A pavement system basically consists of a surface layer, a base course, a subbase (optional) and the subgrade. As per MEPDG and 1993 AASHTO flexible pavement design guide Resilient Modulus (MR) is used as the primary input parameter to determine the stiffness parameters and the constitutive behavior of pavement components, such as subgrade and unbound bases. Generally, pavements are constructed on compacted soils that are typically unsaturated with degrees of saturation varying from 75 to 90%. The main focus of this research is to determine the effect of matric suction on the resilient moduli property of the base materials. The second objective of the research is to study the use of MEPDG models to calibrate resilient moduli properties either as a function of moisture content or soil suction variables. In order to assess these objectives, these unbound materials were tested using suction controlled MR and moisture controlled MR procedures. Amendments were done by preparing the specimens at five different moisture content and dry density conditions. Suction controlled MR testing took longer time to reach the equilibrium conditions and the results obtained were close to the results obtained from moisture controlled MR procedure. The initial suction conditions are studied using Fredlund device (Tempe cell). Test results indicate that the specimens compacted on the dry side of the optimum have high resilient modulus due to the stress hardening behavior. MEPDG program procedure was followed to predict the soil water characteristic curve. Lastly, two three model parameter models developed by Cary and Zapata (2010) and Modified Universal model are studied and analyzed in detail. Validity of the correlation equations are addressed by comparing measured MR to predicted MR values. Results suggest that the models used are well suited for predicting the resilient modulus and soil water characteristic curve of the two unbound base materials.

According to the new Mechanistic Empirical Pavement Design Guide (MEPDG) and 1993 AASHTO flexible pavement design guide, Resilient Modulus (MR) has been used extensively as an important material property in structure design of pavement. The modulus is used as the primary input parameter to determine the stiffness parameters and constitutive behavior of pavement components. The system of pavement basically consists of the layers of surface, base, subbase (optional), and subgrade. The compacted subgrade soils supporting pavement structure are typically unsaturated with degrees of saturation varying from 75% to 90%. The effect of unsaturated soil behavior on the mechanical properties of compacted pavement materials become an important variable and need to be considered. The main purpose of this study is to study the resilient moduli properties of compacted and unsaturated subgrade materials and to determine the effect of compaction moisture content, which is related to matric suction of the soils, on the resilient moduli properties. The second objective is to study the use of MEPDG models to calibrate resilient moduli properties either as a function of moisture content or soil suction variables. To accomplish these objectives, soil specimens were prepared at five different moisture content and dry density conditions and tested using conventional resilient modulus testing as per AASHTO T-307 procedure. The basic soil tests such as grain size distribution, Atterberg's limits, and standard proctor compaction were initially performed. Then, the advanced soil tests consisting of soil water characteristic curve (SWCCs), unconfined compressive strength (UCS) test, and conventional resilient modulus test were conducted. The soil suction conditions of the prepared specimens were determined based on the SWCCs information and the compaction moisture content. The test results indicate that compaction moisture content affected the values of resilient modulus of the subgrade soils. The specimens compacted at dry side of optimum moisture content (OMC) showed higher values of resilient modulus compared with the specimens compacted at OMC and wet side of OMC. The testing data were also analyzed with the models provided in MEPDG program. The level 2 input for predicting SWCCs provided in MEPDG gave the predicted SWCCs in similar trend to the measured SWCCs. However, the curves were not quite well matched. Lastly, the modified universal model and the model proposed by Cary and Zapata (2010) were studied and analyzed in detail. The results showed that the universal model is well suited for predicting the resilient modulus of the subgrade soils. However, the resilient modulus values predicted by the model of Cary and Zapata, sometime, showed the higher values than measured results especially, the specimens compacted at 0.8OMC.

This volume presents selected papers presented during the 4th International Conference on Transportation Geotechnics (ICTG). The papers address the geotechnical challenges in design, construction, maintenance, monitoring, and upgrading of roads, railways, airfields, and harbor facilities and other ground transportation infrastructure with the goal of providing safe, economic, environmental, reliable and sustainable infrastructures. This volume will be of interest to postgraduate students, academics, researchers, and consultants working in the field of civil and transport infrastructure.

New theories and testing techniques related with Unsaturated Soil Mechanics have proven to be valuable tools to study a broad spectrum of geo-materials which includes rocks, rock fills, frozen soils and domiciliary solid wastes. These new theories and testing techniques have permitted the analysis of several traditional problems from a new perspective (e.g., swelling or collapsible soils and compacted soils or pavements materials), and they have also shown their efficiency to study new energy-related problems like CO2 sequestration and nuclear waste disposal. Advances in Unsaturated Soils is a collection of papers from the 1st Pan-American Conference on Unsaturated Soils organized in Cartagena de Indias, Colombia, in February 2013. The volume includes 76 research papers coming for all over the world, as well as 7 keynotes papers by well known international researchers. The contributions present a variety of topics including: • Advances in testing techniques • Unsaturated soil behavior • Constitutive modeling and microstructure • Numerical modeling • Geotechnical problems Advances in Unsaturated Soils is expected to become a useful reference to academics and professionals involved in Unsaturated Soil Mechanics.

This book is an outcome of the sixth conference on bearing capacity of roads and airfield held in Lisbon, Portugal. It focuses on railway tracks and covers following topics: bearing capacity policies, concepts, costs and condition surveys; analysis and modelling; design and environmental effects.

Unsaturated Soils: Research and Applications contains 247 papers presented at 6th International Conference on Unsaturated Soils (UNSAT2014, Sydney, Australia, 2-4 July 2014). The two volumes provide an overview of recent experimental and theoretical advances in a wide variety of topics related to unsaturated soil mechanics: - Unsaturated Soil Behavior - Experimentation - Modelling - Case Histories - Geotechnical Engineering Problems - Multidisciplinary and New Areas Unsaturated Soils: Research and Applications presents a wealth of information, and is of interest to researchers and practising engineers in soil mechanics and geotechnical engineering. These proceedings are dedicated to Professor Geoffrey E. Blight (1934-2013), who passed in November 2013.

Applications of Unsaturated Polyester Resins: Synthesis, Modifications, and Preparation Methods takes a practical approach to unsaturated polyester-based materials and their preparation for implementation in a range of innovative areas. Sections introduce the background of polyester and the fundamentals of unsaturated polyester resins (UPRs), including chemistry, additives, curing, and processing methods. Hydrolytic stability and structure-property relationships are also discussed in detail, along with coverage of modification strategies for UPR and the development of bio-composites incorporating natural fiber with unsaturated polyester. Subsequent chapters focus on the preparation of UPR for specific target applications, including in construction, marine and aerospace, adhesives and coatings, insulation systems, electrics, pipeline corrosion, military, biomedicine, and tissue engineering. Finally, the advantages and disadvantages of UPR compared to other resins, in terms of properties and performance, as well as life cycle assessment, are addressed and analyzed. Presents processing methods, morphology, structure-property relationship, and modification strategies for unsaturated polyester Explores sustainability in terms of lifecycle assessment of unsaturated polyester and bio-composites incorporating unsaturated polyester Guides the reader to advanced applications across construction, marine and aerospace, adhesives and coatings, electrics and many more areas