UUnniivveerrssiittyy ooff WWiinnddssoorr SScchhoollaarrsshhiipp aatt UUWWiinnddssoorr Electronic Theses and Dissertations Theses, Dissertations, and Major Papers 2013 IIDDEENNTTIIFFIICCAATTIIOONN OOFF CCOONNCCRREETTEE FFRRAACCTTUURREE PPAARRAAMMEETTEERRSS UUSSIINNGG DDIIGGIITTAALL IIMMAAGGEE CCOORRRREELLAATTIIOONN AANNDD IINNVVEERRSSEE AANNAALLYYSSIISS Wafa Polies Asmaro University of Windsor Follow this and additional works at: https://scholar.uwindsor.ca/etd Part of the Civil and Environmental Engineering Commons RReeccoommmmeennddeedd CCiittaattiioonn Polies Asmaro, Wafa, "IDENTIFICATION OF CONCRETE FRACTURE PARAMETERS USING DIGITAL IMAGE CORRELATION AND INVERSE ANALYSIS" (2013). Electronic Theses and Dissertations. 4952. https://scholar.uwindsor.ca/etd/4952 This online database contains the full-text of PhD dissertations and Masters’ theses of University of Windsor students from 1954 forward. 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IDENTIFICATION OF CONCRETE FRACTURE PARAMETERS USING DIGITAL IMAGE CORRELATION AND INVERSE ANALYSIS By Wafa Polies Asmaro A Dissertation Submitted to the Faculty of Graduate Studies through Civil and Environmental Engineering in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy at the University of Windsor Windsor, Ontario, Canada 2013 © 2013 Wafa Polies IDENTIFICATION OF CONCRETE FRACTURE PARAMETERS USING DIGITAL IMAGE CORRELATION AND INVERSE ANALYSIS By Wafa Polies APPROVED BY: ___________________________________ P. Leger, External Examiner Ecole Polytechnique Montreal, University of Montreal ______________________________________________ D. Green, Outside Department Reader Department of Mechanical, Automotive & Materials Engineering ______________________________________________ A. El Ragaby, Department Reader Department of Civil and Environmental Engineering ______________________________________________ M. Madugula, Department Reader Department of Civil and Environmental Engineering ______________________________________________ F. Ghrib, Principal Advisor Department of Civil and Environmental Engineering ______________________________________________ S. Cheng, Co-Advisor Department of Civil and Environmental Engineering June 14, 2013 DECLARATION OF ORIGINALITY I hereby certify that I am the sole author of this dissertation and that no part of this dissertation has been published or submitted for publication. I certify that, to the best of my knowledge, my dissertation does not infringe upon anyone’s copyright nor violate any proprietary rights and that any ideas, techniques, quotations, or any other material from the work of other people included in my dissertation, published or otherwise, are fully acknowledged in accordance with the standard referencing practices. Furthermore, to the extent that I have included copyrighted material that surpasses the bounds of fair dealing within the meaning of the Canada Copyright Act, I certify that I have obtained a written permission from the copyright owner(s) to include such material(s) in my thesis and have included copies of such copyright clearances to my appendix. I declare that this is a true copy of my dissertation, including any final revisions, as approved by my dissertation committee and the Graduate Studies office, and that this thesis has not been submitted for a higher degree to any other University or Institution. iii ABSTRACT Concrete is one of the oldest materials used for construction, yet it still poses fundamental problems for engineers and researchers. The most critical problem is the propagation of cracks in concrete structures, but the mere presence of cracks does not necessarily mean that the concrete structure has reached the limit of its service life; however, instability caused by the propagation of these defects could result in the failure of a concrete structure. Thus, the focus of fracture mechanics is on assessing the stability of a structure, rather than detecting the presence of cracks. An accurate analysis of the progress of a fracture is required for assessing the integrity of a concrete structure and to predict its future performance. Accordingly, finite element analysis was used to model the performance of cracked concrete structures using available damage models, which require accurate evaluation of the mechanical and fracture properties. While concrete’s mechanical properties are well known, the identification of concrete’s fracture parameters poses an ongoing challenge. Concrete is a heterogeneous material with complicated fracture patterns. Therefore, sensors attached directly to the specimen to measure the crack opening do not provide accurate measures. The objective of this research is to develop a new methodology to study a cracked concrete structure’s performance using a non-contact technique to monitor the development of the fracture process zone without causing interference during fracture. Consequently, Digital Image Correlation was chosen and iv applied successfully to the Wedge Splitting Test to study a cracked structure’s response, represented by the mean of the load-crack tip opening displacement. Since the WST is an indirect fracture test, the experimental data was used to identify concrete fracture parameters by means of inverse analysis based on the cohesive crack model. The associated forward problem is based on the cracked hinge model, which is capable of accounting for the softening phenomenon. The use