Download or read book Targeting Aggregate Marginality from a Chemical and Materials Perspective to Improve Pavement Performance written by Ebrahim Sangsefidi and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unbound granular aggregates, due to a comparatively lower cost in comparison to bound pavement layers, are extensively used in the construction of road pavements. Thus, it is not surprising that a careful testing and selection of these materials is required to ensure a longlasting pavement life that avoids early and costly maintenance intervention. In order to appropriately evaluate the road aggregates, a series of standardised laboratory tests are undertaken to aid appropriate decision making prior to construction phases beginning. Generally, it is assumed if properly constructed, that the selection of aggregates based on these tests largely guarantees a satisfactory performance of them in the structure of pavements. Based on the results of a number of laboratory tests, aggregates have typically been categorized into two groups; premium and marginal. Where marginal aggregates are excluded from being used in high-trafficked pavement sections or State Highways in New Zealand. However, the depletion of high-quality aggregates, in conjunction with the significant cost of transport haul distance to site and its adverse environmental effects, has led road agencies in New Zealand to consider using locally available aggregates that have a more marginal quality. Due to their inherent mineralogical properties, marginal aggregates are usually more susceptible to adverse environmental conditions of the pavement structure. Therefore, their engineering characteristics can be progressively affected by the in-service weathering processes. Generally, because of the initial mechanical crushing, strong compaction, continuous in-service traffic loading, and direct interaction with the surrounding environment, the process of weathering can be significant in unbound aggregates. This topic is of even higher relevance for New Zealand, where there is a high demand for unbound aggregates and its young geologically sourced aggregates are generally more susceptible to the diverse environmental and climatic conditions. Although weathering processes may happen in a relatively short time and can cause ageing and deterioration of the structure of aggregates, a quantitative evaluation of its effect on road aggregates over the lifetime of the pavement is usually disregarded and properties of aggregates are assumed to be constant over time and location. In order to better understand the weathering process of aggregates and achieve a more efficient use of them this research develops a field and laboratory- based experimental methodology (as follows). Two sources of andesitic unbound aggregates are used in this study, one source of aggregates is characterised to be of high quality and the other of more marginal quality according to the local standard New Zealand Transport Agency (NZTA) M4 specification. - Field-based experiment: The chemical and physical degradation of road aggregates within quarries are considered as an observable analogue of in-situ weathering of aggregates in the pavement structure. A variety of analytical methods, including thin section petrography, X-Ray Fluorescence (XRF), and X-ray Diffraction (XRD) reveal the short-term (less than 15 years) in-situ weathering of aggregates. Overall, the immediate loss of bases and production of clay minerals are the notable trend of chemical weathering of selected aggregates. Moreover, thin-section analysis reveals changes in the textural features of aggregates during the weathering. - Lab-based experiment (loose aggregates): In order to make the current New Zealand standard Weathering Quality Index (WQI) testing a better representative of in-service condition of unbound aggregates a series of modifications are proposed to this testing methodology. These modifications include improved wetting and drying processes, varied characteristics of the weathering solution, and a testing of the wider gradation of aggregates. Compared to standard WQI test, the results show 200% and 70% increase in CI value and 130% and 230% increase in WCI results of produced fines in premium and marginal aggregates, respectively. Thus, it is believed that the modified WQI test method better represents the potential in-field pavement weathering of andesitic road aggregates.in harsh environmental conditions. - Lab-based experiment (loose aggregates): Water is usually known to be a key factor in the performance of the structural elements of road pavements. To gain more insight into the water-aggregate interactions of UGM, a testing methodology is devised to determine the real-time appetite of aggregates for water in various environmental conditions. It is concluded that the water absorption of road aggregates depends upon the temperature and composition of the solution. Due to the increase in the water temperature, 160% and 100% increase in the absorbed water is reported for premium and marginal aggregates, respectively. Furthermore, it is concluded that the standard water absorption testing methodology generally under-estimates the appetite of aggregates to absorb water. In extreme cases, the proposed testing methodology results in 130% higher water absorption compared to the standard test. - Lab-based experiment (compacted aggregates): The effect of Wetting and Drying (WD) cycles on the performance of compacted aggregates are investigated by conducting California Bearing Ratio (CBR) alongside Repeated Load Triaxial (RLT) tests. The results show that W-D can affect the properties of fines in the compacted specimens and controls the swelling behavior of marginal aggregates. W-D cycles result in approximately 40% increase in CI and WCI results of produced fines in both sources of aggregates. The W-D can also have an appreciable effect on the permanent deformation, resilient modulus and CBR values of specimens. 160% increase in permanent deformation is reported for soaked-conditioned premium aggregates, whereas marginal aggregates fail in the last stage of the loading. Overall, a thorough investigation of andesitic aggregate weatherability has been undertaken based upon the fundamental testing techniques required during the selection procedures of aggregates to ensure engineering life performance. This investigation includes an understanding of the ageing properties of the available aggregates and the local environmental condition where the aggregates are to be placed. This can be quite important for marginal aggregates, whose properties are usually more susceptible to environmental conditions. Furthermore, the Pass/fail criteria of the traditional testing methodologies do not adequately consider the durability of road aggregates in the construction, maintenance and environmental conditions that an aggregate is placed. It is believed that a grey-scale labelling (i.e. non-binary pass/fail status) of aggregates would be more effective in describing the materials' natural variability and statistical distribution to subsequently characterise an aggregates performance given the associated environmental and climatic conditions of the target location.
