The Influence of Surface Friction and Other Parameters on Concrete's Response to Loading

• Other Authors: Bouchard, Nicholas (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Civil engineering; Environmental engineering
• Online Access: http://purl.flvc.org/fsu/fd/FSU_migr_etd-7102

This thesis presents an evaluation of concrete behavior under loading. Currently, concrete theories and codes are inadequate in explaining the full gamut of concrete responses due to loading. It is, therefore, of great interest to formulate a theory that is capable of explaining the wide array of concrete responses in order to better understand concrete behavior and to build safer, stronger, and more cost effective structures. The purpose of this thesis is to aid in formulating a concrete failure theory that will account for variations in concrete behavior under loading. In order to achieve this, an extensive investigation of past concrete research is performed. Important concrete phenomena such as microcracking, Poisson's effect, size effect, response to confinement, and the response to loading rate are discussed. The procedure and test results of a concrete compression test with reduced surface friction are also presented. In this thesis, evidence is presented to dispute the existence and the influence of both size effect and the concrete response to the rate of loading. It is also proven that axial cleavage fracture is the true failure mode of concrete under uniaxial compression, not shear failure. The crack pattern of a cylindrical concrete specimen that reaches failure under uniaxial compression consists of a series of rather straight cracks running the entire length of the specimen parallel to the direction of the applied compressive load. This is a stark contrast to the typically expected cracks inclined toward the center of the specimen accompanied by uncracked ends. A case is also made that concrete failure in compression is due to lateral tensile strains caused by the existence of Poisson's effect. An investigation of strain is also performed. This investigation and the discussion of the topics previously listed lead to the development of a proposed strain failure theory. A series of proposed testing procedures is also presented. === A Thesis submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Master of Science. === Spring Semester, 2010. === March 31, 2010. === Includes bibliographical references. === Michelle Rambo-Roddenberry, Professor Directing Thesis; Virgil Ping, Committee Member; Kamal Tawfiq, Committee Member.