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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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      <title>HOW GOOD ARE SOME RHEOLOGICAL MODELS OF DYNAMIC MATERIAL FUNCTIONS OF ASPHALT? (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/488042</link>
      <description><![CDATA[The main objective of this paper is to show the advantages and disadvantages of several rheological models applied to regular and polymer modified asphalts.  The choice of any model is dictated by the purpose of the modelling, however, a "good" model should be able to describe as completely as possible the linear viscoelastic functions of the studied materials.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488042</guid>
    </item>
    <item>
      <title>RELATIONSHIPS BETWEEN THE STRUCTURE AND THE MECHANICAL PROPERTIES OF PAVING GRADE ASPHALT CEMENTS (WITH DISCUSSION AND CLOSURE)</title>
      <link>https://trid.trb.org/View/488043</link>
      <description><![CDATA[Since the late sixties, different models have been proposed in the literature to describe asphalt cement (AC) rheology.  Most of these models, based on the plot of rheological master-curves and the determination of shift factors, imply that the Time-Temperature Superposition Principle (TTSP) holds for AC. However, a few authors questioned the applicability of TTSP to AC.  In this paper AC structure is described using the colloidal picture.  At high temperature, the peptization equilibrium of the solid asphaltene particles is believed to evolve with temperature, causing the TTSP not to apply.  On the other hand, at low temperature, vitrification of the liquid maltene phase prevents the structure from changing, causing the TTSP to apply. As a consequence of the colloidal nature of ACs, their viscoelastic properties can be separated according to two relaxation phenomena:  an "a" relaxation, due to the asphaltene particles' Brownian motion, which leads to a transition from a Newtonian to a viscoelastic behavior; and a "b" relaxation, due to the vitrification of the maltene phase, which induces a transition from a viscoelastic flow to a solid glassy behavior. These ideas are shown to apply to several paving grade ACs from two different crude sources.  In the end, eight structure-related parameters are needed to describe the viscoelastic properties of AC.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488043</guid>
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    <item>
      <title>FATIGUE CHARACTERIZATION OF ASPHALT CONCRETE USING VISCOELASTICITY AND CONTINUUM DAMAGE THEORY (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/488044</link>
      <description><![CDATA[A mechanistic approach to fatigue characterization of asphalt-aggregate mixtures is presented in this paper.  This approach is founded on a uniaxial viscoelastic constitutive model that accounts for damage evolution under cyclic loading conditions.  The elastic-viscoelastic correspondence principle is applied in order to evaluate damage growth and healing in cyclic loading separately from time-dependent characteristics of the material.  The damage growth during loading cycles and healing during rest periods are modeled using the work potential theory, a continuum damage theory based on thermodynamics of an irreversible process.  Internal state variable formulation was used in developing the analytical representation of the model. Tensile uniaxial fatigue tests were performed under the controlled-strain mode with different strain amplitudes to determine model parameters.  The resulting constitutive model successfully predicts the damage growth of asphalt concrete under monotonic loading of varying strain rates and damage growth and recovery due to complex loading histories, in both controlled-strain and controlled-stress modes, composed of randomly applied multi-level loading with different loading rates and varying durations of rest.  Fatigue lives of two different mixtures are predicted with a reasonable accuracy using the constitutive model for the constant stress/strain amplitude cyclic loading histories with and without rest periods.  Recommendations are made on how the resulting constitutive model can be used for practical fatigue performance prediction of asphalt concrete.  Some discussions are given on the relationships between chemical properties of asphalt binder and beneficial effects of rest periods on fatigue performance.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488044</guid>
    </item>
    <item>
      <title>THE CHANGE IN PROPERTIES OF POLYMER MODIFIED BINDERS WITH SIMULATED FIELD EXPOSURE (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/488045</link>
      <description><![CDATA[The aims of the study were to:  (i) develop a method for dynamic shear rheometry (DSR) measurement on undisturbed samples subjected to a laboratory aging procedure which realistically simulated field exposure, and to thus determine whether the properties of polymer modified binders (PMBs) changed during pavement service; (ii) modify Rolling Thin Film Oven (RTFO) test equipment so that it could be used for PMBs; and (iii) determine whether an extended form of the modified RTFO test could be used to indicate the long term oxidation resistance of PMBs.  It was found that long term laboratory exposure at a temperature below the maximum encountered in pavement service resulted in large changes in the rheological behavior of the PMBs and that these changes were likely to reduce the advantage which fresh PMBs have over unmodified asphalts in service.  In the fresh state there were considerable differences in properties between the different PMBs but these differences were reduced after exposure.  Simple modifications were made to RTFO test equipment so that RTFO treatment could be used with PMBs.  Extended RTFO treatment was found to produce similar rheological changes to simulated field exposure for all the binders except an ethylene vinyl acetate (EVA) binder at low loading frequencies.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488045</guid>
