Call number: LD2668 .T4 1953 M34 / Master of Science

Call number: LD2668 .T4 1954 D3

Call number: LD2668 .T4 1961 M57

Call number: LD2668 .T4 1963 S38 / Master of Science

Call number: LD2668 .T4 1984 R43 / Master of Science

Call number: LD2668 .T4 1951 M334 / Master of Science

The report presents an evaluation of a modification to an asphalt-debonding test procedure when used with a water debonding apparatus developed at the University of Arizona, the Pore-Water Pressure Debonding Device. The method being modified is that outlined by Jimenez in his report "Testing for Debonding of Asphalt from Aggregates". A regular test specimen, 4 inches in diameter by 2½ inches high, is water-saturated at 122°F and subjected to repeated pore-water pressure varying from 5 to 30 psi. The above factors are kept constant and the following ones are varied: air void content, stress frequency, stress repetition, stress duration and testing temperature. Test results of the modified testing procedure demonstrated the following trend: the higher the value of any of the aforementioned test variables, i.e., the void content, stress frequency, stress repetition, or stress duration, or any combination of these variables, the greater the loss of the mix resistance to stripping.

In this report the influence of several variables including asphalt content, mixing temperature, compaction temperature and compaction energy on void content, voids-in-the-mineral-aggregate (VMA), density and stability of asphaltic concrete mixtures was established. Straight lines were obtained on double logarithmic paper for each asphalt content when the logarithm of Marshall stability values as ordinate were plotted versus the logarithm of the corresponding number of blows of a Marshall compactor as the abscissa. The straight lines were very nearly parallel and therefore, it was possible to develop a single empirical formula expressing the relationship between stability at any compactive effort, within the range of 20 to 110 blows per face, in terms of the standard stability at 75 blows per face of specimen. Results indicate that void content, VMA, density and stability were significantly affected by compaction temperature, asphalt content, compactive effort and mixing temperature.

Master of Science / Department of Civil Engineering / Hayder A. Rasheed / The development of column interaction diagrams for unconfined concrete is a standard analysis procedure. However, the need to develop analysis tools for the actual ultimate capacity of columns is evident. Modern codes and standards are introducing the need to perform extreme event analysis. In previous studies, various models were implemented to assess the ultimate confined capacity of columns under concentric axial loads. On the other hand, the effect of confinement in case of the eccentric axial load and the corresponding bending moment are not investigated in such models. So it is demanded to relate the strength and ductility to the degree of confinement utilization in a new model. The more the eccentricity the less the confinement engaged till the effect of the confinement vanishes at pure bending. Accordingly, the ultimate confined strength and the maximum strain range between the fully confined values (at zero eccentricity) and the unconfined values (at infinite eccentricity) depending on the level of eccentricity. Radial loading with constant eccentricity is followed in the nonlinear moment of area concept that considers the finite layer procedure and the secant stiffness approach, to achieve equilibrium points up to failure. Three different comparisons are made to ensure the accuracy of the analysis. The first is to compare the unconfined analysis results with the well-known software (CSI-Section Builder). Secondly, the ultimate capacity of the confined section is compared with experimental data. Finally, the new eccentricity model is compared with the widely used Mander model, which is applicable to concentric columns, to examine the accuracy versus safety.

Increased oil exploration necessitates building of conc~ete structures for its production and storage. The effects of crude oil on concrete properties are not well known and little data is available in the published works. This investigation covers HCP, mortar and concrete. First, it studies the effects of cracking and direction of casting on the flow of water or oil of different constitutions through concrete storage tanks. Secondly, it studies the relationships between the pore structure and permeability of HCP, mortar and concrete as influenced by w/c ratio, hydration and aggregate content. OPC was used for the tests. Experimental results show that, in concrete specimens, the flow of water through cracks is generally greater than the flow of crude oil through the same type of cracks. Sorptivity can predict reasonably accurately the flow of liquids and is useful in characterizing the flow of various oil types th:r:( ,ugh HCP, mortar and concrete. No specific oil property appears to control the oil flow through cement composites. Concrete tanks should be lined when used for storing diesel and parafin. Crude oil flow through concrete tank wall was found to be 1.06 - 1.81 times flow through the tank floor. Increasing the w/c ratio, increases the total porosity, pore surface area and threshold radius but decreases the density and does not effect the hydraulic radius. Increasing the age of HCP (w/c = 0.7) from 7 days to 6 months decreases the total porosity, pore surface area, threshold radius and hydraulic radius by 12%, 19%, 71% and 9% respectively, but increases the density by 13%. Adding sand to HcP, reduces the total pore volume and the pore surface area but increases the density. Wax deposits from the crude oils blocked all pore radii <650A, which is called the "critical pore radius" (Pcr). Saturation in crude oil appears to alter the internal structure of the cement composites. Dry curing increased most pore parameters but decreased the strength of the mortars. Permeability of mortar and concrete increases with w/c ratio, applied pressure, aggregate volume concentration and drying temperature but decreases with the test period and hydration. permeability was found to relate reasonably accurately to pore structure using Kozeny's theory provided the pore parameters are for pores of radii >650A.