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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <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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      <title>An evaluation of the effect of crushed waste glass on the performance of cold bituminous emulsion mixtures</title>
      <link>https://trid.trb.org/View/1648621</link>
      <description><![CDATA[Large quantities of waste glass are generated each year, as municipal solid waste, and disposed of. There are industries who could make use of this product, specifically road pavement manufacturers. The current technology for paving roads will soon become financially unsustainable because of the rapid and continuous growth of community transportation. To address this issue, this study aims to evaluate the effect of replacing local virgin aggregates with crushed waste glass, which has similar gradation of virgin fine aggregate with 2.36 mm Nominal Maximum Aggregate Size (NMAZ). Four replacement percentages were assessed, namely 25%, 50%, 75% and 100% from virgin fine limestone aggregates content in Cold Bituminous Emulsion Mixtures (CBEMs), as CBEM technology has several environmental, sustainable and economic advantages over hot mix asphalt (HMA). The test protocol involved the evaluation of the mechanical properties of CBEMs in terms of the Marshall Test, Indirect tensile strength (ITS), wheel track test (WTT) and dynamic stability (DS) properties. Moisture damage, in respect of Retained Marshall Stability (RMS), was also evaluated for the modified mixes. The test results show that the addition of crushed glass (up to 100%) as a fine aggregate, resulted in a new CBEM with mechanical and durability properties higher than traditional HMA. While slight reductions in mechanical and durability properties were noted when compared with untreated CBEM, it was still within local specification limits of the Iraqi General Specifications for Roads and Bridges, (GSRB). In terms of mechanical and durability performance, it was concluded that the new mixture (CBEM-100%FGA) can be used as a structural surface layer for heavily trafficked loading conditions. It is necessary however, to note that the new mix still has high air void contents.]]></description>
      <pubDate>Mon, 09 Sep 2019 15:06:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1648621</guid>
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      <title>Development of 4.75mm Superpave Mixes, MBTC-2030</title>
      <link>https://trid.trb.org/View/1629766</link>
      <description><![CDATA[Until recently, the Superpave asphalt mix design specification did not include the 4.75mm nominal maximum aggregate size (NMAS).  Such mixes have the potential to create a smooth riding surface, extend pavement life, improve ride quality, improve safety characteristics, enhance appearance, increase durability, reduce permeability, and reduce road-tire noise.  Also, because of the ability to place these mixes in thin lifts, they can be used to correct surface defects, decrease construction time, decrease construction costs, and to extend maintenance dollars. The Arkansas State Highway and Transportation Department does not currently use a 4.75mm NMAS mix.  Thus, the objectives of this project were to evaluate the benefits and impacts associated with 4.75mm mixture implementation. In this study, three aggregate sources (limestone, sandstone, and syenite) were used to develop 4.75mm nominal maximum aggregate size (NMAS) mixtures.  From each source, six mixtures were designed at varying design air void contents and design compaction levels.  Two air void levels (4.5 and 6.0 percent) and three compaction levels (Ndes = 50, 75, and 100) were evaluated in order to determine the most advantageous design parameters with respect to rutting, stripping, and permeability.  Also, the use of natural sand was investigated.   The results of the study indicate that 4.75mm mixes can be successfully designed using existing aggregate sources.  In some cases, minor modifications to existing stockpile gradations improved design success.  Design air voids and compaction level were both important to the performance of the mixes.  The greatest resistance to rutting and stripping was provided for low- and medium-volume mixes when designed at 6.0 percent air voids, and for high-volume mixes when designed at 4.5 percent air voids.  Thus, different design air void levels were recommended for different applications.  Some aggregate sources were able to tolerate the addition of natural sand.  In general, however, rutting and stripping potential increased as the natural sand content increased.  When compared to mixes with larger NMAS, the 4.75mm mixes exhibited rutting and stripping resistance similar to, and sometimes greater than, that of typical 12.5mm surface mixes.  The permeability of the 4.75mm mixes was determined to be very low, and thus there is excellent potential for using these mixes to seal surfaces that may be prone to permeability problems. Overall, the results of the study indicated that 4.75mm mixes have the potential to successfully provide many benefits.  Thus, it was recommended that the 4.75mm NMAS be added to the Arkansas mix design specification.]]></description>
