Multi-Level Laboratory Performance Evaluation of Conventional and High Polymer-Modified Asphalt Mixtures

2021 ◽  
pp. 036119812110566
Author(s):  
Jhony Habbouche ◽  
Ilker Boz ◽  
Brian K. Diefenderfer ◽  
Sungho Kim
Keyword(s):  
Comprehensive Evaluation ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
High Polymer ◽  
Binder Type ◽  
Polymer Modified Asphalt ◽  
Virginia Department ◽  
Long Term Performance ◽  
Term Performance

Asphalt concrete (AC) overlays have been one of the most common treatments used by the Virginia Department of Transportation (VDOT) for maintaining/rehabilitating pavements. However, when the overlay is placed on existing composite pavements or cracked AC pavements, differential movements across any cracks or joints can result in physical tearing of the AC overlay. Thus, the long-term performance of many AC overlays will highly depend on their ability to resist cracking. The purpose of this study was to assess the viability of using high polymer-modified (HP) AC mixtures in Virginia as a crack mitigation technique or when deemed appropriate as a tool for increased resistance to rutting and cracking on higher volume facilities. Another objective was to assess the ability of various testing protocols to discern the performance of pavements through a comprehensive evaluation of three conventional polymer-modified (PMA) and five HP field-produced mixtures placed in Virginia. This included laboratory testing at multiple levels of complexity (basic, intermediate, and advanced) on collected asphalt binders, plant-produced asphalt mixtures, and field cores. The performance characteristics of PMA and HP mixes were evaluated in the laboratory in relation to durability and resistance to rutting and cracking. Based on the mixes tested, stone matrix asphalt (SMA) mixes showed better performance than dense-graded surface mixes (SM) regardless of the asphalt binder type. Moreover, HP mixes showed better performance than PMA mixes regardless of the mixture type. Overall, SMA-HP mixes showed the most promising performance among all evaluated mixes.

Fatigue-Based Structural Layer Coefficient of High Polymer-Modified Asphalt Mixtures

2020 ◽  
Vol 2674 (3) ◽  
pp. 232-247 ◽  
Author(s):  
Jhony Habbouche ◽  
Elie Y. Hajj ◽  
Peter E. Sebaaly ◽  
Adam J. Hand
Keyword(s):  
Positive Impact ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Engineering Properties ◽  
High Polymer ◽  
Florida Department ◽  
Mechanistic Analysis ◽  
Polymer Modified Asphalt ◽  
And Performance ◽  
Structural Layer

Florida Department of Transportation uses the 1993 AASHTO guide to conduct new and rehabilitation designs for all the state’s flexible pavements. Based on previous experience, a structural layer coefficient of 0.44 was found to be well representative of the department’s conventional polymer-modified (PMA) asphalt concrete (AC) mixtures. If the positive impact of the polymer on the layer is assumed to be maintained at higher contents, then the use of high polymer-modified (HP) asphalt binder may lead to a higher AC structural layer coefficient and a reduced AC layer thickness for the same design traffic and serviceability design loss. The objective of this paper was to determine a fatigue-based structural layer coefficient for asphalt mixtures that contain HP binder using comprehensive mechanistic analyses. This approach relied on combining measured engineering properties and performance characteristics of AC mixtures with advanced flexible pavement modeling (3D-Move). A total of eight PMA and eight HP AC mixtures were designed and evaluated in the laboratory. Overall, the HP AC mixtures showed similar or lower dynamic modulus and better fatigue performance models when compared with those of their respective PMA AC mixtures. However, the fatigue-based structural layer coefficients, determined via mechanistic analysis using the service life approach, ranged between 0.33 (lower than 0.44) and 1.32 (greater than 0.44). Using advanced statistical analyses, a fatigue-based structural layer coefficient of 0.54 was determined for HP AC mixtures. This coefficient should still be verified for other modes of distress.

scholarly journals Influence of Selected Warm Mix Asphalt Additives on Cracking Susceptibility of Asphalt Mixtures

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 202 ◽  
Author(s):  
Marcin Stienss ◽  
Cezary Szydlowski
Keyword(s):  
Low Temperature ◽  
Warm Mix Asphalt ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Test Results ◽  
Specimen Test ◽  
Low Temperature Cracking ◽  
Long Term Performance ◽  
Term Performance

Warm mix asphalt (WMA) has been widely accepted as a future asphalt paving technology. Besides clear advantages, there are still some concerns regarding durability and long-term performance of pavements made with this type of asphalt mixtures. One of the most important issues is low temperature behaviour of WMA because certain additives used for temperature reduction can affect bitumen properties. This paper presents the evaluation of low-temperature properties of laboratory-produced asphalt concrete for wearing course with selected WMA additives. One type of bitumen with paving grade 50/70 and five WMA additives of different nature (organic, surface tension reducer and combination of both) were used in this study. The production and compaction temperature of mixtures containing WMA additives was 25 °C lower in comparison with the temperature of the reference mix. To assess the susceptibility of WMA to low-temperature cracking, Semi-Circular Bending (SCB) and Thermal Stress Restrained Specimen Test (TSRST) were used. Supplementary rating was made by analysing Bending Beam Rheometer (BBR) test results of asphalt binders.

