Evaluation Of Warm Mix Asphalt Mixtures Containing Rap Using Accelerated Loading Tests

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Evaluation Of Warm Mix Asphalt Mixtures Containing Rap Using Accelerated Loading Tests

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Author : Munir D. Nazzal
language : en
Publisher:
Release Date : 2011

Evaluation Of Warm Mix Asphalt Mixtures Containing Rap Using Accelerated Loading Tests written by Munir D. Nazzal and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Accelerated loading tests categories.

This paper presents the results of a study that was conducted to evaluate the performance and constructability of warm mix asphalt (WMA) mixtures containing reclaimed asphalt pavement (RAP). Four sections were constructed at the indoor Accelerated Pavement Loading Facility at Ohio University. Aspha-min, Sasobit, and Evotherm WMA mixtures were used in the wearing course layer of the first three sections. In addition, the fourth section had a conventional hot mix asphalt (HMA) mixture, which was used as a control. Temperature was monitored during the production, placement, and compaction of WMA and HMA mixtures. Furthermore, emission tests were conducted at the asphalt plants during the production of each of the evaluated mixtures. Falling weight deflectometer (FWD) and rolling wheel tests were conducted at different temperatures on all evaluated sections. The results of this study showed that emissions were reduced during the production of the Aspha-min and Sasobit WMA mixtures by at least 50 % for volatile organic compounds, 60 % for carbon monoxide, 20 % for nitrogen oxides, and 83 % for sulfur dioxide, when compared to the control HMA mixture. In addition, although WMA mixtures were produced and compacted at much lower temperatures, they achieved better field densities than the control HMA mixture. The FWD test results showed that at 40°F (4°C) test temperature, the control HMA mixture had significantly lower stiffness than that of the WMA mixtures. However, the FWD stiffness measurement of the HMA and the WMA mixtures were statistically indistinguishable at the intermediate and high test temperatures of 70°F (21.1°C) and 104°F (40°C), respectively. Finally, the rolling wheel test results indicated that the three WMA sections, especially the Evotherm section, exhibited more rutting than the control HMA section during the post primary compaction stage. However, the rutting rate of the HMA section was higher than those of the WMA sections in the secondary stage, which suggests that the rutting difference may slowly be mitigated.

Evaluation Of Moisture Damage In Warm Mix Asphalt Containing Recycled Asphalt Pavement

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Author : Emily Dawn Shrum
language : en
Publisher:
Release Date : 2010

Evaluation Of Moisture Damage In Warm Mix Asphalt Containing Recycled Asphalt Pavement written by Emily Dawn Shrum and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.

Warm mix asphalt (WMA) has been used worldwide for many years, primarily in Europe. The National Asphalt Pavement Association first brought WMA to the United States in 2002. By using warm mix technology, the temperature of an asphalt mixture during production, transportation, and compaction decreases dramatically. Several concerns about WMA arise due to the reduced mixing temperature. One of the primary concerns in asphalt pavement is the moisture damage. The lower mixing temperature may not be high enough to vaporize all the moisture absorbed in the aggregate, and part of the moisture may be entrapped in the pavements during compaction. This thesis presents a laboratory study to evaluate the moisture susceptibility of warm mix asphalt (WMA) produced through plant foaming procedure. Two types of mixtures were evaluated. A base mixture meeting the state of Tennessee "BM-2" mix criteria was evaluated at 0, 30, 40, and 50 percent fractionated recycled asphalt pavement (RAP), and a surface mixture meeting the state of Tennessee "411-D" mix criteria was evaluated at 15, 20, 30, 40 percent fractionated RAP. WMA mixture specimens were obtained and compacted at the asphalt plant. The WMA specimens were compared to hot-mix asphalt (HMA) specimens through a set of laboratory mixture performance tests. In addition to traditional AASHTO T283 freeze and thaw (F-T) tensile strength ratio (TSR), Superpave indirect tensile test (IDT) with F-T and MIST conditioning, and Asphalt Pavement Analyzer (APA) Hamburg wheel tracking tests were utilized to evaluate asphalt mixtures. Moisture tests indicated that with the higher inclusions of RAP, specimens exhibited lower rut depths and higher tensile strength retention. Tensile strength ratio tests indicated that HMA specimens had higher tensile strength retention when freeze thaw conditioned. Dynamic modulus conditioned specimens indicated that simple performance tests can show the difference between conditioned and unconditioned specimens. HMA specimens showed lower susceptibility to moisture compared to WMA specimens for both BM-2 and 411-D mixtures. The higher percentages of RAP in WMA and HMA in both BM-2 and 411-D mixtures showed a reduction to moisture susceptibility.