    </item>
    <item>
      <title>PROPERTIES OF AGED ASPHALT BINDER RELATED TO ASPHALT CONCRETE FATIGUE LIFE</title>
      <link>https://trid.trb.org/View/488046</link>
      <description><![CDATA[The proposed Strategic Highway Research Program (SHRP) asphalt binder specification includes a parameter that is represented as a fundamental binder property that contributes to pavement fatigue life.  However, it has been the observation of some that the fatigue parameter, G* sin delta, does not correlate adequately with field performance data.  There has also been some concern expressed that the parameter may actually allow the use of binders which, in previous experiences, have been used in pavements that have exhibited very poor fatigue life.  Thus, a study was conducted to compare binder properties with the fatigue life of mix containing various binders, including some with "extreme" properties, for which documented performance data exists.  The evaluation of the binders in a controlled laboratory mix "failure" test was considered a necessary tie between the binder properties and the field performance data.  The laboratory fatigue test provides for better control of variables, while the field data are a necessary reality check on the performance ranking.  A part of this tie is the degree to which the laboratory failure test simulates field conditions, such as aging.  While it was intentioned to address this in the fatigue testing in the SHRP research, time limitations precluded this task.  Thus, for this study, the binders were all aged using binder accelerated aging procedures prior to their incorporation into a mix.  This approach was chosen over long-term oven-aging of mix because, currently, the binder aging procedure has been correlated specifically with the appearance of premature fatigue cracking in the climate where the performance data exists (the desert) on some of the binders used in this study.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488046</guid>
    </item>
    <item>
      <title>INFLUENCE OF BINDER LOSS MODULUS ON THE FATIGUE PERFORMANCE OF ASPHALT CONCRETE PAVEMENTS</title>
      <link>https://trid.trb.org/View/488047</link>
      <description><![CDATA[This paper evaluates the effects of binder loss stiffness, the parameter included in the Strategic Highway Research Program (SHRP) binder specification to control fatigue response, on pavement performance.  Results of two studies are included:  (1) that performed during the SHRP research program which evaluated the fatigue response of mixes containing eight asphalts and two aggregates and their simulated performance in representative pavement structures, and (2) a detailed study of the effects of binder loss stiffness on the simulated fatigue performance of 18 different pavement sections designed according to California Department of Transportation procedures and used in three different temperature environments in California.  Results of both investigations indicate that the loss stiffness of the binder is not a sufficient indicator, by itself, of the fatigue performance of asphalt concrete in actual pavement structures. Moreover, they highlight the basic conflict between the current specification which sets a maximum limit on loss modulus and field performance simulations which suggest that larger moduli are beneficial for most pavement structures.  The paper recommends the elimination of the fatigue requirement binder loss modulus from the binder specification.  This recommendation would retain control of binder characteristics at high and low temperatures using current requirements.  For mixes containing other than conventional dense-graded aggregates and/or modified binders, a mix design and analysis procedure, which includes flexural fatigue testing, is recommended and the procedure is described in the paper.  The paper emphasizes that the binder alone does not determine fatigue response in the pavement structure.  Mix characteristics as well as the pavement structure itself and the environment within which it is located have a significant role in determining pavement performance.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488047</guid>
    </item>
    <item>
      <title>RECYCLING OF ASPHALT PAVEMENTS - AN OVERVIEW</title>
      <link>https://trid.trb.org/View/488048</link>
      <description><![CDATA[This paper gives a brief overview of the recycling of asphalt pavements.  Five recycling methods are presented:  (1) cold planing; (2) hot recycling; (3) hot in-place recycling; (4) cold in-place recycling; and (5) full depth reclamation.  Strategies for selecting an appropriate recycling method are discussed. The performance of different recycling processes based on the review of literature is presented.  Economics, legislation/specification limits, and structural design associated with recycling of asphalt pavement are also presented.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488048</guid>
    </item>
    <item>
      <title>HOT MIX RECYCLING: STATE-OF-THE-PRACTICE</title>
      <link>https://trid.trb.org/View/488049</link>
      <description><![CDATA[Since the mid-1970s, tens of millions of tons of Reclaimed Asphalt Pavement (RAP) have been used to produce recycled Hot Mix Asphalt (HMA) that has the same performance characteristics as HMA made with all virgin materials.  Substantial savings have been achieved by using RAP in mixes.  The purpose of this report is to provide a review of the state-of-the-practice for the use of RAP, addressing the generation and handling of RAP materials, mix design techniques, handling RAP in the HMA facility (including environmental concerns), and placement and performance issues.  The use of RAP has evolved into an everyday occurrence in many areas of the country.  In Florida for example, 75% of the RAP generated is recycled into HMA.  The Federal Highway Administration estimates that 33% of all asphalt pavement removed is recycled into HMA production.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488049</guid>
