Untitled in english

Author(s)

Maria Cristiana do Nascimento Guimarães

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2001-11-20

Examining board members

Antonio Domingues de Figueiredo; Vanderley Moacyr John; Newton de Oliveira Pinto Júnior

• Advisor: Antonio Domingues de Figueiredo

Abstract

The quality control of the steel fiber reinforced concrete is accomplished through the test of flexural toughness. Such property is related with the area under the load-deflection curves that is obtained as a result of the test method. However, there is no national standard and international consensus regarding the most efficient approach for toughness quantification and the reliability of the material quality control. Besides this, the toughness results could vary strongly and it can be influenced by several aspects, the type of equipment used, for example. So, this study intends to analyze the possible variations obtained on toughness measurement of steel fiber reinforced concrete according to several approaches and to verify the suitability of each one regarding with its reproducibility and repeatability. Different groups of load-deflection curves were used in the analysis of these criteria. The load-deflection curves were obtained by testing prismatic specimens (10x10x40cm) casted with steel fiber reinforced concrete using 20 and 60 kg/m3 of fiber consumption. The tests were carried out with two different ages (7 and 28 days) and, in consequence, two different levels of compressive strength of the matrix. Two types of short fibers with two levels of yielding strength were used in function of the mechanical resistant. With the results, the superiority of the EFNARC (1996) approach was figured out. These tests also demonstrated extremely difficult conditions relatedto the reproducibility of the test. One another conclusion permits to affirm that the results obtained in the different laboratories are not comparable, which represents the dependence of the results to the laboratory where that the testes were made. (AU)