DEVELOPMENT OF A PERFORMANCE BASED, INTEGRATED DESIGN/SELECTION MIXTURE METHODOLOGY FOR FIBER REINFORCED CONCRETE AIRFIELD PAVEMENTS
Bennie, Stewart David
Goulias, Dimitrios G
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ABSTRACT Title of dissertation: DEVELOPMENT OF A PERFORMANCE BASED, INTEGRATED DESIGN/SELECTION MIXTURE METHODOLOGY FOR FIBER REINFORCED CONCRETE AIRFIELD PAVEMENTS Stewart David Bennie, Doctor of Philosophy, 2004 Dissertation directed by: Professor Dimitrios G. Goulias Department of Civil Engineering Recent advances in polymer technology have given rise to new research regarding conventional building materials like concrete and the rheological material properties of polymer fiber-concrete composites. Polymers such as polypropylene fiber are now the industry standard for manufacture of geosynthetics which are used as the structural element in earth walls, stabilized slopes, and to improve soft soil bearing capacity. Both industry and researchers now recognize the benefits of polypropylene fiber reinforced concrete in reducing temperature and shrinkage cracking and crack widths, which is important distress criteria in airfield pavements. However, little attention has been given to the use of high tensile strength polypropylene as a structural component of concrete pavements. As important as the research, is the methodology used to obtain the results. There is a need to consider concrete mixture design and selection in conjunction with pavement design since specific mixture properties' behavior and performance characteristics are set by pavement design requirements. Such approach will permit the development of an "integrated mixture selection- pavement design methodology". This study quantified the beneficial strength properties of small volume (less than 0.5%) polypropylene fiber reinforced concrete (FRC) as an airfield pavement to meet both military and civilian aviation needs. Polypropylene fiber reinforcement in small volumes displays none of the historical problems of poor workability, or excessive pavement deflections associated with fiber-concrete composites in larger volumes. Through laboratory testing of material properties such as fatigue, toughness and flexural strength and computer modeling this composite showed a consistent improvement in those strength properties that would increase the life of the pavement structure under repetitive aircraft traffic. Perhaps, the most unique property of this composite is its ability to continue to absorb energy after first crack, ductile properties not typically associated with a brittle material like concrete. This increase in toughness is significant to the military in mitigating heaved pavement around bomb damaged runway craters during rapid runway repair. Analogues to safety glass, FRC will mitigate radial fracturing of airfield pavement located around the crater impact area reducing time to repair heaved pavement, an important criteria to air base survivability. This dissertation serves as a blueprint to comprehensively evaluate both design and performance of any fiber concrete composite.