      <pubDate>Tue, 25 Jun 2019 09:57:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1629766</guid>
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    <item>
      <title>Rutting Susceptibility of Asphalt Mixes with High RAP Content Using Rheological and Performance-Based Test Methods</title>
      <link>https://trid.trb.org/View/1558667</link>
      <description><![CDATA[The rutting susceptibility of asphalt mixes containing high amounts of reclaimed asphalt pavement (RAP) was evaluated through a laboratory testing program. A commonly used PG 64-22 asphalt binder, RAP, aggregates and mix design sheets required for the production of an asphalt mix with a nominal maximum aggregate size of 19 mm containing 35% RAP were collected from a local asphalt plant in Oklahoma. The rutting susceptibility of the laboratory-produced asphalt mix was determined using the Hamburg Wheel Tracking test. The asphalt mix with 35% RAP content was found to exhibit satisfactory rutting resistance. Also, asphalt binder was extracted from the collected RAP and blended with the PG 64-22 binder at a rate of 40% by the weight of binder. The rheological characterization of the asphalt binders was conducted using multiple stress creep and recovery (MSCR) and Superpave methods. The continuous high temperature PG grade of asphalt binder was found to increase and the non-recoverable creep compliance (J sub nr) value was found to decrease with the addition of RAP binder to the neat binder. The findings of this study are expected to help pavement engineers in Oklahoma to understand the performance properties of asphalt mix with high RAP content.]]></description>
      <pubDate>Sun, 16 Dec 2018 21:39:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1558667</guid>
    </item>
    <item>
      <title>Effect of RAP on Cracking and Rutting Resistance of HMA Mixes</title>
      <link>https://trid.trb.org/View/1558666</link>
      <description><![CDATA[The use of recycled asphalt pavement (RAP) has significantly increased in construction and rehabilitation of flexible pavements to ensure proper utilization of limited natural resources and for environmental benefits. Performance measures of asphalt pavement like cracking and rutting resistance under repetitive traffic and environment induced load are important criteria to assess the viability of the use of RAP in hot-mix asphalt (HMA). This research was conducted to evaluate the effect of RAP on cracking and rutting resistance of HMA mixes. Three different mixtures, Control (0% RAP), 20% RAP, and 24% RAP mixtures, were considered for the study. Nominal maximum aggregate size (NMAS) used for all mixes was 12.5 mm. Eight specimens (150 mm diameter and 75 mm high each) were compacted at a target 7% air void content using gyratory compactor. Six of the specimens were tested with the asphalt pavement analyzer (APA) to determine their rutting resistance. While other two specimens were tested using disc-shaped compact tension (DCT) to determine the cracking resistance at 10°C higher than low-temperature grade of the binder in the mixes. The cracking resistance was evaluated in terms of fracture energy. The results showed that mixes with RAP performed better than virgin mixes in terms of rutting and worse in terms of cracking resistance. 20% RAP, not 24% RAP mix, was the most rut resistant mix.]]></description>
      <pubDate>Sun, 16 Dec 2018 21:39:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1558666</guid>
    </item>
    <item>
      <title>Conceptualizing the asphalt film thickness to investigate the Superpave VMA criteria</title>
      <link>https://trid.trb.org/View/1540664</link>
