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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>
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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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    <item>
      <title>Using Predictive Models to Estimate the Properties of Binders in Reclaimed Asphalt Pavement Mixes using Fine Aggregate Matrix Mix Testing</title>
      <link>https://trid.trb.org/View/1602163</link>
      <description><![CDATA[A number of predictive models, such as the Hirsch and Al-Khateeb models, have been proposed to determine the properties of asphalt binders from asphalt concrete mix testing results. Fine aggregate matrix (FAM) mix testing can also provide useful insights into the likely performance of asphalt concrete mixes. Consequently, FAM mix testing can be an appropriate means of assessing the predictive power of these models. In this study, FAM mixes prepared with two virgin binders, PG58-28 and PG64-16, and then with different percentages of reclaimed asphalt pavement (RAP) were tested to determine their stiffness and phase angle using temperature-frequency sweeps in a dynamic shear rheometer. The data from the control mixes with no RAP were used along with the rheological properties of the virgin binders to fit the Hirsch and Al-Khateeb models. The fitted models were then used to estimate the properties of the binders in the 15% and 25% RAP FAM mixes. A comparison of the estimated binder properties with the measured binder properties clearly indicated that the fitting parameters are binder dependent. Moreover, the estimated binder moduli deviate from the measured moduli, particularly at high temperatures. The estimated complex shear moduli from the model were found to be consistently higher than the measured shear moduli values of the chemically extracted binders. It was thus concluded that the predictive models studied, in their current form, fail to provide a reliable estimate of the binder properties in mixes containing RAP.]]></description>
      <pubDate>Wed, 17 Jul 2019 17:24:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/1602163</guid>
    </item>
    <item>
      <title>Evaluation of asphalt–aggregate interaction based on the rheological properties</title>
      <link>https://trid.trb.org/View/1512932</link>
      <description><![CDATA[The silicon dioxide (SiO₂) and calcium oxide (CaO) analytical reagents are selected to prepare asphalt mastics and the effects of aggregate chemical composition on asphalt–aggregate interactions (AAI) are evaluated based on the complex modulus and phase angle. It is found that the oxide analytical reagents significantly affect the rheological properties such as complex shear modulus and phase angle, and the effects of CaO are greater than SiO₂ due to the stronger interaction between asphalt binder and CaO analytical reagents. Both the modulus stiffening ratio and the phase angle-based K. Ziegel-B coefficient could be used to evaluate the AAI, and the latter is the better index. Results show that the indexes increase with the test temperature, but decrease with the loading frequency, and tend to be constant. The higher adhesive strength between asphalt binder and limestone than basalt is likely attributed to the higher content of CaO in limestone aggregate and the stronger asphalt–CaO interaction.]]></description>
      <pubDate>Mon, 21 May 2018 11:38:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1512932</guid>
    </item>
    <item>
      <title>Viscosity-Based Complex Modulus and Phase-Angle Predictive Models for the Superpave Asphalt Mixtures of New Mexico</title>
      <link>https://trid.trb.org/View/1497710</link>
      <description><![CDATA[The recently developed mechanistic-empirical design method of pavement uses the nationally calibrated dynamic modulus predictive model for the design and analysis of asphalt pavements. This study calibrates this model for the local Superpave asphalt concrete mixtures of New Mexico. Although the calibrated model shows good correlation, this study develops a new regression-based model which shows improved correlation with the tested data. A total of 54 asphalt-aggregate mixtures are compacted, cored, and sawed to cylindrical specimens and tested for dynamic modulus and phase angle. The time-temperature superposition principle is applied to develop master curves at a reference temperature of 70°F (21.1°C). The master curve parameters are correlated with the aggregate and binder properties. The local predictive models are validated for the dynamic modulus and phase angle of other AC mixtures which were not used to develop the models. Statistical evaluation shows that fairly accurate estimations of dynamic modulus and phase angle of the local mixes are possible by using these local predictive models.]]></description>
      <pubDate>Tue, 20 Feb 2018 09:35:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/1497710</guid>
    </item>
    <item>
