Avaliação de parâmetros de resistência de solos com fibras de polipropileno reciclado
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Data
2019-07-12
Autores
Marçal, Régis
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Universidade Estadual Paulista (Unesp)
Resumo
Este trabalho avaliou a influência da inclusão de fibras extraídas de recipientes reciclados de polipropileno (PP) na resistência mecânica de dois tipos de solo: arenoso da região de Bauru (SP) e argiloso da região de Pederneiras (SP). Foram realizados ensaios de compressão uniaxial, cisalhamento direto e CBR nos solos com e sem fibras. Inicialmente, as fibras de PP foram adicionadas aleatoriamente em porcentagens previamente definidas de 0,25; 0,50; 0,75; 1,00; 1,50 e 2,00% em relação à massa de solo seca, a fim de se obter o teor ótimo de fibra, isto é, o percentual em massa de fibra que representa a máxima resistência à compressão não confinada (uniaxial) da mistura. De posse do teor ótimo de fibra e com base nos parâmetros ótimos de compactação, foram realizados ensaios de cisalhamento direto a fim de se avaliar a resistência ao cisalhamento do solo, além de ensaios CBR. Os principais resultados mostram que os teores ótimos de fibras obtidos na compressão uniaxial foram de 2,00% com L = 30 mm (solo arenoso) e de 1,5% com L = 30mm (solo argiloso). Nesse sentido, notam-se aumentos de 52,27% e 48,12%, respectivamente, para os solos arenoso e argiloso nos valores de resistência à compressão uniaxial em relação ao solo sem a adição de fibras. Em relação aos parâmetros de resistência obtidos por meio de ensaio de cisalhamento direto, notam-se, após a adição das fibras, aumentos de 126,49% (coesão) e 14,01% (ângulo de atrito) para o solo arenoso. O solo argiloso apresentou um pequeno decréscimo no valor da coesão (17,90%). O solo arenoso teve um aumento de cerca de 117% no valor do CBR, ao passo que o solo argiloso sofreu ligeira redução no valor deste parâmetro.
This work evaluated the influence of the fibers extracted from recycled polypropylene (PP) containers on the mechanical strength of two types of soil: sandy soil from Bauru (SP) region and clayey soil from Pederneiras (SP). Uniaxial compression, direct shear tests and CBR tests were performed in soils with and without fibers. Initially, PP fibers were randomly added at predetermined percentages of 0.25; 0.50; 0.75; 1.00; 1.50 and 2.00% in relation to the dry soil mass in order to obtain the optimum fiber content, that is, the percentage of fiber mass representing the maximum unconfined (uniaxial) compression strength of the mixture. With the optimum fiber content and based on the optimum compaction parameters, direct shear tests were performed in order to evaluate the shear strength of the soil, in addition to CBR tests. The main results show that the optimum fiber content obtained in uniaxial compression was 2.00% with L = 30 mm (sandy soil) and 1.5% with L = 30 mm (clay soil). In this sense, there were increases of 52.27% and 48.12%, respectively, for sandy and clayey soils in the values of uniaxial compression resistance in relation to the soil without the addition of fibers. In relation to the resistance parameters obtained by means of a direct shear test, increases of 126.49% (cohesion) and 14.01% (friction angle) were observed for the sandy soil after the addition of the fibers. The clay soil presented a small decrease in the value of cohesion (17.90%). The sandy soil had an increase of about 117% in the CBR value, while the clay soil had a slight reduction in the value of this parameter.
This work evaluated the influence of the fibers extracted from recycled polypropylene (PP) containers on the mechanical strength of two types of soil: sandy soil from Bauru (SP) region and clayey soil from Pederneiras (SP). Uniaxial compression, direct shear tests and CBR tests were performed in soils with and without fibers. Initially, PP fibers were randomly added at predetermined percentages of 0.25; 0.50; 0.75; 1.00; 1.50 and 2.00% in relation to the dry soil mass in order to obtain the optimum fiber content, that is, the percentage of fiber mass representing the maximum unconfined (uniaxial) compression strength of the mixture. With the optimum fiber content and based on the optimum compaction parameters, direct shear tests were performed in order to evaluate the shear strength of the soil, in addition to CBR tests. The main results show that the optimum fiber content obtained in uniaxial compression was 2.00% with L = 30 mm (sandy soil) and 1.5% with L = 30 mm (clay soil). In this sense, there were increases of 52.27% and 48.12%, respectively, for sandy and clayey soils in the values of uniaxial compression resistance in relation to the soil without the addition of fibers. In relation to the resistance parameters obtained by means of a direct shear test, increases of 126.49% (cohesion) and 14.01% (friction angle) were observed for the sandy soil after the addition of the fibers. The clay soil presented a small decrease in the value of cohesion (17.90%). The sandy soil had an increase of about 117% in the CBR value, while the clay soil had a slight reduction in the value of this parameter.
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Palavras-chave
Solos com fibras, Resistência ao cisalhamento, CBR, Polipropileno, Soil with fibers, Shear strength, Polypropylene