Publication: CARACTERIZACIÓN DE LAS PROPIEDADES DE HORMIGONES REFORZADOS CON FIBRAS SINTÉTICAS PARA USO EN SHOTCRETE
No Thumbnail Available
Date
2017
Authors
RAMOS ISHIHARA, NATALIA MYLENNE
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Para caracterizar el comportamiento de los hormigones reforzados con fibra en el rango post-agrietamiento, es necesario disponer de un sistema de ensayo capaz de obtener una transición estable entre el régimen pre y post fisura del material. Los sistemas de ensayo idóneos son conocidos como ensayos de tracción directa o tracción uniaxial, pero presentan una ejecución dificultosa en laboratorio, además de una alta dispersión de datos.Por ello se recomienda utilizar ensayos a flexo tracción, los cuales tienen un proceder más simplificado en el laboratorio, y permiten una mejor representación de las condiciones de carga a la que es sometido un HRF.El objetivo de esta investigación es caracterizar el comportamiento de hormigones reforzados con fibras, mediante los ensayos normalizados por la norma europea EN-14651:2007+A1 y EFNARC 1996, a realizarse en el laboratorio LEMCO de la Universidad Técnica Federico Santa María.En primera instancia para la norma europea EN 14651 se utilizarán vigas con entalla para caracterizar el comportamiento de los hormigones reforzados con fibras, utilizando como variable de control la apertura de fisura y la carga máxima. Obteniendo luego del ensayo a flexión con carga central, los valores de resistencia residual y un diagrama de carga-desplazamiento del borde de la fisura.Luego para EFNARC 1996, se utilizarán paneles de 600x600x100 mm, en los cuales se le aplicará una carga central puntual; y de este ensayo se obtendrán la máxima carga mantenida y la energía absorbida, el primer parámetro no es de gran importancia ya que no tiene relación directa con el comportamiento de las fibras; por el contrario, la energía absorbida es un punto importante ya que, a mayor absorción de energía, mayor es la capacidad de soportar cargas en el estado de fisuración.Para la realización del análisis propuesto se fabricarán probetas, vigas y paneles de hormigón reforzado con distintos tipos de fibras existentes en el mercado, en una misma dosificación, con ello mediante los ensayos respectivos, se podrá determinar directamente cual tiene un mejor comportamiento según lo requerido.Utilizando los parámetros definidos a partir de la respuesta carga-deflexión (EFNARC 1996) o carga – CMOD (EN 14651) obtenida a partir de los ensayos de flexión mencionados se puede establecer una relación que permita describir el comportamiento de los distintos HRF.Finalmente se compararán gráficamente los resultados y valores obtenidos, para cada tipo de fibra utilizada en las distintas amasadas determinando de esta manera los parámetros que caracterizan a cada una de ellas y señalar que tipo de fibra es más óptima según requerimientos.
In order to characterize the behavior of fiber-reinforced concretes in the post-cracking range, it is necessary to have a test system capable of obtaining a stable transition between the pre-crack and post-crack regime of the material. Suitable test systems are known as direct traction tests or uniaxial traction tests, but they are difficult to perform in the laboratory, besides a high data dispersion.It is therefore recommended to use flexo traction tests, which have a more simplified procedure in the laboratory, and allow a better representation of the loading conditions to which a FRC is subjected.The aim of this investigation is to characterize the behavior of reinforced concrete with fibers, by means of the tests normalized by the European standard EN-14651: 2007 + A1 and EFNARC 1996, to be realized in the LEMCO laboratory of the Technical University Federico Santa Maria.In first instance for European standard EN 14651, notched beams will be used to characterize the behavior of reinforced concrete with fibers, using as a control variable the crack opening and the maximum load. Obtaining after the bending test with central load, residual resistance values and a loading-displacement diagram of the edge of the crack.Then for EFNARC 1996, there will be used panels of 600x600x100 mm, in which a punctual central load will be applied; and from this test it will be obtained the maximum maintained load, and the energy absorbed. The first parameter is not of great importance since it has no direct relation with the behavior of the fibers; on the contrary, the energy absorbed is an important parameter because, the greater the energy absorption, the greater the capacity to bear loads in the state of crack.In order to carry out the proposed analysis there will be manufactured in the same dosage, test tubes, beams and reinforced concrete panels with different types of fibers available on the market. By means of the respective tests, it will be possible to determine directly which one has a better behavior according to the requirements.Using the parameters defined from the load-deflection response (EFNARC 1996) or load-CMOD (EN 14651) obtained from the mentioned flexural tests, a relation that allows to describe the behavior of the different FRC can be established.Finally, the results and values obtained will be compared graphically for each type of fiber used in the different kneading processes, thus determining the parameters that characterize each one of them and indicating which type of fiber is more optimal according to the requirements.
In order to characterize the behavior of fiber-reinforced concretes in the post-cracking range, it is necessary to have a test system capable of obtaining a stable transition between the pre-crack and post-crack regime of the material. Suitable test systems are known as direct traction tests or uniaxial traction tests, but they are difficult to perform in the laboratory, besides a high data dispersion.It is therefore recommended to use flexo traction tests, which have a more simplified procedure in the laboratory, and allow a better representation of the loading conditions to which a FRC is subjected.The aim of this investigation is to characterize the behavior of reinforced concrete with fibers, by means of the tests normalized by the European standard EN-14651: 2007 + A1 and EFNARC 1996, to be realized in the LEMCO laboratory of the Technical University Federico Santa Maria.In first instance for European standard EN 14651, notched beams will be used to characterize the behavior of reinforced concrete with fibers, using as a control variable the crack opening and the maximum load. Obtaining after the bending test with central load, residual resistance values and a loading-displacement diagram of the edge of the crack.Then for EFNARC 1996, there will be used panels of 600x600x100 mm, in which a punctual central load will be applied; and from this test it will be obtained the maximum maintained load, and the energy absorbed. The first parameter is not of great importance since it has no direct relation with the behavior of the fibers; on the contrary, the energy absorbed is an important parameter because, the greater the energy absorption, the greater the capacity to bear loads in the state of crack.In order to carry out the proposed analysis there will be manufactured in the same dosage, test tubes, beams and reinforced concrete panels with different types of fibers available on the market. By means of the respective tests, it will be possible to determine directly which one has a better behavior according to the requirements.Using the parameters defined from the load-deflection response (EFNARC 1996) or load-CMOD (EN 14651) obtained from the mentioned flexural tests, a relation that allows to describe the behavior of the different FRC can be established.Finally, the results and values obtained will be compared graphically for each type of fiber used in the different kneading processes, thus determining the parameters that characterize each one of them and indicating which type of fiber is more optimal according to the requirements.
Description
Catalogado desde la version PDF de la tesis.
Keywords
FIBRAS SINTETICAS ESTRUCTURALES , HORMIGONES REFORZADOS , SHOTCRETE