      <title>Evaluation of mixing and compaction temperatures of modified and unmodified asphalt binders</title>
      <link>https://trid.trb.org/View/1481462</link>
      <description><![CDATA[The Brookfield Rotational Viscometer (BV) is widely used to determine the mixing and compaction temperatures of different types of asphalt binders based on an equi-viscous approach, recommended by the Asphalt Institute. In this approach (referred to as BV method in this paper), temperatures correspond to a viscosity of a binder equal to 0.17±0.02 Pa.s and 0.28±0.03. Pa.s are considered to estimate a range of the mixing and compaction temperatures, respectively. Several researchers have reported that the BV method works reasonably well for unmodified binders; however, it may fail to determine a suitable range of temperatures for polymer and crumb rubber modified binders. This paper presents two different methods, namely, steady shear flow (SSF) and phase angle method (PAM), conducted using dynamic shear rheometer (DSR), to estimate the mixing and compaction temperatures of unmodified and modified asphalt binders. One unmodified binder, VG 30 and two modified and binders: polymer modified (PMB 40) and crumb rubber modified binders (CRMB 60) were used in this study. The analysis of the data showed that mixing and compaction temperatures range for unmodified binder (VG 30) determined from the BV method was 154°C to 160°C and 143°C to 148°C, respectively, which is close to the ranges mentioned in Ministry of Road Transport and Highways (MoRTH) (mixing temperature: 150°C to 156°C, and compaction temperature: >140°C). However, this method predicted approximately 18°C to 43°C and 41°C to 63°C, higher range of the mixing and compaction temperatures, respectively for modified binders (PMB 40 and CRMB 60) compared to the range listed in Indian Roads Congress (IRC):SP:53. The SSF and PAM methods estimated approximately 15°C and 50°C, less mixing and compaction temperatures, respectively, for modified binders (PMB  40 and CRMB 60) when compared with the BV method. For PMB 40, the SSF method gives approximately a similar range of mixing temperatures as mentioned in IRC:SP:53. Overall, the three methods (i.d., BV, SSF and PAM) were found to be suitable for unmodified binder, while the SSF and PAM methods worked well for modified binders. It is expected that the approaches discussed in this paper may be helpful to revise and formulate a procedure to estimate a proper range of the mixing and compaction temperatures for modified and unmodified binders.]]></description>
      <pubDate>Wed, 27 Sep 2017 10:17:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1481462</guid>
    </item>
    <item>
      <title>Evolution of energy dissipation during four-point bending of bituminous mixtures</title>
      <link>https://trid.trb.org/View/1468363</link>
      <description><![CDATA[In this investigation, the fatigue life of bituminous mixtures is characterised using the four-point bending test. Two sets of bituminous concrete samples, one produced with unmodified binder and other with plastomer-modified binder, are subjected to repeated strain-controlled sinusoidal loading at 10 Hz frequency and 20°C. The test is conducted for three different strain amplitudes of 200, 400 and 600 microstrain and the corresponding stress and strain data are collected at 1/1000 second interval. In the first approach, these data are used to calculate total energy dissipation. The dissipation due to damage is determined by separating viscoelastic dissipation from the total dissipation. For this purpose, a linear viscoelastic model is used. In the second approach, the discontinuity in the evolution of phase lag determined from the stress–strain plot is taken as the onset of fatigue damage. The fatigue failure, as quantified by these two approaches, was found to be closer to the fatigue life computed using energy ratio method.]]></description>
      <pubDate>Tue, 27 Jun 2017 16:10:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1468363</guid>
    </item>
    <item>
      <title>A novel back-calculation approach for determining the rheological properties of RAP binder</title>
      <link>https://trid.trb.org/View/1448231</link>
      <description><![CDATA[The determination of the rheological properties of the aged binder in Reclaimed Asphalt Pavement (RAP) materials is a challenging problem. Conventionally, extraction and recovery are used to obtain the RAP binder for further experimental characterisation; however, this procedure is not entirely reliable and accurate. Alternative and more precise approaches are based on asphalt mixture tests in combination with complex and sophisticated back-calculation methods, which are costly and time-consuming. In this paper a new and simple approach to estimate the rheological properties of RAP binder at intermediate temperature is proposed. This is based on Dynamic Shear Rheometer (DSR) tests performed on mortars, composed of a selected fine fraction of RAP and virgin binder, together with a new back-calculation solution. The properties of the bituminous blend of virgin and RAP binders are obtained through the manipulation of the Nielsen model equation to take into account the effects of frequency and temperature on mortar stiffness. The Voigt model is then used to estimate the complex modulus and the phase angle of the RAP binder from the complex modulus and the phase angle of the back-calculated binder blend.]]></description>