Performance Evaluation Of Warm Mix Asphalt Mixtures Incorporating Reclaimed Asphalt Pavement

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Author : Brian Hill
language : en
Publisher:
Release Date : 2011

Performance Evaluation Of Warm Mix Asphalt Mixtures Incorporating Reclaimed Asphalt Pavement written by Brian Hill and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.

Sustainability is a cornerstone of today0́9s engineering world. Warm mix asphalt (WMA) and reclaimed asphalt pavement (RAP) are the most prominent sustainable materials in asphalt concrete pavements. WMA is a not a new concept, however new innovations and increased usage of WMA has been spurred by the increased focus on sustainable infrastructure systems. WMA enables reduced production temperatures through the use of wax, water, or other chemical packages. The effects of reduced production temperatures include fuel use and emissions reductions, improved compaction, and possible RAP concentration increases. RAP is the primary recycled product of the aged asphalt concrete pavements and its use leads to reductions in virgin aggregate and asphalt demand. However, significant performance issues can stem from the individual integration of WMA or RAP materials in asphalt concrete. In particular, WMA technologies can increase moisture and rutting susceptibility while RAP significantly increases the stiffness of the resulting mixture. Consequently, quality performance of sustainable asphalt pavements may require the combined use of WMA and RAP to produce mixtures with sufficient stiffness and moisture and fracture resistance. This study evaluates the potential of WMA technologies and their integration with RAP. Initially, an extensive literature review was completed to understand the advantages, disadvantages, and past field and lab performance of WMA and RAP mixtures. Rotational viscometer and bending beam rheometer tests were then used to evaluate Sasobit, Evotherm M1, and Advera WMA modified and unmodified binders. Finally, virgin and 45% RAP mixtures were designed and tested to examine the rutting, moisture, and fracture resistance of WMA and HMA mixtures. The results of this experiment provided several key observations. First, viscosity reductions may not be the primary cause for the availability of reduced production temperatures for WMA technologies. Second, WMA additive properties have a significant effect upon fracture, moisture, and rutting resistance. Furthermore, the addition of RAP to WMA mixtures improved the rutting and moisture sensitivity performance as characterized in the Hamburg and Tensile Strength Ratio testing procedures.

Performance Assessment Of Warm Mix Asphalt Wma Pavements

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Author :
language : en
Publisher:
Release Date : 2009

Performance Assessment Of Warm Mix Asphalt Wma Pavements written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with Pavements, Asphalt categories.

