Influence Of Aging On Foamed Warm Mix Asphalt
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Influence Of Aging On Foamed Warm Mix Asphalt
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Author : Sunday Akinbowale
language : en
Publisher:
Release Date : 2014
Influence Of Aging On Foamed Warm Mix Asphalt written by Sunday Akinbowale and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Asphalt categories.
Over the years, the use of warm mix in pavement structures has continued to gain increasing attention in United States because of its implicit advantages over the traditional hot mix. This has necessitated increased research efforts into understanding different aspects of its behaviour and performance. Aging of asphalt is particularly of much importance because it leads to several problems such as pavement rutting, fatigue cracking and thermal cracking. The aging that occurs during mixing and compaction is commonly referred to as short term aging while the aging that occurs during the pavement service life is called long term aging. The main reason for aging in binders is oxidation and binders become stiffer due to oxidation. Several research projects have been carried out on investigating the aging behavior of warm mix asphalt (WMA) produced by different chemical additives. But no major study has been conducted to understand the aging behavior of foamed WMA. Therefore, this study characterizes the aging behavior of foamed (WMA) as it compares to the traditional hot mix asphalt (HMA) using the Dynamic Shear Rheometer (DSR), Fourier Transforms Infrared Spectroscopy (FTIR), and Gel Permeation Chromatography (GPC) tests. Investigation of the effect of extraction and recovery with trichloroethylene on the stiffness of binders was initially carried out. In addition to preparation of mixtures, aging of binders (RTFO and PAV) and aging of mixtures (STOA and LTOA) being simulated in the laboratory using PG 70-22M and PG 64-22 binder grades, field cores were also obtained from test sections which had been in service for five years. Binders were extracted and recovered from both laboratory and field samples for subsequent physical and chemical tests. These results were analysed and used to evaluate the aging behavior of foamed WMA as it compares to HMA. It was observed that extraction and recovery procedure with trichloroethylene had minimal effect on PG 70-22M binders while it had a reductive effect on rutting and fatigue parameter values of PG 64-22 binders at different levels of aging. Both foamed WMA and HMA for PG 70-22M responded similarly to field and laboratory-simulated aging conditions. But for PG 64-22 binders, foamed WMA was found to be less susceptible to aging than the traditional HMA. Therefore, it implies that when the foamed warm mix technology is used, it may be expected to have a better performance in fatigue cracking but more susceptible to rutting or permanent deformation that takes place in pavement early years when compared to the traditional Hot Mix Asphalt.
Influence Of Warm Mix Asphalt On Aging Of Asphalt Binders
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Author : Ala R. Abbas
language : en
Publisher:
Release Date : 2014
Influence Of Warm Mix Asphalt On Aging Of Asphalt Binders written by Ala R. Abbas and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Asphalt categories.
Aging Characterization Of Foamed Warm Mix Asphalt
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Author : Mir Shahnewaz Arefin
language : en
Publisher:
Release Date : 2015
Aging Characterization Of Foamed Warm Mix Asphalt written by Mir Shahnewaz Arefin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Asphalt categories.
