FIELD MONITORING OF SHRINKAGE CRACKING POTENTIAL IN A HIGH-PERFORMANCE CONCRETE BRIDGE DECK By TIM WALKOWICH A Thesis submitted to the Graduate School – New Brunswick Rutgers, The State University of New Jersey in partial fulfillment of the requirements for the degree of Master of Science Graduate Program in Civil and Environmental Engineering Written under the direction of Dr. Hani Nassif and approved by New Brunswick, New Jersey January 2011 ABSTRACT OF THE THESIS Field Monitoring of Shrinkage Cracking Potential in a High- Performance Concrete Bridge Deck Thesis Director: Dr. Hani H. Nassif Over the past decade many state engineers throughout New Jersey have reported cracking on High Performance Concrete (HPC) bridge decks at early ages. The presence of cracking early in the life of a high performance deck offsets the benefits gained in using the material as the potential for corrosion begins at the onset of cracking. While many factors apply to bridge deck cracking, the shrinkage of the concrete’s mass is a primary concern. Because of shear studs and boundary conditions, among other causes that act in restraining the deck itself, it is important to understand the mechanics of concrete under restraint. The AASHTO Passive Ring Test (PP 34-06) is seeing an increase in use in studies analyzing restrained shrinkage. The test simulates a concrete member of infinite length and allows researchers to study the effects of various parameters on restrained shrinkage. This thesis presents the results of a study that analyzed the ring test’s ability to simulate restrained shrinkage on HPC bridge decks. The investigation incorporated an instrumented, simply supported ii composite bridge deck with laboratory samples taken on the day of the pour as well as a finite element analysis. The results suggest the AASHTO Passive Ring Test simulates the restrained shrinkage of simply supported HPC decks reasonably well. Fewer than 1% of all cracking present on the ring specimens saw complete penetration through the sample with 80-90% of all cracking considered to be micro cracking. While the presence of several cracks along the bridge deck itself showed no correlation with the shrinkage ring specimens, finite element analysis suggests these cracks are a result of adjacent live load. Also, the findings of this study highlight the importance of following design in the field as well as the effect of live load on staged construction of HPC bridge decks. iii ACKNOWLEDGMENTS I would like to thank Dr. Hani H. Nassif for all the opportunities I have been fortunate enough to take as well as his support throughout my time at Rutgers. The knowledge and experience I have gained through my relationship with him has been and I am sure will continue to be invaluable. I would also like to thank Dr. Husam S. Najm and Dr. Kaan Ozbay for being on my committee and providing their insight. I would like to thank my father and mother, Anthony and Mary Ellen Walkowich for helping me to grow into the person I am today. Without their guidance I would not have achieved half of what I have at this point in my life. Special thanks to my sisters, Heather and Jessica, without whom I would not have the laughter and memories that keep me going when times are rough. I am forever in debt to Carl Fleurimond, Dan Su, Etkin Kara, Ufuk Ates and Gunup Kwan. Their friendship and guidance were critical in my success at Rutgers and I wish them all nothing but the best in their future efforts. Without the help and participation of both the NJ Turnpike Authority and the SHAW Group, Inc., this thesis would not be possible. Thank you in particular to Adel, Scott, and Paul for allowing me on site whenever my research required. Thank you to Mike, Chris, Alex, Parth, John, Peng and everyone and anyone that ever helped in the lab in any way big or small. The assistance you provided made my experience at Rutgers possible. iv Last, I would like to thank my closest friends Artie, Eric, Chris, Bryan, Matt and Jake. Through the good times and the bad you have all stuck with me and I cannot put into words what that has meant to me. v TABLE OF CONTENTS ABSTRACT OF THE THESIS ii ACKNOWLEDGMENTS vi CHAPTER I – INTRODUCTION 1 1.1. PROBLEM STATEMENT 1 1.2. RESEARCH OBJECTIVES AND SCOPE 2 1.3. THESIS ORGANIZATION 2 