The use of plastic concrete for cutoff walls in dams for remediation of seepage issues has become more widely used in the past 25 years, however, the in-situ material properties are still not well understood. The research presents a new testing procedure that combines two existing testing methods, triaxial shear and permeability testing. By developing this laboratory testing method, material properties of the cutoff wall backfill material can be more accurately examined and explained using changes in the permeability of the material to discern the ductility and stiffness.

Made available in DSpace on 2015-12-10T14:22:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-31. Added 1 bitstream(s) on 2015-12-10T14:29:13Z : No. of bitstreams: 1 000854214.pdf: 2053071 bytes, checksum: 26fbb318c26a7f6004c27be21f798af1 (MD5) / Este trabalho de pesquisa apresenta um estudo sobre a influência da Cinza de Casca de Arroz - CCA e da cal no comportamento do Solo Cimento Auto-Adensável - SCAA no estado fresco e endurecido, e um estudo preliminar sobre a reologia do SCAA e sua relação com o fator água/cimento. Foram adotadas 18 misturas de SCAA, variando-se as quantidades de água, cimento, CCA, cal e superplastificante, utilizando parâmetros adequados como base de estudo. A proposta principal visa analisar a ação de materiais pozolânicos e hidráulicos na mistura de SCAA, nas condições de trabalhabilidade no estado fresco, e na evolução de sua resistência ao longo do tempo. No estado fresco, foram realizados ensaios de espalhamento slump flow, ensaio do Funil e ensaios de segregação por peneiramento; no estado endurecido, corpos-de- prova cilíndricos de 5 cm de diâmetro e 10 cm de altura foram submetidos a ensaios de resistência à compressão mecânica e absorção de água aos 7, 28, 56 e 84 dias. Observou-se que, no estado fresco, para o maior teor de cimento adotado no estudo, a mistura mostrou uma diminuição de trabalhabilidade com a adição de CCA. No estado endurecido, foi observado uma diminuição da absorção e um crescimento da resistência mecânica à compressão com os teores de cimento, de CCA, de cal, e dos dois conjuntamente. A ação benéfica da CCA na resistência mecânica a compressão aumentou, em geral, com o teor de cimento na mistura, e através do tempo a partir de 28 dias de cura. Uma diminuição desta ação é visível a partir de 84 dias de cura. Foram alcançados, aos 28 dias de cura, tensões limites de 7,99 MPa para as misturas sem adições, e de 11,45 MPa com adjunção de 10% de CCA em relação com a massa de cimento. O estudo adicional que foi realizado durante essa pesquisa teve como proposta a análise do comportamento reológico do SCAA fresco para três das... / This paper present a study about the influence of Rice Husk Ash - RHA and lime on the behaviour of Self-Compacting Soil Cement - SCSC at fresh and hardened state, and a preliminary study about the rheology of SCSC and its relationship with the water-cement ratio. 18 mixes were made by varying the amounts of water, cement, RHA, lime and superplasticizer, using appropriate parameters as a baseline. The main proposal aims to analyze the action of pozzolans and hydraulic materials in the SCSC mixtures, on workability conditions at fresh state, and on compressive strength over time. Slump Flow, Funnel and Segregation tests were performed at fresh state. At hardened state, cylindrical specimens of 50 mm diameter and 100 mm height, were subjected to unconfined compression test and water absorption test after 7, 28, 56 and 84 days. It was observed that, at fresh state, for the higher cement content adopted in this study, the mixture showed a decrease in workability with the addition of RHA. At hardened state, the material showed a decrease in absorption and an increase in compressive strength with cement, RHA and lime contents, and with the addition of RHA and lime together. The beneficial action of CCA on the strength of SCSC increased, on average, with the cement content in the mix, and through time from 28 days of curing. A decrease of that action is visible at 84 days of curing. After 28 days of curing, ultimate tensile strength of 7.99 MPa for mixes without additions, and 11.45 MPa with ratio CCA:cement of 1:10. In the additional study related in this paper, the rheological behavior of fresh SCAA developed in the study was analyzed. Three mixes, without addition, were chosen within the 18 mixes of the main study with the purpose of observing the water-cement ratio influence. The additional study adhered to the determination of the rheological model - representing the behavior of the fresh material ...

