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BENEFICIAL USE OF RECYCLED MATERIALS IN CONCRETE MIXTURES by Patrick Lance Maier B.S. Civil Engineering, University of Colorado Denver, 2008 A thesis submitted to the University of Colorado Denver In partial fulfillment of the requirements for the degree of Master of Science, Structural Engineering Civil Engineering 2011 This thesis for the Master of Science degree by Patrick L. Maier has been approved by Dr. Chengyu Li Date Maier, Patrick Lance (M.S. Structural, Civil Engineering Department) Beneficial Use ofRecycled Materials in Concrete Mixtures Thesis directed by Dr. Stephan A. Durham ABSTRACT The need to produce concrete mixtures with recycled materials is becoming more important than ever before. Not only does using recycled materials in concrete mixtures create landfill avoidance, but it decreases the depletion of virgin raw materials. The basis for this research was to investigate the effects of using recycled materials, in varying amounts, on the fresh and hardened concrete properties. This research includes the design of concrete mixtures composed of varying amounts of recycled material replacements. The recycled materials in this study consisted of ground granulated blast furnace slag (GGBFS), recycled concrete (crushed hardened concrete) and crushed waste glass. The GGBFS was used as a replacement for the cement. The recycled concrete and waste glass were used to replace the coarse and fine aggregates, respectively. The concrete mixtures designed ranged from a twenty five percent replacement to one hundred percent replacement with recycled materials. These mixtures were compared against a standard concrete mixture using cement and virgin aggregates. For comparison purposes, all mixtures were held constant in regards to water to cementitious ratio. The fresh concrete properties examined included slump, air content and unit weight. The hardened properties examined included compressive strength, rate of strength gain, freeze-thaw durability, permeability, and alkali-silica reactivity potential. A concrete mixture composed entirely of recycled materials was developed. This concrete mixture developed substantial strength and durability and is comparable to a normal strength concrete mixture in several aspects. This concrete made from 100% recycled materials was a very low permeable concrete with a compressive strength of 4300 psi (29.6 MPa). A concrete composed of 50% and 75% recycled materials that achieved strengths of nearly 7000 psi (48 MPa) and 6300 psi (43.4 MPa) respectively were also developed. The beneficial and negative effects of using recycled aggregates and GGBFS in a concrete mixture were determined. The deleterious expansions caused by the waste glass reacting with alkalis in the cementitious paste (ASR) were also determined. It was found that GGBFS, when used at replacement levels of 50%, eliminated these concerns when waste glass is used at even 10 0% aggregate replacement levels. The point at which replacement with recycled materials becomes detrimental to the concrete mixture, in regards to strength, durability and workability was determined. A replacement of 50% recycled materials was determined to be an optimum replacement amount for concrete. The use of recycled materials was determined to be a benefit with regards to strength and durability up to 50% when compared with a normal concrete made from virgin materials. However, it was shown that even a concrete with recycled materials in excess of 50% can be very beneficial and comparable to a normal, regular strength concrete. Although freeze-thaw durability's decreased for concretes made with recycled contents in excess of75%, the permeability's of these mixtures are extremely low and when coupled with substantial strength, these concretes would be suitable for use in many applications. This abstract accurately represents the content of the candidate's thesis. I recommend its publication. Signed ------ _______ __ DEDICATION PAGE I dedicate this thesis to my family and friends for their never ending support. To my mother for her continued support and showing me that giving up is not an option. To my brothers for their inspiration to become an engineer. To the many relationships that have been severed and the friendships that were lost over the many years during my undergraduate and graduate studies. ACKNOWLEDGMENT I would like to thank my academic advisor, Dr. Stephan A. Durham. His continued support throughout the years has encouraged me and many others. I would like to thank my long time undergraduate advisor Dr. Kevin Rens for his patience, support and humor over the last decade. I would like to acknowledge Dr. Jonathan Wu, for his inspiration and always having his door open for a wondering mind. I would like to thank Dr. Li for his support and participating on my thesis committee. I would like to thank Dr. N.Y. Chang for his guidance, support and kindness through the years. I would also like to thank Rui Liu, Brian Volmer, Driss Majdoub and Adam Kardos for their support and much appreciated help during my research I would like to thank Katie Bartojay and Bill Kepler for their support during this research. Without their experience, knowledge and contacts in the concrete industry, this research would not have been successful. I would like to thank Morgan Johnson and LEHIGH Cement for their generous contribution of ground granulated blast furnace slag for this research. I would like to thank Tony Able and Rocky Mountain Bottle Recycling for their contributions of waste glass. I would also like to thank John Kent and Oxford Recycling for their donations of recycled concrete. I would like to especially thank Bud Werner and his remarkable staff at CTL Thompson for their generous help testing for potential ASR. Additionally, I would like to thank the faculty and staff of the University of Colorado Denver, Civil Engineering Department for their support and guidance throughout my educational career at UCD. TABLE OF CONTENTS Figures ........................................................................................ xi Tables ......................................................................................... xiii Chapter 1. Introduction .................................................................... . 2. Literature Review............................................................. 6 2.1 Preface.............................................................................. 6 2.2 Ground Granulated Blast Furnace Slag (GGBFS) . . . . . . . . . . . . . . . . . . . . . ... 6 2.2.1 Production....................................................................... 6 2.2.2 Physical, Chemical and Reactive Properties.............................. 