Download or read book The Effect of Mixing Moisture Oxidative Aging and Tire Pressures on the Performance of Asphalt Mixes written by Ok-kee Kim and published by . This book was released on 1987 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research undertaken consisted of the study of three topics affecting the performance of asphalt concrete mixtures, that is, mixing moisture, oxidative aging and higher tire pressures and axle loads. This thesis presents the findings of the research comprising these three topics. In the first study, the effects of mixing moisture (0,1,3%) and additives (lime, Pavebond Special) on performance of asphalt mixtures were evaluated using repeated load diametral testing of laboratory samples in terms of resilient modulus, fatigue life, and permanent deformation. To evaluate the long-term durability of mixes, the modified Lottman conditioning procedure was used. Test results show that inferior performance occurred for mixes with 3% moisture and the addition of lime resulted in distinct improvement of performance for moist mixtures. In the second study, the effects of oxidative aging on asphalt mixtures used in the construction of three projects in Oregon were evaluated. The repeated load diametral test for mixtures and Fraass test for asphalt cements were used. A modified Pressure Oxidation Bomb (POB) laboratory accelerated aging method with pure oxygen was adopted. As evaluation parameters, the modulus ratio and Fraass breaking temperature are good indicators of the aging rate of mixtures and asphalt cements, respectively. The third study, the effect of increased axle loads and tire pressures of trucks on the performance of asphalt concrete pavements, included a survey of existing truck operating characteristics in Oregon and an investigation of the current mix design criteria. In particular, stability of asphalt mixtures was evaluated. Six different aggregate gradations including the Fuller maximum density gradation using aggregate from four different sources were used. The correlation analyses between creep behavior and mix design criteria of asphalt mixtures were made. The results of the survey showed that 87% of the tires were of radial construction, and the average measured tire pressures of radial and bias are 102 and 82 psi, respectively. Theoretical equivalency factors taking into account the effect of tire pressures were developed. A 25% increase in tire pressure could result in a 40 to 60% increase in equivalency for a dual tired single axle of 18 kips and a tandem axle of 34 kips.

Download or read book Effect of Moisture and Aging on Asphalt Pavement Life Effect of aging written by and published by . This book was released on 1986 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1987 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Moisture and Aging on Asphalt Pavement Life Effect of moisture written by and published by . This book was released on 1986 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Index to American Doctoral Dissertations written by and published by . This book was released on 1989 with total page 1252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Capturing Individual Or Combined Environmental Effects from Longer Term Field Aging of Asphalt Mixtures written by Rabeea Waheed Bazuhair and published by . This book was released on 2019 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, asphalt mixtures can be complex and have many ingredients to meet economic, performance, and/or environmental requirements. Economic and environmental factors have been driving performance in the positive direction for rutting, but the negative direction for brittleness, cracking, and overall durability. Recent research has also shown that two of the national standards to assess aging or effects of environmental factors (AASHTO T283 and R30) do not always simulate the amount of aging or behaviors mentioned in the documents. Also, these methods generally view one environmental effect at a time, and do not consider simultaneous environmental effects on aging (e.g. oxidation, moisture, freeze-thaw effects). However, pavements are exposed to combined environmental effects. As such, there is a lack of understanding of the combined environmental effects on asphalt pavement, and improve methods are needed for laboratory settings, resulting in less than optimal design and materials selection protocols. This dissertation focuses on investigating combined environmental effects of oxidation, moisture, and freeze-thaw. The dissertation includes four years of field aging of plant mixed asphalt mixtures containing no recycled materials and three different warm mix technologies that were also exposed to eight laboratory conditioning protocols including individual and combined environmental effects of oxidation, moisture and freeze-thaw to investigate mixture properties measured at high, intermediate, and low temperatures with several mixture tests that were complimented with tests on recovered binder. Major findings are summarized below: • Cantabro mass loss captured individual and combined effects damage in laboratory and field conditions better than other mixture testing utilized herein and was recommended for mixture assessment. • Laboratory conditioning protocols with combined effects were the only ones able to consistently represent four or more years of field aging in the Mississippi climate. • Field aging of laboratory compacted specimens in PVC sleeves did not fully represent field aging of field placed pavement. Temperature and moisture conditions varied between the two cases. • Use of Cantabro mass loss and laboratory conditioning consisting of hot air, hot water, and freeze-thaw conditions was shown to provide combined effects improvements relative to at least some typical practices. Guidance was provided on how to use these tools to assess combined effects.