Download or read book Characterisation and Evaluation of Marginal Basecourse Aggregates and the Performance Improvement with Stabilisers written by Wentao Li and published by . This book was released on 2018 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of marginal materials in reducing road construction costs has been realised by road agencies around the world. However, utilising marginal materials without any treatment in the road base can still cause rutting and shear failure of the pavement due to their defects in mechanical, chemical and geological properties. Consequently, to make better use of marginal basecourse materials, two objectives are made in this research: Understanding the 'the marginal' component of aggregates and improving the performance of the marginal aggregates by targeting the reason for marginality. Five greywacke aggregates were studied in this research. The testing methodology is designed to understand the marginality of materials and evaluate the stabilisation techniques. These aggregates have been tested according to the local standard New Zealand Transport Agency (NZTA) M4 specification and assigned to either premium or marginal aggregate categories. To better understand the 'marginality' of aggregates, the mineralogical composition of all aggregates was determined using geological testing methods. A one-dimensional swelling test was developed to determine the effect of swelling minerals on the performance of the water-saturated aggregates. The stress-strain behaviour of unbound granular aggregates was investigated using repeated load triaxial (RLT) tests under soaked and drained conditions. Lime and cement were used to treat marginal materials. The stress-strain behaviour of stabilised marginal materials was investigated under a soaked condition. The results show that the mineralogical and geological characteristics of granular materials have a great impact on the mechanical performance of these materials. Sufficient detrimental minerals, particularly swelling clay minerals, contained in a material will result in the material transforming into a marginal or unacceptable material, particularly when in contact with water. It is insufficient to evaluate the quality of the materials by only using a 'pass/fail' categorisation of engineering tests (specified by local standards). Further infrequently used testing methods (e.g. XRD, the swelling test and RLT test) are required, alongside standard test performance measures, carried out in the context of the intended aggregate loading/environment. Cement and lime stabilisation both improve the mechanical behaviour of marginal aggregate 2 under soaked conditions. However, cement stabilisation is more effective than the lime stabilisation.
Download or read book Proceedings written by Association of Asphalt Paving Technologists and published by . This book was released on 1991 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Asphalt Paving Technology written by Association of Asphalt Paving Technologists and published by . This book was released on 1991 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Superpave Mix Design written by Asphalt Institute and published by . This book was released on 2001-01-01 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Eco efficient Pavement Construction Materials written by Fernando Pacheco-Torgal and published by Woodhead Publishing. This book was released on 2020-01-18 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eco-efficient Pavement Construction Materials acquaints engineers with research findings on new eco-efficient pavement materials and how they can be incorporated into future pavements. Divided into three distinctive parts, the book emphasizes current research topics such as pavements with recycled waste, pavements for climate change mitigation, self-healing pavements, and pavements with energy harvesting potential. Part One considers techniques for recycling, Part Two reviews the contribution of pavements for climate change mitigation, including cool pavements, the development of new coatings for high albedo targets, and the design of pervious pavements. Finally, Part Three focuses on self-healing pavements, addressing novel materials and design and performance. Finally, the book discusses the case of pavements with energy harvesting potential, addressing different technologies on this field. Offers a clear and concise lifecycle assessment of asphalt pavement recycling for greenhouse gas emission with temporal aspects Applies key research trends to green the pavement industry Includes techniques for recycling waste materials, the design of cool pavements, self-healing mechanisms, and key steps in energy harvesting
Download or read book Integrated Materials and Construction Practices for Concrete Pavement written by and published by . This book was released on 2006 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Manual of integrated material and construction practices for concrete pavements.
Download or read book Practices for Unbound Aggregate Pavement Layers written by E. Tutumluer and published by . This book was released on 2013 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: "TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 445: Practices for Unbound Aggregate Pavement Layers consolidates information on the state-of-the-art and state-of-the-practice of designing and constructing unbound aggregate pavement layers. The report summarizes effective practices related to material selection, design, and construction of unbound aggregate layers to potentially improve pavement performance and longevity."--Publisher website.