Warm Mix Asphalt (WMA) is a new technology that was introduced in Europe in 1995. WMA offers several advantages over conventional asphalt concrete mixtures, including: reduced energy consumption, reduced emissions, improved or more uniform binder coating of aggregate which should reduce mix surface aging, and extended construction season in temperate climates. Three WMA techniques, Aspha-min, Sasobit, and Evotherm, were used to reduce the viscosity of the asphalt binder at certain temperatures and to dry and fully coat the aggregates at a lower production temperature than conventional hot mix asphalt. The reduction in mixing and compaction temperatures of asphalt mixtures leads to a reduction in both fuel consumption and emissions. This research project had two major components, the outdoor field study on SR541 in Guernsey County and the indoor study in the Accelerated Pavement Load Facility (APLF). Each study included the application of four types of asphalt surface layer, including standard hot mix asphalt as a control and three warm mixes: Evotherm, Aspha-min, and Sasobit. The outdoor study began with testing of the preexisting pavement and subgrade, the results of which indicated that while the pavement and subgrade were not uniform, there were no significant problems or variations that would be expected to lead to differences in performance of the planned test sections. During construction, the outdoor study included collection of emissions samples at the plant and on the construction site as well as thermal readings from the site. Afterwards, the outdoor study included the periodic collection and laboratory analysis of core samples and visual inspections of the road. Roughness (IRI) measurements were made shortly after construction and after a year of service. The indoor study involved the construction of four lanes of perpetual pavement, each topped with one of the test mixes. The lanes were further divided into northern and southern halves, with the northern halves having a full 16 in (40 cm) perpetual pavement, and with the southern halves with thicknesses decreasing in one in (2.5 cm) increments by reducing the intermediate layer. The dense graded aggregate base was increased to compensate for the change in pavement thickness. The southern half of each lane was instrumented to measure temperature, subgrade pressure, deflection relative to top of subgrade and to a point 5 ft (1.5 m) down, and longitudinal and transverse strains at the base of the fatigue resistance layer (FRL). The APLF had the temperature set to 40°F (4.4°C), 70°F (21.1°C), and 104°F (40°C), in that order. At each temperature, rolling wheel loads of 6000 lb (26.7 kN), 9000 lb (40 kN), and 12,000 lb (53.4 kN) were applied at lateral shifts of 3 in (76 mm), 1 in (25 mm), -4 in ( -102 mm), and -9 in ( - 229 mm) and the response measured. Then each plane was subjected to 10,000 passes of the rolling wheel load of 9000 lb (40 kN) at about 5 mph (8 km/h). Profiles were measured after 100, 300, 1000, 3000, and 10,000 passes with a profilometer to assess consolidation of each surface. After the 10,000 passes of the rolling wheel load were completed, a second set of measurements was made under rolling wheel loads of 6000 lb (26.7 kN), 9000 lb (40 kN), and 12,000 lb (53.4 kN) at the same lateral shifts as before. Additionally, the response of the pavement instrumentation was recorded during drops of a Falling Weight Deflectometer (FWD).

Characterization Of Reclaimed Asphalt And Performance Based Evaluation Of Its Use In Recycled Mixtures

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Author : Jesse David Doyle
language : en
Publisher:
Release Date : 2011

Characterization Of Reclaimed Asphalt And Performance Based Evaluation Of Its Use In Recycled Mixtures written by Jesse David Doyle and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Asphalt categories.

Reclaimed asphalt pavement (RAP) is a valuable resource that can be recycled into new asphalt mixtures. In recent years, the continued rise of raw material costs has generated considerable interest in increasing RAP usage. Warm mix asphalt (WMA) is a modern development in the asphalt industry that can potentially help increase RAP usage and achieve adequate mixture performance. The purpose of this dissertation is to: 1) develop a method to characterize the absorbed, inert and effective bituminous components in RAP; and 2) evaluate performance of high RAP-WMA mixtures for various pavement applications including airfield surfaces, highway surfaces and highway bases. A unique approach was taken to characterize RAP properties that coupled a dataset of 568 asphalt mix designs spanning five years of practice and testing 100% RAP with added virgin binder; 394 compacted specimens and 68 loose specimens were tested. A method to predict RAP absorbed asphalt was developed and shown to yield more reasonable results than conventional methods which were shown very likely to give incorrect absorbed asphalt contents in some conditions. The relative effectiveness of RAP surface asphalt was evaluated and estimates of inert and effective RAP asphalt were made for a variety of temperature, compactive effort, and warm mix additive conditions. Results showed different behaviors between RAP sources and between hot and warm mix temperatures. These results were also observed in volumetrics of high RAP mixtures. Performance evaluation was based on testing 75 slab specimens and more than 1100 gyratory specimens. Test data indicated a potential for decreased durability as RAP content increases; however 25% RAP highway surface mixtures and 50% RAP base mixtures had similar performance to current practice. Low temperature mixture stiffness testing and thermal cracking analysis indicated slightly increased stiffness with high RAP and 25% RAP highway surface mixtures that had comparable performance to current practice. Dry rut testing indicated high RAP mixtures are rut resistant. Moisture damage testing of high RAP mixtures indicated passing results in tensile strength ratio testing but potential for moisture damage in loaded wheel tracking. Overall, 25% RAP highway surface mixtures are recommended for immediate implementation.

