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Author : Michael J. Mengelt
Publisher :
ISBN 13 :
Total Pages : 394 pages
Book Rating : 4.:/5 (89 download)
Download or read book Reinforcement of Flexible Pavement Structures Using Geocells written by Michael J. Mengelt and published by . This book was released on 2000 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Wai-leuk Lau
Publisher :
ISBN 13 :
Total Pages : 372 pages
Book Rating : 4.:/5 (89 download)
Download or read book Use of Geocells in Flexible Pavements Over Poor Subgrades written by Wai-leuk Lau and published by . This book was released on 2001 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Anu Muthumala George
Publisher :
ISBN 13 :
Total Pages : 254 pages
Book Rating : 4.:/5 (132 download)
Download or read book Utilization of Geocell-reinforced RAP Material Base Layer in Flexible Pavements written by Anu Muthumala George and published by . This book was released on 2019 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reclaimed asphalt pavement (RAP) materials have been considered as one of the most sustainable and cost-effective options in the pavement industry. The use of RAP materials in pavement construction reduces natural resources depletion and the volume of construction debris discarded into the landfills. However, the low shear strength and high permanent deformation (PD) of RAP materials often limit their application in road bases. Utilization of mechanical stabilizers, such as geocell, for stabilizing RAP bases, have found to be effective in improving the pavement performance. The main objective of this study is to assess the efficacy of high-density polyethylene (HDPE) geocell reinforcements in enhancing the strength and stiffness properties of RAP bases and for mitigating PD behavior. In this dissertation research, several large-scale static and repeated load tests were performed on the unreinforced RAP base (URB) and geocell-reinforced RAP bases (GRRB) over clay subgrade. The performance of the geocell reinforcement was evaluated based on various parameters including bearing capacity (q), elastic deformation (ED), PD, resilient modulus (Mr), traffic benefit ratio (TBR), and rut depth reduction (RDR). Test results showed that the HDPE geocell layer increased the Mr and reduced the PD of the RAP base layer when compared to URB. Numerical models of the GRRB sections were developed to assess the load transfer mechanism of geocell reinforcement under static and dynamic loading. These models were developed in FLAC3D (special character) software by employing finite-difference (FD) approach. The unreinforced and reinforced FD models were validated with experimental results and a good agreement between both was observed. The validated FD model was then used to perform parametric studies to assess the factors affecting the performance of geocell-reinforced bases. Additionally, a life-cycle assessment (LCA) and life-cycle cost analysis (LCCA) were performed to estimate the current and future cost of the pavement section with GRRB. This analysis considered agency, user, environmental, and health impact costs incurred during the service life of the pavement section. Finally, an LCA-LCCA framework was developed to assess the sustainability of the pavement infrastructure using a sustainability index. The results showed that the GRRB can be successfully used as a sustainable and cost-effective replacement for virgin aggregate bases. The findings from this research would aid in the development of design charts for assessing the response of geocell-reinforced pavement bases under static and repeated loading.
Author : T. G. Sitharam
Publisher : Springer Nature
ISBN 13 : 9811560951
Total Pages : 484 pages
Book Rating : 4.8/5 (115 download)
Download or read book Geocells written by T. G. Sitharam and published by Springer Nature. This book was released on 2020-07-23 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is designed to serve as a comprehensive resource on cellular confinement systems or geocells, covering technologies and their applications in geotechnical engineering. The book discusses all aspects of geocells and related technologies, and covers the subjects from conceptual basics to recent advances. The chapters of this book are written by renowned international experts and its contents include detailed case studies from both academic and industry experts. This book is a one-stop reference work for academicians, students, and practicing engineers in the global geotechnical community.
