Mechanistic Evaluation Of The Effect Of Wma Additives On Wettability And Moisture Susceptibility Properties Of Asphalt Mixes

This study used a mechanistic framework (i.e., surface free energy) to evaluate the moisture susceptibility of warm mix asphalt (WMA) with three different WMA additives, namely, Sasobit, Advera, and Evotherm. The surface free energy (SFE) components of modified PG64-22 asphalt binder with different percentages of WMA additives and selected aggregates were measured in the laboratory. The wettability, the work of adhesion, the work of debonding, and energy ratios were estimated in order to assess the moisture-induced damage potential of combinations of modified asphalt binders and different aggregates. The results indicate that Sasobit and Advera are able to reduce the moisture susceptibility potential of the mixes, but their use is not recommended with highly acidic aggregates such as granite. Evotherm resulted in the highest increases in wettability, total surface free energy, and increased work of adhesion and a reduction in the work of debonding, resulting in a better possible aggregate coating with asphalt binder and lower moisture susceptibility with all types of tested aggregates relative to those of other WMA additives. Furthermore, tensile strength ratio (TSR) tests were conducted on Advera and Evotherm-modified and neat (unmodified) asphalt mixes, and the results were compared with those from the SFE test. It was found that the SFE approach is a better indicator of moisture susceptibility than the traditional TSR test. The findings of the present study would help the highway engineers and agencies to better understand the moisture damage potential of flexible pavements constructed with WMA technologies.

This book presents challenges in transportation engineering, recent developments and advancements in technologies, and design and construction using sustainable materials. The articles presented in this volume focus on fundamental investigations on various aspects of civil engineering materials and structures. The scope of this volume is the application of findings for solving problems in geotechnical, pavement, and transportation engineering using emerging techniques. Papers were selected from the 5th GeoChina International Conference 2018 on Civil Infrastructures Confronting Severe Weathers and Climate Changes Conference, held on July 23 to 25, 2018 in HangZhou, China.

Bituminous Mixtures and Pavements VIII contains 114 papers as presented at the 8th International Conference ‘Bituminous Mixtures and Pavements’ (8th ICONFBMP, 12-14 June 2024, Thessaloniki, Greece). The contributions reflect the research and practical experience of academics and practicing engineers from thirty-four (34) different countries, and cover a wide range of topics: Session I: Bitumen, Modified binders, Aggregates, and Subgrade Session II: Bituminous mixtures (Design, Construction, Testing, Performance) Session III: Pavements (Design, Construction, Maintenance, Sustainability, Energy and Environmental consideration) Session IV: Pavement management and Geosynthetics Session V: Pavement recycling Session VI: Pavement surface characteristics, Pavement performance monitoring, Safety Session VII: Biomaterials in pavement engineering Session VIII: Prediction models of pavement performance Bituminous Mixtures and Pavements VIII covers recent advances in highway materials technology and pavement engineering, and will be of interest to scientists and professionals involved or interested in these areas. The ICONFBMP-conferences have been organized every four years since 1992. This 8th conference was jointly organized by: Laboratory of Highway Engineering, Aristotle University of Thessaloniki, Greece; Built Environment Research Institute (BERI), University of Ulster, UK; University of Texas San Antonio (UTSA), USA; Laboratory for Advanced Construction Technology (LACT), Technological Institute of Iowa, USA; Technological University of Delft (TUDelft), The Netherlands, and University of Antwerp, (UA), Belgium.

"TRB's National Cooperative Highway Research Program (NCHRP) Report 763: Evaluation of the Moisture Susceptibility of WMA Technologies presents proposed guidelines for identifying potential moisture susceptibility in warm mix asphalt (WMA). The report also suggests potential revisions to the Appendix to AASHTO R 35, "Special Mixture Design Considerations and Methods for WMA" as a means to implement the guidelines."--publisher's description

Effective measurement of the composition and properties of petroleum is essential for its exploration, production, and refining; however, new technologies and methodologies are not adequately documented in much of the current literature. Analytical Methods in Petroleum Upstream Applications explores advances in the analytical methods and instrumentation that allow more accurate determination of the components, classes of compounds, properties, and features of petroleum and its fractions. Recognized experts explore a host of topics, including: A petroleum molecular composition continuity model as a context for other analytical measurements A modern modular sampling system for use in the lab or the process area to collect and control samples for subsequent analysis The importance of oil-in-water measurements and monitoring The chemical and physical properties of heavy oils, their fractions, and products from their upgrading Analytical measurements using gas chromatography and nuclear magnetic resonance (NMR) applications Asphaltene and heavy ends analysis Chemometrics and modeling approaches for understanding petroleum composition and properties to improve upstream, midstream, and downstream operations Due to the renaissance of gas and oil production in North America, interest has grown in analytical methods for a wide range of applications. The understanding provided in this text is designed to help chemists, geologists, and chemical and petroleum engineers make more accurate estimates of the crude value to specific refinery configurations, providing insight into optimum development and extraction schemes.

