Thesis (Ph. D.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains vii, 145 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 71-72).

The problem of the investigation of the mechanism of failure in compression of neat cement and mortar specimens is considered in this thesis. The study was made on two hundred specimens of cement paste and mortar, of which approximately one half were tension briquets and the other half compression cylinders. The underlying theory which led to this study was that failure in compression in specimens with aggregate (mortar and concrete) is due to the wedging action of the particles of aggregate within the matrix of cement paste. Steam-curing was used to avoid delay in the hardening of cement. It was found that the cement used was of the type which continues hardening after being steam-cured. The importance of having the specimens at a constant temperature throughout their mass and at room temperature when the tests were performed was realized. An investigation of the effect of end conditions on test cylinders in compression was conducted. It is considered that the confined rubber end conditions used were an improvement on testing with lubricated ends only. Observations were made on the effect of the bursting action of water in compression tests of moist specimens. A study of the effect of stress concentration around voids was made on tension specimens. Compression specimens made of neat cement, mortar and cement with inclusions in the form of balls were studied. Inclusions were placed in cement cylinders to imitate the action of the aggregate in mortar and concrete specimens. Tests on compression specimens with inclusions were useful in the interpretation of results of tests on neat cement and mortar cylinders and in the study of the stress-strain curves. Transverse bending tests of cylinders were made with the purpose of investigating the presence of transverse cracks formed in the cylinders as a consequence of the application of compressive loads. They did not provide a good method of investigation but were very useful in that they were an aid to realizing the effect of the horizontal cracks in the stress-strain curves. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

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"It is well known that singularities occur when solving elliptic value problems with non-convex domains or when some part of the data or the coefficients of the PDE are not smooth. Such problems and correspondent singularities often arise in practice, for instance, in fracture mechanics, in the material science with heterogeneities, or when dealing with mixed boundary conditions. A great deal is known about the nature of the singularities, which arise in some of these problems. In this thesis, we consider the scalar transmission problems with straight interfaces and with cross points across coefficients and possibly on a non-convex region ($L$-shaped domain). It is known that only $H^{1+au}$ ($0 < au< 1$) regularity on the solution is obtained and therefore the use of finite element method with the piecewise linear continuous function space does not give optimal accuracy. In this thesis, we introduce a new algorithm which are second order accurate on the (weighted) $L_2$, first order accurate on the (weighted) $H_1$ norm and second order accurate for the Stress Intensive Factor (SIF). The new methods take advantage of Mortar techniques. The main feature of the proposed algorithms is that we use primal singular functions {it without} cutting-off functions. The old algorithms use cutting-off functions as a tool of satisfying boundary conditions. In algorithms proposed in this thesis, use instead Mortar finite element technique to match the boundary and interfaces conditions. In this thesis, we also consider non-matching meshes sizes for different coefficients. We note that a new Mortar Lagrange multiplier is required in order to obtain optimal consistence errors for transmission problems. The proposed algorithms are very appealing over other methods because they are very accurate, do not require complicated numerical quadratures or interpolations, it is simple to design PCGs, and it can be generalized to other PDEs and to higher order methods."

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Ben Wang, Florida State University, FAMU-FSU College of Engineering, Dept. of Industrial Engineering. Title and description from dissertation home page (Apr. 7, 2004). Includes bibliographical references.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

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Thesis (M.S.)--University of Pennsylvania, 2006. / Title from PDF title page (viewed on Aug. 11, 2008). Includes bibliographical references (p. (71-85) and index.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.