Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xx, 618 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

Thesis (Master)--İzmir Institute of Technology, İzmir, 2006 / Keywords: polymer composites, Nanoparticles, glass fiber, mechanical properties, thermal properties. Includes bibliographical references (leaves 75-79).

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 162-163). Also available in electronic version. Access restricted to campus users.

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains x, 103 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 84-87).

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xvi, 204 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 155-158).

abstract: The concept of Creep is a term used to define the tendency of stressed materials to develop an increasing strain through time under a sustained load, thus having an increase in deflection or having an elongation with time in relation to the short term strain. While the subject of compression creep of concrete is well developed, use of concrete under tension loads has been limited at best due to brittleness of concrete. However with the advent of using fiber reinforced concrete, more and more applications where concrete is expected to carry tensile loads due to incorporation of fibers is gaining popularity. While the creep behavior of concrete in tension is important, the main case of the study is what happened when the concrete that is cracked in service is subjected to sustained loads causing creep. The relationship of opening cracks under these conditions are of utmost importance especially when the serviceability criteria is addressed. Little work has been reported in literature on the long-term behavior of FRC under sustained flexural loadings. The main objective of this study is to investigate the Long Term Flexural Behavior of Pre-Cracked Fiber Reinforced Beams under Sustained Loads. The experimental reports document the effect of loading and temperature on the creep characteristics of concrete. A variety of study has been carried out for the different responses generated by the creep tests based on factors like effect of temperature and humidity, effect of fiber content, effect of fiber type, and effect of different loading levels. The Creep Testing Experimental Methodology is divided into three main parts which includes: (1) The Pre-cracking Partial Fracture Test; (2) Creep Test; (3) Post Creep Full Fracture Test. The magnitude of load applied to a specific specimen during creep testing was based on the results of average residual strength (ARS) tests, determined using EN14651. Specimens of the synthetic FRC mixture were creep tested at loads nominally equivalent to 30% and 50% of the FR1 value. The creep tests are usually continued until a steady Time versus CMOD response was obtained for the specimen signifying its presence in the secondary stage of creep. The creep recovery response is generated after unloading the specimen from the creep set up and later a full fracture test is carried out to obtain the complete post creep response of the beam under flexure. The behavior of the Creep Coefficient versus Time response has been studied using various existing models like the ACI 209-R 92 Model and the CEB-FIP Model. Basic and hybrid rheological viscoelastic models have also been used in order to generate the material behavior response. A study has been developed in order to understand the applicability of various viscoelastic models for obtaining the material response of real materials. An analytical model for predicting the Flexural Behavior of FRC under sustained creep loads is presented at the end. This model helps generate the stress strain and Moment Curvature response of FRC beams when subjected to creep loads post initial cracking / Dissertation/Thesis / Masters Thesis Civil Engineering 2017

By adding annealed plain carbon steel fibers and stainless steel fibers into Ultra-High Performance Concrete (UHPC), we have increased UHPC’s toughness through optimized thermal processing and alloy selection of steel fiber reinforcements. Currently, steel fiber reinforcements used in UHPCs are extremely brittle and have limited energy dissipation mainly through debonding due to matrix crumbling with some pullout. Implementing optimized heat treatments and selecting proper alternative alloys can drastically improve the post-yield carrying capacity of UHPCs for static and dynamic applications through plastic deformations, phase transformations, and fiber pullout. By using a phase transformable stainless steel, the ultimate flexural strength increased from 32.0 MPa to 42.5 MPa (33%) and decreased the post-impact or residual projectile velocity measurements an average of 31.5 m/s for 2.54 cm and 5.08 cm thick dynamic impact panels.

UHPC (ultra-high performance concrete) is a relatively new type of concrete that exhibits mechanical properties that are far superior to those of conventional concrete and in some cases rival those of steel. The main characteristics that distinguish UHPC from conventional reinforced concrete are the improved compressive strength, the tensile strength, the addition of steel fibers, and the resistance to corrosion and degradation. The mechanical properties of UHPC allow for smaller, thinner, lighter sections to be designed while strength is maintained or improved. The use of UHPC has been limited to a few structural applications due to the high cost of the materials and the lack of established design guidelines. A proposed material model based on material and finite element models has served as the foundation of this research effort. The model was used to minimize the dimension of an optimum section in order to limit the material usage and maximize the performance. In the model, the top flange served as the riding surface and contained no reinforcing steel to resist shear. The lack of steel reinforcement allowed for the possibility of a punching shear failure to occur from the application of a point load such as a wheel tire patch load. The model and optimized section served as the foundation for this research, the characterization of punching shear capacity of thin UHPC plates. A total of 12 UHPC slabs were tested to failure to determine the boundary between a flexural failure and a punching shear failure. The variables considered were the slab thickness and loading plate dimensions. The results of the testing were compared to existing models for punching shears and other failure modes, with varying success. The test results aided in the development of a design equation for the prediction of punching shear in UHPC slabs. After evaluation of the test results, recommendations are made as to which model predicts the punching shear capacity of UHPC slabs and the minimum slab thickness required to prevent a punching shear failure. / Master of Science

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 73-77). Also available on the World Wide Web.

Master of Science / Department of Architectural Engineering and Construction Science / Kimberly W. Kramer / Reinforced concrete is a common building material used for blast resistant design. Adding fibers to reinforced concrete enhances the durability and ductility of concrete. This report examines how adding steel fibers to reinforced concrete for blast resistant design is advantageous. An overview of the behavior of blasts and goals of blast resistant design, and advantages of reinforced concrete in blast-resistant design, which include mass and the flexibility in detailing, are included in the blast resistant design section. The common uses for fiber-reinforced concrete, fiber types, and properties of fiber reinforced concrete varying with fiber type and length, and concrete strength are discussed in the fiber-reinforced concrete section. Two studies, Very High-Strength Concrete for Use in Blast-and-Penetration Resistant Structures and Blast Testing of Ultra-High Performance Fiber and FRP-Retrofitted Concrete Slabs, are reviewed. Lastly, the cost, mixing and corrosion limitations of using steel fiber-reinforced concrete are discussed. Reinforced concrete has been shown to be a desirable material choice for blast resistant design. The first step to designing a blast resistant reinforced concrete structure is to implement proper detailing to ensure that structural failures will be contained in a way that preserves as many lives as possible. To design for the preservation of lives, a list of priorities must be met. Preventing the building from collapse is the first of these priorities. Adding steel fibers to concrete has been shown to enhance the concrete’s post-crack behavior, which correlates to this priority. The second priority is reducing flying debris from a blast. Studies have shown that the failure mechanisms of steel fiber reinforced concrete aid in reducing flying debris when compared to conventional reinforced concrete exposed to blast loading. The major design considerations in designing steel fiber reinforced concrete for blast resistant design include: the strength level of the concrete with fiber addition, fiber volume, and fiber shape. As research on this topic progresses, the understanding of these factors and how they affect the strength characteristics of the concrete will increase, and acceptance into the structural design industry through model building codes may be possible.