This study evaluated the aging characteristic of foamed warm mix asphalt (WMA) produced by water injection in comparison to traditional hot mix asphalt (HMA). Four types of asphalt binders (PG 64-22, PG 64-28, PG 70-22, PG 76-22) were used in the preparation of the foamed WMA and HMA mixtures. All mixtures were prepared using limestone aggregates with a nominal maximum aggregate size (NMAS) of 12.5 mm that met the Ohio Department of Transportation (ODOT) Construction and Material Specifications (C&MS) for Item 442 (Superpave Asphalt Concrete).The short-term and long-term aging of the asphalt binders were simulated using the rolling thin film oven (RTFO) and the pressure aging vessel (PAV), respectively, while the short-term and long-term aging of the laboratory-prepared asphalt mixtures were simulated according to AASHTO R 30 (Mixture Conditioning of Hot Mix Asphalt).The dynamic shear rheometer (DSR) was used to characterize the viscoelastic behavior of the unaged, RTFO-aged, and PAV-aged asphalt binders, while the dynamic modulus (lE*l) test was used to characterize the viscoelastic behavior of the short-term and long-term aged foamed WMA and HMA mixtures.In addition, the mechanistic-empirical pavement design guide (MEPDG) global aging model was used to predict the effect of aging on the dynamic modulus (lE*l) of foamed WMA and HMA mixtures, and the MEPDG global aging model predictions were compared to dynamic modulus (lE*l) test results obtained in the laboratory for both asphalt mixtures. By comparing the DSR test results following RTFO and PAV to those obtained for the unaged asphalt binders, it was observed that PG 64-22 was the least susceptible to aging followed by PG 70-22, PG 76-22, and PG 64-28. Similar trends were also observed from the dynamic modulus test, where little difference was noticed between the short-term and long-term aged specimens prepared using PG 64-22 for both foamed WMA and HMA mixtures.The dynamic modulus test results also revealed slightly lower lE*l values for foamed WMA mixtures in comparison to traditional HMA mixtures. This indicates that foamed WMA mixtures are slightly more susceptible to rutting than HMA mixtures. However, by comparing the dynamic modulus of the long-term aged specimens to the short-term aged specimens, it was observed that the increase in stiffness for the foamed WMA mixtures was less than that for the traditional HMA mixtures. This indicates that foamed WMA mixtures are less susceptible to aging and subsequently fatigue cracking than HMA mixtures.Finally, by the comparing the MEPDG global aging model predictions to the dynamic modulus test results for both foamed WMA and HMA mixtures, it was observed that the MEPDG global aging model provided more reasonable predictions, especially at higher frequencies, but overestimated or underestimated the dynamic modulus at lower frequencies. This was observed for both foamed WMA and HMA mixtures, which suggests that this model can be used for both types of mixtures.
Performance Evaluation Of Foamed Warm Mix Asphalt Produced By Water Injection
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Author : Ayman Ali
language : en
Publisher:
Release Date : 2013
Performance Evaluation Of Foamed Warm Mix Asphalt Produced By Water Injection written by Ayman Ali and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Asphalt categories.
In recent years, a new group of technologies has been introduced in the United States that allow producing asphalt mixtures at temperatures 30 to 100oF lower than what is used in traditional hot mix asphalt (HMA). These technologies are commonly referred to as Warm Mix Asphalt (WMA). From among these technologies, foamed WMA produced by water injection has gained increased attention from the asphalt paving industry in Ohio since it does not require the use of costly additives. This type of asphalt mixtures is advertised as an environmentally friendly alternative to traditional HMA and promoted to have better workability and compactability. In spite of these advantages, several concerns have been raised regarding the performance of foamed WMA because of the reduced production temperature and its impact on aggregate drying and asphalt binder aging. Main concerns include increased propensity for moisture-induced damage (durability) and increased susceptibility to permanent deformation (rutting). Other concerns include insufficient coating of coarse aggregates, and applicability of HMA mix design procedures to foamed WMA mixtures. This dissertation presents the results of a comprehensive study conducted to evaluate the laboratory performance of foamed WMA mixtures with regard to permanent deformation, moisture-induced damage, fatigue cracking, and low-temperature (thermal) cracking; and compare it to traditional HMA. In addition, the workability of foamed WMA and HMA mixtures was evaluated using a new device that was designed and fabricated at the University of Akron, and the compactability of both mixtures was examined by analyzing compaction data collected using the Superpave gyratory compactor. The effect of the temperature reduction, foaming water content, and aggregate moisture content on the performance of foamed WMA was also investigated. Furthermore, the rutting performance of plant-produced foamed WMA and HMA mixtures was evaluated in the Accelerated Pavement Load Facility (APLF) at Ohio University, and the long-term performance of pavement structures constructed using foamed WMA and HMA surface and intermediate courses was analyzed using the Mechanistic-Empirical Pavement Design Guide (MEPDG). Based on the experimental test results and the subsequent analyses findings, the following are the main conclusions made: In general, comparable laboratory test results were obtained for foamed WMA and HMA mixtures prepared using 30°F (16.7°C) temperature reduction, 1.8% foaming water content, and fully dried aggregates. Therefore, the performance of the resulting foamed WMA is expected to be similar to that of the HMA. Surface foamed WMA mixtures had comparable rutting performance in the APLF to that of the HMA mixtures. This was also the case for intermediate foamed WMA and HMA mixtures. These results indicate the field performance of the foamed WMA mixtures is similar to that of the HMA mixtures.