Laboratory Evaluation Of Warm Mix Asphalt Influence On Theoretical Maximum Specific Gravity

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Author : Jianhua Yu
language : en
Publisher:
Release Date : 2012

Laboratory Evaluation Of Warm Mix Asphalt Influence On Theoretical Maximum Specific Gravity written by Jianhua Yu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Asphalt concrete categories.

Warm mix asphalt (WMA) technology provides sufficient workability for asphalt mixtures at reduced mixing and compaction temperatures. Depending on the WMA technology, the typical temperature reduction range is 20 °C to 55 °C below hot mix asphalt (HMA) production temperatures. WMA involves chemical and wax additives that are added to an asphalt binder or incorporated through the use of foaming technology. The main advantages of WMA are reduced emissions and a reduction in combustible fuel consumption. Ongoing WMA research projects have documented some differences between HMA and WMA mixes, prompting numerous research projects that are investigating these concerns. The purpose of this research is to evaluate the volumetric properties by directly comparing laboratory produced WMA and HMA mixes. This study investigates the impact of WMA additives on the volumetric properties, specifically, the theoretical maximum specific gravity (Gmm). The Gmm testing followed the procedure of ASTM D2041. Two mix designs with HMA binder were produced, one without recycled asphalt pavement (RAP) and the other with 30 % RAP. After the mix designs were completed, no additional changes were made to account for the addition of the WMA technology. The mixes included the WMA technologies Sasobit and Advera, as well as an HMA control, for a total of six different laboratory produced mixes. Each mix was produced at 120 °C, 135 °C, and 150 °C, and each mix was oven cured for 1, 2, and 4 h. The test results were analyzed using statistical principles to determine whether differences in the Gmm values were statistically significant. The results show that temperature has little impact on Gmm. Gmm was not affected by curing times of 1 and 2 h, but the longer curing time of 4 h resulted in a statistically significant increase in Gmm. Further analysis revealed that the mix sensitivity to curing time depends on the amount of RAP in the mix. For the mix designs studied, the Advera Gmm values were similar to the HMA values, but the Sasobit Gmm values were statistically lower than the Advera values.

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.

Recent Developments In Pavement Design Modeling And Performance

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Author : Sherif El-Badawy
language : en
Publisher: Springer
Release Date : 2018-10-30

Recent Developments In Pavement Design Modeling And Performance written by Sherif El-Badawy and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-10-30 with Science categories.

This volume includes a collection of research and practical papers from an international research and technology activities on recent developments in pavement design, modeling and performance, and effects on infrastructure, green energy, technology and integration. Sustainability is increasingly a key priority in engineering practices. With the aging transportation infrastructure and renewed emphasis on infrastructure renovation by transportation agencies, innovations are urgently needed to develop materials, designs, and practices to ensure the sustainability of transportation infrastructure. The volume is based on the best contributions to the 2nd GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2018 – The official international congress of the Soil-Structure Interaction Group in Egypt (SSIGE).

Evaluation Of Moisture Susceptibility Of Warm Mix Asphalt

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Author : Maria Lorena Garcia Cucalon
language : en
Publisher:
Release Date : 2013

Evaluation Of Moisture Susceptibility Of Warm Mix Asphalt written by Maria Lorena Garcia Cucalon and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.

Economic, environmental and engineering benefits promote the rapid implementation of WMA technologies. However, concerns remain based on changes in the production process that may lead to moisture susceptibility in the early life as compared to HMA. To evaluate WMA moisture susceptibility during this critical period, standard laboratory tests were used for three field projects each with an HMA control mixtures and multiple WMA mixtures. Different specimen types were also evaluated to capture differences in mix design, quality control/quality assurance, and field performance. Specimens were evaluated for moisture susceptibility by Indirect Tensile (IDT) Strength, Resilient Modulus (MR) and Hamburg Wheel-Track Testing (HWTT). Specimens for IDT and MR were tested dry and then tested wet after conditioning as described in AASHTO T283 with one freeze-thaw cycle. HWTT was used to assess both moisture susceptibility and rutting potential under repeated loads in the presence of water at elevated temperatures (i.e., 122°F [50°C]), and the output parameters used for evaluation were the calculated Stripping Inflection Point (SIP) and the rut depth at 5000 load cycles. Based on the results of the laboratory tests performed on PMFC cores acquired at construction and with time, WMA during its early life exhibited inferior moisture resistance when compared to HMA. However, with time, specifically after one summer, the dry and wet properties of WMA became equivalent to those of HMA. For WMA constructed in the fall, the results from this study suggest that the inclusion of recycled asphalt pavement (RAP) or an anti-stripping agent may alleviate possible moisture susceptibility issues in the early life during wet, winter weather conditions. While some laboratory test results demonstrated that WMA is more moisture susceptible than HMA, field performance reported to date from the three projects used in this study shows no evidence of moisture damage. Therefore the search for a laboratory test to screen mixtures for moisture susceptibility continues. An alternative approach, applying Griffith crack growth theory and utilizing IDT, MR and air voids% the adhesive bond energy of asphalt mixtures was calculated for Texas field project. This value holds promise for characterizing performance of asphalt mixtures by considering basic properties and grouping into one representative value. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149392

Performance Characterization Of Recycled Asphalt Pavements With Warm Mix Asphalt Technologies

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Author : Sandeep Pandey (Researcher in civil and environmental engineering)
language : en
Publisher:
Release Date : 2016

Performance Characterization Of Recycled Asphalt Pavements With Warm Mix Asphalt Technologies written by Sandeep Pandey (Researcher in civil and environmental engineering) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Electronic books categories.

This study evaluated the laboratory performance characteristics of Recycled Asphalt Pavements (RAP) with Warm Mix Asphalt (WMA) Technologies. RAP was introduced in mixtures at three levels: 0, 15 and 35% of RAP contents. Five WMA technologies were evaluated against all the mentioned levels of RAP content. The study was conducted in two phases, each phase with a separate aggregate and RAP source. Standard Marshall Mix design method was followed for the mix design purpose, with some modification to introduce RAP and WMA. Rheological properties of both the virgin and recovered asphalt binders were determined. Laboratory designed mixtures were evaluated for moisture resistance, dynamic modulus, rutting resistance and thermal resistance behavior. Moisture resistance of the mixtures were evaluated by performing the indirect tensile strength test for 0 and 1 freeze-thaw cycles. Resistance to rutting was evaluated by determining flow number using the Asphalt Mixture Performance Tester (AMPT) machine. Finally, thermal resistance of the mixtures were evaluated by conducting Uniaxial Thermal Stress and Strain Test (UTSST). The study determined that the moisture susceptibility of the mixtures increased with the increase in number of freeze thaw cycles. Dynamic modulus of the mixtures were higher for a higher RAP content. Further, HMA mixtures were determined to have higher dynamic modulus and tensile strengths than the WMA mixtures. Even though, the strength values for WMA mixtures were lower than the HMA mixtures, WMA mixtures satisfied the required criteria defined by agency. HMA mixtures were found to have higher rutting resistance than WMA mixtures, and this resistance increased with the increase in RAP content. Even though HMA mixtures with higher RAP content performed better in terms of rutting, such mixtures exhibited a huge drop in thermal resistance capacity. Varying aggregate source did not significantly influenced the performance of mixtures, except in the case of rutting. Further study is need in order to validate the use of higher RAP content in the mixtures.