Orientador: Marco Antonio de Morais Alcantara / Co-orientador: Antonio Anderson da Silva Segantini / Banca: Geraldo de Freitas Maciel / Banca: Gilberto Carbonari / Resumo: Este trabalho de pesquisa apresenta um estudo sobre a influência da Cinza de Casca de Arroz - CCA e da cal no comportamento do Solo Cimento Auto-Adensável - SCAA no estado fresco e endurecido, e um estudo preliminar sobre a reologia do SCAA e sua relação com o fator água/cimento. Foram adotadas 18 misturas de SCAA, variando-se as quantidades de água, cimento, CCA, cal e superplastificante, utilizando parâmetros adequados como base de estudo. A proposta principal visa analisar a ação de materiais pozolânicos e hidráulicos na mistura de SCAA, nas condições de trabalhabilidade no estado fresco, e na evolução de sua resistência ao longo do tempo. No estado fresco, foram realizados ensaios de espalhamento "slump flow", ensaio do Funil e ensaios de segregação por peneiramento; no estado endurecido, corpos-de- prova cilíndricos de 5 cm de diâmetro e 10 cm de altura foram submetidos a ensaios de resistência à compressão mecânica e absorção de água aos 7, 28, 56 e 84 dias. Observou-se que, no estado fresco, para o maior teor de cimento adotado no estudo, a mistura mostrou uma diminuição de trabalhabilidade com a adição de CCA. No estado endurecido, foi observado uma diminuição da absorção e um crescimento da resistência mecânica à compressão com os teores de cimento, de CCA, de cal, e dos dois conjuntamente. A ação benéfica da CCA na resistência mecânica a compressão aumentou, em geral, com o teor de cimento na mistura, e através do tempo a partir de 28 dias de cura. Uma diminuição desta ação é visível a partir de 84 dias de cura. Foram alcançados, aos 28 dias de cura, tensões limites de 7,99 MPa para as misturas sem adições, e de 11,45 MPa com adjunção de 10% de CCA em relação com a massa de cimento. O estudo adicional que foi realizado durante essa pesquisa teve como proposta a análise do comportamento reológico do SCAA fresco para três das... / Abstract: This paper present a study about the influence of Rice Husk Ash - RHA and lime on the behaviour of Self-Compacting Soil Cement - SCSC at fresh and hardened state, and a preliminary study about the rheology of SCSC and its relationship with the water-cement ratio. 18 mixes were made by varying the amounts of water, cement, RHA, lime and superplasticizer, using appropriate parameters as a baseline. The main proposal aims to analyze the action of pozzolans and hydraulic materials in the SCSC mixtures, on workability conditions at fresh state, and on compressive strength over time. Slump Flow, Funnel and Segregation tests were performed at fresh state. At hardened state, cylindrical specimens of 50 mm diameter and 100 mm height, were subjected to unconfined compression test and water absorption test after 7, 28, 56 and 84 days. It was observed that, at fresh state, for the higher cement content adopted in this study, the mixture showed a decrease in workability with the addition of RHA. At hardened state, the material showed a decrease in absorption and an increase in compressive strength with cement, RHA and lime contents, and with the addition of RHA and lime together. The beneficial action of CCA on the strength of SCSC increased, on average, with the cement content in the mix, and through time from 28 days of curing. A decrease of that action is visible at 84 days of curing. After 28 days of curing, ultimate tensile strength of 7.99 MPa for mixes without additions, and 11.45 MPa with ratio CCA:cement of 1:10. In the additional study related in this paper, the rheological behavior of fresh SCAA developed in the study was analyzed. Three mixes, without addition, were chosen within the 18 mixes of the main study with the purpose of observing the water-cement ratio influence. The additional study adhered to the determination of the rheological model - representing the behavior of the fresh material ... / Mestre