Author : Richard D. Barksdale
Publisher : Transportation Research Board National Research
ISBN 13 :
Total Pages : 68 pages
Book Rating : 4.3/5 (555 download)
Download or read book Potential Benefits of Geosynthetics in Flexible Pavement Systems written by Richard D. Barksdale and published by Transportation Research Board National Research. This book was released on 1989 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Steven W. Perkins
Publisher :
ISBN 13 :
Total Pages : 140 pages
Book Rating : 4.:/5 (414 download)
Download or read book Geosynthetic Reinforcement of Flexible Pavements written by Steven W. Perkins and published by . This book was released on 1999 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the course of the last 17 years, approximately 12 different studies have shown the potential for the use of geosynthetic materials (geogrids and geotextiles) as a reinforcement inclusion in the base course aggregate layer of flexible pavements. The attraction of this application lies in the possibility of reducing the thickness of the base course layer such that a roadway of equal service life results or in extending the service life of the roadway. While several existing studies have provided data that aid in describing mechanisms of reinforcement, detailed information required to understand the mechanisms by which geosynthetics reinforce flexible pavements is lacking. In the absence of this information, it has historically been difficult to create mechanistic based models that adequately describe the process. As such, efforts to establish design solutions have been based largely on empirical data and considerations. Existing design solutions have not been met with open acceptance due to their inability to predict performance for conditions other than those established in the experiments for which the solution was based. This research was undertaken to provide experimental data that could be used to further establish the mechanisms of geosynthetic reinforcement that lead to enhanced pavement performance. Subsequent work will involve the use of these data in developing numerical models and design solutions for this application. Pavement test sections have been constructed in a laboratory based pavement test facility. The facility consists of a large concrete box in which field scale pavement layers can be constructed. Loading is provided through the application of a cyclic, 40 kN load applied to a stationary plate resting on the pavement surface. The test sections have been instrumented with an extensive series of stress and strain cells. Test section variables have included geosynthetic type (two biaxial geogrid products and one woven geotextile), subgrade type and strength, placement position of the geosynthetic in the base course layer and base course layer thickness. The results have shown that the inclusion of a geosynthetic provides a significant reinforcement effect. The geosynthetic is shown to have an influence on the amount of lateral spreading that occurs in both the bottom of the base course layer and in the top of the subgrade. Reinforcement is also seen to produce a more distributed vertical stress distribution on the top of the subgrade. As a result of these effects, reinforcement limits the vertical strain developed in the base and subgrade layers, leading to less surface deformation. Given that these mechanisms result from the development of shear interaction between the base and the geosynthetic, the combination of these effects is termed a mechanism of a shear resisting interface. These effects are seen to be most significant for a soft subgrade where substantial improvement in pavement performance has been observed. Geosynthetic type, strength, stiffness and placement position are also seen to influence observed improvement.
Author : Irfan Pekgurbuz
Publisher :
ISBN 13 :
Total Pages : 124 pages
Book Rating : 4.:/5 (486 download)
Download or read book Flexible Pavement Structures written by Irfan Pekgurbuz and published by . This book was released on 1965 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Stacy L. Hilbrich
Publisher :
ISBN 13 :
Total Pages : 72 pages
Book Rating : 4.3/5 (555 download)
Download or read book Design Considerations for Flexible Pavement Widening written by Stacy L. Hilbrich and published by . This book was released on 2007 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Ryan Berg
Publisher :
ISBN 13 :
Total Pages : 352 pages
Book Rating : 4.:/5 (547 download)
Download or read book GMA White Paper Ii written by Ryan Berg and published by . This book was released on 2000 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geosynthetic reinforcement of the base, or subbase, course of pavement structures is addressed. The value added with reinforcement, design criteria/protocols, and practices for design and for material specifications are presented. Base, or subbase, reinforcement is defined within as the use of geosynthetic reinforcement in flexible pavements to support vehicular traffic over the life of a pavement structure. Primary base reinforcement benefits are to improve the service life and/or obtain equivalent performance with a reduced structural section. Substantial life-cycle cost savings are possible with base reinforcement. The use of geosynthetic reinforcement to aid in construction over low strength subgrades, termed subgrade restraint within, is also addressed. Geosynthetic reinforcement is used to increase the support equipment during construction of a roadway. Geogrid, geotextile, and geogrid-geotextile composite materials are addressed within.
Author : Christopher William LaRoche Nelsen
Publisher :
ISBN 13 :
Total Pages : 340 pages
Book Rating : 4.:/5 (19 download)
Download or read book Experimental Evaluation of Geocell Reinforcement Behavior Using Transparent Soil Techniques written by Christopher William LaRoche Nelsen and published by . This book was released on 2018 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geocells are a growing type of geosynthetic product used in many applications, including the reinforcement of unbound granular materials for the construction of flexible pavements. Although significant research has been conducted to quantify the performance of geocell-reinforced soil masses, there is no universally accepted design method for these structures. The Mechanistic-Empirical Pavement Design Guide (MEPDG) is a solid framework on which to base a geocell design method. The resilient modulus of a material is constitutive relationship between the imposed stress state and the resilient strain. It is the relevant design parameter that should be modified in the MEPDG for the design of pavement structures using geocells. However, a more robust understanding of the behavior and mechanisms that contribute to the overall performance of geocell-reinforced materials is necessary to develop theoretically-sound model. As such, the materials and equipment necessary to conduct a thorough analysis of geocells were conceived and implemented as part of this study. This equipment is based around the transparent soil concept – transparent soils are two-part media consisting of solid particles and a saturating fluid with matching refractive indices. Fused quartz and mineral oil were selected as appropriate materials to use as a granular soil surrogate. The large-scale equipment consists of a steel-framed tank with cast acrylic sides. Many lessons were learned with regard to the use of transparent soil techniques in large-scale experiments. Preliminary results indicate the equipment is adequate to validate the results of prior geocell experiments. Additional improvements will allow for the full utilization of transparent soil capabilities and the direct observation of geocell reinforcement behavior and mechanisms in-situ.
Author : Steven W. Perkins
Publisher :
ISBN 13 :
Total Pages : 156 pages
Book Rating : 4.:/5 (79 download)
Download or read book Mechanistic-empirical Modeling and Design Model Development of Geosynthetic Reinforced Flexible Pavements written by Steven W. Perkins and published by . This book was released on 2001 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report provides an appendix for the report with the reference: Perkins, S.W. (2001) Mechanistic Empirical Modeling and Design Model Development of Geosynthetic Reinforced Flexible Pavements: Final Report, Montana Department of Transportation, Helena, Montana, FHWA/MT 01 002/99160 1A, 156p. This report contains output from the software program DARWin for each design example provided in Appendix B of the above referenced report.
Author : Ronald L. Baus
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (278 download)
Download or read book Investigation of Subgrade Resilent Modulus in Flexible Pavement Design, Phase I written by Ronald L. Baus and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Eddie Chou
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (573 download)
Download or read book Structural Support of Lime Or Cement Stabilized Subgrade Used with Flexible Pavements written by Eddie Chou and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Behnoud Kermani
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (13 download)
Download or read book Experimental and Numerical Study of Subgrade Soil Migration Into Pavement Subbase and Mitigation Using Geotextile written by Behnoud Kermani and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle transport and its subsequent deposition in porous media play a significant role in the performance of civil infrastructure such as pavements. Pavement structure typically consists of an asphalt concrete or concrete surface layer, underlying granular layers (subbase and/or base), and a compacted subgrade soil layer. As the subgrade is saturated during wet seasons, cyclic loading caused by heavy traffic may lead to pumping of fine particles from the subgrade into the granular layers. Additionally, in rigid pavements, the repeated traffic loading may also result in redistribution of materials underneath the slabs, which contributes to faulting of rigid pavement slabs. Pumping of fines negatively impacts the performance and service life of the pavement and ultimately may lead to failure. The main objectives of this research are to (1) investigate occurrence of migration of fines and simulate and quantify the magnitude and rate of such migration in both flexible and rigid pavements and for different classes of roadways, (2) evaluate the effectiveness of geotextiles as a separation and filtration layer in preventing subgrade fines migration, and (3) understand the mechanisms of fines migration in pavement and provide a reasonable prediction of the amount of fines migration using a numerical model on particle transport in porous media.The cyclic traffic loading is simulated on geometrically-scaled models of flexible and rigid pavements representing a typical collector road and interstate highways using a one-third-scale Model Mobile Load Simulator (MMLS3), an accelerated pavement testing (APT) device. The pavement sections are constructed on partially saturated aggregate subbase overlying non-plastic saturated silt as subgrade. To evaluate the effectiveness of geotextile separation and filtration in reducing subgrade fines migration, identical tests simulating flexible collector road and rigid interstate highway are repeated, except that a geotextile layer is placed at the interface of subgrade and subbase layers. The results obtained from the tests with and without geotextile separator layer are then compared. The lab testing reveals that, under repeated traffic loading, a significant amount of fines migrated into the subbase. More migration occurs in the simulated collector road than in the interstate highway. The subgrade fines migration in mass percentage increases with the simulated traffic loading cycles. The resulting gradation of subbase also varies with the depth in the subbase, with more fines deposited in the lower section (closer to the subgrade) than in the upper section of the subbase. In the jointed rigid pavement, more fines accumulated in the subbase beneath the approach slab than beneath the leave slab, confirming that migration of fines counter to the direction of traffic occurs when the load moves to the leave slab. A geotextile separation layer at the subgrade-subbase interface can be used as an effective means to reduce pumping of subgrade fines in pavement by providing both separation and filtration. Finally, a numerical model is formulated to understand the mechanisms of particle transport in pavement and to provide a reasonable prediction of the amount of fines migration in pavement. The model is verified using the results from the scaled pavement testing conducted on flexible pavements to quantify the magnitude and rate of subgrade fines migration. The numerical study suggests that the deposition of the subgrade soil into subbase is governed by hydraulic condition, grain size of subgrade, grain size and pore size of subbase, permeability of subbase, and viscosity of pore fluid in the subbase. Moreover, magnitude and duration of applied load play a leading role in the amount of pumping in pavement, as also revealed in the experimental study.
Author : James W. Andrew
Publisher :
ISBN 13 :
Total Pages : 314 pages
Book Rating : 4.:/5 (434 download)
Download or read book Resolving Seasonal Fluctuations in Flexible Pavement Subgrade Response written by James W. Andrew and published by . This book was released on 1998 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Steven W. Perkins
Publisher :
ISBN 13 :
Total Pages : 97 pages
Book Rating : 4.:/5 (486 download)
Download or read book Numerical Modeling of Geosynthetic Reinforced Flexible Pavements written by Steven W. Perkins and published by . This book was released on 2001 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies conducted over the course of the past 20 years have demonstrated both general and specific benefits of using geosynthetics as reinforcement materials in flexible pavements. Existing design solutions are largely empirically based and appear to be unable to account for many of the variables that influence the benefit derived from the reinforcement. Advanced numerical modeling techniques present an opportunity for providing insight into the mechanics of these systems and can assist with the formulation of simplified numerical methods that incorporate essential features needed to predict the behavior of these systems. Previous experimental work involving the construction of geosynthetic reinforced test sections has shown several difficulties and uncertainties associated with the definition of reinforcement benefit for a single cycle of load application. Even though many reinforcement mechanisms are apparent and often times striking during the application of the first load cycle, the distinction between reinforced test sections is not nearly so clear as that which is seen when examining long term performance, where long term performance is defined in terms of permanent surface deformation after many load cycles have been applied. This indicates the need for an advanced numerical model that is capable of describing the repeated load behavior of reinforced pavements. In particular, models for the various pavement layers are needed to allow for a description of the accumulation of permanent strain under repeated loads. To meet these needs, a finite element model of unreinforced and geosynthetic reinforced pavements was created. The material model for the asphalt concrete layer consisted of an elastic perfectly plastic model where material property direction dependency could be added. This model allowed for the asphalt concrete layer to deform with the underlying base aggregate and subgrade layers as repeated pavement loads were applied. A bounding surface plasticity model was used for the base aggregate and subgrade layers. The model is well suited for the prediction of accumulated permanent strains under repeated loading and is most suitable for fine grained materials. A material model containing components of elasticity, plasticity, creep and direction dependency was formulated for the geosynthetic and calibrated against a series of in air tension tests. A Coulomb friction model was used to describe shear interaction between the base aggregate and the geosynthetic. The model is essentially an elastic-perfectly plastic model, allowing for specification of the shear interface stiffness and ultimate strength. This model was calibrated from a series of pull out tests. Finite element models were created to match the conditions in pavement test sections reported by Perkins (1999a). Membrane elements were used for the geosynthetic and a contact interface was used between the geosynthetic and the base course aggregate. Models of unreinforced and reinforced pavement sections were created and compared to test section resuts.
Author : R. B. Beattie
Publisher :
ISBN 13 :
Total Pages : 126 pages
Book Rating : 4.:/5 (221 download)
Download or read book Studies of Flexible Pavements Built on Sand Subgrades written by R. B. Beattie and published by . This book was released on 1962 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
