at the Illinois Department of Transportation and it has been used since the early 1980s.  It aims at the improvement of the gradation selection by volume of aggregates and consequently, the performance of hot mix asphalt.  Through a systematic process of selection and adjustment of the aggregate gradation, it provides a hot mix asphalt with a rutting resistant aggregate skeleton, which is the result of an adequate amount of voids in the mineral aggregate and allows higher binder content and the improvement of the mixture durability.  This work aims to evaluate the effects of aggregate gradation on the behavior of asphalt mixtures through the comparison of mixtures designed by the Bailey Method with gradations selected by conventional trial and error procedures.  It also verifies the applicability of Bailey Method control parameters to adjust the gradation to achieve volumetric properties requested by highway agencies, which were the main concerns of researches previously published.  Two types of mineral aggregates are considered (basalt and gabbro) and the results of static creep test, resilient modulus, and indirect tensile strength test presented in this paper show evidences that asphalt mixtures designed by the Bailey Method can perform better than asphalt mixtures produced with the same materials, even though with aggregates gradation selected by conventional procedures.]]></description>
      <pubDate>Mon, 30 Jul 2007 09:46:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/813504</guid>
    </item>
    <item>
      <title>Evaluation of Aggregate Gradation and Master Ranges on Performance of Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/804156</link>
      <description><![CDATA[The Strategic Highway Research Program (SHRP) developed a rational volumetric mix design procedure called Superpave mix design.  It originally required aggregate gradations to pass through a selected number of control points and avoid a restricted zone.  However, it has been reported that the effect of Superpave gradation on asphalt pavement performance has been contradictory and/or inconclusive.  Also, some agencies experienced difficulty meeting the new gradation requirements and had to adjust the gradation in the field.  In addition, the gradation requirement introduced in the Superpave mix design has not fully considered aggregate structure.  Therefore, there is a need to modify the Superpave Mix-Design and/or to develop a new procedure to design proper aggregate structure for various types of aggregates in Rhode Island.  The present study utilized various existing methods including the Bailey method.  The Bailey method provides a systemic approach to determine aggregate structure based on aggregate packing properties.  After evaluating the procedures of the Rhode Island Department of Transportation (RIDOT), Superpave Mix Design, and Bailey method, a systemic procedure has been developed to optimize mineral aggregates for high-performing asphalt mixtures.  It is anticipated that volumetric properties of these mixtures can be adjusted by controlling Bailey aggregate ratios.]]></description>
      <pubDate>Wed, 21 Mar 2007 15:20:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/804156</guid>
    </item>
    <item>
      <title>Compactability and Performance of Superpave Mixtures with
Aggregate Structures Designed Using the Bailey Method (With Discussion)</title>
      <link>https://trid.trb.org/View/798162</link>
      <description><![CDATA[This study analyzes the compaction and performance characteristics of asphalt concrete mixtures with aggregate structures that were designed using the Bailey method of aggregate gradation evaluation. Three aggregate types were considered in this study: limestone, sandstone, and granite. All the aggregates were crushed. Three different aggregate structures were designed for each aggregate type. All the mixtures had a nominal maximum aggregate size (NMAS) of 12.5mm, and were designed for high traffic level. During compaction, force measurement was made using a small accessory inserted in the compaction mold called the Pressure Distribution Analyzer (PDA). The compaction characteristics of the mixtures were analyzed using data from the PDA and the traditional Superpave Gyratory Compactor (SGC) data. Simulative (Hamburg Wheel Tracking Test) and fundamental (Indirect Tensile Strength Test, and Semi-Circular Fracture Test) tests were conducted to determine laboratory performance properties and evaluate the mixtures under different loading and environmental conditions. The compaction characteristics and gradation parameters were correlated with the results from the laboratory tests. The data indicate that the designed mixtures considered were impermeable and presented excellent resistance to rutting and moisture damage.]]></description>
      <pubDate>Tue, 30 Jan 2007 13:29:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/798162</guid>
    </item>
    <item>
      <title>Investigation of the Bailey Method for the Design and Analysis of Dense-Graded HMAC Using Oregon Aggregates</title>
      <link>https://trid.trb.org/View/793170</link>