    </item>
    <item>
      <title>HOT-IN-PLACE RECYCLING STATE-OF-THE-PRACTICE</title>
      <link>https://trid.trb.org/View/488050</link>
      <description><![CDATA[Since the last symposium on recycling in 1979, many changes have occurred that have improved the overall concept of recycling asphalt pavements.  Not only has recycling become widely accepted and practiced, the technology, equipment and procedures have advanced as well.  The use of hot central plant recycling has improved our understanding of mixtures and associated equipment so that adding 10-30% recycled asphalt pavement is now normal practice.  Cold in-place recycling has advanced in both mixture and equipment design so that over-the-road reconstruction is now a routine method in many areas.  But the prospect of true hot in-place recycling (HIR) offers an opportunity that not only provides a high quality new surface, but disruption to the public can be minimized.  Over the past twenty years or so, several approaches to HIR have been attempted with varying degrees of success.  These have ranged from simple direct-flame heating, heater-scarifying, combined cold milling/hot mixing, and more recently both infrared heating and infrared heating combined with hot air.  Key goals in improving this technology have included recycling to greater depths, ability to add new materials, reducing damage to the existing pavement, and reducing air pollution to acceptable levels.  This paper discusses these elements and the progress being made in the overall technology.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488050</guid>
    </item>
    <item>
      <title>FULL DEPTH PAVEMENT RECLAMATION: STATE-OF-THE-PRACTICE</title>
      <link>https://trid.trb.org/View/488051</link>
      <description><![CDATA[Full depth reclamation in the United States increasingly is being selected by cities, counties, state departments of transportation, federal agencies, airports and consulting engineers to reconstruct severely deteriorated asphalt pavements.  This process allows complete reconstruction using 100% of existing pavement materials and grade, cross slope and underlying pavement problems can be corrected.  A new base course is produced by the recycling of existing asphalt pavement materials and, when required, some underlying materials.  This method of cold recycling an asphalt pavement has the environmental advantages of reduced energy consumption, greatly reduced use of new materials and depletion of their sources, little to no disposal of existing pavement materials (in landfills), and reduced air pollution.  A thorough project evaluation is essential for project selection, design and construction.  The procedures in the evaluation process that must be completed are (1) conducting a pavement condition survey, (2) pavement coring or placing test holes, (3) sampling of the asphalt pavement, any granular base and subgrade, (4) laboratory testing of materials, (5) pavement structural design, and (6) an economic analysis for initial and life cycle costs. Also, proper construction procedures and quality control are critical along with an experienced contractor that is committed to both.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488051</guid>
    </item>
    <item>
      <title>COLD MIX RECYCLING: STATE-OF-THE-PRACTICE (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/488052</link>
      <description><![CDATA[The current state of the art for cold recycling of asphalt pavements is only about ten years old, so only a few long term performance evaluations have been reported.  However, short term performance has been so promising that cold in-place recycling (CIR) is growing rapidly.  Generally CIR has been found to be an economical, environmentally friendly and effective asphalt pavement rehabilitation method for many types of distress.  At current asphalt prices, a 100-mm (4-in.) thick CIR pavement costs less than a 37-mm (1.5-in.) hot mix asphalt overlay.  A significant amount of energy is also saved due to the elimination of trucking and heating of the pavement mix.  Bridge clearances and guiderail elevations are maintained and side road and driveway tie-ins and shoulder paving are minimized.  Ride quality will be improved as well as pavement profile, crown and cross-slope.  High production rates (2.5 to 3.5 km per day) reduce the disruptions to the traveling public.  Our existing highway system is an extremely valuable resource containing many millions of tons of high quality asphalt and aggregate.  The widely used rehabilitation method of just overlaying aged and cracked pavements no longer makes sense from an economic or engineering standpoint.  Cracks and failed areas of the existing pavement quickly reflect through the overlay and the deterioration process starts over.  During recycling, those areas are restored structurally and by using the in-place materials, savings of 50% or more can be realized.]]></description>
      <pubDate>Mon, 10 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488052</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF A MIX DESIGN PROCEDURE FOR STONE MATRIX ASPHALT (SMA) MIXTURES (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/488028</link>
