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An experimental apparatus and test procedure to measure the sorption isotherm of moisture in porous building materials was developed and tested for its reliability and accuracy. The apparatus shows excellent potential for determining reliable moisture storage property data. The data are used in heat and moisture transport models. The apparatus consists of a small test chamber, with an external forced-air temperature and humidity conditioning system. The conditioning system supplies moist air to the test chamber at 20°C dry-bulb temperature over a range of 0.4 to 85 per cent relative humidity. The new system circumvents problems associated with the use of saturated salt-in-water solutions. Moisture content is determined gravimetrically without removing specimens from their conditioned environment. The mass is monitored in situ such that external ambient conditions have no effect on the data. The control of test chamber relative humidity and dry-bulb temperature is automated. Test results consisting of sorption isotherms and scanning curves for sugar pine, southern pine, and an exterior grade plywood are presented. The maximum uncertainty in moisture content measurement is 0.023 kg/kg-dry mass at 85 per cent RH. Results are compared to data from the literature. The study shows a need for a standard test method for measuring sorption isotherms. Minimum recommendations for such a standard test method are included. A comparison of scanning data to an analytical model from the literature show that further investigation of scanning is needed. The present method is well suited for such a study. / Master of Science

The effects of maximum size coarse aggregate on the relationship between accelerated strength and 14-day normally cured strength of normal and superplasticized concrete have been investigated. The results obtained show that differences among maximum size coarse aggregates are greater in normal concrete than in superplasticized concrete in strength-producing properties. Among the various sizes of aggregates investigated, one-half inch maximum size of coarse aggregate exhibited higher strength producing properties. This report includes the test results as well as the procedures for the preparation and testing of concrete specimens. These specimens were prepared and tested at the concrete laboratory at Virginia Polytechnic Institute and State University. / Master of Science / incomplete_metadata

In recent years there has been considerable development along the lines or using coal powdered to a fineness resembling talcum powder for the production of power in practically all the new and larger power plants. This pulverized coal burns similarly to gas when blown into the combustion chamber. Because or the fineness of the individual particles of coal, a very fine ash termed "fly ash" is formed when combustion occurs, a large portion of which is carried on up and out the smoke stack. The "fly ash," if allowed to go up the stack and out over the surrounding territory, becomes a health hazard as well as a nuisance to the cleanliness of the community. The average fly ash is about fifty per cent silica (SiO₂) which should classify it as a silicosis hazard. To avoid this nuisance and hazard, the fly ash may be collected in one of several ways, the most important being by electrostatic precipitation, wet scrubbing, and with cyclone separators. It must then either be used or disposed of. Several attempts have been made to use fly ash for some useful purpose, but it is not adaptable for filling in, for road construction, or for similar uses made of clinker ash. In this investigation, an attempt has been made to determine the optimum conditions of both the process and composition which should be used in the manufacture or a building material from fly ash, and special reference will be made to the ash of the Virginia Polytechnic Institute Power Plant, Blacksburg, Virginia. / M.S.

M.S.

From articles found in publications of the past five to ten years, it appears that in many industries the actual image of purchasing does not coincide with its textbook image, which is that of being one of the most important functions within the company. Therefore, it is the purpose of this study to show that in Virginia manufacturing firms, the actual image of purchasing is different from the one presented in textbooks. Several hypotheses are developed and tested in this study. The general hypothesis states that the image of purchasing in Virginia manufacturing firms does not coincide with its textbook image of being one of the most highly recognized and important management functions, equal in status with sales and production. Many books, articles, related studies, and surveys were reviewed for pertinent data. In addition, two questionnaires were developed. One was used to survey VPl students in the fields of Business Administration and Engineering to acquire information about their knowledge and opinions of the purchasing field. The second one was used to survey 250 manufacturing firms in the State of Virginia concerning the purchasing functions. A return of 41.6 percent was experienced, and of these, 40 companies were classified as large businesses and 62 classified as small businesses on the basis of the number of employees. In investigating the purchasing image, the data from the questionnaires were compiled and presented in the following categories: location in the organizational structure, responsibilities, salaries, recognition, position status, career advancement, sources of purchasing personnel, personal characteristics, and educational background. Data from books and articles reviews in this study were combined with the questionnaire results in order to present a more complete analysis of the purchasing image. Based on the findings of the study, the general hypothesis stated above was rejected. It was concluded that progress had been made in developing the image of purchasing in Virginia manufacturing firms, but additional efforts are required to make the actual image of purchasing coincide with the theoretical image. Most of the other hypotheses were accepted based on the findings and the lack of contradictory evidence. Several recommendations were made which should be of assistance in improving this image. These recommendations were directed toward company management for use in their role of improving the purchasing image. / Master of Science

