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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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/20341 |
| Date | 20 February 2015 |
| Creators | Fontoura, Tahyara Barbalho |
| Contributors | 35816384449, http://lattes.cnpq.br/1573496204231636, Fonseca, Antonio Joaquim Pereira Viana da, 00000000000, http://lattes.cnpq.br/6442601220960101, Ingunza, Maria Del Pilar Durante, 00871819406, http://lattes.cnpq.br/1925954531585024, Coutinho, Roberto, 07531893487, Severo, Ricardo Nascimento Flores, Santos J?nior, Olavo Francisco dos |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA CIVIL, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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