      <description><![CDATA[Asphalt binder film thickness (FTb) is the key factor that is responsible for durability of asphalt mixtures. Mixtures with coarse aggregate gradations have difficulty meeting the Superpave minimum voids in mineral aggregate (VMA) criteria even though they tend to have thick asphalt films. In this study, the concept of asphalt binder film thickness (FTb) was used to investigate the Superpave VMA criteria. Superpave aggregate gradations of three nominal maximum aggregate sizes (NMAS): 9.5, 12.5 and 19.0 mm, were used. Aggregate gradations passing above, below, crossover through, humped, and through restricted zone were all considered. Superpave Gyratory Compactor test data of 126 compacted asphalt mixtures were used in the study. The current Superpave VMA criteria relate the mixture durability with VMA and set the same VMA value for mixtures with the same NMAS regardless of other parameters. However, a poor relationship was found between VMA and FTb (a durability measure) with an R² ≅ 0.01, and yet a relatively good relationship (R² ≅ 0.38) was found between voids filled with asphalt (VFA) and FTb although the VFA volumetric phase is part of the VMA volumetric phase in the mixture. This result was justified by the poor relationship between VFA and VMA (R² ≅ 0.13). Despite that the effective binder content (P sub be ) as a volumetric phase represents the VFA in the mixture, the relationship between FTb and P sub be  was found to be more significant (higher R²) than the relationship between FTb and VFA. In this study, asphalt mixtures that did fail the Superpave VMA criteria in some cases had adequate asphalt FTb, and mixtures that passed the criteria did not necessarily have adequate FTb. In conclusion, although the current Superpave VMA criteria are significant, findings of this study support the tendency to modify the current criteria.]]></description>
      <pubDate>Mon, 01 Oct 2018 14:39:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/1540664</guid>
    </item>
    <item>
      <title>Establishing Relationship Between Engineering Properties of Asphalt Concrete and Mix Parameters Using Impact Resonance Test</title>
      <link>https://trid.trb.org/View/1497038</link>
      <description><![CDATA[The sensitivity of the asphalt concrete resonant frequency response to mixture parameters was evaluated using the impact resonance (IR) test. A total of 72 asphalt concrete specimens, covering a range of nominal maximum aggregate sizes, specific gravities, binder contents, and air void contents, were fabricated for the IR testing. A PG 64-22 asphalt binder was used for all specimens. The IR tests were conducted on disk-shaped asphalt concrete specimens at the transverse (flexural) mode of vibration at a temperature range of approximately -10 to 50 °C. Test results indicated that the relationship between the resonant frequency and temperature was described by a second order polynomial fit, and it was shown through statistical analysis that the slopes of the fit were significantly affected by mixture parameters such as air void content and binder content. Also, the statistical formulation (predictive model) between the resonant frequency and the asphalt concrete mixture parameters were established for a given aggregate gradation of nominal maximum size and an aggregate specific gravity. The prediction accuracy of the model was evaluated by independent data sets, and the test results indicated that the maximum error between the measured and predicted resonant frequencies did not exceed 9 percent.]]></description>
      <pubDate>Tue, 06 Mar 2018 16:22:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1497038</guid>
    </item>
    <item>
      <title>Effect of Superpave restricted zone on volumetric and compaction properties of asphalt mixtures</title>
      <link>https://trid.trb.org/View/1487673</link>
      <description><![CDATA[The Superpave aggregate criteria originally include a restricted zone that lies along the maximum density line and through which gradations are not recommended to pass. The debate with regard to whether or not such a restriction needs to be imposed has been ongoing and inconclusive. In this study, fifteen different gradations of limestone aggregate having three nominal maximum aggregate sizes (NMAS) of 19.0, 12.5, and 9.5 mm and covering five types: above, below, crossover through, hump through, and through restricted zone (ARZ, BRZ, CRZ, HRZ, and TRZ) were used to investigate the effect of restricted zone on mixture properties. The Superpave gyratory compactor (SGC) was used to produce the asphalt mixture samples according to the Superpave system. Findings of the study showed that the CRZ, HRZ, and TRZ mixtures generally could meet the Superpave voids in mineral aggregate (VMA) criteria easier than the BRZ and ARZ mixtures. Contrary to the expected trend, the VMA values for the BRZ mixtures were found to be higher than those of the ARZ mixtures for the 19.0-mm NMAS. The HRZ mixtures similar to the ARZ and BRZ mixtures had high effective asphalt binder content. ARZ mixtures generally could violate the Superpave criteria for compaction properties (% of maximum specific gravity at the initial number of gyrations, %G sub mm at N sub initial, and % of maximum specific gravity at the maximum number of gyrations, %G sub mm at N sub maximum). The TRZ mixtures in general provided the highest dust proportion (DP) values, whereas, the BRZ mixtures provided the lowest DP values.]]></description>
      <pubDate>Mon, 13 Nov 2017 16:31:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1487673</guid>
    </item>
    <item>
      <title>Evaluation of Georgia Asphalt Mixture Properties Using a Hamburg Wheel-Tracking Device</title>
      <link>https://trid.trb.org/View/1480558</link>
      <description><![CDATA[This study used a Hamburg Wheel-Tracking Device (HWTD) to evaluate the resistance of Georgia asphalt mixtures to rutting and stripping. It aimed to develop an HWTD test procedure and criteria aligned with Georgia Department of Transportation's (GDOT’s) asphalt materials and mixture design. Aggregates, reclaimed asphalt pavement (RAP), and asphalt binders from four representative hot mix asphalt plants - A1, A2, A3 and A4 - were selected for the test. All mixtures contained RAP. Asphalt binders of performance grade (PG) 64-22 and PG 76-22 were used, and four nominal maximum aggregate size (NMAS) Superpave mix types (25 mm, 19 mm, 12.5 mm, 9.5 mm T1 and T2), a 4.75 mm dense-graded and a 12.5 mm stone matrix asphalt (SMA) mixture were selected for this study. For Superpave and dense-graded mixtures, 30% RAP was used for A1 and A2 sources, and 25% RAP for A3 and A4. For SMA mixtures, 15% RAP was used regardless of source. Three temperatures of 50, 64, and 70°C were selected for each asphalt mix type. In total, 216 mixture samples were made by Superpave gyratory compactor (SGC), and 216 sets were tested by HWTD. The results are as follows: 1) Rut depths were very small - less than 5 mm, even after 20,000 wheel passes at 50°C and increased remarkably at the higher test temperatures; most mixtures reached 20.0 mm within 20,000 wheel passes at 70°C. 2) Rut depths may reflect the influence of the type and size of the aggregates and the binders at test temperatures of 64°C and higher. 3) Rut depths from the mixtures with NMAS of 25 mm and 19 mm were obviously lower than those from NMAS of 12.5 mm, 9.5 mm, and 4.75 mm. 4) Rut depths increased and stripping inflection point (SIP) decreased as the NMAS of the gradation decreased. 5) Overall, mixtures using modified binders had lower rut depths than those using unmodified binders; in addition, the rut depths of 12.5 mm SMA using modified binders was much higher than those of 12.5 mm Superpave mixtures. 6) The raw material sources of aggregate and RAP had an apparent effect on rutting and stripping performance. 7) RAP preprocessing methods during laboratory mixing – either not heating or preheating in a 110°C oven for 2 hours before the RAP was mixed with the virgin aggregates and binder - affected rutting and stripping performance, regardless of temperature and mix type. 8) HWTD test procedures were proposed for evaluating Georgia asphalt mixtures.]]></description>
      <pubDate>Sun, 27 Aug 2017 18:11:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/1480558</guid>
    </item>
    <item>
      <title>Guidelines for TxDOT in Selecting Seal Coat Materials</title>
      <link>https://trid.trb.org/View/1461044</link>
      <description><![CDATA[This report is presented in two sections.  The first section, Guidelines for Selecting Aggregates for Seal Coats, discusses the selection of aggregate size and gradation, as well as precoating requirements. The second section, Guidelines for Selecting Asphalt Binders for Seal Coats, discusses asphalt rubber binders, asphalt cement, emulsions, polymer modification, and seal coat binder selection guidelines.]]></description>
      <pubDate>Mon, 01 May 2017 17:40:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/1461044</guid>
    </item>
    <item>
      <title>Microstructural Investigation of Hot Mix Asphalt (HMA) Mixtures Using Digital Image Processing (DIP)</title>
      <link>https://trid.trb.org/View/1453919</link>
      <description><![CDATA[It is well known that Nominal Maximum Aggregate Size (NMAS) significantly affects several mechanical properties of asphalt pavement layers both at low and high temperatures. Two different aggregate NMAS, 9.5 mm and 12.5 mm, are commonly used for surface layer mixture. Most of the past research studies investigated the effect of different aggregate NMAS on asphalt mixture properties through experimental testing, while the impact of NMAS on asphalt mixtures microstructure has received little attention. In this paper, asphalt mixtures with two NMAS, 9.5 mm or 12.5 mm, two air voids percentages, 4% and 7%, and two binder contents, 4% and 7%, were prepared. Then, the effect of aggregate NMAS on materials properties was investigated by performing low temperature