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:

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.

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:

Download or read book Evaluation of Geosynthetics Reinforcement in Flexible Pavement Structures Using Accelerated Pavement Testing written by Baoshan Huang and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

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.

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.

Download or read book Evaluating the Effectiveness of a Hybrid Geosynthetic Reinforcement System to Mitigate Differential Heave on Flexible Pavement Due to Expansive Subgrades written by Mir Md Tamim and published by . This book was released on 2017 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Transportation industries encounter substantial challenges with respect to ride quality and serviceability when they deal with expansive soils underneath roadway structures. These soils exhibit swell-shrink behavior with moisture variations, which cause surficial heaving on the pavement structure and cost billions of dollars for the maintenance of pavements. For the past four decades, a particular stretch of US-95 (Oregon line to Elephant Butte) exhibited recurrent swelling distresses due to the underlying expansive soils. Despite remedial measures that exhibited satisfactory results for most of the sections, recurrent damage still continued in few sections. Further research indicated that the problematic soils were located at a depth below 1.82 m. Conventional chemical remediation methods typically performed at a depth no greater than 0.9 to 1.2 m. To be able to address the adverse effects of this swell-shrink behavior of soil at a deeper depth, hybrid geosynthetic systems were proposed. Hybrid geosynthetic systems were successfully used to mitigate expansive soil swelling in railroad applications. Hence, this research study explored this idea of using hybrid geosynthetic reinforcement systems (geocell-geogrid combination) to mitigate differential pavement heaving resulting from underlying expansive soils. To evaluate the use of hybrid geosynthetic systems in reducing differential heaving from expansive subgrades, a large-scale box test was developed to simulate a pavement section with a base course and expansive subgrade (asphalt overlay was ignored). The surficial heaving on the base course reinforced with geocell, geogrid and hybrid geosynthetic reinforced system (HGRS) were measured over time and compared with the unreinforced case. The large-scale box test results showed that the geosynthetic systems significantly reduced the maximum surficial heave along with the differential swelling on the pavement section. HGRS exhibited better performance than geocells and geogrids. Numerical analysis using the finite element approach was conducted to study the response of other soil types not tested in the box. The numerical model was first calibrated using using the box test results and the calibrated model was used to change soil properties for two other soil types with different swelling charecteristics. In the numerical model, swelling behavior of expansive soils was simulated using material models that incorporate volumetric swelling and suction as a function of moisture content. The modulus of the unreinforced base was determined using laboratory tests while the modulus that for the reinforced sections was calibrated using large scale test data. The calibration of control model was performed by controlling the moisture percolation through subgrade."--Boise State University ScholarWorks.

Download or read book Recent Advances in Mechanics of Functional Materials and Structures written by Poonam Kumari and published by Springer Nature. This book was released on with total page 587 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Subsurface Characterization of Flexible Pavements Constructed Over Expansive Soil Subgrades and Selection of Suitable Rehabilitation Alternatives written by Kazi Moinul Islam and published by . This book was released on 2017 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Expansive soils present significant engineering challenges, with annual costs associated with repairing structures constructed over expansive soils estimated to run into several billion dollars. Volume changes in expansive soil deposits induced by fluctuations in the moisture content can result in severe damage to overlying structures. A flexible pavement section near the Western Border of Idaho has experienced recurrent damage due to volume changes in the underlying expansive soil layer; traditional stabilization methods have provided partial success over the years. The main objective of this research effort was to characterize the problematic soil layer contributing to the recurrent pavement damage and propose suitable rehabilitation alternatives. An extensive laboratory test matrix was carried out to characterize soil samples collected from underneath the problematic pavement section. Laboratory tests showed that the problematic expansive soil deposit was often at depths greater than 6 ft. (183 cm) from the pavement surface. Potential Vertical Rise (PVR) values calculated for ten boreholes strategically placed along the problematic pavement section closely matched with the surface roughness profile observed in the field. Liquidity Index (LI) calculations indicated that the active-zone extended to a depth of least 11 ft. (335 cm) from the pavement surface, and therefore, most of the heaving likely originates from soil layers as deep as 11 ft. (335 cm) from the pavement surface. Clay mineralogy tests indicated the presence of high amounts of Montmorillonite that can lead to significant volume changes. Moreover, high sulfate contents were detected in soil samples obtained from several of the boreholes, indicating a potential for sulfate-induced heaving upon chemical stabilization using calcium-based stabilizers. Based on findings from the laboratory testing, it was concluded that chemical stabilization or shallow treatment alternatives are not likely to be successful in mitigating the recurrent differential heave problems. A mechanical stabilization approach using geocells was proposed as a likely rehabilitation alternative for this pavement section. By dissipating the heave-induced stresses over a wider area, this reinforcement configuration was hypothesized to significantly reduce the differential heave. Finite-element models of the pavement section comprising six alternative geocell-reinforced configurations were prepared using the commercially available package, ABAQUS. Moisture swelling and suction properties for the expansive soil deposit were established in the laboratory and were used in the numerical model to simulate the swelling behavior. Results from the numerical modeling effort established that placing two layers of geocell within the unbound granular base layer led to the highest reduction (~60%) in the differential heave. Placing a single layer of geocell, on the other hand, reduced the differential heave magnitude by approximately 50%. A single layer of geocell was therefore recommended for implementation to achieve the optimal balance between pavement performance and construction costs."--Boise State University ScholarWorks.

