Download or read book Fiber Dosage Effects in Asphalt Binders and Hot Mix Asphalt Mixtures written by Ashraf Alrajhi and published by . This book was released on 2012 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of fibers and other materials in asphalt mixes has been studied and applied over the past five decades in order to improve pavement performance around the world. This thesis highlights the characteristics and performance properties of modified asphalt mixes using a blend of polypropylene and aramid fibers, The main objective of this study was to evaluate the effect of adding different fiber dosages on the laboratory performance of both asphalt binder and mixture. The laboratory study was conducted on sixteen different dosages and blends of the fibers, with various combinations of polypropylene and aramid, using binder tests as well as hot mix asphalt tests. The binder tests included: penetration, softing point, and Brookfield viscosity tests. The asphalt mixture tests included the dynamic modulus, and indirect tensile strength. The binder test results indicated that the best viscosity - temperature susceptibility performance would be from the blend of three dosages of polypropylene and one dosage of aramid, the dynamic modulus test results also confirmed this finding. Overall, in almost every case, the addition of fibers resulted in an increase in mixture stiffness regardless of fiber content. From the indirect tensile strength results, the polypropylene fibers had less of an effect on post peak failure than the aramid fibers. Overall, the aramid fibers yielded better results than the polypropylene fibers. This study has important implications for the future of pavement design and the prospect of using optimal dosages of polypropylene and aramid fibers in further research to further determine their long-term performance and characteristics used in real world applications.

Download or read book Assessment of the Impact of Fiber Types on the Performance of Fiber Reinforced Hot Mix Asphalt written by Christopher J. DeCarlo and published by . This book was released on 2020 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study aims to evaluate the impact of fiber types on the performance of hot mix asphalt (HMA) mixtures. Specifically, the impacts of fiber type on HMA mix design and laboratory performance are investigated. Four types of fiber (fiberglass, basalt, carbon, and polyolefin/aramid blend) were used to produce four fiber-reinforced HMA mixes, and a control mix without fibers was also prepared. The fiber dosage rates used in this study were 0.16% (fiberglass, basalt, and carbon) and 0.05% (polyolefin/aramid) by total mixture weight, based on manufacturer recommendations. Two mixing procedures for introducing fibers into HMA were also evaluated: dry and 15-s dispersion methods. The dry method involved mixing the fibers with aggregates before the addition of asphalt binder while the 15-s dispersion method involved adding the fibers into the mix every 15 seconds (as aggregates were coated by asphalt binder during the mixing process). All the HMA mixtures (unreinforced and fiber-reinforced) were then subjected to several different laboratory performance tests: dynamic complex modulus, Cantabro durability, asphalt pavement analyzer, flow number, and indirect tensile strength. Analysis of variance was conducted to evaluate statistically the impact of fibers on mix performance. Results showed that fibers affected the volumetric properties, mix durability, and rutting resistance of HMA mixes. It was also found that the process for introducing fibers into the mix (i.e., mixing method) affected the consistency of fiber-reinforced HMA samples. Overall, the results of this study showed that the use of fibers improved the rutting and durability performance of asphalt mixtures in the laboratory.

Download or read book Hot mix Asphalt Mixtures written by and published by . This book was released on 1999 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of the Effects of Asphalt Binder on the Properties of Hot Mix Asphalt at Intermediate Temperatures written by Haifang Wen and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The asphalt binder is an essential component of asphaltic mixtures. The performance of an asphaltic mixture is directly related to mechanical characteristics of the binder. With the development of new material characterization methods for both asphalt binder and asphaltic mixture, there is a need to re-evaluate the relationship between the properties of binders and asphaltic mixtures such that a proper understanding and selection of an asphalt binder can be made to improve the performance of an asphaltic mixture. In this study, the effects of asphalt binder properties on asphaltic mixtures at intermediate temperatures were evaluated based on recent developments on material characterization methods for both binder and asphaltic mixture. Five asphalt binders and five asphalt mixtures containing these binders with one aggregate were tested. Four of the binders were based on a modification of a base binder with different techniques. Complex shear modulus and monotonic constant shear-rate tests were conducted on asphalt binders, whereas dynamic modulus and indirect tensile strength tests were conducted on the mixtures. The effects of modification techniques on the properties of asphalt binders and the relationships between the properties of binders and asphaltic mixtures were evaluated in this study.