Performance Of Foamed Warm Mix Asphalt In Virginia Over Four To Six Years
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Author : Stacey D. Diefenderfer
language : en
Publisher:
Release Date : 2017
Performance Of Foamed Warm Mix Asphalt In Virginia Over Four To Six Years written by Stacey D. Diefenderfer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Asphalt concrete categories.
The Virginia Department of Transportation (VDOT) began allowing the use of warm mix asphalt (WMA) in 2008 and has become a national leader in the use of WMA technologies. Several WMA technologies were investigated in research projects prior to implementation; however, foamed WMA was not. This study was designed to evaluate the properties and performance of foamed WMA placed during the initial implementation of the technology to determine if the technology has performed as expected. Six mixtures produced using plant foaming technologies and placed between 2008 and 2010 were identified and subjected to field coring and laboratory testing to provide insight as to the performance of foamed WMA mixtures. All coring was performed in 2014, which resulted in pavement ages ranging from 4 to 6 years. Three comparable hot mix asphalt (HMA) mixtures were cored and evaluated to provide average values for comparison. All cores were tested to determine air-void contents and permeability and were subjected to dynamic modulus, repeated load permanent deformation, and Texas overlay testing. In addition, binder was extracted and recovered for performance grading. Test results found similar properties for the WMA and HMA mixtures evaluated. One WMA mixture exhibited high dynamic modulus and binder stiffness, but overlay testing did not indicate any tendency toward premature cracking. All binders were found to have aged between two and three performance grades above that which was specified at construction. WMA binders and one HMA binder aged two grades higher, and the remaining two HMA binders aged three grades, indicating a likely influence on aging from the reduced temperatures at which the early foamed mixtures were typically produced. Overall results indicated that foamed WMA should be expected to perform similarly to HMA. WMA has been fully adopted by VDOT as an alternative to HMA since 2008; however, at the time of implementation of foamed WMA, no studies had been conducted by VDOT to assess the performance of WMA relative to that of HMA. This study validated the assumption that the properties and performance of foamed WMA are similar to those of HMA.
Evaluation Of Short Term Aging Effect Of Hot Mix Asphalt Due To Elevated Temperatures And Extended Aging Time
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Author : Rubben Lolly
language : en
Publisher:
Release Date : 2013
Evaluation Of Short Term Aging Effect Of Hot Mix Asphalt Due To Elevated Temperatures And Extended Aging Time written by Rubben Lolly and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Binders (Materials) categories.
Heating of asphalt during production and construction causes the volatilization and oxidation of binders used in mixes. Volatilization and oxidation causes degradation of asphalt pavements by increasing the stiffness of the binders, increasing susceptibility to cracking and negatively affecting the functional and structural performance of the pavements. Degradation of asphalt binders by volatilization and oxidation due to high production temperature occur during early stages of pavement life and are known as Short Term Aging (STA). Elevated temperatures and increased exposure time to elevated temperatures causes increased STA of asphalt. The objective of this research was to investigate how elevated mixing temperatures and exposure time to elevated temperatures affect aging and stiffening of binders, thus influencing properties of the asphalt mixtures. The study was conducted in two stages. The first stage evaluated STA effect of asphalt binders. It involved aging two Performance Graded (PG) virgin asphalt binders, PG 76-16 and PG 64-22 at two different temperatures and durations, then measuring their viscosities. The second stage involved evaluating the effects of elevated STA temperature and time on properties of the asphalt mixtures. It involved STA of asphalt mixtures produced in the laboratory with the PG 64-22 binder at mixing temperatures elevated 25OF above standard practice; STA times at 2 and 4 hours longer than standard practices, and then compacted in a gyratory compactor. Dynamic modulus (E*) and Indirect Tensile Strength (IDT) were measured for the aged mixtures for each temperature and duration to determine the effect of different aging times and temperatures on the stiffness and fatigue properties of the aged asphalt mixtures. The binder test results showed that in all cases, there was increased viscosity. The results showed the highest increase in viscosity resulted from increased aging time. The results also indicated that PG 64-22 was more susceptible to elevated STA temperature and extended time than the PG 76-16 binders. The asphalt mixture test results confirmed the expected outcome that increasing the STA and mixing temperature by 25oF alters the stiffness of mixtures. Significant change in the dynamic modulus mostly occurred at four hour increase in STA time regardless of temperature.
