USE OF FILLED POLYMERS FOR STRUCTURAL APPLICATIONS By WOLFGANG RYOR 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 CONSTRUCTION MANAGEMENT UNIVERSITY OF FLORIDA 2018 © 2018 Wolfgang Ryor ACKNOWLEDGMENTS First, I would be remiss without acknowledging my parents who, as professional educators, instilled within me the pursuit of academic goals. Several people were integral to the completion of the foregoing research. Grateful appreciation to Dr. Nancy Ruzycki who was invaluable as a guide through technical and conceptual difficulties.
Many thanks are also owed to the staff and entire department of materials engineering at the University of Florida. Testing would not have been possible without their help. Speaking of testing, thank you to Ebenezer Tackey Otoo, who provided his research and spent many hours explaining various mixtures. A special nod, also, to Dr.
The idea for this thesis was born in her mechanics class. Strain gauge guru, Dr. Peter Ifju, gave his time to educate the author regarding the operation of those essential tools. Professor Michael Cook helped with materials estimating.
I’d like to thank my chair, Dr. Larry Muszynski, and my committee, Dr. Raymond Issa and Dr. I have often interrupted their busy schedules to seek their advice.
Finally, Wendy Thornton has been superb as editor of this manuscript. 3 TABLE OF CONTENTS page ACKNOWLEDGMENTS .3 LIST OF TABLES .6 LIST OF FIGURES .8 CHAPTER 1 A FLORIDA EXPERIMENT .10 Conceptualizing the Phenomenon of Change .12 Employing the Means of Change .14 Case Study of Change Utilization.16 Allowing for Variety within Change .19 The Ultimate Simplicity of Change .22 The Solution of Functional Learning Curves .22 Change is Dependent upon Time .29 3D Printing of Plastic Structural Components.29 Rejecting Polymer Extrusion in a Process Developed from 3D Polymer Printing .30 Subordination of Polymer Alternatives to Concrete Practices .30 Cementitious Materials as Polymer-centric Transition .33 The Current Situation .33 Advocating for a Polymer Bench .34 Constructability and Perception of Concrete Versus Plastic .38 Properties of a Corner Wall Section and Faux Wood.39 Education through a Shifted Paradigm .41 Marketing Plastic Homes .51 A Limited Hypothesis using Contour Crafting .51 The Marketing of Faux Wood .52 Concrete Versus Cementitious Material .52 An Aside into Competing Life Cycle Claims .52 Life Cycle of Concrete.54 More Accurate Assessment of Materials Costs .65 7 LIMITATIONS AND SUGGESTED FURTHER RESEARCH .83 5 LIST OF TABLES Table page 6-1 Summary of materials properties.71 6 LIST OF FIGURES Figure page 1-1 Optimistic blog item regarding thermosets.28 3-1 Concrete stress-strain graph.48 3-2 Polymer stress-strain graph.48 3-3 Fracture toughness and Young’s Modulus Ashby graph.49 3-4 Author’s photo of walking bridge at the University of Florida student union.49 3-5 USCB information of proportion of private to public construction.50 4-1 Flexural Strength against Relative Cost .58 4-2 Back-end energy costs of materials.58 6-1 Calculations for polymer gel and concrete amalgam volumes.68 6-2 Core wall unit construction.68 6-3 Revit image created by author.69 6-4 Expected physical properties of structural faux wood and concrete.69 6-5 Unit cost comparison between generic concrete amalgam and a given structural polymer, ordered from Sigma-Aldrich.70 7 Abstract of 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 Construction Management USE OF FILLED POLYMERS FOR STRUCTURAL APPLICATIONS By Wolfgang Ryor August 2018 Chair: Larry Muszynski Major: Construction Management Members of the construction industry overwhelmingly believe that concrete is the most desirable structural material. This ubiquity is based upon many factors, not least a historical predilection towards that composite. It is trusted due to millennia of regular use, and the ease of locating the ingredients.
The material is also very tactile; workable as clay, then hard as steel. Concrete is familiar. Polymers bring up entirely different associations. They are commonly regarded as flimsy, cheap, and “tacky.” The synthetic nature of plastics creates distrust.
The perception of chemists in white coats and vats of gelatinous goo comes to mind. The material is distant from direct sensation. Far greater conceptualization must be engaged in when approaching polymers. Previous research has mirrored these assumptions, and appeared almost apologetic when considering plastics for wider applications.
This research has the goal of analysis of polymers without preconception, often expressing findings in layman’s terms. In this way, objectives based on true merit, or deficiency, may be discovered by researchers beyond a limited audience. Application of these methods will clarify relative value in the use of concrete and polymers. Identification of the relationship of attitudes is a correlative of that investigation.
Evaluation of respective loading capacities will be 8 performed in the laboratory, testing relative compressive strengths. Compilations of properties, in chart and table format, will further elaborate the materials comparison. Therefore, a combination of actual testing and reliance upon published and unpublished sources will be used. 9 CHAPTER 1 A FLORIDA EXPERIMENT In the wake of the development of increasingly light and effective sustainable building materials, the status of traditional modes of construction are being rethought.
This is not just a private sector phenomenon. More conservative public entities, such as the Florida Department of Transportation (FDOT), are also utilizing this innovation. During concrete building, for example, the standard has been employment of steel bars, known as “rebar,” to distribute tensile forces. However, as structural plastics have increased in status, displacement of steel, and even concrete, has increased.