Laboratory Evaluation of a Plant-Produced High Polymer–Content Asphalt Mixture

2017 ◽  
Vol 2631 (1) ◽  
pp. 144-152 ◽  
Author(s):  
Benjamin F. Bowers ◽  
Stacey D. Diefenderfer ◽  
Brian K. Diefenderfer
Keyword(s):  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Aggregate Size ◽  
Asphalt Binders ◽  
Laboratory Evaluation ◽  
Maximum Aggregate Size ◽  
Polymer Content ◽  
High Polymer ◽  
Modified Binder ◽  
Virginia Department

Reflective cracking in asphalt overlays placed over jointed concrete pavements is of major concern in Virginia, as well as nationally, and has generated interest in various reflective crack mitigation techniques that are easy to implement. One technique is the use of binder modifiers, such as asphalt rubber, polymer-modified asphalt binders, or high polymer–content (HP) modified binders. In the summer of 2014, the Virginia Department of Transportation placed an HP asphalt mixture produced by using an asphalt binder that contained approximately 7.5% styrene-butadiene-styrene polymer in a trial section within a subdivision as a low-risk means to assess constructability and laboratory performance. The HP mixture was evaluated in comparison with a typical surface asphalt mixture with a 9.5-mm nominal maximum aggregate size, as a control. Testing was performed on specimens fabricated from reheated control and HP mixture samples, as well as on specimens fabricated from site-compacted samples and road cores of the HP mixture. In addition, binder grading was performed on the control binder and modified binder. The HP binder was significantly more elastic than the control binder. Comparable dynamic moduli were found for reheated mixture specimens, although site-compacted and road core specimens from the HP mixture had lower stiffness than the control mixture. The HP mixture performed better in rutting and in fatigue. The Texas overlay test indicated similar crack resistance between the two mixtures; however, measured loads of the HP specimens were nearly half those of the control specimens. The results of laboratory testing indicated that the mixture incorporating the HP binder should have a far greater fatigue life and rut resistance than the control mixture.

scholarly journals Mechanical Characteristics of Graphene Nanoplatelets-Modified Asphalt Mixes: A Comparison with Polymer- and Not-Modified Asphalt Mixes

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2434
Author(s):  
Laura Moretti ◽  
Nico Fabrizi ◽  
Nicola Fiore ◽  
Antonio D’Andrea
Keyword(s):  
Fatigue Resistance ◽  
Graphene Nanoplatelets ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Asphalt Mixes ◽  
Modified Asphalt ◽  
Bituminous Mixtures ◽  
Water Sensitivity ◽  
Polymer Modified Asphalt ◽  
Mechanical Performances

In recent years, nanotechnology has sparked an interest in nanomodification of bituminous materials to increase the viscosity of asphalt binders and improves the rutting and fatigue resistance of asphalt mixtures. This paper presents the experimental results of laboratory tests on bituminous mixtures laid on a 1052 m-long test section built in Rome, Italy. Four asphalt mixtures for wearing and binder layer were considered: two polymer modified asphalt concretes (the former modified with the additive Superplast and the latter modified with styrene–butadiene–styrene), a “hard” graphene nanoplatelets (GNPs) modified asphalt concrete and a not-modified mixture. The indirect tensile strength, water sensitivity, stiffness modulus, and fatigue resistance of the mixtures were tested and compared. A statistical analysis based on the results has shown that the mixtures with GNPs have higher mechanical performances than the others: GNP could significantly improve the tested mechanical performances; further studies will be carried out to investigate its effect on rutting and skid resistance.