Download or read book Improved Mix Design Evaluation and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content written by Randy Clark West and published by Transportation Research Board. This book was released on 2013 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 752: Improved Mix Design, Evaluation, and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content describes proposed revisions to the American Association of State Highway and Transportation Officials (AASHTO) R 35, Superpave Volumetric Design for Hot Mix Asphalt, and AASHTO M 323, Superpave Volumetric Mix Design, to accommodate the design of asphalt mixtures with high reclaimed asphalt pavement contents.

Download or read book Bearing Capacity of Roads Railways and Airfields written by Andreas Loizos and published by CRC Press. This book was released on 2017-07-20 with total page 3209 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bearing Capacity of Roads, Railways and Airfields includes the contributions to the 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields (BCRRA 2017, 28-30 June 2017, Athens, Greece). The papers cover aspects related to materials, laboratory testing, design, construction, maintenance and management systems of transport infrastructure, and focus on roads, railways and airfields. Additional aspects that concern new materials and characterization, alternative rehabilitation techniques, technological advances as well as pavement and railway track substructure sustainability are included. The contributions discuss new concepts and innovative solutions, and are concentrated but not limited on the following topics: · Unbound aggregate materials and soil properties · Bound materials characteritics, mechanical properties and testing · Effect of traffic loading · In-situ measurements techniques and monitoring · Structural evaluation · Pavement serviceability condition · Rehabilitation and maintenance issues · Geophysical assessment · Stabilization and reinforcement · Performance modeling · Environmental challenges · Life cycle assessment and sustainability Bearing Capacity of Roads, Railways and Airfields is essential reading for academics and professionals involved or interested in transport infrastructure systems, in particular roads, railways and airfields.

Download or read book Pavement Roadway and Bridge Life Cycle Assessment 2020 written by John Harvey and published by CRC Press. This book was released on 2020-07-02 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: An increasing number of agencies, academic institutes, and governmental and industrial bodies are embracing the principles of sustainability in managing their activities. Life Cycle Assessment (LCA) is an approach developed to provide decision support regarding the environmental impact of industrial processes and products. LCA is a field with ongoing research, development and improvement and is being implemented world-wide, particularly in the areas of pavement, roadways and bridges. Pavement, Roadway, and Bridge Life Cycle Assessment 2020 contains the contributions to the International Symposium on Pavement, Roadway, and Bridge Life Cycle Assessment 2020 (Davis, CA, USA, June 3-6, 2020) covering research and practical issues related to pavement, roadway and bridge LCA, including data and tools, asset management, environmental product declarations, procurement, planning, vehicle interaction, and impact of materials, structure, and construction. Pavement, Roadway, and Bridge Life Cycle Assessment 2020 will be of interest to researchers, professionals, and policymakers in academia, industry, and government who are interested in the sustainability of pavements, roadways and bridges.

Download or read book Performance Survey on Open graded Friction Course Mixes written by Gerald Huber and published by Transportation Research Board. This book was released on 2000 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This synthesis will be of interest to pavement construction, maintenance, design, and materials engineers; pavement contractors; and others interested in the use of open-graded friction course (OGFC) mixes. It describes the current state of the practice on the use of OGFC mixes, including information regarding design, materials, construction, maintenance, and rehabilitation strategies. Alternative treatments to traditional OGFC are also identified and discussed. Information was collected by surveying U.S. and Canadian transportation agencies and by conducting a literature search to gather additional insight into North American and European practices. This TRB report describes the recent performance of North American OGFC mixes and European porous asphalt by identifying benefits and stress indicators. A new generation of OGFC mixes has evolved over the last 5 years with changes that have been reported to dramatically improve performance. This synthesis describes new materials and design methods being used, as well as the applicability of the new generation of open-graded mixtures to North American use.