      <description><![CDATA[Historically Oregon has specified gradations for dense-graded hot mix asphalt concrete (HMAC) using a combination of broadband limits and recommended “ideal” gradations. The recent adoption of SuperPave™ and Stone Matrix Asphalt (SMA) technology has created new criteria for selecting gradations. This study evaluated a method of gradation design and analysis called the Bailey Method. The method uses specific ratios developed for aggregates in Illinois. The research involved using the Bailey Method to design and evaluate Oregon specific aggregate blends. Specimens were compacted and tested using the gradations developed under the Bailey Method. Finally, rut testing was performed on those mixture specimens. The study recommended that a modified Bailey Method analysis should be used as an additional tool to develop and select trial blends for the design of dense-graded mixes. The study noted that the Bailey Method design process led to extremely fine mixes not common in Oregon. Additional sieves were recommended to be included to allow for the development of additional ratios.]]></description>
      <pubDate>Tue, 07 Nov 2006 10:31:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/793170</guid>
    </item>
    <item>
      <title>The Bailey Method: A Tool for Evaluating HMA Volumetrics and Field Compactability</title>
      <link>https://trid.trb.org/View/790333</link>
      <description><![CDATA[This article reports on the Bailey method, a series of analytical procedures used to evaluate hot mix asphalt (HMA) mixtures.  The Bailey method of gradation focuses on the aggregate properties that affect the way aggregates fit together (or pack) in a confined space or volume.  Properties that can influence compaction include gradation, compactive effort, strength, shape, surface texture, and size.  The author notes that once a mix designer has been taught the principles of the Bailey method and how to apply them, he or she can then begin to predict how changes in the factors that affect packing will change the volumetrics and compactability of a particular mixture.  The author concludes by describing a workshop, sponsored by the Asphalt Institute, entitled The Practical Guide to Achieving HMA Volumetrics.  The workshops are taught by the Field Engineering staff of the Institute and are intended to provide participants with the ability to predict the packing properties of their own individual aggregates.]]></description>
      <pubDate>Fri, 29 Sep 2006 10:36:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/790333</guid>
    </item>
    <item>
      <title>THE BAILEY METHOD OF GRADATION EVALUATION : A TOOL FOR MIX DESIGN AND QUALITY CONTROL</title>
      <link>https://trid.trb.org/View/743636</link>
      <description><![CDATA[This article focuses on the Bailey Method, a tool for understanding aggregate packing and  how it relates to compactability and segregation susceptibility. This method of gradation evaluation can help define coarse and fine in an aggregate blend, break the blend into narrow size ranges, and look at particle distribution within each range. Gradation is analyzed in narrow ranges of sizes. The packing potential, or how densely the particles can pack, is then evaluated for each range. While the Bailey Method is not intended for use as a specification, it offers a set of principles that a designer can use to determine which particles create voids and which ones fill the voids, as well as using the appropriate volumes of each for a specific mix type.]]></description>
      <pubDate>Mon, 01 Nov 2004 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/743636</guid>
    </item>
    <item>
      <title>AGGREGATE BLENDING FOR ASPHALT MIX DESIGN: BAILEY METHOD</title>
      <link>https://trid.trb.org/View/726645</link>
      <description><![CDATA[From the beginning of asphalt mixture design it was desired to understand the interaction of aggregates, asphalt, and the voids created during their compaction.  In asphalt mixture design, guidance is lacking in the selection of the design aggregate structure and understanding the interaction of that aggregate structure and mixture volumetric properties.  Asphalt mixture design concepts are presented that use aggregate interlock and aggregate packing to develop an aggregate blend that meets volumetric criteria and provides adequate compaction characteristics.  The concepts rely on coarse aggregate for the skeleton of the mixture with the proper amount of fine aggregate to provide a properly packed aggregate structure.  The objective is to use aggregate packing concepts to analyze the combined gradation and relate the packing characteristics to the mixture volumetric properties and compaction characteristics.  The new concepts presented for asphalt mixture design and analysis include an examination of aggregate packing and aggregate interlock, blending aggregates by volume, a new understanding of coarse and fine aggregate, and analysis of the resulting gradation.  These concepts are the result of many years of field experience and are the backbone of the Bailey method for asphalt mix design.  These methods are under continued development as the improved method for asphalt mixture design, which will assist with the transition to contractor mix design.]]></description>
      <pubDate>Fri, 04 Oct 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/726645</guid>
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