7 2.2.3 The Effects of GGBFS on Fresh Concrete Properties.................... 10 2.2.3.1 Slump............................................................................. 10 2.2.3.2 Air Content. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 11 2.2.3.3 Time of Set..................................................................... 12 2.2.3.4 Temperature.................................................................... 13 2.2.4 The Effects of GGBFS on Hardened Concrete Properties............... 14 2.2.4.1 Strength......................................................................... 14 2.2.4.2 Permeability.................................................................... 21 2.2.4.3 Freeze-Thaw Durability....................................................... 24 2.2.4.4 Resistance to Sulfate Attack................................................. 25 2.2.4.5 Alkali-Silica Reactivity...................................................... 29 2.2.5 Summary........................................................................ 33 2.3 Waste Glass as Aggregate................................................... 34 VII 2.3.1 Production...................................................................... 35 2.3.2 Physical and Chemical Properties.......................................... 36 2.3.3 The Effects of Waste Glass on Fresh Concrete Properties............... 38 2.3.3.1 Slump........................................................................... 38 2.3.3.2 Air Content..................................................................... 40 2.3.4 The Effects of Waste Glass on Hardened Concrete Properties......... 41 2.3.4.1 Strength......................................................................... 41 2.3.4.2 Permeability.................................................................... 44 2.3.4.3 Freeze-Thaw Durability...................................................... 46 2.3.4.4 Alkali-Silica Reactivity (ASR).............................................. 47 2.3.5 Summary........................................................................ 50 2.4 Recycled Concrete as Aggregate (RCA)................................... 52 2.4.1 Production...................................................................... 52 2.4.2 Physical and Chemical Properties.......................................... 53 2.4.3 The Effects of RCA on Fresh Concrete Properties....................... 54 2.4.3.1 Slump........................................................................... 54 2.4.3.2 Air Content..................................................................... 57 2.4.4 The Effects of RCA on Hardened Concrete Properties.................. 58 2.4.4.1 Strength. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 2.4.4.2 Permeability.................................................................... 67 2.4.4.3 Freeze-Thaw Durability...................................................... 71 2.4.4.4 Alkali-Silica Reactivity (ASR).............................................. 74 2.4.5 Summary........................................................................ 74 2.5 Expectations................................................................... 76 3. Problem Statement............................................................ 78 3.1 Statement....................................................................... 78 VIII 4. Experimental Plan............................................................. 80 4.1 Design Summary.............................................................. 80 4.2 Material Properties............................................................ 81 4.2.1 Ground Granulated Blast Furnace Slag (GGBFS)... ... ... . . . ... ... . .. .. . 81 4.2.2 Portland Cement............................................................... 82 4.2.3 (Virgin) Coarse and Fine Aggregates....................................... 84 4.2.4 (Recycled) Coarse and Fine Aggregates................................... 84 4.2.4.1 Waste Glass as Fine Aggregate............................................. 85 4.2.4.2 Recycled Concrete as Coarse Aggregate (RCA).......................... 88 4.2.5 Chemical Admixtures......................................................... 91 4.2.5.1 Air Entraining Admixture (AEA)........... .............. ... . . . . . . . . . . . . . ... 91 4.2.5.2 High Range Water Reducing Admixture (HRWRA).... .. .. . . . . . .. .. .... 91 4.3 Mixture Designs............................................................... 92 4.3.1 Mixture Batching........................................................... ... 96 4.3.2 Curing........................................................................... 97 4.4 Concrete Testing............................................................... 97 5. Experimental Results......................................................... 99 5.1 General.......................................................................... 99 5.2 Problems with this Study..................................................... 99 5.2.1 Re-Batch of Mixture #2 (1 00-RA-C) and Mixture #3 (1 00-RA-BF) Due to Consolidation Concerns............................................. 99 5.2.2 Re-Batch ofMixture #2 (100-RA-C) Due to Lack of Specimen Quantities....................................................................... 101 5.2.3 Freeze-Thaw Chamber........................................................ 101 5.3 Fresh Concrete Properties.................................................... 103 5.3.1 Slump........................................................................... 103 IX 5.3.2 AirContent..................................................................... 107 5.3.3 Unit Weight.................................................................... 108 5.4 Hardened Concrete Properties............................................... 111 5.4.1 Compressive Strength......................................................... 111 5.4.2 Permeability.................................................................... 124 5.4.3 Freeze-Thaw Durability...................................................... 130 5.4.4 Alkali-Silica Reactivity (ASR). .. .. . ... . ..... ......... ... .. . . ...... .. ... . ... 149 6. Conclusions and Recommendations........................................ 157 6.1 Summary........................................................................ 157 6.2 Recommendations for Future Studies....................................... 161 Appendix A. Concrete Mixture Designs................................................... 169 B. Material Product Data Sheets................................................ 176 Bibliography................................................................................ 164 X