Sorption isotherms and scanning data were obtained for three test materials at three different temperatures. These data resulted from further investigating the operating range of an existing experimental apparatus and procedure. During the course of the research, the operating range and control of the existing apparatus were extended, and its temperature range was tested for the first time. The apparatus is composed of a small test chamber, which is capable of containing from one to six test samples, and an external forced-air relative humidity and temperature conditioning system. The conditioning system maintains test chamber relative humidity and temperature, as directed by a GW-BASIC computer program. Sample moisture content is gravimetrically determined in situ. The system can maintain dry-bulb temperatures between 10 C and 70 C. At room temperature, the apparatus can maintain relative humidities between o and 90 per cent. Low temperature set points have a significantly lower maximum relative humidity range as a result of the formation of condensation in the concentric tube counterflow heat exchanger. High temperature set points are also severely limited, due to the formation of condensation in the test chamber during data collection. Sorption isotherms were measured for oriented strand board, fiber board sheathing, and exterior grade plywood over the relative humidity range limits at 12 C, 25 C, and 55 C. Scanning curves were measured from the 50 per cent relative humidity set points on the adsorption and desorption curves of the 25 C isotherms. / Master of Science

A novel way to ensure stability of mortarless structures – topological interlocking – is examined. In this type of interlocking the overall shape and arrangement of the building blocks are chosen in such a way that the movement of each block is prevented by its neighbours. (The methodological roots of topological interlocking can be found in two ancient structures: the arch and the dry stone wall.) The topological interlocking proper is achieved by two types of blocks: simple convex forms such as the Platonic solids (tetrahedron, cube, octahedron, dodecahedron and icosahedron) that allow plate-like assemblies and specially engineered shapes of the block surfaces that also allow assembling corners. An important example of the latter – so-called Osteomorphic block – is the main object of this research with some insight being provided by numerical modelling of plates assembled from tetrahedra and cubes in the interlocking position. The main structural feature of the interlocking assemblies is the need of the peripheral constraint (for the Osteomorphic blocks this requirement can be relaxed to uni-directional constraint) to keep their integrity. We studied the least visible constraint structure – internal pre-stressed cables which run through pre-fabricated holes in Osteomorphic blocks. It is shown that the pre-stressed steel cables can provide the necessary constraint force without creating appreciable residual stresses in the cables, however the points of connection of the cables are the weakest points and need special treatment. The main mechanical feature of the interlocking structures is the absence of block bonding. As a result, the blocks have a certain freedom of translational and rotational movement (within the kinematic constraints of the assembly) and their contacts have reduced shear stresses which hampers fracture propagation from one block to another. These features pre-determine the specific ways the interlocking assemblies behave under mechanical and dynamic impacts. These were studied in this project and the following results are reported. As the blocks in the interlocking structure are not connected, the main issue is the bearing capacity. The study of the least favourable, central point loading in the direction normal to the structure shows elevated large-scale fracture toughness (resistance to fracture propagation). However when the central force imposes considerable bending the generated tensile membrane stresses assist fracturing of the loaded block. Prevention of bending considerably enhances the strength therefore the most efficient application of the interlocking structures would be in protective coatings and covers. Furthermore, proper selection of the material properties and the interface friction can increase the system overall strength and bearing capacity. The results of the computer simulations suggest that both Young’s modulus and the friction coefficient are the key parameters whose increase improves the bearing capacity of topologically interlocking assemblies.

This thesis examines the availability and use of manufactured and imported building materials in southern and central Indiana before 1850. Specifically, it seeks to identify the extent to which materials such as paint, machine-cut nails, window glass and prefabricated sash, architectural hardware, and cast iron stoves were imported into the region from both foreign and domestic sources. It examines the transition from handmade and hand-wrought to standardized, mass-produced, and prefabricated building materials and explores the impact of emerging American consumerism, changing economic policy, and advancements in technology and transportation on the built environment of the Indiana frontier. / Historical context -- Whitewash and paint -- Wrought and cut nails -- Window glass and prefabricated sash -- Architectural hardward -- Cast iron stoves. / Department of Architecture