Publication: CARACTERIZACIÓN DE HORMIGONES REFORZADOS CON ALTAS CUANTIAS DE FIBRAS SINTETICAS
Date
2017
Authors
CASTRO CONTRERAS, PEDRO PABLO
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Abstract
Las aplicaciones de los hormigones reforzados han dado resultados muy positivos en el estado post fisuración del hormigón, así como en la resistencia residual que este obtiene, es por esto que en los últimos años el estudio de su comportamiento y pruebas de laboratorio, se ha desarrollado ampliamente.Una de las ventajas comparativas de las macro fibras es su bajo peso, alcanzando a más de 45000 fibras por kilogramo, constituyendo un refuerzo ampliamente distribuido en la masa de hormigón, con una baja sustitución volumétrica. Esto ha permitido que hormigones reforzados con dosis relativamente bajas las fibras sintéticas cumplan con los requisitos para ser clasificados como materiales estructurales, de acuerdo a los criterios establecidos en el Código Modelo del Comité Euro-Internacional del Hormigón. No, obstante, el uso de dosis relativamente altas de fibras sintéticas produce disminuciones de trabajabilidad y mayor presencia de oquedades en el hormigón.El objetivo de esta memoria es caracterizar las propiedades en estado fresco y endurecido de hormigones reforzados con altas dosis de fibras sintéticas.Para lograr el objetivo propuesto, se prepararon hormigones reforzados con 12 kg/m3 de fibras sintéticas, con los que se moldearan probetas para determinar la tenacidad y resistencias residuales de acuerdo a los procedimientos establecidos en las normas EN 14651, ASTM C 1609 y UNE 83515. Los resultados obtenidos se compararan con datos disponibles de otras investigaciones realizadas con hormigones reforzados con menores dosis de fibras.Tanto, en la comparación de ensayos ASTM C 1609 como EN 14651, la cuantía de 12 kg/m3 supera a las menores en tenacidad y resistencia residual en las probetas ensayadas, esto permite concluir que para esta dosificación, dicha cantidad de fibra tiene un comportamiento considerablemente más dúctil por lo que consigue un mejor comportamiento esperado en vigas post-fisuracion. En el ensayo UNE 83515 se presenta una diferencia de un 13% de la resistencia residual entre las ultimas cuantías por lo tanto a esta escala el aumento de cuantía de fibras es despreciable. De los valores de tenacidad se obtiene que, aumenten en función de la cuantía, por lo que concuerda con lo presentado en los otros ensayos.Por otro lado la trabajabilidad del hormigón es inversamente proporcional a la cantidad de fibra adicionada a la mezcla, no obstante, la adición de aditivo permite mejorar esta característica. Esta memoria se enmarca en el desarrollo del Proyecto Fondecyt N°1150881.
The applications of reinforced concrete have produced very positive results in the post cracking of concrete state, as well as the residual resistance that this gets, which is why in recent years the study of their behavior and laboratory tests has been developed widely.One of the comparative advantages of the macro fibers is their low weight, reaching more than 45,000 fibers per kilogram, constituting a widely distributed reinforcement in the concrete mass, with low volume replacement. This has allowed concrete reinforced with relatively low doses of synthetic fibers meet the criteria to be classified as structural materials, according to the criteria set out in the Model Code Euro-International Concrete Committee. Not, however, the use of relatively high doses of synthetic fibers produces decreases in workability and presence of voids in the concrete.The objective of this report is to characterize the properties of fresh and hardened concrete reinforced with high doses of synthetic fibers.To achieve the objective, concrete reinforced with 12 kg/m³ of synthetic fibers with which specimens be molded to determine the tenacity and residual resistance in accordance with the procedures set out in EN 14651, ASTM C 1609 is prepared and UNE 83515 . The results were compared with data available from other research with reinforced concrete with lower doses of fibers.Thus, in comparing assays ASTM C 1609 and EN 14651, the amount of 12 kg / m³ beats lower in toughness and residual strength in the specimens tested, the conclusion is that this dosage, said quantity of fiber has a behavior considerably more ductile so it gets a better performance expected in post-cracking beams. In the test UNE 83515 it presents a difference of a 13% residual strength between the last amounts therefore this scale increased amount of fibers is negligible. Tenacity values obtained that increase depending on the amount, so consistent with what is presented in the other trials.Furthermore the workability of concrete is inversely proportional to the amount of fiber added to the mixture, however, the addition of additive improves this feature. This memory is part of the development of Fondecyt N° 1150881.
The applications of reinforced concrete have produced very positive results in the post cracking of concrete state, as well as the residual resistance that this gets, which is why in recent years the study of their behavior and laboratory tests has been developed widely.One of the comparative advantages of the macro fibers is their low weight, reaching more than 45,000 fibers per kilogram, constituting a widely distributed reinforcement in the concrete mass, with low volume replacement. This has allowed concrete reinforced with relatively low doses of synthetic fibers meet the criteria to be classified as structural materials, according to the criteria set out in the Model Code Euro-International Concrete Committee. Not, however, the use of relatively high doses of synthetic fibers produces decreases in workability and presence of voids in the concrete.The objective of this report is to characterize the properties of fresh and hardened concrete reinforced with high doses of synthetic fibers.To achieve the objective, concrete reinforced with 12 kg/m³ of synthetic fibers with which specimens be molded to determine the tenacity and residual resistance in accordance with the procedures set out in EN 14651, ASTM C 1609 is prepared and UNE 83515 . The results were compared with data available from other research with reinforced concrete with lower doses of fibers.Thus, in comparing assays ASTM C 1609 and EN 14651, the amount of 12 kg / m³ beats lower in toughness and residual strength in the specimens tested, the conclusion is that this dosage, said quantity of fiber has a behavior considerably more ductile so it gets a better performance expected in post-cracking beams. In the test UNE 83515 it presents a difference of a 13% residual strength between the last amounts therefore this scale increased amount of fibers is negligible. Tenacity values obtained that increase depending on the amount, so consistent with what is presented in the other trials.Furthermore the workability of concrete is inversely proportional to the amount of fiber added to the mixture, however, the addition of additive improves this feature. This memory is part of the development of Fondecyt N° 1150881.
Description
Catalogado desde la version PDF de la tesis.
Keywords
ASTM , BCN , EN , FIBRAS SINTETICAS , HORMIGON REFORZADO