The implementation of warm-mix asphalt (WMA) is becoming more widespread in the United States of America with a growing number of contractors choosing to utilize various WMA technologies. WMA technologies were developed in order to reduce mixing and compaction temperatures of hot mix asphalt (HMA) without affecting the quality of the pavement. Research into the effects of WMA additives suggests that it may be more susceptible to rutting and moisture damage than traditional HMA pavements. The objective of this research is to evaluate the effects of a single WMA additive on resistance to rutting and moisture damage on lab mixed and field mixed pavements. This objective was completed by conducting extensive laboratory experiments to determine and assess the performance of both WMA and HMA mixtures produced using Iowa aggregates. The conclusions of this study are as follow: * Reduced mixing and compaction temperatures were achieved using the selected additive. * The selected WMA additive was successfully used and samples were taken during a local resurfacing project. * Moisture sensitivity of both field mixed WMA and field mixed HMA were comparable although both failed to meet Iowa DOT standards. * Dry Indirect Tensile Strength values of lab mixed WMA and HMA samples were nearly the same. * TSR values of lab mixed HMA surpassed those of lab mixed WMA although both failed to meet Iowa DOT standards. * The aged field mixed HMA successfully passed the Hamburg Wheel Tracker Test and provided the best creep and stripping values compared to all other field mixed specimens. * Lab mixed HMA using a PG 64-22 binder performed the best compared to all other lab mixed specimens although none of the lab mixed specimens successfully passed the Hamburg Wheel Tracker Test.

The purpose of this research effort was to evaluate the use of warm-mix additives with modified (polymer-modified and terminal blend tire rubber) asphalt mixtures from Nevada and California. This research was completed in two stages: Sasobit and Advera were evaluated in first stage while Evotherm and Foaming were evaluated in second stage. The three main components of the experimental plan include: evaluation of mixture resistivity to moisture damage, pavement performance characteristics of the mixtures, and mechanistic analysis of the mixtures for simulated flexible pavement. The moisture resistivity of all mixtures were checked by Indirect Tensile Strength (ITS), and Dynamic Modulus (E*) tests. Dynamic Modulus Ratio (ECR) and Tensile Strength Ratio (TSR) were computed at multiple Freeze-Thaw (F-T) cycles for further evaluation of moisture sensitivity of mixtures. Flow Number (FN) and Flexural beam fatigue tests were conducted to evaluate the performance characteristics of WMA additives/technology. The terminal blend tire rubber-modified binder with lime treatment works effectively in resisting moisture damage, rutting, and to significantly-reasonably improve the fatigue life of the WMA Evotherm, Foaming, Advera and Sasobit mixtures. Hence, it is the best solution for the design and construction of sustainable asphalt pavements. The use of terminal blend rubberized asphalt binder is an excellent and economical selection in reducing tire waste and environmental impacts.

The intention of this research effort is to evaluate the use of warm mix additives with typical polymer-modified and terminal blend tire rubber asphalt mixtures from Nevada and California. The research effort is broken into three phases that are intended to evaluate the impacts of warm mix additives with typical polymer-modified and terminal blend tire rubber asphalt mixtures from Nevada and California: moisture damage, performance characteristics, and mechanistic analysis. In Phase I of this research effort, mixture resistance to moisture damage was evaluated using the indirect tensile test and the dynamic modulus at multiple freeze-thaw cycles. Laboratory testing was conducted to address the following: (1) the impact of warm mix additive and reduced production temperatures on the moisture damage resistance of asphalt mixtures, (2) the impact of residual aggregate moisture on the moisture damage resistance of WMA mixtures, (3) the impact of warm mix additives on the moisture damage resistance of anti-strip treated WMA mixtures, and (3) the impact of long-term aging on strength gain and the moisture damage resistance of WMA mixtures. A total of one aggregate source, four warm mix asphalt technologies (Advera, Sasobit, Revix and Foaming) and three asphalt binder types (neat, polymer-modified and terminal blend tire rubber modified asphalt binders) typically used in both Nevada and California are being evaluated in this study. This thesis will only summarize the test results and findings of the Phase I of the study for two warm-mix additives: Advera and Sasobit. The evaluation of the other two technologies (i.e. Revix and Foaming) as well as the Phase II testing are still in progress and have not been completed.

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.

Warm Mix Asphalt (WMA) technology has the capability of lowering the temperature at which the asphalt is mixed and compacted by 30°C or more without compromising the performance of asphalt pavement. The reduced difference between asphalt mix and ambient temperature results in a lower cooling rate thus allows for long haul, sufficient compaction time and late season projects compared to the conventional Hot Mix Asphalt (HMA). In northern climate, asphalt paving season is relatively short and paving is often done late in the season when weather conditions are less than ideal. The potential benefit of WMA, among others, is an extended paving season for the City of Winnipeg. Reduction in production temperature also comes with other positive impacts both economically and environmentally. The objective of this study is to evaluate the installation of WMA, compile experiences with this technology and evaluate their effects on construction methods and performance. The study further attempts to evaluate the effectiveness of the WMA chemical additives and its dosage rate as liquid anti-strip agents on the properties of WMA mixtures through field and laboratory testing programs. In addition to the overall effectiveness of WMA, the study aimed to evaluate its economic cost relative to Hot Mix Asphalt (HMA). A chemical additive was used at three different dosages (0.3, 0.5 and 0.7 percent by weight of asphalt cement). The additive has the ability to improve mixing, aggregate coating, workability, compaction and adhesion with no change in materials or job mix formula required. The study showed that WMA could be successfully placed using conventional HMA paving practices and procedures. Among the different additive dosages used, 0.5% had a better overall performance. The moisture sensitivity tests indicated the highest Tensile Strength Ratio (TSR) at this dosage, suggesting the lowest moisture damage susceptibility. All four mixtures had low rutting resistance potential with no significant difference among them. The WMA showed a higher cracking resistance compared to HMA. The WMA price was between 2% to 11% higher than conventional HMA including the costs of additional testing as well as the WMA additives.