A material formerly thought of as unworthy of structural use, polymers continue to gain greater influence as a fundamental building component. One polymer, common in the private sector, which strengthens concrete and acts as an independent structural unit, is called Fiber Reinforced Plastic (FRP). This family of Plexiglas may be used in many ways, with flexible modeling potential. The Florida Department of Transportation (FDOT) has taken a keen interest in this malleable material in current state construction projects.
The reasons for this are various – corrosion protection, acceleration of construction schedules, simplified procurement with less expense, and use of large and light components, such as plastic bridge piers. In fact, FRP and concrete share a symbiosis in bridge abutment and pier erection. A prevalent danger in this type of work, using steel rebar, is corrosion. This problem is often viewed in terms of anodic and cathodic relationships, essentially a chemistry problem of managing electronegativity of adjacent metals or materials.
Corrosion also takes place when salt water, or vapor, infiltrates concrete. This will directly corrode interior steel rebar. However, if polymers were to be used effectively, there would be no need for any consideration of corrosion. Fiber Reinforced Plastic (FRP) has very low conductivity and a neutral electromagnetic charge.
10 Using an FRP admixture would simplify concrete preparations for pouring, because no rebar work would need be included in the formwork. In the case of tube encasement, as described below, the form is the FRP structure itself. Therefore, costly and time-consuming procurement and laying of rebar would be absent. Furthermore, scheduling difficulties may be mitigated, with project acceleration as a result.
Fiber Reinforced Plastics may be associated with concrete in dust, fiber, extruded, and pultruded form. The material varies from polymerized products which are manufactured in Portland cement plants, such as fly ash and slag, in that they are not merely collected from furnace refuse. FRP is more sophisticated in its chemical engineering. As a product of Plexiglas, it is derived from an elastomer with laminar properties.
Therefore, it may be ground, or shaved, into dust or a fiber concrete mix additive. It may also be extruded and pultruded into virtually any shape. FRP is used in bridge piers as an assemblage to give the support characteristics of steel rebar. According to researchers, “Results show that external confinement of concrete by FRP tubes can significantly enhance the.
strength of concrete” (Saafi et al. Another structural approach is achieved through the process of pultrusion. This manufacturing process increases density exponentially. The product created is a so-called “profile section,” often used in conjunction with a stiff foam or pultruded corrugated interior.
Both the tube and profile are modular innovations with quite acceptable Young’s moduli and performance, rivaling that of steel and concrete. Despite these promising developments, there are drawbacks to wide application of these technologies in Florida. Construction using FRP techniques will leave polymer detritus, some of large size and weight, long after the life of associated composites have expired. While steel 11 reinforcement will corrode and degrade, as would concrete, the thermoplastic or thermoset FRP would have to be collected, or allowed to lay in situ.
Collection would presuppose an infrastructural innovation of large scale recycling. Judging by current FDOT department-issued literature on the subject, it seems these hazardous consequences have not yet been fully appreciated in FDOT planning. Such a recycling effort could include strategies of policing sites and configuring the waste into extruder-ready material for solidification into storable units. The Plexiglas characteristics would be retained, and exploited again when the unit is shaved, crushed, extruded, or pultruded for a new task.
Though initially expensive, FDOT has the capacity and regulatory muscle to implement this type of infrastructural innovation over several years. Recycling conditions could even be included in Request for Qualifications parameters in bidder responses for future state work. It is evident that Fiber Reinforced Plastics have significant potential benefits when applied to FDOT projects. These attributes include structural capabilities comparable with metal rebar and concrete, potential easing of schedule constraints, likely reduction of procurement burdens, and strong stand-alone polymers of light weight.
However, these technologies are not a panacea. It could be argued that sensitivity to environmental concerns would mandate future state responsibility to provide an infrastructure of recycling with adoption of FRP-based construction. This could infuse unanticipated costs into Florida’s transportation budget for at least a decade. Conceptualizing the Phenomenon of Change This experience in Florida, matching the properties of polymers with concrete, indicates human beings are creatures of habit.
It is easier to understand new concepts in the context of previous experience. The Florida Department of Transportation has adopted use of a 12 conceptually flimsy material as a heavy structural component for bridge piers. But has this process been thought through? From the exploration just recounted, it would appear FDOT assumes that FRP has the same life cycle properties as concrete. This is not the case, and any use of FRP must carry the attribute of recycling on a massive scale.
An entire future infrastructure is implied, which would include identifying and collecting a huge amount of material that must be treated for reuse. Preparations for such an endeavor are currently lacking. The central argument of this study is that the Florida example is typical of any proposed use of polymers in relation to concrete. It may be argued that bias toward prior understanding of polymers is the main obstacle in the wide adoption of this material for structural use.
The word “bias” has a pejorative connotation. However, any psychologist would assert this condition is necessary for the survival of our species. An ever-changing kaleidoscope of images and sensations would bar formation of any model for the operation of this world, without bias. When does bias become harmful, the status quo insufficient? This thesis is concerned with that phenomenon.
Change occurs in two essential ways, through coercion or consent (O’Rourke 1994). When applied to the topic of environmental sustainability of construction processes and materials, change may be viewed in two basic ways, as either continuous or revolutionary. The point of historical observation will determine application of “the new” to society. For example, the model of a caesura between past and present could be asserted.
This type of presentation is given by groups such as the International Council of Local Environmental Initiatives (ICLEI). A political agenda is the primary component of this option. Sustainability concerns are couched in rhetoric describing rights of indigenous populations and responsibilities of industry. The entire question is framed as an abrupt transformation of society, dismissive of the individual.