Download or read book Concrete Pavement Design Construction and Performance written by Norbert Delatte and published by CRC Press. This book was released on 2007-09-12 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addressing the interactions between the different design and construction variables and techniques this book illustrates best practices for constructing economical, long life concrete pavements. The book proceeds in much the same way as a pavement construction project. First, different alternatives for concrete pavement solutions are outlined. The desired performance and behaviour parameters are identified. Next, appropriate materials are outlined and the most suitable concrete proportions determined. The design can be completed, and then the necessary construction steps for translating the design into a durable facility are carried out. Although the focus reflects highways as the most common application, special features of airport, industrial, and light duty pavements are also addressed. Use is made of modeling and performance tools such as HIPERPAV and LTPP to illustrate behavior and performance, along with some case studies. As concrete pavements are more complex than they seem, and the costs of mistakes or of over-design can be high, this is a valuable book for engineers in both the public and private sectors.
Download or read book The Aggregates Handbook Second Edition written by National Stone, Sand & Gravel Association and published by . This book was released on 2013-03-20 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Guide for Pavement Friction written by and published by AASHTO. This book was released on 2008 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains guidelines and recommendations for managing and designing for friction on highway pavements. The contents of this report will be of interest to highway materials, construction, pavement management, safety, design, and research engineers, as well as others concerned with the friction and related surface characteristics of highway pavements.
Download or read book Proceedings of the 5th International Symposium on Asphalt Pavements Environment APE written by Marco Pasetto and published by Springer Nature. This book was released on 2019-08-29 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume highlights the latest advances, innovations, and applications in the field of asphalt pavement technology, as presented by leading international researchers and engineers at the 5th International Symposium on Asphalt Pavements & Environment (ISAP 2019 APE Symposium), held in Padua, Italy on September 11-13, 2019. It covers a diverse range of topics concerning materials and technologies for asphalt pavements, designed for sustainability and environmental compatibility: sustainable pavement materials, marginal materials for asphalt pavements, pavement structures, testing methods and performance, maintenance and management methods, urban heat island mitigation, energy harvesting, and Life Cycle Assessment. The contributions, which were selected by means of a rigorous international peer-review process, present a wealth of exciting ideas that will open novel research directions and foster multidisciplinary collaboration among different specialists.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Construction Sand and Gravel written by and published by . This book was released on 1993 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Highway Engineering written by Athanassios Nikolaides and published by CRC Press. This book was released on 2014-11-24 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt: An International Textbook, from A to ZHighway Engineering: Pavements, Materials and Control of Quality covers the basic principles of pavement management, highlights recent advancements, and details the latest industry standards and techniques in the global market. Utilizing the author's more than 30 years of teaching, researching, and consulting e
Download or read book Sustainable Concrete Pavements written by and published by . This book was released on 2012 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developed as a more detailed follow-up to a 2009 briefing document, Building Sustainable Pavement with Concrete, this guide provides a clear, concise, and cohesive discussion of pavement sustainability concepts and of recommended practices for maximizing the sustainability of concrete pavements. The intended audience includes decision makers and practitioners in both owner-agencies and supply, manufacturing, consulting, and contractor businesses. Readers will find individual chapters with the most recent technical information and best practices related to concrete pavement design, materials, construction, use/operations, renewal, and recycling. In addition, they will find chapters addressing issues specific to pavement sustainability in the urban environment and to the evaluation of pavement sustainability. Development of this guide satisfies a critical need identified in the Sustainability Track (Track 12) of the Long-Term Plan for Concrete Pavement Research and Technology (CP Road Map). The CP Road Map is a national research plan jointly developed by the concrete pavement stakeholder community, including Federal Highway Administration, academic institutions, state departments of transportation, and concrete pavement-related industries. It outlines 12 tracks of priority research needs related to concrete pavements. CP Road Map publications and other operations support services are provided by the National Concrete Pavement Technology Center at Iowa State University. For details about the CP Road Map, see www.cproadmap.org/index.cfm.
Download or read book AASHTO Guide for Design of Pavement Structures 1993 written by American Association of State Highway and Transportation Officials and published by AASHTO. This book was released on 1993 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design related project level pavement management - Economic evaluation of alternative pavement design strategies - Reliability / - Pavement design procedures for new construction or reconstruction : Design requirements - Highway pavement structural design - Low-volume road design / - Pavement design procedures for rehabilitation of existing pavements : Rehabilitation concepts - Guides for field data collection - Rehabilitation methods other than overlay - Rehabilitation methods with overlays / - Mechanistic-empirical design procedures.