Download or read book Mixing and Compaction Temperatures of Asphalt Binders in Hot mix Asphalt written by Randy Clark West and published by Transportation Research Board National Research. This book was released on 2010 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report identifies improved test methods for determining laboratory mixing and compaction temperatures of modified and unmodified asphalt binders. The report will be of immediate interest to materials engineers in state highway agencies and the hot-mix asphalt (HMA) construction industry.

Download or read book Advanced Asphalt Materials and Paving Technologies written by Zhanping You and published by MDPI. This book was released on 2018-05-04 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Advanced Asphalt Materials and Paving Technologies" that was published in Applied Sciences

Download or read book Asphalt and Asphalt Mixtures written by Haitao Zhang and published by BoD – Books on Demand. This book was released on 2019-12-11 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, with the rapid development of the world transportation industry, the proportion of asphalt pavement in road engineering is increasing. Therefore, while the demand for asphalt and asphalt mixture is increasing, the quality requirements for materials are also improving. In particular, new materials and new technologies are constantly emerging, and the application technology, theory, and technical specifications of asphalt materials have made great progress.

Download or read book Characterization and Modeling of Dispersed Synthetic Fibers in Dense Graded Asphalt Mixtures written by Ahmed Milad Muftah and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The premature deterioration of hot mix asphalt pavements is one of the common issues concern many transportation agencies. Innovative solutions are needed to enhance the serviceable life of pavement. Various techniques are widely utilized. One of the most popular and common methods is fiber reinforcement. Fibers have been used extensively in Portland Cement Concrete (PCC) since 1950's. However, use of fibers in asphalt mixtures is relatively new. There are limited studies that investigate the effect of fibers in asphalt mixtures. Some laboratory testing showed that fibers improved the resistance of asphalt mixtures to rutting and fatigue. However, these investigations did not provide a comprehensive understanding of the interaction mechanism between asphalt mixture constituents and fibers. The goal of this research was to evaluate and quantify the effect of fibers on the mix performance characteristics. Furthermore, the research aimed at evaluating the healing characteristics, developing a method to detect the fiber dispersion in the mix and to develop a finite element model (FEM) to study the resistance of fiber-modified asphalt mixtures to permanent deformation. Three types of synthetic fibers were used. Fiber #1 (aramid and polyolefin fibers), fiber #2 (a wax treated aramid fiber) and fiber #3 (glass fiber). A number of laboratory tests were conducted on laboratory-prepared test samples and extracted field cores. A FEM model to simulate the accelerated performance test was developed and was calibrated using material parameters from direct laboratory testing. X-ray tomography was used to evaluate and quantify the level of fiber dispersion in the mix. The results show slightly improved performance at higher fiber contents than those recommended by the manufacturers. Asphalt healing study revealed that presence of fibers has increased healing rate and consequently delayed fatigue damage. The developed finite element model (FEM) can be used to predict a long-term rutting performance of asphalt pavements. It was found out that X-ray tomography was not suitable to detect fiber dispersion. An optical image processing technique in conjunction with a lab-based method using UV light was developed and found to be more successful to evaluate the fiber dispersion in the mix.

Download or read book Carbon Fibers and Their Composites written by Peter Morgan and published by CRC Press. This book was released on 2005-05-20 with total page 1200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most literature pertaining to carbon fibers is of a theoretical nature. Carbon Fibers and their Composites offers a comprehensive look at the specific manufacturing of carbon fibers and graphite fibers into the growing surge of diverse applications that include flameproof materials, protective coatings, biomedical and prosthetics application

Download or read book Special Mixture Design Considerations and Methods for Warm Mix Asphalt written by and published by Transportation Research Board. This book was released on 2012 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 714: Special Mixture Design Considerations and Methods for Warm-Mix Asphalt: A Supplement to NCHRP Report 673: A Manual for Design of Hot-Mix Asphalt with Commentary presents special mixture design considerations and methods used with warm-mix asphalt. NCHRP Report 714 is a supplement to NCHRP Report 673: A Manual for Design of Hot-Mix Asphalt. All references to chapters in NCHRP Report 714 refer to the corresponding chapters in NCHRP Report 673.

