Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-26T20:00:09Z No. of bitstreams: 1 TahyaraBarbalhoFontoura_DISSERT.pdf: 7478783 bytes, checksum: b6e15d5fd03c19ed46e5a9a91fa42f46 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-29T20:14:41Z (GMT) No. of bitstreams: 1 TahyaraBarbalhoFontoura_DISSERT.pdf: 7478783 bytes, checksum: b6e15d5fd03c19ed46e5a9a91fa42f46 (MD5) / Made available in DSpace on 2016-04-29T20:14:41Z (GMT). No. of bitstreams: 1 TahyaraBarbalhoFontoura_DISSERT.pdf: 7478783 bytes, checksum: b6e15d5fd03c19ed46e5a9a91fa42f46 (MD5) Previous issue date: 2015-02-20 / Nas ?ltimas d?cadas v?rios trabalhos v?m sendo realizados no sentido de compreender o comportamento dos solos com cimenta??o (natural ou artificial) entre as part?culas. As areias, objeto de estudo desse trabalho, geralmente apresentam boa capacidade de suporte. Entretanto, muitas vezes se faz necess?ria a realiza??o de melhoramento do solo, para aumento da capacidade de suporte est?tica ou mesmo de se considerar o efeito da cimenta??o natural que ocorre em algumas areias. Para isso, ? necess?rio que se compreenda o comportamento mec?nico dos solos cimentados. O objetivo geral deste estudo foi descrever o comportamento tens?o - deforma??o - resist?ncia de uma areia origin?ria de Dunas de Natal cimentada artificialmente atrav?s de ensaios de compress?o simples e ensaios de compress?o triaxial drenados. Foi avaliada a influ?ncia do teor de cimento, da umidade de moldagem, do ?ndice de vazios e da tens?o confinante sobre a resist?ncia e verificada a validade do uso do fator vazios/cimento na estimativa da resist?ncia ? compress?o simples, da resist?ncia ao cisalhamento em condi??es drenadas e do comportamento tens?o-deforma??o. As amostras dos ensaios de compress?o simples foram moldadas com diferentes teores de umidade de moldagem (6%, 9% e 12%), diferentes teores de cimento (2,5%; 5,0%; 7,5% e 10%) e ?ndice de vazios de 0,6. Nos ensaios de compress?o triaxial, todas as amostras foram moldadas na umidade de 6%, com tr?s ?ndices de vazios (0,6; 0,7 e 0,8) e quatro teores de cimento (0,0%; 2,5%; 5,0% e 7,5%), sendo rompidas sob diferentes tens?es confinantes (50, 100, 200 e 300 kPa). O agente cimentante utilizado foi o Cimento Portland de Alta resist?ncia inicial resistente aos sulfatos (CP-V ARI ? RS). Concluiu-se que, a resist?ncia a compress?o simples cresce com o aumento do teor de cimento e com a diminui??o da umidade de moldagem. Quanto a resist?ncia ao cisalhamento, verificou-se que esta aumenta com o aumento da quantidade de cimento e com a diminui??o do ?ndice de vazios. Percebeu-se ainda que a varia??o nos valores de ?ngulo de atrito se mostrou praticamente negligenci?vel quando comparado com a varia??o do intercepto coesivo. Por fim, foi verificado que o fator vazios/cimento mostrou-se ser um par?metro muito eficaz e confi?vel na previs?o do comportamento da areia de Natal para dosagem de solo-cimento. / In recent decades a number of studies have been conducted in order to understand the behavior of soil with cementation (natural or artificial) between particles. The sands studied here generally exhibit good bearing capacity. However, it is often necessary to improve the soil to increase static support capacity or even to consider the effect of natural cementing that occurs in some sands. To that end, it is important to understand the mechanical behavior of cemented soils. The general aim of this study was to describe stress-strain-strength behavior of artificially-cemented sand from the Dunes of Natal, Brazil by means of unconfined compression and drained triaxial compression tests. The influence of cement content, molding moisture, void ratio and confining stress on strength was assessed and the validity of using the void/cement factor in estimating unconfined compressive strength, shear strength in drained conditions and stress-strain behavior was determined. Unconfined compression test samples were molded using different molding moisture levels (6%, 9% and 12%), different cement content (2.5%; 5.0%; 7.5% and 10%) and a void ratio of 0.6. In triaxial compression tests, all the samples were molded in 6% moisture with three void ratios (0.6; 0.7 and 0.8) and four cement contents (0.0%; 2.5%; 5.0% and 7.5%), and rupture occurred under different confining stresses (50, 100, 200 and 300 kPa). The cementing agent used was high-early-strength Portland cement, with sulphate resistance (CP-V ARI ? RS). It was concluded that unconfined compressive strength rises with an increase in cement content and a decline in molding moisture. It was found that shear strength increases with a rise in the amount of cement and a decrease in void ratio. It was also observed that the variation in friction angle values was practically negligible when compared to the change in cohesion intercept. Finally, it was found that the void/cement factor was a very effective and reliable parameter for predicting the behavior of Natal Sand in order to determine the soil-cement dosage.