      <pubDate>Thu, 30 Mar 2017 09:56:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1448231</guid>
    </item>
    <item>
      <title>Impacts of Multiple-Polymer Components on High-Temperature Performance Characteristics of Airfield-Modified Binders</title>
      <link>https://trid.trb.org/View/1438549</link>
      <description><![CDATA[Polymer modified asphalt binders have been commonly used to improve the resistance of the airfield pavements to distresses, especially wheel rutting. The objective of this study was to investigate the rheological and chemical properties of the modified binders containing anti-rutting agent (ARA), polyethylene (PE) and styrene-butadiene-styrene (SBS) before and after a short-term aging procedure. Rotational viscosity, penetration degree, softening point as well as performance grade, multi-stress creep recovery (MSCR), frequency and amplitude sweep were performed to determine the effects of ARA and PE on rut depths at high temperatures. In addition, Fourier Transform Infrared Spectroscopy (FTIR) was conducted to determine the chemical properties of various polymerized binders. The test results showed that, as expected, the addition of PE and ARA polymer increased the rotational viscosity, softening point and rutting factor values and reduced the penetration degree. However, ARA can only increase complex modulus while PE had an influence on both the complex modulus and phase angle of the modified binders. In addition, the rising tendency of phase angle during frequency sweep test was totally different in terms of the binders with or without PE. Furthermore, the FTIR test results showed that the ARA has no significant effects on aging resistance, while the modified binders with PE have better resistance to aging.]]></description>
      <pubDate>Mon, 13 Mar 2017 16:05:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1438549</guid>
    </item>
    <item>
      <title>Generalized Regression Approach to Develop Predictive Models for Dynamic Modulus and Phase Angle of Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/1438371</link>
      <description><![CDATA[Dynamic modulus (|E*|) and phase angle (δ) are viscoelastic properties of asphalt mixtures that are necessary for determination of constitutive response of mixtures to traffic and thermal loading. These parameters are necessary for analysis and design of asphalt pavements. While a number of |E*| and δ predictive models have been developed, many of them require lab measured properties, such as, gradation and binder complex modulus (G*) for accurate predictions. Furthermore, the majority of previous work has been focused on prediction of |E*| and only few models have been explored for prediction of δ. This research utilized generalized regression modelling to develop |E*| and δ prediction models using nominal asphalt mix properties (such as, asphalt content, air void and aggregate size) that are often readily available during initial mixture design and specification process. Using nominal properties not only eliminates need for even the simplest lab tests, but also provides the pavement design engineers with the ability to conduct mechanistic analysis with reliable material properties. A total of 81 asphalt mixtures and 4374 lab measurements of |E*| and δ each were used for model development. The accuracy of prediction models is verified through statistical analysis. A case study is presented to demonstrate applicability of these models for performance predictions. The case study also presents verification that there are minimal differences in performance predictions when using predicted properties as compared to lab measured properties.]]></description>
      <pubDate>Tue, 07 Mar 2017 17:27:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/1438371</guid>
    </item>
    <item>
      <title>Development of Duplicate Shear Test for Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/1438088</link>
