A Structural Material Model for Granular Bases

A Structural Material Model for Granular Bases
Author:
Publisher:
Total Pages:
Release: 1997
Genre:
ISBN:

Techniques typically used in mechanistic analyses to characterize the behavior of unbound granular materials in a flexible pavement often predict stress conditions exceeding the material's static strength. Some pavement analysis tools such as ILLI-PAVE attempt to adjust predicted stresses in unbound layers so that they do not violate the Mohr-Coulomb failure envelope. However, the adjusted stresses are used only to calculate the resilient modulus to be used in the next iteration of the model, resulting in final stresses that are questionable and that frequently exceed the material's strength. Laboratory resilient modulus tests were conducted on granular at stress states exceeding the material's static shear strengths. Based on the data obtained, a material model for unbound granular material was developed that is a modification of the commonly used k-theta-n model for unbound granular materials. In addition, an advantage of the modified model is the ability to analyze the structural effects of granular materials having different shear strength characteristics. For the covering abstract of this conference see IRRD number 872978.

Deformation Characteristics of Granular Materials Subjected to Rapid, Repetitive Loading

Deformation Characteristics of Granular Materials Subjected to Rapid, Repetitive Loading
Author: Wayne A. Dunlap
Publisher:
Total Pages: 444
Release: 1967
Genre: Aggregates (Building materials)
ISBN:

The engineering behavior of soils and aggregates is a function of their basic properties and the environment to which they are subjected. In pavement design the effect of repeated loading is in important environmental condition which has received little attention, especially for granular materials. This report present results showing the influence of repetitive triaxial stressing on the deformation of granular (flexible base course) materials. The materials examined were a) hard rounded material (gravel), b) hard angular material manufactured by crushing oversized pieces of the gravel, and c) a soft crushed limestone. Each material -- except the soft -- was tested at three separate gradations representing the coarse, medium and fine ranges allowed by Texas Highway Department specifications for such materials. The total strain characteristics of the materials were quantitatively related to the applied stresses and number of stress repetitions. It was shown that the behavior under repetitive stresses was not closely related to static shear strengths as determined by the Texas triaxial method. Rebound strains could only be expressed qualitatively. Under repetitive stressing the rounded material, which ranked lowest in static shear tests, was at least equivalent to the angular material for the stress range expected in roadways; both were superior to the soft material. It is believed that the relative densities of the respective materials influenced their behavior more than particle shape or hardness. Finally, recommendations were made for improving equipment and testing procedures which should simplify analysis of results and reduce experimental error in future investigations.

Paving Materials and Pavement Analysis

Paving Materials and Pavement Analysis
Author: American Society of Civil Engineers
Publisher: Amer Society of Civil Engineers
Total Pages: 592
Release: 2010
Genre: Technology & Engineering
ISBN: 9780784411049

Pavement Design And Paving Material Selection are important for efficient, cost effective, durable, and safe transportation infrastructure Paving Materials and Pavement Analysis contains 73 papers examining bound and unbound material characterization, modeling, and performance of highway and airfield pavements. The papers in this publication were presented during the GeoShanghal 2010 International Conference held in Shanghai, China, June 3-5, 2010.

Advances in Geotechnical Engineering

Advances in Geotechnical Engineering
Author: R. J. Jardine
Publisher: Thomas Telford
Total Pages: 708
Release: 2004
Genre: Technology & Engineering
ISBN: 9780727732644

The main body of the first volume is taken up by five major keynote papers written by a team of international experts, that survey the enormous advances that have taken place in geotechnical engineering since Skempton's pioneering early work. The second volume contains more than 80 articles that report recent research and advances in practice from around the world. The papers focus on the broad range of geotechnical issues, that most interested Professor Skempton, and are grouped under the headings of: - Soil behaviour, characterisation and modelling - Foundations - Slopes and embankments - Ground performance - The influence of geology on civil engineering.

Design and Construction of Pavements and Rail Tracks

Design and Construction of Pavements and Rail Tracks
Author: Antonio Gomes Correia
Publisher: CRC Press
Total Pages: 220
Release: 2007-05-24
Genre: Technology & Engineering
ISBN: 0203937546

Design and Construction of Pavements and Rail Tracks - Geotechnical Aspects and Processed Materials is a compilation of selected contributions produced between 2002 and 2005 by the International Committee TC3 - Geotechnics of Pavements of the International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE), a committee dedicated to gat

Introduction to Unmanned Aircraft Systems, Second Edition

Introduction to Unmanned Aircraft Systems, Second Edition
Author: Douglas M. Marshall
Publisher: CRC Press
Total Pages: 1944
Release: 2015-10-26
Genre: Political Science
ISBN: 113802693X

The proliferation of technological capability, miniaturization, and demand for aerial intelligence is pushing unmanned aerial systems (UAS) into the realm of a multi-billion dollar industry. This book surveys the UAS landscape from history to future applications. It discusses commercial applications, integration into the national airspace system (NAS), System function, operational procedures, safety concerns, and a host of other relevant topics. The book is dynamic and well-illustrated with separate sections for terminology and web- based resources for further information.

Unbound Aggregates in Roads

Unbound Aggregates in Roads
Author: R.H. Jones
Publisher: Butterworth-Heinemann
Total Pages: 437
Release: 2016-04-20
Genre: Technology & Engineering
ISBN: 1483163210

Unbound Aggregates in Roads contains the proceedings of the International Symposium on Unbound Aggregates in Roads (UNBAR3) held at the University of Nottingham, England, on April 11-13, 1989. The papers focus on unbound aggregates used in road construction and cover topics ranging from drainage and permeability to placement and compaction of unbound aggregates, design philosophy, specification, and compliance. This book consists of 49 chapters divided into eight sections and opens with an overview of the functions of unbound aggregates in roads, followed by a discussion on the mechanical properties of different aggregates and theoretical aspects of granular materials. The following chapters focus on granular drainage layers in pavement foundations; residual stresses caused by compaction in granular materials; and alternative materials for road construction such as steel slags and natural and waste materials. The use of unbound road aggregates in various countries such as Italy, France, Germany, and Portugal is also considered. This monograph will be a useful resource for designers, aggregate producers, contractors, specification writers, and materials engineers.