creep test of asphalt mixture through the Bending Beam Rheometer (BBR) and advanced Digital Image Processing (DIP) analysis of two-dimensional images of asphalt mixture combined with numerical evaluations of 2- and 3- point correlation functions. As a result, asphalt mixtures containing smaller NMAS showed higher stiffness compared to those prepared with larger aggregates at low temperature. The spatial distributions of aggregates, asphalt mastic, and air voids were not significantly affected by the addition of aggregates with different NMAS. However, an increase in Auto Correlation Length (ACL) was observed for asphalt mixtures having smaller NMAS, which suggests that low temperature creep properties are associated to ACL.]]></description>
      <pubDate>Fri, 28 Apr 2017 10:40:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1453919</guid>
    </item>
    <item>
      <title>Effect of Asphalt Mixture Type on Interlayer Shear Properties</title>
      <link>https://trid.trb.org/View/1439330</link>
      <description><![CDATA[This study compares the interlayer shear properties of pavement layers composed of different asphalt mixture types. Two dense asphalt mixtures (D, BM) and one open-graded friction course (OGFC) mixture were selected for the comparison. The direct shear test was conducted with and without normal stress to assess the shear strength and shear stiffness at different tack coat application rates. Results show that the friction angle between BM aggregate and OGFC aggregate was larger than the angle between D aggregate and OGFC aggregate. At 0.2 MPa normal stress, the specimens of two dense mixtures gave higher shear properties than those with OGFC as the upper layer. This is due to the fact that the non-contact area between OGFC and underlying layer compromised the bonding between the two layers. Among the samples of two dense layers, the D-BM specimens showed a higher interlayer shear resistance resulting from a larger interlayer roughness caused by a better aggregate interlock between D and BM mixtures. This indicates an upper layer with a small nominal maximum aggregate size (NMAS) and an underlying layer with a large NMAS could provide a better bonding. For specimens of OGFC and a dense mixture (D or BM), OGFC-BM showed a better shear performance at the optimal tack coat application rate than OGFC-D, which is due to the double effects of a larger interface contact area and a larger interface roughness than OGFC-D.]]></description>
      <pubDate>Sun, 26 Mar 2017 17:39:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/1439330</guid>
    </item>
    <item>
      <title>Effect of Aggregate Sizes on Performance of Georgia Asphalt Mixtures Evaluated by Hamburg Wheel-Tracking Device</title>
      <link>https://trid.trb.org/View/1439145</link>
      <description><![CDATA[The objective of this paper was to examine the effect of aggregate sizes on the rutting and stripping performance of asphalt mixtures typically used in the state of Georgia by the Hamburg Wheel Tracking Device (HWTD). Four nominal maximum aggregate sizes of 25, 19, 9.5 and 4.75 mm were considered. Three test temperatures of 50, 64 and 70 °C were selected for the HWTD testing to observe the temperature sensitivity in the rutting and stripping characteristics. The test results were analyzed in terms of five indexes: number of loading passes at failure, rut depth at 20,000 wheel passes, stripping inflection point, creep slope and stripping slope. The major findings through the experimental program include that 1) a large sized-gradation of Superpave mixtures performed better than a small sized-one in both rut and anti-stripping properties, 2) the coefficient of determination from relationships between the wheel pass and the nominal aggregate size, the stripping inflection point and the nominal maximum aggregate size were 0.64 and 0.7, respectively, 3) test temperature of 64 °C was found the most appropriate among all the three temperatures for the HWTD to evaluate Georgia asphalt mixtures.]]></description>
      <pubDate>Mon, 13 Feb 2017 17:19:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1439145</guid>
    </item>
    <item>
      <title>4.75 mm SMA Performance and Cost-Effectiveness for Asphalt Thin Overlays</title>
      <link>https://trid.trb.org/View/1407285</link>