      <description><![CDATA[Permanent shear deformation is the main cause for rutting in asphalt concrete layers. The paper presents the development of a new test device to replicate similar loading conditions and constraints of the Superpave Shear Tester (SST). The Duplicate Shear Tester (DST) determines the mechanical average of the shear properties and responses of two specimens loaded simultaneously. The DST device is simple and inexpensive and can be used with any universal testing machine that can provide repeated dynamic and static axial loads in a temperature-controlled environment. The two most used SST tests, the Frequency Sweep Test at Constant Height (FSCH) and the Repeated Shear Test at Constant Height (RSCH) were performed with the DST device mounted inside of a UTM-25 test system.To evaluate the effectiveness of the DST, four asphalt surface mixtures were subjected to FSCH tests at 30°C and RSCH tests at 50°C. For each mixture, three pairs of specimens were tested. The data analysis indicated that the DST test is highly repetitive and reliable in measuring the shear dynamic modulus and phase angle at load frequencies between 0.5 Hz to 10 Hz, for which a variability of less than 10 percent was observed. A variability higher than 10 percent was recorded for the FSCH tests done at frequencies lower than 0.5 Hz. A variability slightly higher than 10 percent was observed in the RSCH test for the permanent shear deformation for two of the four asphalt mixtures.]]></description>
      <pubDate>Thu, 26 Jan 2017 14:32:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1438088</guid>
    </item>
    <item>
      <title>Predicting the Dynamic Modulus of Asphalt Concrete by Binder DSR Testing</title>
      <link>https://trid.trb.org/View/1417357</link>
      <description><![CDATA[This study proposes a completely new regression-based predictive model to estimate dynamic modulus (|E*|) of asphalt concrete (AC) from the dynamic shear modulus (|G(subscript b)*|) and phase angle (δ(subscript b)) of the asphalt binder used in the AC mix. Other parameters related to the aggregate gradation and volumetric are also incorporated in the model. In this study, a total of 10 AC mixes with 5 binders having different performance grades (PG) and sources were collected from the manufacturing plants. The AC mixes were compacted and cored to cylindrical specimens. After that, the samples were tested in the laboratory for |E*| at different temperatures and loading frequencies. The collected binders were tested for |G(subscript b)*| and δ(subscript b) using dynamic shear rheometer (DSR). The statistical comparison shows that a fairly accurate estimation of |E*| can be found by using this new |E*| predictive model.]]></description>
      <pubDate>Thu, 01 Sep 2016 09:06:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/1417357</guid>
    </item>
    <item>
      <title>Modifying the Viscosity Based Witczak Model and Developing Phase Angle Predictive Model for New Mexico’s Superpave Mixes</title>
      <link>https://trid.trb.org/View/1393198</link>
      <description><![CDATA[This study modifies the viscosity (η) based Witczak dynamic modulus (|E*|) predictive equation which is used in the recently developed American Association of State Highway and Transportation Officials (AASHTO)Ware pavement Mechanistic-Empirical (ME) design software. A total of 21 Superpave (SP) mixtures with different gradations and binder grades were tested for |E*| at different temperatures and frequencies of loading. Results show that the η-based Witczak model underestimates the |E*| for New Mexico’s SP mixes. Therefore, revised model is developed using regression analysis. A phase angle (ϕ) predictive model is also developed using the ϕ-values obtained during the |E*| testing. It was found that the revised η- based Witczak model determines the |E*| more accurately compared to the original η-based Witczak model.]]></description>
      <pubDate>Thu, 24 Mar 2016 10:49:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/1393198</guid>
    </item>
    <item>
      <title>Using Space Diagrams to Evaluate the Effect of Softer Binder and Warm Mix Technologies in Reclaimed Asphalt Pavement Mixtures</title>
      <link>https://trid.trb.org/View/1392559</link>
      <description><![CDATA[This study was conducted to investigate if rheological plots of the shear modulus (G*) and the phase angle (δ), commonly known as a Black Space Diagram, and binder rheological parameters derived from master curves using the Christensen-Anderson model (ω₀ – R-value Space diagrams) can be used to evaluate the binder in high Reclaimed Asphalt Pavement (RAP) mixtures in terms of aging and performance. Additionally, these diagrams were utilized to analyze the binder from the same mixtures with the incorporation of Warm Mix Asphalt (WMA) technologies. Finally, mixture performance tests were conducted to validate the results obtained from the binder plots. A Superpave mixture incorporating all virgin materials (no RAP) and a PG64-28 binder was designed. The same mixture was then designed with the incorporation of 15%, 25%, 35% and 50% RAP with the same PG64-28 binder. A PG52-34 softer binder and the PG64-28 with WMA were also used for the 35% and 50% RAP mixtures. The results from the rheological space diagrams were compared to mixture test results for rutting, moisture damage susceptibility and fatigue cracking to determine if they correlate. The rheological space diagrams indicated that increased RAP content led to a binder in the mixture that was more aged than the binder in the virgin material control mixture. The use of the softer PG52-34 binder or a WMA technology decreased the degree of aging with the softer binder being more effective than the WMA technologies. These results generally agreed with the mixture tests.]]></description>
      <pubDate>Thu, 04 Feb 2016 08:37:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1392559</guid>
    </item>
    <item>
      <title>Determination of Mixing and Compacting Temperatures for Neat and Modified Bitumen</title>
      <link>https://trid.trb.org/View/1375684</link>
      <description><![CDATA[Use of modified bitumen in hot mix asphalt has increased tremendously in the last two decades. The traditional equiviscous method used for determining the mixing and compacting temperatures for modified asphalt is based on simple viscosity measurements of asphalt, which usually results in excessive high temperatures in case of modified binders. In this study, two new methods, namely Steady Shear Flow (SSF) method and Phase angle method, have been used to determine and compare the mixing and compacting temperatures by using Dynamic Shear Rheometer (DSR) for neat bitumen and bitumen modified with 3%, 5% and 7% styrene-butadiene-styrene (SBS) and ethylene vinyl acetate (EVA). From the tests it was concluded that both Steady Shear Flow method and Phase Angle method provide lower mixing and compacting temperatures for modified bitumen compared to equiviscous method.]]></description>
      <pubDate>Wed, 25 Nov 2015 09:14:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1375684</guid>
    </item>
    <item>
      <title>Accelerated short-term ageing effects on the rheological properties of modified bitumens with similar high PG grades</title>
      <link>https://trid.trb.org/View/1350602</link>
      <description><![CDATA[The main purpose of the study was to evaluate the effects of rolling thin-film oven (RTFO) ageing on some rheological properties of modified bitumens. They are graded as PG 76-xx and were obtained from a 50/70 bitumen graded as PG 64-xx. Three types of polymers – polyethylene (PE), styrene–butadiene–styrene (SBS) copolymer and ethylene butylacrylate glycidylmethacrylate (Elvaloy®) terpolymer – and polyphosphoric acid (PPA) were selected. Ageing mainly increased the complex modulus (G*) and decreased the phase angle (δ) of the bitumens, thereby increasing their stiffness and elasticity. The existence of plateau regions in the master curves of δ for the bitumen+Elvaloy+PPA and the bitumen+SBS can be explained by the distinctive characteristics of the modifiers, since these plateaus were not observed for the other bitumens. The bitumen+SBS and the bitumen+PE showed very high sensitivity to ageing from the point of view of G* and δ, and the opposite is observed for the conventional properties.]]></description>
      <pubDate>Mon, 27 Apr 2015 09:48:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1350602</guid>
    </item>
    <item>
      <title>Predictive Models to Estimate Phase Angle of Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/1328778</link>
      <description><![CDATA[The main objective of this study was to develop predictive models to estimate the viscoelastic phase angle (ϕ) of different asphalt mixtures using robust mathematical functions and operators in the form of a powerful beta distribution format. A total of 163 conventional dense-graded asphalt concrete (DGAC), 13 asphalt-rubber asphalt concrete (ARAC) gap graded, and 7 asphalt-rubber friction course (ARFC) open-graded mixes were available, amounting to a total of 5,490 data points. The asphalt materials parameters were used to develop ϕ predictive equations for DGAC, ARAC, and ARFC mixes separately using principal component analyses techniques and mathematical regression. In addition, ϕ master curves were developed for each mix type using the predicted ϕ. The statistical goodness of fit measured for all of the predictive models, DGAC, ARAC, and ARFC, were very good to excellent with R²adj between 0.80 and 0.85, and Se/Sy less than 0.35. The performance and accuracy of the ϕ predictive models was assessed by comparing the predicted and the actual ϕ measured on similar mixtures obtained from past studies. The ϕ model predictions had very good to excellent correlations with the measured values indicated by very high R²≥90%. Overall, the models and the relationships showed low bias and high precision indicating that the newly developed ϕ models are an excellent means of acquiring the ϕ for the three different asphalt mixes in the absence of testing capabilities. Furthermore, it is envisioned that ϕ can be incorporated in futuristic sustainable flexible pavement designs and practices, complementing stiffness parameters such as moduli and contributing to a comprehensive understanding of the intricate viscoelastic characteristics of the asphalt mixes.]]></description>
      <pubDate>Wed, 29 Oct 2014 11:27:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1328778</guid>
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