Download or read book Asphalt Paving Technology 2012 written by Eugene Skok and published by DEStech Publications, Inc. This book was released on 2012-12-21 with total page 870 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises over 30 new and not previously published technical papers from the Association of Asphalt Paving Technologists on all phases of asphalt research and applications, including mixing, mixture elements, and testing. Includes an accompanying CD-ROM.

Download or read book Influence of Mixture Characteristics on the Oxidative Aging of Asphalt Binders written by Nathaniel Evan Morian and published by . This book was released on 2014 with total page 1802 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research effort focused on the evaluation of asphalt mixtures with respect to thermal cracking. Preliminary investigations soon indicated that a fundamental evaluation of thermal cracking was highly dependent upon the more complicated understanding of asphalt binder oxidation. The oxidation of asphalt binders within an asphalt mixture were understood to potentially be influenced by the mixture characteristics (i.e. air void levels, binder content, etc.) and aggregate properties (i.e. aggregate absorption, gradation, etc.). Therefore, this study was conducted in order to investigate and quantify the effects different aggregate sources and mixture properties may have on the oxidation and thermal cracking performance of asphalt mixtures. The investigation specifically focused on quantifying the oxidation of the asphalt binder alone and as part of the asphalt mixture when subjected to isothermal oven aging. The oxidation parameters of pan-aged asphalt binders were quantified, according to the standard of practice in the industry. These parameters were then compared to extracted and recovered mixture-aged asphalt binders to examine the influence of the main aggregate and mixture factors on the binder oxidation. The study observed differences between the pan-aged and mixture-aged asphalt binders in terms of oxidation kinetics, rheological measures, and the combined effect represented as the hardening susceptibility. Further evaluation of the binder oxidation based upon the dynamic modulus measures indicated marked influences of the mixture characteristics, the individual component materials, and the interactions between the investigated factors. Differentiation of the experimental factors was further identified by the newly developed low-temperature evaluation method, Uniaxial Thermal Stress and Strain Test (UTSST). The UTSST provides a fundamental approach to characterize the thermo-viscoelastic properties of asphalt mixtures permitting the pragmatic evaluation of changes in the stiffness and overall behavior of mixtures as a function of oxidative aging. Five distinct stages in the UTSST modulus were identified as thermo-viscoelastic properties, which are identified as a function of temperature: viscous softening, viscous-glassy transition, glassy hardening, crack initiation, and fracture stages. Through consideration of the thermo-viscoelastic properties, marked differences in the binder oxidation were noted between the experimental factors. Typically, decreases in the viscous response of the mixtures as well as increases in both the stiffness and brittle behavior were observed with aging. The evaluation method provides definitive measures to monitor multiple aspects of the performance of asphalt mixtures subjected to thermal loading.