CHAPTER II – LITERATURE REVIEW 4 2.1. INTRODUCTION 4 2.2. TYPES OF SHRINKAGE 4 2.2.1. PLASTIC SHRINKAGE 5 2.2.2. THERMAL SHRINKAGE 5 2.2.3. AUTOGENOUS SHRINKAGE 6 2.2.4. DRYING SHRINKAGE 6 2.3. SHRINKAGE FACTORS 7 2.4. RESTRAINED SHRINKAGE RING TEST 8 2.4.1. RING TEST BACKGROUND 8 2.4.2. RING TEST SETUP 11 2.5. PREVIOUS WORK 12 CHAPTER III – EXPERIMENTAL SETUP 35 3.1. INTRODUCTION 35 3.2. MATERIAL PROPERTIES OF MIX 36 3.3. MIXING AND FRESH SAMPLING OF CONCRETE 37 3.3.1. SLUMP TEST 38 3.3.2. AIR CONTENT 39 3.3.3. SAMPLING OF SPECIMENS AND CONSOLIDATION 40 3.3.4. CURING 41 3.4. INSTRUMENT DETAILS AND FIELD IMPLEMENTATION 42 3.4.1. EMBEDDED VIBRATING WIRE STRAIN GAUGES 42 3.4.2. PORTABLE DATA LOGGER 45 3.4.3. ACCELEROMETERS 46 3.4.4. LASER DOPPLER VIBROMETER 46 3.4.5. STRUCTURAL TESTING SYSTEM 47 3.5. LABORATORY TESTING PROCEDURES 49 3.5.1. COMPRESSIVE STRENGTH OF CONCRETE SPECIMENS 49 3.5.2. SPLITTING TENSILE STRENGTH OF CONCRETE SPECIMENS 50 3.5.3. MODULUS OF ELASTICITY 51 3.5.4. FREE SHRINKAGE TEST 52 3.5.5. RESTRAINED SHRINKAGE TEST 53 3.5.5.1. ENVIRONMENTAL CHAMBER 54 vi CHAPTER IV – TEST RESULTS 56 4.1. INTRODUCTION 56 4.2. MECHANICAL PROPERTIES 56 4.2.1. COMPRESSIVE STRENGTH 56 4.2.2. SPLITTING TENSILE STRENGTH 58 4.2.3. ELASTIC MODULUS 59 4.2.4. FREE SHRINKAGE 60 4.3. LABORATORY TEST RESULTS 61 4.3.1. SHRINKAGE RINGS 61 4.4. FIELD TEST RESULTS 68 4.4.1. FIELD STRAINS 68 4.4.2. BRIDGE DECK CRACKING 76 CHAPTER V – FINITE ELEMENT MODELING 82 5.1. INTRODUCTION 82 5.1.1. MODEL ELEMENT TYPES 82 5.1.1.1. BEAM ELEMENT 83 5.1.1.2. SHELL ELEMENT 83 5.1.1.3. STEEL REINFORCEMENT 84 5.1.1.4. SHEAR STUDS 84 5.1.1.5. BOUNDARY CONDITIONS 84 5.1.1.6. CONSTRAINT AND RELEASE ELEMENTS 85 5.1.2. MATERIAL PROPERTIES 85 5.2. FINITE ELEMENT ANALYSIS RESULTS 87 5.2.1. BRIDGE DECK ANALYSIS 87 5.2.2. FINITE ELEMENT CONCLUSION 102 CHAPTER VI – SUMMARY AND CONCLUSIONS 103 6.1. SUMMARY AND CONCLUSIONS 103 6.2. FUTURE SCOPE OF WORK 104 REFERENCES 105 vii LIST OF TABLES Table 2.5-1. Phase I and II Mix Proportions (Whiting, et. al. 2000) 17 Table 2.5-2. Time to First Crack for FDD Mixes (Whiting, et. al. 2000) 20 Table 2.5-3. Time to First Crack for TDO Mixes (Whiting, et. al. 2000) 20 Table 2.5-4. Time to First Crack for Phase II Mixes (Whiting, et. al. 2000) 21 Table 2.5-5. North Eastern Ohio Field Survey Results (Delatte, et. al.) 23 Table 2.5-6. Absorptive Light Weight Aggregate Mix Proportions (Delatte, et. al.) 23 Table 2.5-7. Cracking Dates for Ring Specimens (Delatte, et. al.) 24 Table 2.5-8. Time to Cracking of Ring, RE and RBE Test Samples (Weiss, et. al.) 26 Table 3.2-1. NJ Turnpike Mix Design 37 Table 3.2-2. NJ Turnpike Admixture Content 37 Table 3.4-1. VWSG Orientations and Locations 44 Table 3.5-1. Summary of Laboratory Tests Performed 49 Table 4.2-1. Compressive Strength of Concrete Mix over Time 57 Table 4.2-2. Compressive Strength of Concrete Mix over Time 58 Table 4.2-3. Compressive Strength of Concrete Mix over Time 60 Table 4.2-4. Free Shrinkage of Concrete Mix over Time 61 Table 4.3-1. Crack Width Distribution Over All Samples 67 Table 4.4-1. Crack Map Details 77 Table 5.2-1. Strain Validation 88 Table 5.2-2. Concrete Properties for New Concrete Sections 89 Table 5.2-3. FE Model Strains Resulting from Case 1 Loading 91 Table 5.2-4. FE Model Strains Resulting from Case 2 Loading 93 Table 5.2-5. FE Model Strains Resulting from Case 3 Loading 95 Table 5.2-6. FE Model Strains from Case 4 Loading 96 Table 5.2-7. FE Model Strains from Case 4 Loading 97 Table 5.2-8. FE Model Strains from Case 6 Loading 99 Table 5.2-9. FE Model Strains from Case 7 Loading 100 Table 5.2-9. FE Model Strains from Case 7 Loading 101 viii LIST OF FIGURES Figure 2.4.1. AASHTO Ring Test Geometry 11 Figure 2.5.1. Shah, Ouyang, et. al. Element Mesh 14 Figure 2.5.2. Tensile Strength Prediction (A) and Experimental (B) (Shah, Ouyang, et. al.) 16 Figure 2.5.3. Shrinkage of HPC mixes with varying w/c and silica fume content (Whiting, et. al) 18 Figure 2.5.4. Shrinkage of HPC mixes with varying geometry and w/c (Whiting, et. al) 19 Figure 2.5.5. RE and RBE Test Method Setup (Weiss, et. al.) 25 Figure 2.5.6. Typical Cracking Observed on NJ Bridge Decks (Saadeghvaziri and Hadidi) 27 Figure 2.5.7. Bridge Survey Distribution throughout NJ (Saadeghvaziri and Hadidi) 27 Figure 2.5.8.