Isolated Or Coupled Oxidative Moisture And Freeze Thaw Effects On Warm Mix Asphalt
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Author : Carl Pittman
language : en
Publisher:
Release Date : 2018
Isolated Or Coupled Oxidative Moisture And Freeze Thaw Effects On Warm Mix Asphalt written by Carl Pittman and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
This thesis aims to contribute to the growing body of warm mix asphalt (WMA) research by evaluating the differences in behavioral properties of three WMA mixtures, representing the three warm mix technology (WMT) categories (foaming, chemical additives, and organic waxes), relative to a control hot mix asphalt (HMA) in a specific set of conditions which is not well documented in literature. These conditions are: plant produced mixtures with all virgin aggregates and binder (i.e. no recycled materials) and no additives other than the warm mix technology. These mixtures were evaluated at low, intermediate, and high testing temperatures before and after a set of conditioning protocols (CPs), which utilized varying levels of isolated and combined oxidative, moisture, and freeze-thaw damage. A key feature of this thesis is that damage induced by these CPs has been benchmarked relative to measured field aging effects through studies which evaluated the three WMA mixtures and one HMA mixture used to obtain the results presented here, along with additional mixtures not considered in this thesis.
Warm Mix Asphalt Study
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Author : Frank Farshidi
language : en
Publisher:
Release Date : 2013
Warm Mix Asphalt Study written by Frank Farshidi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Asphalt-rubber categories.
Advances In Functional Pavements
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Author : Yuqing Zhang
language : en
Publisher: CRC Press
Release Date : 2023-11-09
Advances In Functional Pavements written by Yuqing Zhang and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-11-09 with Technology & Engineering categories.
Advances in Functional Pavements is a collection of papers presented at the 7th Chinese-European Workshop (CEW) on Functional Pavement (Birmingham, UK, 2-4 July 2023). The focus of the CEW series is on field tests, laboratory test methods and advanced analysis techniques, and covers analysis, material development and production, experimental characterization, design and construction of pavements. The main areas covered by the book include: Green pavements for circular and low-carbon economy Intelligent pavements for future and smart cities Durable pavements for long-life infrastructures Safe pavements for user-friendly build environments Advances in Functional Pavements aims at contributing to the establishment of a new generation of pavement design methodologies in which rational mechanics principles, advanced constitutive models and advanced material characterization techniques shall constitute the backbone of the design process. The book will be much of interest to professionals, academics and practitioners in pavement engineering and related disciplines as it should assist them in providing improved road pavement infrastructure to their stakeholders. .
Isolated Or Coupled Oxidative Moisture And Freeze Thaw Effects On Warm Mix Asphalt
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Author :
language : en
Publisher:
Release Date : 2018
Isolated Or Coupled Oxidative Moisture And Freeze Thaw Effects On Warm Mix Asphalt written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
This thesis aims to contribute to the growing body of warm mix asphalt (WMA) research by evaluating the differences in behavioral properties of three WMA mixtures, representing the three warm mix technology (WMT) categories (foaming, chemical additives, and organic waxes), relative to a control hot mix asphalt (HMA) in a specific set of conditions which is not well documented in literature. These conditions are: plant produced mixtures with all virgin aggregates and binder (i.e. no recycled materials) and no additives other than the warm mix technology. These mixtures were evaluated at low, intermediate, and high testing temperatures before and after a set of conditioning protocols (CPs), which utilized varying levels of isolated and combined oxidative, moisture, and freeze-thaw damage. A key feature of this thesis is that damage induced by these CPs has been benchmarked relative to measured field aging effects through studies which evaluated the three WMA mixtures and one HMA mixture used to obtain the results presented here, along with additional mixtures not considered in this thesis.