Effectiveness of Loaded Wheel Tracking Test to Ascertain Moisture Susceptibility of Asphalt Mixtures

2021 ◽  
pp. 036119812110363
Author(s):  
Moses Akentuna ◽  
Louay N. Mohammad ◽  
Sanchit Sachdeva ◽  
Samuel B. Cooper ◽  
Samuel B. Cooper
Keyword(s):  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Creep Recovery ◽  
Moisture Susceptibility ◽  
Freeze Thaw ◽  
Wheel Tracking ◽  
Mixture Samples

Moisture damage of asphalt mixtures is a major distress affecting the durability of asphalt pavements. The loaded wheel tracking (LWT) test is gaining popularity in determining moisture damage because of its ability to relate laboratory performance to field performance. However, the accuracy of LWT’s “pass/fail” criteria for screening mixtures is limited. The objective of this study was to evaluate the capability of the LWT test to identify moisture susceptibility of asphalt mixtures with different moisture conditioning protocols. Seven 12.5 mm asphalt mixtures with two asphalt binder types (unmodified PG 67-22 and modified PG 70-22), and three aggregate types (limestone, crushed gravel, and a semi-crushed gravel) were utilized. Asphalt binder and mixture samples were subjected to five conditioning levels, namely, a control; single freeze–thaw-; triple freeze–thaw-; MiST 3500 cycles; and MiST 7000 cycles. Frequency sweep at multiple temperatures and frequencies, and multiple stress creep recovery tests were performed to evaluate asphalt binders. LWT test was used to evaluate the asphalt mixture samples. Freeze–thaw and MiST conditioning resulted in an increase in stiffness in the asphalt binders as compared with the control. Further, freeze–thaw and MiST conditioning resulted in an increase in rut depth compared with the control asphalt mixture. The conditioning protocols evaluated were effective in exposing moisture-sensitive mixtures, which initially showed compliance with Louisiana asphalt mixture design specifications.

A critical review of high polymer-modified asphalt binders and mixtures

2018 ◽  
Vol 21 (6) ◽  
pp. 686-702 ◽  
Author(s):  
Jhony Habbouche ◽  
Elie Y. Hajj ◽  
Peter E. Sebaaly ◽  
Murugaiyah Piratheepan
Keyword(s):  
Critical Review ◽  
Asphalt Binders ◽  
High Polymer ◽  
Modified Asphalt ◽  
Polymer Modified Asphalt

Nonlinear Viscoelastic Response of Crumb Rubber Modified Asphalt Binder Under Large Strains

2020 ◽  
Vol 2674 (3) ◽  
pp. 139-149
Author(s):  
Saqib Gulzar ◽  
B. Shane Underwood
Keyword(s):  
Asphalt Binder ◽  
Crumb Rubber ◽  
Oscillatory Shear ◽  
Asphalt Binders ◽  
Large Strains ◽  
Viscoelastic Response ◽  
Modified Asphalt ◽  
Nonlinear Viscoelastic ◽  
Modified Asphalt Binder ◽  
Polymer Modified Asphalt

Agencies have been increasing their use of polymer modified asphalt binders in recent years to address performance issues and lengthen the useful life of their pavements. When deployed these materials likely experience strain levels exceeding their linear viscoelastic (LVE) limits. The same situation exists in non-polymer modified asphalt binders as well, but the effect may be more pronounced in polymer modified systems because of their bi-phasic nature. In this study, terminally blended crumb rubber (CR-TB) modified asphalt is studied to understand and quantify the nonlinear viscoelastic response under large strains. The CR-TB binders are extensively used in pavements subjected to high vehicular loads and extreme climatic conditions; thereby, their response under large strains becomes more critical. The current standard characterization techniques are based on LVE response using small amplitude oscillatory shear rheology only and do not consider the behavior of binders under large strains. In this study, large amplitude oscillatory shear (LAOS) rheology is used as a framework to more thoroughly investigate the complete response of the CR-TB modified asphalt binder under large strains at 30°C, 40°C, 50°C, and 60°C and at the frequencies of 0.5, 1, and 5 Hz. The LAOS response is analyzed using Fourier-transform rheology and the orthogonal stress decomposition method involving Chebyshev polynomial representation. It is found that nonlinearity manifests greatly in this study material as strain levels increase and frequencies decrease. The relative nonlinearity increases with increasing strain amplitude and is more significant towards lower end of the tested temperature range. The CR-TB binder shows strain-stiffening/softening and shear-thinning/thickening behavior depending upon a specific temperature, strain level, and frequency.

