Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 177-183).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1972. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

The research presented in this thesis can be split into two well-defined areas. Firstly, the effects of the addition of lime (either 2%, 4%, 6% or 8% Ca(OH)2 or 1.5%, 3%, 4.5% or 6% CaO) on various engineering properties of a sulphide (pyrites) rich, naturally occurring clay - Lower Oxford Clay (LOC) - were studied. Experimental tests representing, or relating to, tests outlined in the Design and Construction of Lime Stabilised Capping Specification (DoT, 1995) were utilised and consisted of Atterberg (consistency) tests, compaction tests, unconfined compressive strength tests, linear expansion measurements and durability tests. Also, sulphate (S03) analyses, pH measurements, differential thermogravinietric (DTG) analyses and X-ray diffraction (XRD) tests were employed to confirm experimental data. Environmental conditions were chosen to reflect temperatures experienced in the UK - between 5°C, 10°C and 20°C. The majority of samples were mellowed (the time delay between initial mixing and compaction) for 3 days at 20°C prior to testing. The results show that small additions of lime (i. e. 2% Ca(OH)2 or 1.5% CaO) modify the engineering properties of LOC by causing flocculation, and also increase S03 levels due to increased gypsum levels via pyrites oxidation. However, strength development is poor as little cementitious bonding is formed. Mellowing further modifies the engineering properties as the increased time allows greater flocculation leading to a less dense, more porous material. Also ettringite forms during mellowing allowing expansive reactions to occur prior to compaction, consuming both calcium and sulphate in the process and leading to slightly reduced pH levels compared to similar unmellowed samples. Further additions of lime give further change to the engineering properties of the LOC, up to an addition of 6% Ca(OH)2 or 4.5% CaO. Further additions result only in supplying an excess of calcium. Strength development is improved with increasing lime additions, especially after 4 weeks of curing at higher curing temperatures (20°C); however linear expansion increases and durability worsens. However, a period of mellowing prior to compaction reduces linear expansion and improves durability. Sulphate (S03) levels are also increased with increasing additions of lime due to pyrites oxidation. In samples containing >2% Ca(OH)2 or 1.5% CaO, pH levels are maintained to a level where ettringite formation is sustained rather than gypsum formation. Secondly, the effects of a secondary stabilising agent (ground granulated blast furnace slag - GGBS - incorporated at various percentage additions (2%, 4%, 6% or 8%)) on the strength development, linear expansion and durability of mellowed, lime-modified LOC is presented. For comparative purposes, Portland cement (PC) is also used. The results show that although LOC-lime-PC samples exhibit greater strengths (especially when cured for long periods at 20"C), linear expansion is lower and durability is higher in similar LOClime- GGBS samples. As the hydration process of PC produces lime, and as lime is usually consumed during GGBS hydration, then samples containing the former stabiliser will maintain pH levels well above samples containing the latter. Therefore, on soaking disruption and expansion due to the formation of ettringite (which is unstable at pH levels <10.5) is common to LOC-lime-PC samples but not in similar GGBS samples. In conclusion, the findings from this thesis indicate that soil stabilisation with lime and GGBS is particularly effective for naturally occurring sulphide rich clay soils (such as the LOC) and is an environmentally friendly alternative to PC-stabilised soils.