      <description><![CDATA[Stone Matrix Asphalt (SMA) has been used successfully in Europe for over 20 years to provide better rutting resistance and to resist studded tire wear.  Since 1991, the use of SMA has increased steadily in the United States.  At present, some states routinely use SMA even though a standard mixture design procedure is not available.  A mixture design procedure that provides guidance on material properties, aggregate gradation, determination of optimum asphalt content, and mixture properties is needed.  This paper presents a mixture design procedure for SMA mixtures developed by the National Center for Asphalt Technology.  Data for the development of the procedure were collected from a laboratory study conducted with various samples of aggregates, fillers, asphalt binders, and stabilizing additives.  Compacted mixtures were tested to evaluate the effects of aggregate structure, asphalt binder, and binder-fine aggregate mortar.]]></description>
      <pubDate>Fri, 07 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488028</guid>
    </item>
    <item>
      <title>VALIDATION OF THE FATIGUE PERFORMANCE OF ASPHALT MIXTURES WITH SMALL SCALE WHEEL TRACKING EXPERIMENTS (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/488029</link>
      <description><![CDATA[Small scale wheel tracking studies have been performed by many research organizations investigating the performance of asphaltic mixtures.  Unlike full scale pavement trials, results can be generated in a relatively short time scale (less than one month of testing) while the quantities of materials and the cost are relatively low.  This paper describes work conducted using a small scale wheel tracking device on specimens 1 m x 0.5 m.  The equipment was originally designed for research into reinforced asphalt and was further developed for these fatigue tests.  The paper includes details of the experimental work associated with fatigue wheel tracking experiments and describes work conducted to establish correlations between these test results and other test data collected including fatigue test results.]]></description>
      <pubDate>Fri, 07 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488029</guid>
    </item>
    <item>
      <title>PRACTICAL FATIGUE CHARACTERIZATION OF BITUMINOUS PAVING MIXTURE</title>
      <link>https://trid.trb.org/View/488030</link>
      <description><![CDATA[This paper details the development and subsequent use of the Indirect Tensile Fatigue Test (ITFT) as a routine practical method for evaluating the life to crack initiation of bituminous paving mixtures.  Although this test has been in use for many years, a recent project involving close collaboration between industry, highway authorities and the University of Nottingham has led to significant practical improvements.  The ITFT has a biaxial state of stress that, although more representative of field conditions than a uniaxial stress state, complicates the calculations of stress and strain.  However, the use of linear elastic theory is shown to be suitable for this purpose provided the test temperature does not exceed 30 deg C.  The data also confirm the use of tensile strain as the principal criterion for fatigue crack initiation.  A high degree of correlation was demonstrated between results for the ITFT and two more fundamental test methods, the trapezoidal cantilever and the uniaxial tension-compression test.  The ITFT method can be used to characterize a material in as little as two hours, and as a result of this research it has been extensively used both in the UK and in Europe.  The repeatability and the reproducibility of the test showed that when comparing results from nine laboratories, the scatter in the data was small.  The test method is regarded as suitable for a British Standard and is a serious candidate for adoption within Europe.  The final section of the paper describes on-going research being carried out at Nottingham into the application of Linear Elastic Fracture Mechanics (LEFM) to characterize crack propagation using a slightly modified form of the ITFT test geometry.]]></description>
      <pubDate>Fri, 07 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488030</guid>
    </item>
    <item>
      <title>VALIDATION OF ASPHALT BINDER AND MIXTURE TESTS THAT PREDICT RUTTING SUSCEPTIBILITY USING THE FHWA ALF (WITH DISCUSSION)</title>
      <link>https://trid.trb.org/View/488031</link>
      <description><![CDATA[The Federal Highway Administration's (FHWA's) Accelerated Loading Facility (ALF) is being used to validate the Superpave binder parameter for rutting and several mixture tests that have been developed to predict rutting susceptibility.  The ALF is a pavement testing machine that applies one half of a single rear truck axle load.  The binders being used in this study are AC-5, AC-10, AC-20, Novophalt (trademark), and Styrelf (trademark) 1-D, having Superpave Performance Grades of 58-34, 58-28, 64-22, 76-22, and 82-22.  All five binders were used with a gradation having a nominal maximum aggregate size of 19.0 mm.  The AC-5 and AC-20 binders were also used with a gradation having a nominal maximum aggregate size of 37.5 mm.  Superpave uses G*/sin delta to rank binders according to rutting susceptibility.  As G*/sin delta increases, rutting susceptibility should decrease.  In this study, binders with higher G*/sin delta generally provided mixtures with lower rutting susceptibilities for a given nominal maximum aggregate size.  The main discrepancy between G*/sin delta and the pavement performances of the five surface mixtures was that the Styrelf binder had the highest G*/sin delta followed by Novophalt, but Novophalt had a lower susceptibility to rutting. The ALF, French Pavement Rutting Tester, Georgia Loaded-Wheel Tester, Hamburg Wheel-Tracking Device, and the cumulative permanent strains from a repeated load test ranked the five surface mixtures similarly based on the average data.  Rankings based on statistics were different, and no laboratory mixture test clearly was the best test based on ALF.  The increase in nominal maximum aggregate size significantly decreased rutting susceptibility based on ALF.  None of the laboratory mixture tests adequately predicted this effect.]]></description>
      <pubDate>Fri, 07 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/488031</guid>
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