Download or read book Implication of Aggregates in the Design Construction and Performance of Flexible Pavements written by Hans G. Schreuders and published by ASTM International. This book was released on 1989 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of the Effect of Oxidative Aging on Asphalt Mixtures for Pavement Performance Prediction written by Farhad Yousefi Rad and published by . This book was released on 2018 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book THE LABORATORY PERFORMANCE AND AGING CHARACTERISTICS OF RUBBER MODIFIED ASPHALT MIXTURE USING A DRY PROCESS written by and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : The accumulation of waste tires generates severe environmental issues. Using crumb rubber processed from waste tires on the pavement could relieve the pressure of waste tire on the environment and improve the performance of the pavement as well. The application of crumb rubber on the pavement using the dry process was proved to be a cost-effective strategy in some projects, however, the interaction between the rubber and asphalt binder was unknown in the rubber modified asphalt mixture using the dry process, especially when reclaimed asphalt pavement was adopted. The performance improvement of the rubber particle to the asphalt mixture was closely related to the interaction. The influence of aging on the characteristics of rubber modified asphalt mixture using the dry process is critical to its long-term performance. The scope of the dissertation is to evaluate the performance of rubber modified asphalt mixture using a dry process when reclaimed asphalt pavement was adopted. The influence of aging on the characteristics of the rubber modified asphalt mixture and the extracted asphalt binder were investigated. This dissertation proposed the volumetric design of rubber modified asphalt mixture using the dry process. The aggregate gradation determination, rubber modified asphalt mixture preparation, design binder content determination, and moisture susceptibility evaluation were proposed. The quality control of the laboratory mixture design procedure was critical to guarantee the consistency of the asphalt mixture design in the laboratory and the results of mixture construction in the plant. The high temperature rutting performance and the low temperature cracking performance of plant mixed and laboratory compacted asphalt mixture was evaluated. The influence of various factors, which included mixture design parameters of the asphalt mixture (nominal maximum aggregate size, reclaimed asphalt pavement content, and asphalt content), rubber modification, mixture air void content, test temperature, and aging procedure, on the rutting and low temperature characteristics of asphalt mixtures were evaluated. Based on the evaluation of different assessment parameters, the rubber addition and the rubber addition and aging were the two most critical factors that influenced the rutting and low temperature cracking performance of different asphalt mixtures. The effect of the Trichloroethylene solvent in asphalt binder was investigated, and the extracted asphalt binder was assessed and compared with the base asphalt binder and rubber modified base asphalt binder. Both the existence of Trichloroethylene and the content of Trichloroethylene had a significant influence on the |G*| of unaged and PAV aged asphalt binder. The Trichloroethylene in the extracted asphalt binder significantly influenced the actual performance of the asphalt binder in the reclaimed asphalt binder, thus potentially compromising the success mixture design. The modified extraction procedure was proposed to improve the accuracy of the extraction procedure. The rubber particles in the asphalt mixture using the dry process were not totally interacted with asphalt binder, only the interacted rubber particles were extracted, and the influence of the interacted rubber particle was assessed. The aged asphalt binder weakened the low temperature performance of the extracted asphalt binder. The aged asphalt binder and rubber in extracted asphalt binder guaranteed the asphalt binder to sustain heavy traffic load, thus improved the permanent deformation resistance of asphalt binder.

Download or read book Effect of Testing Conditions on Laboratory Moisture Test for Asphalt Mixtures written by Junyan Yi and published by . This book was released on 2016 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Moisture damage is one of the major causes of premature failure in asphalt pavements, and it also accelerates the severity of other distresses. To date, no moisture test has been widely accepted that is reliable and practical in predicting the field moisture performance of the asphalt mix during the design stage. One reason is because the sample conditioning methods cannot represent the field conditions, resulting in inconsistent results with the field performance of some mixtures. Taken into account this concern, this paper investigates how different testing conditions, including sample preparation, moisture saturation, and loading methods, can affect the results of laboratory moisture tests. In conclusion, it is found that the degree of vacuum pressure for achieving moisture saturation and air voids distribution has a significant impact on the moisture testing results. Multiple freeze-thaw cycles have a limited effect on the variation of mechanical performance (i.e., compressive dynamic modulus). If one or several freeze-thaw cycles are to be used in a moisture test, the effect of aging should be considered. It is recommended that a sample without coring and cutting should be used for a moisture test as the coring and cutting process is found to change the air voids distribution, i.e., the percent of connected air voids, thus making the sample not representative to the field condition. Finally, the moisture test results are more sensitive under tension mode than under compression mode.