Made available in DSpace on 2014-06-11T19:29:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-04-05Bitstream added on 2014-06-13T20:59:25Z : No. of bitstreams: 1 casarotti_eg_me_ilha.pdf: 1046762 bytes, checksum: b3101241568cb1eabd1384cb9c88c4f7 (MD5) / Umas das formas de garantir a disposição final adequada das águas residuárias é submetê-las ao tratamento através das lagoas de estabilização. Um dos fatores consideráveis para estas unidades de tratamento são as características hidrodinâmicas presentes no processo. Um das lagoas de estabilização é a influência dos ventos na massa líquida. O presente projeto de pesquisa avaliou a influência do vento no comportamento da circulação da massa líquida da Lagoa Facultativa 2 da Estação de Tratamento de Esgotos (ETE) da cidade de Álvares Florence – SP, por meio de flutuadores de diferentes dimensões (15, 21 e 35 cm). Foram confeccionados 9 flutuadores, 3 grupos com 3 flutuadores (um de cada dimensão) e lançados nas 3 entradas existentes na lagoa. A pesquisa foi dividida em duas etapas: na primeira etapa foram averiguados o tempo de percurso dos flutuadores ao longo de uma célula da lagoa facultativa 2 e o efeito de borda. Na segunda etapa foi verificada a influência dos ventos na movimentação da massa líquida e as condições de mistura proporcionadas por esta influência por meio dos flutuadores e análises de DQO. O método dos flutuadores para verificação da influência do vento e a circulação de uma lagoa facultativa mostrou-se como uma alternativa efetiva e simples quando comparado ao método com traçadores / One of the ways to ensure the proper disposal of wastewater is subject them to treatment by stabilization ponds. One of the significant factors for these treatment units are the hydrodynamic characteristics present in the process. Wind is external physical aspects that affect the hydrodynamic behavior of the stabilization ponds due to their influence on the circulation of the liquid mass. This research project evaluated the influence of wind on the behavior of the liquid mass flow of the facultative pond 2 of Sewage Treatment Plant in the city of Álvares Florence – SP, by means of floats of different sizes (15, 21 and 35 cm). Nine floats were made, three groups with three floats (one of each size) and released in three entries in the pond. The research was divided into two stages: the first step, were checked the travel time of the floats along of the facultative pond 2 and edge effect. In the second step was verified the influence of wind on movement of the liquid mass and mixing conditions provided by this influence by means of floats and COD analysis. The method for verification of the floats of the wind influence and the movement of a facultative pond proved to be a simple and effective alternative when compared with the tracer method

The stress/strain relationship for most engineering materials is known to be time dependent. This is most evident during a creep test in which continual deformations are observed under constant stress conditions. In the laboratory, a specimen of cohesive soil subjected to a constant shear stress may fail after having deformed alt relatively slow rates for a considerable time. This type of failure, termed creep rupture, is also known to occur in the field. Results of drained and undrained triaxial creep rupture tests are presented in this thesis. These tests were performed on a sensitive marine clay from western Canada which was consolidated to various stress histories. Pore pressure measurements were taken during undrained tests using an electrical transducer. In addition to the creep rupture tests, incremental load and constant strain rate triaxial tests were performed for comparative purposes. The strain rate during a creep rupture test was observed to initially decrease as the specimen strained, reach a transient minimum strain rate, and then increase until rupture. Failure was found to be inevitable whenever the strain rate started to increase after having reached a minimum value. Pore pressures measured during the undrained tests did not reflect the onset of creep rupture at the transient minimum strain rate, and therefore, the onset of creep rupture cannot be explained in terms of effective stresses. A relationship was found to exist between the deviator stress, strain and current strain rate during undrained triaxial tests having the same consolidation history. This relationship permitted the prediction of the results of constant strain rate tests based on the results of creep rupture tests. This resulted in an understanding of the interrelation between the transient minimum strain rate of a creep rupture test and the maximum deviator stress of a constant strain rate test. Once the transient minimum strain rate had been reached, the results of creep rupture tests showed that the strain rate was inversely proportional to the time remaining before rupture. This relationship is independent of stress level, consolidation history and drainage conditions. As a result, it is suggested that measurement of deformations in the field can be used to predict the time until a sudden failure would be anticipated. The upper yield strength, defined as the maximum compressive stress which will not cause a creep rupture failure, was evaluated from both creep rupture and constant strain rate tests. It was found that the compressive strength increased as a linear function of the cube root of the strain rate. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

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The purpose of this study was to determine the optimum phosphate treatment method to stabilize lead contaminated soil from a firing range. Seven different phosphate sources at five different concentrations were added to soil collected from a firing range on a military base. A series of tests were performed to determine a generic phosphate treatment method. The selected generic phosphate treatment was compared to an untreated control soil sample and to four commercially available treatments provided by invited vendors selected from industry. The four vendors processes, control, and generic treatments were subjected to a series of physical and chemical tests at 0, 14, and 28 days of curing time to determine the effectiveness of each treatment. The generic treatment using Hydroxyapatite developed in the MSU laboratory was competitive with three vendors? treatments. The fourth vendor?s treatment was more effective at reducing the lead leachability of the contaminated soil.

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