NANOTECHNOLOGY IN CONCRETE: CRITICAL REVIEW AND STATISTICAL ANALYSIS by Jonathan Glenn A Thesis Submitted to the Faculty of The College of Engineering and Computer Science In Partial Fulfillment of the Requirements for the degree of Master of Science Florida Atlantic University Boca Raton, Florida May 2013 ACKNOWLEDGEMENTS I would like to thank all of the people who made this thesis and degree possible starting with my advisor Dr. Khaled Sobhan who has been a great help guiding me not only in my graduate studies but also as an undergraduate student. Also the members of my committee, Dr. D.V. Reddy and Dr. Yan Yong, who have supported and helped me in every step of this thesis. I also want to thank Dr. Ramesh Teegavarapu for his help in the Monte Carlo analysis portion of this thesis. I want to thank my friends and family who have helped support me through my studies especially my parents for all of their love and support. As well as my girlfriend Jessica Mendoza who has been there encouraging me and supporting me every step of the way. I also thank my Lord and savior Jesus Christ without whom I would not have made it to this point. iii ABSTRACT Author: Jonathan Glenn Title: Nanotechnology in Concrete: State of the Art and Practice Institution: Florida Atlantic University Advisor: Dr. Khaled Sobhan Degree: Master of Science in Engineering Year: 2013 This thesis investigates the use of nanotechnology in an extensive literature search in the field of cement and concrete. A summary is presented. The research was divided into two categories: (1) nanoparticles and (2) nanofibers and nanotubes. The successes and challenges of each category is documented in this thesis. The data from the literature search is taken and analyzed using statistical prediction by the use of the Monte Carlo and Bayesian methods. It shows how statistical prediction can be used to analyze patterns and trends and also discover optimal additive dosages for concrete mixes. iv NANOTECHNOLOGY IN CONCRETE: CRITICAL REVIEW AND STATISTICAL ANALYSIS CHAPTER 1: INTRODUCTION ...............................................................................................................1 1.1 Background………………………………………………………………….....1 1.2 Objectives……………………………………………………………………....7 CHAPTER 2: NANOPARTICLES .....................................................................................8 2.1 Nanoparticles…………………………………………………………………...8 2.2 Effect of Nanosilica Particles to Cement Pastes, with a Focus on C-S-H Gel…………………………………………………………………………….9 2.3 Effect of Nano-SiO2 Particles Produced by Using the Sol-Gel Method on Cement Systems………………………………………………………………….15 2.4 Effect of Nanosilica on Concrete Strength and Stiffness by Homogenization Model……………………………………………………………..18 2.5 Effect of Nanoclays on Fresh State of Concrete……………………………...23 2.6 Effect of Nanoparticles on Mechanical Properties of Air-Entrained Concrete…………………………………………………………………………… 27 v 2.7 Effect of Nanoporous Film Coatings on Aggregate Surface to Improve Interfacial Transition Zone…………………………………………………....32 2.8 Effect of Nanocement on Reactive Powder Concrete………………………...37 CHAPTER 3: NANOFIBERS AND NANOTUBES ........................................................43 3.1 Nanofibers and Nanotubes……………………………………………………43 3.2 Methods of Distribution of Carbon Nanofibers and Nanotubes in Cement Paste………………………………………………………………………..44 3.3 Carbon Nanofibers Directly Synthesized on Cement Particles……………….49 3.4 Effect of Carbon Nanotubes on Mechanical Properties of Cement Mortar…..53 3.5 Effect of High-Range Water Reducer on Distribution and Strength of Carbon Nanofiber-Cement Composites…………………………………………….57 3.6 Effect of Carbon Nanotubes and Carbon Fibers on the Behavior of Plain Cement Composite Beams……………………………………………………61 CHAPTER 4: ANALYSIS & RESULTS ..........................................................................67 4.1 Background…………………………………………………………………...67 4.2 Analysis Methodology………………………………………………………..69 4.3 Analysis Results………………………………………………………………74 CHAPTER 5: CONCLUSION ..........................................................................................96 5.1 State of the Art: Research and Practice…………………………………….....97 vi 5.2 Statistical Prediction…………………………………………………………..99 APPENDIX ......................................................................................................................101 BIBLIOGRAPHY ............................................................................................................104 vii LIST OF TABLES Table 1: Performance of Nano- Mortars ........................................................................... 17 Table 2: Hardened Concrete Properties at 28 Days .......................................................... 