      <description><![CDATA[This paper presents the design of stone matrix asphalt (SMA) with 4.75-mm nominal maximum aggregate size (NMAS) and alternative surfacing cross-section for an asphalt wearing course that may improve pavement performances while controlling costs by using locally available aggregates. The 4.75 -mm NMAS dense-graded mix was previously used in several states to reduce layer thickness and cost. Because of its poor friction and limited performance, however, it was generally used as leveling binder and placed on low-volume roads. The 4.75-mm SMA is proposed for thinner asphalt overlays in this study to improve its performance as well as surface texture. The ultimate goal of this study is to develop the 4.75-mm SMA and evaluate its performance and engineering benefits as a wearing course under laboratory and field conditions. Test pavement sections were constructed in Northern Illinois and on-site performance tests were conducted to evaluate its performance under actual traffic loading. The engineering cost-benefit analysis with respect to performances from both laboratory and field studies suggests the proper application of 4.75-mm SMA as an efficient and cost-effective wearing course for asphalt thin overlays.]]></description>
      <pubDate>Tue, 24 May 2016 19:04:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1407285</guid>
    </item>
    <item>
      <title>Evaluation of deformation properties of asphalt mixture using aggregate slip test</title>
      <link>https://trid.trb.org/View/1398585</link>
      <description><![CDATA[Asphalt mixture is a multiphase particulate material composed of aggregate, asphalt and filler. The deformation property of asphalt mixture is an external reflection of aggregate slip behaviour. To evaluate the high-temperature deformation properties of asphalt mixture, an aggregate slip device was developed and aggregate slip tests were conducted on five asphalt mixtures for different gradations under different test conditions. Four evaluation parameters, the slip failure load (F sub s), the slip failure deformation (D sub s), slip modulus parameter (M) and slip energy index (SEI), were obtained according to the load–displacement curves. The relationship between these parameters and rut depth (RD) was analysed. The effects of test temperature and asphalt content on slip resistance of asphalt mixture are studied in this research. The results indicate that the parameter F sub s has limitations for large nominal maximum particle-size mixture, and SEI is an effective parameter to evaluate the aggregate slip properties for different nominal maximum particle-size asphalt mixtures. SEI has the strongest relationship to RD, which is the best parameter to evaluate the slip deformation behaviour of asphalt mixture. With the increase in asphalt content, SEI has a peak value and a valley value. When the optimum asphalt content is used in asphalt mixture, aggregate skeleton effect and asphalt cohesive force can both reach a high level, and asphalt mixture has the best deformation resistance.]]></description>
      <pubDate>Sat, 09 Apr 2016 15:45:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1398585</guid>
    </item>
    <item>
      <title>Effect of Mixture Properties on Fatigue Failure Mechanism in Asphalt Concrete</title>
      <link>https://trid.trb.org/View/1392418</link>
      <description><![CDATA[Fatigue cracking is one of the major distresses in asphalt pavements. The AASHTO·T321 protocol for fatigue characterization using third point loading of a beam is popular in the engineering community due to its simple nature. This protocol requires testing specimens to failure under several strain levels using flexural fatigue loading. The specimen is considered to have failed when the stiffness of the beam is fifty percent of the undamaged stiffness. Empirical models relating initial tensile strain to number of cycles to failure have been developed through regression analysis. Asphalt concrete is viscoelastic in nature, so fatigue relationships developed are dependent on factors like loading rate, loading history, testing temperature, healing and aging. This article presents a critical evaluation of characteristic damage curves obtained from beam fatigue testing using viscoelastic continuum damage mechanics approach. Fatigue test data from one 12.5 mm nominal maximum aggregate size mixture and four 19.0 mm nominal maximum aggregate size asphalt concrete mixtures with different binder grades were used for the analysis. The statistical analysis indicates that there exists a unique relationship between the flexural pseudostiffness and amount of damage in the specimen. A point of inflection was found in the damage characteristic curve beyond which the material loses its structural integrity at a faster rate. It was observed that normalized pseudostiffness at this inflection point is dependent on mixture properties (like binder grade, nominal maximum aggregate size) and testing temperature.]]></description>
      <pubDate>Thu, 04 Feb 2016 08:37:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1392418</guid>
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