Hot Mix Asphalt Rubber Applications in Virginia

1996 ◽  
Vol 1530 (1) ◽  
pp. 18-24 ◽  
Author(s):  
G. W. Maupin
Keyword(s):  
Department Of Transportation ◽  
Short Term ◽  
Ground Tire Rubber ◽  
Asphalt Rubber ◽  
Evaluation Time ◽  
Different Types ◽  
Virginia Department ◽  
Long Term Performance ◽  
Term Performance

Four test sections using asphalt rubber hot mix were placed in Virginia from 1990 to 1993. These installations were to familiarize contractors and Virginia Department of Transportation personnel with the construction process and compare the performance of different types of mixes containing ground tire rubber. The MacDonald and Rouse wet processes were used successfully. Dense graded surface mixes, a gap-graded surface mix, and a base mix were manufactured. A stress-absorbing membrane interlayer was also used on one project in an attempt to deter or eliminate various types of cracking. The asphalt rubber mixes have performed as well as the conventional mixes over the short term. More evaluation time is needed to determine if long-term performance of the asphalt rubber mixes is superior to conventional mixes. The asphalt rubber mixes cost 64 to 102 percent more than conventional mixes. This cost would probably decrease if substantial quantities were placed.

scholarly journals Mechanistic-empirical evaluation of specific polymer-modified asphalt binders effect on the rheological performance

2020 ◽  
Vol 103 (4) ◽  
pp. 003685042095987
Author(s):  
Ghazi G Al-Khateeb ◽  
Waleed Zeiada ◽  
Mohammed Ismail ◽  
Ahmad Shabib ◽  
Adel Tayara
Keyword(s):  
Rheological Properties ◽  
Laboratory Tests ◽  
Complex Modulus ◽  
Heavy Traffic ◽  
Asphalt Binder ◽  
Empirical Evaluation ◽  
Asphalt Binders ◽  
Modified Asphalt ◽  
Pavement Structures ◽  
Polymer Modified Asphalt

Major distresses such as rutting, fatigue, and thermal cracking are facing asphalt pavement structures due to continuous heavy traffic loading and climate change. The modification of asphalt binders (one of the main components of the asphalt paving mix) has the potential to mitigate distresses through using different additives. Polymer modified asphalt (PMA) binders showed a noticeable resistance to pavement distresses as reported in previous studies. The present study aims to evaluate the effect of polymer modification on the rheological properties of asphalt binders through laboratory tests. The polymers included styrene-butadiene-styrene (SBS) and epolene emulsifiable (EE2) types. The 60/70 binder was used as a control for comparison. The Mechanistic-Empirical Pavement Design Guide (MEPDG) was also utilized to simulate the effect of PMA binders on the rheological properties under different climatic conditions and structural capacities. Additionally, the MEPDG was further utilized to compare the effect of asphalt binders on rheological properties using four different binder input levels. Findings of the study showed that laboratory tests experienced varying outcomes regarding the most efficient asphalt binder by means of distresses resistance. However, the MEPDG evaluation showed that the overall ranking of asphalt binders positively impacting the rheological properties was as following: (1) 4.5% EE2 PMA, (2) 4% EE2 PMA, (3) 60/70 binder, (4) 5% SBS PMA, and (5) 4% SBS PMA binders. Furthermore, statistical analysis illustrated that the effect of using different binder input levels on the performance of pavement varied relatively to the evaluated distresses. The analysis showed that using different binder input levels would affect, to a certain extent, the asphalt binder influence on rheological properties only when evaluating rutting and fatigue distresses. Therefore, it is recommended that precise asphalt binder inputs, that is, shear complex modulus (G*) and phase angle (δ) are used when designing pavement structures in regions with hot and mild climate conditions.

Recycled Polyethylene Modified Asphalt Binders and Mixtures: Performance Characteristics and Environmental Impact

2022 ◽  
pp. 036119812110657
Author(s):  
Ibrahim A. Abdalfattah ◽  
Walaa S. Mogawer ◽  
Kevin D. Stuart
Keyword(s):  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Dry Process ◽  
Modified Asphalt ◽  
Wet Process ◽  
Melted Snow ◽  
Recycled Polyethylene ◽  
Asphalt Paving

This study addresses the effects of recycled polyethylene (RPE) on the performances of both asphalt binders and asphalt mixtures. Whether using RPE in an asphalt mixture might leach harmful chemicals into rainwater or melted snow was also determined. Two processes, wet and dry, were used to formulate the RPE modified asphalt binders and mixtures. In the wet process, RPE was added to asphalt binder. In the dry process, it was added to heated aggregates. RPE from two sources and PG 64-22 virgin asphalt binders from two sources were used in this study. In conclusion, RPE improved the rutting resistance of the asphalt binders and asphalt mixtures. However, it had adverse effects on their resistance to intermediate-temperature and non-load associated cracking. The dry process could produce a mixture with a higher RPE dosage compared with the wet process using one virgin asphalt binder but not the other; thus, the virgin asphalt binder source was a significant factor for the dry process. Based on an embryotoxicity test, it was found that RPE can be used by the asphalt paving industry without creating any significant environmental risks.

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