Thesis EQUIVALECIA ENTRE EL ENSAYO DE PANEL EFNARC Y EL ENSAYO DE TRACCIÓN INDIRECTA PRO DOBLE PUNZONAMIENTO
Date
2017
Authors
ESPINOZA TORRES, VALENTINA PAZ
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Abstract
Actualmente, los shotcrete reforzados con fibras utilizados para el sostenimiento de túneles se controlan a través de su capacidad de absorber energía, la que se cuantifica mediante ensayos de paneles de grandes dimensiones de acuerdo a los procedimientos establecidos por la organización europea “European Federation of National Associations Representing for Concrete” (EFNARC) en 1996. Debido a la difícil manipulación de los paneles, estos presentan muchos defectos que alteran los resultados de los ensayos, lo que impide disponer de información válida para la aceptación o rechazo del shotcrete. Para subsanar este problema se ha propuesto utilizar el ensayo de tracción indirecta de doble punzonamiento, también conocido como ensayo Barcelona, para controlar el shotcrete reforzado con fibras, a partir de testigos extraídos directamente desde el hormigón proyectado.El objetivo de la presente memoria de título es establecer una equivalencia empírica entre la energía disipada por el shotcrete reforzado con fibras determinada mediante el ensayo Barcelona y la capacidad de absorción de energía cuantificada mediante el ensayo de panel EFNARC.Para lograr el objetivo propuesto se elaboraron y ensayaron cilindros y paneles usando mezclas de hormigón diseñadas para shotcrete, reforzadas con 4, 8 y 12 kilogramos de fibra por metro cúbico de hormigón. En total se estudiaron 17 cilindros y 12 paneles para fibra Barchip48 y 20 cilindros y 27 paneles para Barchip54. Con los resultados de los ensayos se determinó la energía disipada y la capacidad de absorción de energía de las probetas.De esta forma, se encontraron equivalencias con un alto coeficiente de determinación para ambos tipos de fibra, por lo cual se comprueba que es efectivo utilizar el ensayo Barcelona en vez del ensayo de panel EFNARC en el control sistemático de los shotcrete reforzados con fibras en obra.
2ABSTRACTAt present, the fibre reinforced shotcrete used for the sustenance of tunnels is controlled through its capacity to absorb energy, which is quantified by big dimension panels tests according to the procedures established by the European organization a “European Federation of National Associations Representing for Concrete” (EFNARC) in 1996. Due to the difficult manipulation of the panels, these present many defects that alter the results of the assays, impeding the provision of valid information for the acceptance or rejection of the shotcrete. In order to correct this problem, it has been proposed to use the double punching test of indirect tensile, also known as the Barcelona test. This, to control the fibre reinforced shotcrete from samples extracted directly from the projected concrete.The objective of the present work is to establish empiric equivalence between the energy dissipated by the fibre reinforced shotcrete, determined by he Barcelona test, and the energy absorption capacity, quantified through the EFNARC panel test.In order to fulfill the proposed objective, cylinders and panels of shotcrete-designed concrete were made and tested, reinforced with 4, 8 and 12 kilograms of fiber per cubic meter of concrete. In total, 17 cylinders and 13 panels were tested for Barchip48 fiber, and 20 cylinders and 27 panels for Barchip54. With the result of the assay, the dissipated energy and the energy absorption capacity of the samples was determined.The equivalents with a high determination coefficient for both types of fiber were found, by which it is proven that it is effective to use the Barcelona Test instead of the EFNARC Panel Test in the systematic control of the fiber reinforced shotcrete on site.
2ABSTRACTAt present, the fibre reinforced shotcrete used for the sustenance of tunnels is controlled through its capacity to absorb energy, which is quantified by big dimension panels tests according to the procedures established by the European organization a “European Federation of National Associations Representing for Concrete” (EFNARC) in 1996. Due to the difficult manipulation of the panels, these present many defects that alter the results of the assays, impeding the provision of valid information for the acceptance or rejection of the shotcrete. In order to correct this problem, it has been proposed to use the double punching test of indirect tensile, also known as the Barcelona test. This, to control the fibre reinforced shotcrete from samples extracted directly from the projected concrete.The objective of the present work is to establish empiric equivalence between the energy dissipated by the fibre reinforced shotcrete, determined by he Barcelona test, and the energy absorption capacity, quantified through the EFNARC panel test.In order to fulfill the proposed objective, cylinders and panels of shotcrete-designed concrete were made and tested, reinforced with 4, 8 and 12 kilograms of fiber per cubic meter of concrete. In total, 17 cylinders and 13 panels were tested for Barchip48 fiber, and 20 cylinders and 27 panels for Barchip54. With the result of the assay, the dissipated energy and the energy absorption capacity of the samples was determined.The equivalents with a high determination coefficient for both types of fiber were found, by which it is proven that it is effective to use the Barcelona Test instead of the EFNARC Panel Test in the systematic control of the fiber reinforced shotcrete on site.
Description
Catalogado desde la version PDF de la tesis.
Keywords
ENSAYO BARCELONA , ENSAYO DE PANEL EFNARC , SHOTCRETE REFORZADO CON FIBRAS