This report presents the results of analyzing the critical void ratio concept on weakly cemented sand. The study consists of drained triaxial compression tests performed on artificially cemented sands created to simulate the natural behavior. In order to carry out this study, loose samples were prepared and subjected to different confining pressures such that failure at volumetric contraction could be obtained. The triaxial test results showed that the samples exhibited similar response to drained loading as compared to previous investigations on the static behavior of naturally and artificially cemented sands. Following the empirical method of determining the critical void ratio by plotting volumetric strain at failure against void ratio after consolidation, interpolation of the data points yielded critical void ratios of 0.735, 0.722, 0.703 and 0.668 for confining pressures of 60, 70, 80 and 95, respectively. A comparative analysis was made by plotting instantaneous void ratio during the loading against axial strain and this yielded values of 0.745, 0.735, 0.715 and 0.685 for confining pressures of 60, 70, 80 and 95 respectively. However, this method depends on the test accuracies at strain levels beyond 20% where the specimen becomes severely distorted, thus, making this method unreliable to use. Utilizing the result from volumetric strain-void ratio curves, the relationship between volumetric strain at failure and confining pressure was plotted and yielded critical confining pressures of 125, 94, 78, 67 and 60 psi for void ratios after consolidation of 0.66, 0.68, 0.70, 0.72 and 0.74, respectively. From the above results, the critical state line, which shows the variation of the critical void ratio, e_crit with the magnitude of the cr1 critical confining pressure, σ₃_crit, was defined for the artificially prepared samples with one percent cement. It would be interesting to compare this result with the critical state line of uncemented samples and of samples with higher amounts of cementation. The critical state concept is very important in evaluating the undrained strength of sands from drained tests data. The reader is referred to reference 7 since this is beyond the scope of this investigation. This concept is also an important study used in determining the liquefaction potential of sands. A paper by Castro [2] reported that liquefaction can only occur in sands that are looser than the critical state. The results of consolidated-undrained static tests will indicate whether the sand is looser or denser than the critical void ratio for the appropriate confining pressure, and thus whether the sand is susceptible to liquefaction. The reliability of the parameters obtained depends on a very limited number of data points. The author suggests that more tests on a wic!er range of relative density and confining pressure should be conducted to obtain more data points where a more accurate interpolation or extrapolation could be done. However, the results presented in this report are hoped to provide useful information for further studies to be made on the analysis of critical void ratio concept in cemented sands. / Master of Engineering

Esta investigación comprende la caracterización del suelo que conforma la subrasante de la Av. Padre Salas, Villa Rica, Pasco, el potencial de resistencia y la expansión que presenta el suelo en el sector indicado, la evaluación es realizada mediante ensayos CBR. Se utiliza la técnica de suelo cemento para mejorar las características físicas y mecánicas, este proceso consiste en mezclar al material con cemento Portland Tipo I formando suelo cemento 10%, 15% y 20%, los cuales presentan un incremento del CBR (máximo: 138.7% y mínimo: 91.9%) logrando un tipo de subrasante extraordinaria para resistir la estructura del pavimento y una reducción de 7.18% en la expansión de las muestras. / This study includes found the properties of the soil, which forms Av. Padre Salas, Villa Rica, Pasco subgrade, strength potential and expansion that soil presents at the indicated sector, the evaluation is executed through CBR tests. Soil cement technique is use in order to improve the physical and mechanical characteristics; this process is to combine the material with Ordinary Portland cement making soil cement 10%. 15% y 20%, which have a CBR increase (max: 138.7% and min: 91.9%) achieving an extraordinary subgrade type so as to bear up the pavement structure and an expansion reduction of 7.18% in specimens. / Tesis

Soil-Cement is not a new material; its low cost but high quality make it well-known and the use of this material for highway, dam, and airfield purposes increases every year. The origin of the idea of mixing soil and cement to priduce a structural material has not been definitely established; informal records show that mixing soil and cement was tried in Iowa, Ohio, Texas and probably in other places by 1920 (1). Since the first controllled soil-cement construction was carried out near Johnsonville, South Carolina in 1935 (2), soil-cement has been considered a valuable engineering material. It is now an accepted practice to denote the result of adding cement to soil as a soil-cement mixture (3), or in other words, soil-cement is the stabilization of soil with portland cement, and water. As the cement hydrates, the mixtrue becomes a hard, durable paving material (4).

Cementitiously stabilized soils or soil-cement is a commonly used solution for highway subbase and base course construction, particularly in regions where higher quality soils and aggregates are limited. Even though the utilization of soil-cement as an engineered material has been around for over 70 years, there is still room for advancement with respect to characterizing the performance of these mixtures both in the laboratory and in the field. The first objective of this thesis was to examine the Mississippi Department of Transportation soil-cement database to determine current soil-cement practices in Mississippi. The second objective of this thesis was to develop thermal measurement techniques to characterize compacted cementitiously stabilized soils. Over 800 compacted specimens were prepared and tested to investigate the feasibility and usefulness of performing thermal measurements on soil-cement mixtures.

Soil cement has been used as a means of stabilizing highway pavement layers, airport pavement layers, embankments, and foundations for decades. The technology uses a compacted mixture of soil, cement, and water to form a hardened material layer that has specific strength and durability properties. Even after decades of utilization, however, design of soil cement pavement layers has room for enhancement. This thesis investigates factors that influence the design and performance of cement stabilized pavement layers in Mississippi. A survey was conducted to collect information about soil cement design procedures from across the U.S. The factors examined in the laboratory investigation are strength gain with time, unconfined compressive strength variability, elastic modulus, and wheel tracking. More than 1,100 specimens were tested to determine the influence of these factors on the design and performance of soil cement pavement layers.