Download or read book The Effects of Asphalt Binder Oxidation on Hot Mix Asphalt Concrete Mixture Rheology and Fatigue Performance written by Sung Hoon Jung and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Asphalt oxidation causes major changes to binder properties and is hypothesized to be a major contributor to age-related pavement failure such as fatigue cracking. Extensive laboratory aging research has been done to assess the effects of oxidation on binder properties. Previous work shows binder oxidation makes the binder stiffer and more brittle, leading to higher binder stresses under a given deformation. Failure occurs when these stresses exceed the strength of the binder. However, binder oxidation in pavements has not been studied in the same detail as laboratory aging of neat binders. The impact of binder oxidation on long-term pavement performance has been either underestimated or ignored. This research includes studies of binder oxidation in Texas pavements to compare the field aging with laboratory neat binder aging, the impact of binder oxidation on HMAC mixture aging and HMAC mixture fatigue performance, and fundamental rheological property changes of the binder and the mixture. Binder oxidation is studied in fifteen pavements from locations across Texas. Results indicate that unmodified binders in pavements typically oxidize and harden to a degree that exceeds generally accepted pavement aging assumptions. This hardening may also extend much deeper into the pavement than has been previously assumed or documented. Data suggest that pavements can oxidize at rates surprisingly uniform with depth once early oxidation occurs, and that these rates continue for an extended time. Laboratory-aged HMAC mixtures and binders were tested and analyzed for fatigue resistance and their rheological properties. Mixture aging shows the same aging mechanisms as neat binder aging. Both binder and mixture have a higher modulus with aging and a good rheological correlation. The decline in mixture fatigue life (determined using the calibrated mechanistic fatigue analysis approach with surface energy measurement) due to oxidation is significant. Pavement service life is dependent on the mixture, but can be estimated by a cumulative damage approach that considers binder oxidation and pavement loading rate simultaneously. The differences in expected pavement life arise from differences in the rate of binder stiffening due to oxidation and the impact of this stiffening on the decline of fatigue life.

Download or read book Evaluation of Short Term Aging Effect of Hot Mix Asphalt Due to Elevated Temperatures and Extended Aging Time written by Rubben Lolly and published by . This book was released on 2013 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book The Effect of Moisture on the Performance of Asphalt Mixtures written by CA. Bell and published by . This book was released on 1985 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the results of a laboratory study to investigate the effects of mixing moisture on mechanical properties of asphalt mixtures. The potential benefits of lime and Pavebond Special were also evaluated. The repeated load diametral test device was used to measure the mixture performance in terms of the resilient modulus, fatigue, and permanent deformation characteristics of laboratory specimens prepared with and without moisture (0, 1, and 3%) and with and without lime (1%) and Pavebond (0.5%). Mixtures were prepared that were representative of two projects for which considerable field data were available. One project utilized low quality and high absorptive aggregate and the other good quality aggregate. To evaluate the long-term durability of mixtures, they were tested before and after conditioning using the Lottman approach.

Download or read book Summary Report on Aging of Asphalt aggregate Systems written by Chris A. Bell and published by . This book was released on 1989 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a report on the state of the art of research on the phenomenon of the aging of asphalt-aggregate mixtures. Compared to research on the aging of asphalt cement, there has been little research on the aging of asphalt mixtures. Binder studies are considered as well as mixture sutdies, the relationship between laboratory aging tests and field performance, and the relationship between chemical composition and field performance. Recommendations are made for aging procedures which show promise for laboratory investigation. Test methods to evaluate aging are also considered. It is noted that extended heating procedures show the most promise for short-term aging and pressure oxidation and/or extended heating the most promise for long-term aging.

Download or read book Isolated Or Coupled Oxidative Moisture and Freeze thaw Effects on Warm Mix Asphalt written by Carl Pittman and published by . This book was released on 2018 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.