30 Table 3: Improvements in Mechanical Properties for Later Stages of Curing ................. 35 Table 4: Test Information ................................................................................................. 55 Table 5: Nanomaterials and W/CM range ........................................................................ 70 Table 6: Optimum Dosage for Concrete Containing Nanomaterials at specific W/CM Ratio ...................................................................................................................... 83 Table 7: Complete list of nanomaterials ......................................................................... 101 viii LIST OF FIGURES Figure 1: Calorimetry tests of pastes with 0%, 3%, and 6% by weight nanosilica .......... 10 Figure 2: Compressive strength as a function of the time from mixing ........................... 11 Figure 3: Porosity values obtained by mercury intrusion porosimetry ............................. 12 Figure 4: Schematic representation of OPC hydration and pozzolanic reaction to develop the volume fractions of the four phases for a cement paste RVE ................... 20 Figure 5: Effect of nanosilica on the behavior of cement paste ........................................ 23 Figure 6: Green strength results ........................................................................................ 25 Figure 7: Minipaver schematic ......................................................................................... 26 Figure 8: Coulombs passed in chloride ion penetration test specimens ........................... 36 Figure 9: TEM micrograph of nanocement showing the particles ................................... 39 Figure 10: Compressive strength comparisons with various nanocement additions at various curing ages ........................................................................................ 40 Figure 11: Splitting tensile strength comparisons with various nanocement additions at various curing ages ........................................................................................ 40 Figure 12: (a) Fractured surface of hardened cement paste reinforced with CNFs. (b) Agglomerated and closely packed CNFs in some areas of the fractured surface ....... 47 Figure 13: Type I portland cement particles. .................................................................... 48 ix Figure 14: Schematic of experimental setup based on continuous feeding of cement particles with a screw feeder ............................................................................................. 50 Figure 15: Schematic of experimental setup based on fluidized bed conditions ............. 50 Figure 16: SEM images of hardened cement paste ........................................................... 52 Figure 17: Effect of HRWR on disaggregation and dispersion of CNFs in water suspension ......................................................................................................................... 58 Figure 18: Splitting tensile strength at 7 days for CNF-cement composites .................... 60 Figure 19: Variation of ultimate load for different proportions ........................................ 63 Figure 20: Variation of flexural strength for different proportions .................................. 64 Figure 21: Variation of deflection for different proportions ............................................. 64 Figure 22: Dosage % vs 28 Day Strength of Test Data containing CNTs with a W/CM=0.4-0.5 .................................................................................................................. 75 Figure 23: Dosage % vs 28 Day Strength of Test Data containing CNTs with a W/CM=0.6-0.65 ................................................................................................................ 75 Figure 24: Dosage % vs 28 Day Strength of Test Data containing Nanoclay with a W/CM=0.38 ...................................................................................................................... 76 Figure 25: Dosage % vs 28 Day Strength of Test Data containing Nanoclay with a W/CM=0.45 ...................................................................................................................... 77 Figure 26: Frequency of Compressive Strengths for CNT with W/CM=0.4-0.5 ............. 78 Figure 27: Frequency of Compressive Strengths for CNT with W/CM=0.6-0.65 ........... 79 Figure 28: Frequency of Compressive Strengths for Nanoclay with W/CM=0.38 .......... 80 Figure 29: Frequency of Compressive Strengths for Nanoclay with W/CM=0.45 .......... 81 x Figure 30: Monte Carlo Compressive Strength Prediction for Concrete Containing CNTs at W/CM=0.4-0.5 ..................................................................................................