The objectives of this research were to evaluate the sensitivity of indirect tensile strength (ITS) test results to stabilizer type, stabilizer concentration, and curing time for multiple clayey soils with varying plasticity indices (PIs), identify cases in which an ITS of 30 psi can be obtained, and create a general linear model that predicts ITS. The scope of work included laboratory testing of three clayey soils sampled from Monticello, Utah; Bloomington, Indiana; and San Antonio, Texas. Each soil was tested using two stabilizers, cement or lime, at three concentrations, and two replicate samples were prepared for each combination. ITS testing was performed on two specimens of each combination at curing times of both 7 days and 28 days, for a total of 72 tests. The procedures outlined in this study include soil characterization, determination of moisture-density relationships, Eades and Grim testing, soil preparation, soil compaction, ITS testing, and statistical analysis. Regarding stabilizer type, treatment with cement consistently yielded higher ITS values than treatment with lime. Regarding stabilization concentration, ITS consistently increased with increasing concentrations of cement for all three soils; however, the effect of lime concentration depended on the PI of the soil, where increasing ITS values were only apparent with higher PI values. Regarding curing time, the ITS values corresponding to 28 days were generally higher than those corresponding to 7 days. Differences in ITS among the soils were largely attributable to differences in PI, which can influence pozzolanic reactivity. A cement or lime concentration that was equal to or 2% above the lime concentration indicated by the Eades and Grim test was typically required for a minimum 28-day ITS value of 30 psi to be attained. For the model developed to predict ITS, the significant predictor variables included PI, stabilizer type, actual stabilizer concentration, and curing time, as well as the two-way interactions between PI and stabilizer type, PI and actual stabilizer concentration, PI and curing time, and stabilizer type and actual stabilizer concentration. Overall, the model has an R2 value of 0.943 and an adjusted R2 value of 0.936. The model is best suited for soils having a fines content greater than 50%, a PI greater than 20, and a soluble sulfate concentration less than 3000 ppm.

Orientador: Paulo César Lodi / Resumo: A proposição de uso de materiais alternativos na construção civil que busquem reduzir a produção de resíduos ou utilizar resíduos anteriormente gerados mostra-se cada vez mais necessária, uma vez que a indústria da construção civil situa-se hoje como uma das maiores consumidoras de matérias-primas naturais. Dessa forma, este trabalho avaliou os efeitos que a inclusão de tiras poliméricas de polietileno tereftalato (PET) cortadas a partir de garrafas plásticas descartadas, e de cimento geram na resistência mecânica de um solo arenoso retirado da região de Bauru (SP). Foram realizados ensaios de resistência uniaxial em solo puro e com a inclusão aleatória de tiras de PET em diferentes comprimentos e porcentagens. Além dos ensaios de resistência não confinada, foram realizados também ensaios de compactação com adições de cimento e com adições de tiras de PET, a fim de se analisar os efeitos destas inclusões aos parâmetros compactação da matriz arenosa. Por fim, foram realizados também ensaios de cisalhamento direto em compósitos de solo-tira, solo-cimento e em compósitos de solo-cimento-tira, tornando possível a avaliação dos efeitos individuais de cada tipo inclusão na resistência ao cisalhamento da matriz. Em relação à resistência uniaxial notou-se o aumento da resistência da matriz arenosa devido à inclusão de tiras, independente do tamanho e percentagens analisadas. Quanto aos ensaios de cisalhamento direto, a adição de cimento foi efetiva aumentando tanto a coesão, quanto o... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The proposition of using alternative materials in construction that seek to reduce waste production or use previously generated waste is becoming increasingly necessary, as the construction industry is today one of the largest consumers of natural resources. Thus, this work evaluated the effects that the inclusion of polyethylene terephthalate (PET) strips cut from waste plastic bottles, and cement generate on the mechanical strength of a sandy soil from Bauru (SP). Unconfined strength tests were performed in pure soil and with the random inclusion of PET strips in different lengths and percentages. In addition to the unconfined strength tests, were also performed compaction tests with cement additions and with addition of PET strips, in order to analyze the effects of these inclusions on the sandy soil. Finally, direct shear tests were also performed on soil-strip, soil-cement and soil-cement-strip composites, making it possible to evaluate the individual effects of each inclusion on the shear strength of the analyzed soil. Regarding the uniaxial resistance, the soil resistance increased due to the inclusion of strips, regardless of the size and percentages analyzed. As for the direct shear tests, the cement addition was effective increasing both the cohesion and the soil friction angle in large proportions. The addition of strips to the soil-cement composite had its most pronounced effect on increasing soil cohesion, often reducing the friction angle. In general, the additi... (Complete abstract click electronic access below) / Mestre