ANALYSIS OF MICROCRACK BEHAVIOR IN MASS CONCRETE By ENRIQUE J. VILLAVICENCIO CAMACHO A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN BUILDING CONSTRUCTION UNIVERSITY OF FLORIDA 2006 1 Copyright 2006 by Enrique J. Villavicencio Camacho 2 To my father: thank you for your hard work, sacrifice, and dedication. Your priority in life has been fulfilled: to provide all your children with an education. I admire you and love you always. This work is also dedicated to my wife, Bárbara. Thank you for your patience, love, and support. 3 ACKNOWLEDGMENTS Thank you to the thesis supervisory committee, Dr. Abdol Chini, Dr. Ajay Shanker, and Dr. Robert Stroh, for their guidance and advice. Special thanks to Dr. Abdol Chini, director of the University of Florida M.E. Rinker, Sr. School of Building Construction, for presenting the challenge and opportunity of working on this project. Sincere thanks are due to the staff of the Florida Department of Transportation Materials Research Laboratory for providing the funding and facilities to conduct this project. I wish to thank Tanya Riedhammer for her assistance in the SEM imaging, and Omar Osmanzai of Allied High Tech, Inc. for his assistance in the image analysis applications. Finally, sincere appreciation is due to Hassan Mozahab for his assistance and collaboration on this project. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS ...............................................................................................................4 LIST OF TABLES...........................................................................................................................7 LIST OF FIGURES .........................................................................................................................8 ABSTRACT...................................................................................................................................10 CHAPTER 1 INTRODUCTION ..................................................................................................................12 Background.............................................................................................................................12 Cracking..................................................................................................................................12 Objective.................................................................................................................................14 Scope of Work ........................................................................................................................14 Literature Review ............................................................................................................14 Sample Selection and Specimen Preparation Technique ................................................14 Imaging............................................................................................................................15 Data Analysis...................................................................................................................16 Summary.................................................................................................................................16 2 LITERATURE REVIEW .......................................................................................................17 Introduction.............................................................................................................................17 Mass Concrete ........................................................................................................................17 Studying Microcracks in Concrete .........................................................................................18 Specimen preparation procedures....................................................................................19 Image analysis procedures...............................................................................................19 Microcrack quantification procedures.............................................................................19 Specimen Preparation Techniques..........................................................................................20 Impregnation Techniques ................................................................................................21 Epoxy Impregnation Technique ......................................................................................21 Wood’s Metal Method.....................................................................................................23 Image Processing and Analysis ..............................................................................................23 Microcrack Quantification......................................................................................................25 3 SPECIMEN PREPARATION METHODOLOGY................................................................28 Introduction.............................................................................................................................28 Concrete Sample Selection.....................................................................................................28 Sample Preparation Technique...............................................................................................31 Lab Procedures for Sample Preparation .................................................................................32 Diamond Saw Cutting .....................................................................................................32 5 Sectioning Procedure.......................................................................................................32 Epoxy Impregnation Procedure.......................................................................................33 Grinding and Polishing Procedures.................................................................................36 Preparation for Imaging..........................................................................................................39 Specimen Preparation Test .....................................................................................................40 Oven-Dried Specimens....................................................................................................41 Summary.................................................................................................................................41 4 IMAGE ANALYSIS METHODOLOGY ..............................................................................43 Introduction.............................................................................................................................43 Image Acquisition...................................................................................................................43 Image Analysis and Microcrack Quantification.....................................................................46 Summary.................................................................................................................................51 5 RESULTS...............................................................................................................................52 Introduction.............................................................................................................................52 Test for Validity of Specimen Preparation Procedure............................................................53 Statistical Analysis Method.............................................................................................53 Analysis of Effect of High Curing Temperatures on Microcracking .....................................56 6 SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS .........................................60 Summary.................................................................................................................................60 Conclusions.............................................................................................................................61 Recommendations...................................................................................................................62 APPENDIX A IMAGE ANALYSIS DATA RESULTS AND ANOVA STATISTICS................................64 B GLOSSARY ...........................................................................................................................69 LIST OF REFERENCES...............................................................................................................70 BIOGRAPHICAL SKETCH .........................................................................................................72 6 LIST OF TABLES Table page 3-1 Concrete sample mixes and labels. ....................................................................................30 3-2 Adiabatic temperature rise data for concrete with cement type B, 95°F placing temperature, and high temperature curing. ........................................................................31 3-3 Mixing schedule of epoxy kit per Structure Probe, Inc. product manual. .........................35 3-4 Grinding and polishing procedure for manual preparation of specimens with MPrep3 and consumables by Allied High Tech Products, Inc........................................................38 3-5 Concrete specimen preparation methods for microstructural analysis of concrete. ..........42