Download or read book Design of a High binder high modulus Asphalt Mixture written by G. W. Maupin and published by . This book was released on 2006 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies on long-life flexible pavements indicate that it may be advantageous to design and construct asphalt mixtures comprising the underlying layers in such a manner that very dense mixtures are produced. This will improve not only the fatigue characteristics but also durability through a decrease in air voids. A 19.0 mm mixture was designed and tested at asphalt contents (ACs) higher than the optimum design level. Stiffer binder and recycled asphalt pavement (RAP) were employed to help maintain stiffness in order to prevent instability. The field voids were predicted to decrease approximately 1.0 to 1.5 percent for each 0.4 percent increase in AC, which would improve durability. Flexural stiffness peaked for an 0.5 percent increase in AC, and fatigue life trended upward but needed approximately 1.0 percent additional asphalt for a major beneficial effect. Permeability improved slightly as AC was increased. The researchers think that the Hamburg test would have been more appropriate for this study than the tensile strength ratio test, which indicated no improvement in stripping susceptibility with an increased AC, because it might simulate field conditions better. In addition, the Mechanistic-Empirical Pavement Design Guide Software (Version 0.900) was used to evaluate trial pavement designs with several design alternatives, including varying the binder performance grade, effective binder volume, and air void content to determine the resultant changes in predicted fatigue cracking and rutting of hot-mix asphalt (HMA) layers. This theoretical pavement analysis indicated that increasing the binder content of the HMA intermediate layer beyond the design optimum and increasing the stiffness of the intermediate layer by increasing the high-temperature binder performance grade slightly decreased the predicted fatigue cracking and reduced the rutting of the HMA layers. The analysis also showed that more significant reductions in the predicted fatigue cracking could be realized by increasing the binder content of the HMA base layer slightly beyond the optimum and by reducing the in-place air void content of the HMA base layer. It was recommended that VTRC should further investigate the effects of higher binder contents and lower air voids on the performance of base mixes. Further study of current void criteria to verify optimum pavement performance is also recommended. This project provides a stepping stone to achieve long-lasting perpetual-type flexible pavement. Designs with a high binder content offer the potential to reduce fatigue cracking 20 to 60 percent by incorporating additional asphalt binder and reducing the void content of asphalt base. The use of RAP to maintain the necessary stiffness for high binder contents should provide comparable stiffness to an increasingly expensive PG 70-22 binder for base material. Some effort is taking place in 2007 for reducing voids in base mixes with high RAP content; however, quantification of the economic benefits from that endeavor will be a future goal.

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 Durability and Performance Characteristics of Hot Mix Asphalt Containing Polymer Additives written by Robert Y. Liang and published by . This book was released on 2001 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ohio Department of Transportation has adopted the hot mix asphalt concrete containing polymer modifiers for use in the interstate highway pavement. Among the various reasons cited for the adoption of polymer modifiers are the favorable field experiences by ODOT, extensive literatures reporting enhanced performance, such as rutting resistance, low temperature thermal cracking resistance, and possibly fatigue endurance. However, despite these favorable findings, there are still cases involving premature failure of hot mixtures containing polymer modifiers. Concerns regarding optimum polymer content, compatibility between polymer additives and asphalt cement, proper mixing and compaction procedure remain to be resolved. Furthermore, performance based specifications to ensure production of desirable final asphalt concrete product require additional development. Questions regarding the suitability of Superpave binder testing procedures for the polymer-modified binders need to be clarified.