of Digital Image Correlation made it possible to study the dynamics of crack propagation. Experimental observations are thoroughly discussed, with special attention being placed on the monitoring of the crack’s evolution, and the variation of dissipated energy and tensile damage along the crack path. v DEDICATION TO MY LOVELY CHILDREN RITA, RIVA & RYAN This would not have been possible without your love, patience, and understanding. vi ACKNOWLEDGEMENTS First and foremost, I would like to thank God who gave me strength and patience while guiding me in the work of this Dissertation. Without His blessings, this research work could not have been completed. This project has been carried out under the supervision and guidance of Dr. Faouzi Ghrib to whom I am grateful for his endless constructive commentary, valuable suggestions, and continuous support in making this study a success. I am also grateful to my co-advisor, Dr. Shaohong Cheng, for all her support. I was privileged and honored to have Dr. Pierre Leger as the external examiner. I am in appreciation for his acceptance of this invitation and I am also grateful for the time and effort he dedicated in making valuable recommendations for this dissertation. I would like to express my sincere gratitude to the Outside Department Reader, Dr. Daniel Green, for his encouragements, and the time and effort he dedicated to read this dissertation and provide constructive suggestions. Dr. Daniel Green supplied the ARAMIS system that was crucial to this research work. I would like to thank Dr. Amr El Ragaby, the Department Reader, for the time he dedicated in reading and reviewing this dissertation and also for his support, valuable advices, and recommendations. vii I would like to thank Dr. Murty Madugula, the Department Reader, for his time in reviewing this dissertation and also for his valuable recommendations. Completion of this doctoral dissertation would not have been possible without the technical staff: Lucian Pop, Patrick Seguin, and Matthew St. Louis. Their assistance during laboratory work is crucial and much appreciated. I would like to also thank my colleagues Mena Bebawy, Li Li, Nori Saady, and Muhsin Hamdoon for their constant support. A special thanks is extended to Jan Skoček, from the Technical University of Denmark, for his valuable advice regarding the wedge splitting test set-up. A special appreciation is also extended to the faculty and staff of the Department of Civil and Environmental Engineering including the Faculty of Engineering and the Faculty of Graduate Studies and also to the Leddy Library of the University of Windsor. Finally, I would like to express my deepest gratitude to my husband, Laith, for his understanding and encouragements and also to my lovely children: Rita, Riva, and Ryan for their love, patience, and sacrifices. To all of those people, I would like to say God bless you. viii TABLE OF CONTENTS DECLARATION OF ORIGINALITY .............................................................................. iii ABSTRACT ………………………………………………….…………………….….....iv DEDICATION …………………………………………………………………………………………..vi ACKNOWLEDGEMENTS .............................................................................................. vii LIST OF TABLES ......................................................................................................... xii LIST OF FIGURES ........................................................................................................ xiii CHAPTER I. INTRODUCTION 1.1 General ..............................................................................................1 1.2 Problem Definition ............................................................................ 2 1.3 Research Objectives and Scope ......................................................... 8 1.4 Thesis Contents and Organization .................................................... 11 II. BACKGROUND AND LITERATURE REVIEW OF CONCRETE FRACTURE MECHANICS 2.1 Introduction ...................................................................................... 13 2.2 History of Fracture Mechanics ......................................................... 14 2.3 Mechanical Properties of Concrete .................................................. 17 2.4 Fracture Properties of Concrete ........................................................ 20 2.5 Deficiencies in Concrete Structure ................................................... 23 2.6 Linear Elastic Fracture Mechanics (LEFM) ..................................... 24 2.7 Nonlinear Fracture Mechanics (NLFM) .......................................... 27 2.8 Application of Fracture Mechanics to Concrete Material ................ 29 2.9 Fracture Mechanisms and Structural Design ................................... 31 2.10 Modeling Concrete Fracture Behaviour ........................................... 35 2.11 Simulation of Concrete Structural Damage and Cracking ............... 41 2.12 Experimental Techniques for Concrete Fracture Characterization .. 53 2.12.1 Experimental Determination of Concrete Fracture Parameters ........................................................................... 53 2.12.2 Experimental Investigations of the FPZ and Crack Evolution ............................................................................. 68 2.13 Conclusion ....................................................................................... 76 ix