Download or read book Recommended Practice for Geosynthetic Reinforcement of the Aggregate Base Course of Flexible Pavement Structures written by American Association of State and Highway Transportation Officials and published by . This book was released on 2017 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: This standard practice provides guidance to pavement designers interested in incorporating geosynthetics for the purpose of reinforcing the aggregate base course of flexible pavement structures. Geosynthetic reinforcement is intended to provide structural support of traffic loads over the life of the pavement. For the purpose of this guide, base reinforcement is the use of a geosynthetic within, or directly beneath, the granular base course. When referring to geosynthetics, the discussion is limited to geotextiles, geogrids, or geogrid/geotextile composites.

Download or read book A Study of Geosynthetic Reinforced Flexible Pavement System written by Ranjiv Gupta and published by . This book was released on 2009 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of geosynthetics as reinforcement for the base layer of flexible pavement systems has grown steadily over the past thirty years. In spite of the evidence that geosynthetic reinforcements can lead to improved pavement performance, the specific conditions or mechanisms that enable and govern the reinforcement are unclear, largely remaining unidentified and unmeasured. The appropriate selection of design parameters for geosynthetics is complicated by the difficulty in associating their relevant properties to the improved pavement performance. In addition, pavement structures deteriorate under the combined effects of traffic loading and environmental conditions, such as moisture changes. However, these factors have not been studied together in the evaluation of the overall performance of pavement systems. Consequently, this research focused on the assessment of the effect of geosynthetics on the pavement structural section's ability to support traffic loads and to resist environmental changes. Accordingly, the primary objectives of this research were: (i) to determine the governing mechanisms and relevant properties of geosynthetics that contribute to the enhanced performance of pavement systems; (ii) to develop appropriate analytical, laboratory and field methods that are capable of quantifying the above properties for geosynthetics; and (iii) to enable the prediction of pavement performance depending on the various types of geosynthetics used. To fulfill these three objectives, an evaluative, laboratory and field study was performed. The improved performance of pavements due to addition of geosynthetics was attributed to the ability of geosynthetics to laterally restrain the base course material, thereby providing a confinement effect to the pavement. A parameter to quantify the soil-geosynthetic interaction at low displacement magnitudes based on the solution of an analytical model for geosynthetics confined in pullout box was proposed. The pullout tests were then conducted on various geosynthetics to obtain the proposed parameter for various geosynthetics. The quantitative magnitude of the parameter value from the laboratory tests was compared with the qualitative performance observed in the field test sections. Overall, a good agreement was obtained between the laboratory and field results, thereby providing confidence in the ability of the proposed analytical model to predict the governing mechanism for geosynthetic reinforced pavements.

Download or read book Principles and Practice of Ground Improvement written by Jie Han and published by John Wiley & Sons. This book was released on 2015-05-26 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gain a stronger foundation with optimal ground improvement Before you break ground on a new structure, you need to analyze the structure of the ground. Expert analysis and optimization of the geo-materials on your site can mean the difference between a lasting structure and a school in a sinkhole. Sometimes problematic geology is expected because of the location, but other times it's only unearthed once construction has begun. You need to be able to quickly adapt your project plan to include an improvement to unfavorable ground before the project can safely continue. Principles and Practice of Ground Improvement is the only comprehensive, up-to-date compendium of solutions to this critical aspect of civil engineering. Dr. Jie Han, registered Professional Engineer and preeminent voice in geotechnical engineering, is the ultimate guide to the methods and best practices of ground improvement. Han walks you through various ground improvement solutions and provides theoretical and practical advice for determining which technique fits each situation. Follow examples to find solutions to complex problems Complete homework problems to tackle issues that present themselves in the field Study design procedures for each technique to simplify field implementation Brush up on modern ground improvement technologies to keep abreast of all available options Principles and Practice of Ground Improvement can be used as a textbook, and includes Powerpoint slides for instructors. It's also a handy field reference for contractors and installers who actually implement plans. There are many ground improvement solutions out there, but there is no single right answer to every situation. Principles and Practice of Ground Improvement will give you the information you need to analyze the problem, then design and implement the best possible solution.

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:

Download or read book Structural Improvement of Flexible Pavements Using Geosynthetics for Base Course Reinforcement written by Maine. Department of Transportation and published by . This book was released on 2000 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laboratory Characterization of Geogrid reinforced Unbound Granular Material for Use in Flexible Pavement Structures written by Gael Souci and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Improvements of Flexible Pavements Using Geosynthetics for Base Course Reinforcement written by Karen S. Henry and published by . This book was released on 2009 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: