Toughness evaluation of fiber reinforced concrete using open-loop test

The quality control of the structures elements produced with Fiber Reinforced Concrete (FRC) depends critically of a test method to control toughness that could be considered reliable, economical and compatible with existing design models. The usual control is mainly based on bending tests of beam specimens, requiring specific equipment rarely found in Brazilian concrete control laboratories. The simplified Barcelona test (EBS) appears as a promising alternative test for FRC, as it allows the extraction of sample and uses resources available in most laboratories. This study aims to compare results obtained with the EBS method and the bending of beams through JSCE-SF4, which is the most used in Brazil, seeking to establish correlations between the different responses of these test method. One type of steel fiber and another polypropylene fiber were used with three levels of consumptions. Five beams were molded for test JSCE-SF4 and eight cylinders were extracted from the prisms edges for the EBS. These methods resulted load versus displacement curves. The correlations were obtained by comparing the energy required to cause a crack width equivalent for both methods. The results showed that the open-loop system turns difficult to measure the residual strength (poscracking) at Serviceability Limit States (SLS). The EBS and JSCE-SF4 test methods are correlated in terms of residual strength and toughness. These correlations allow the use of either method without compromising the evaluation of these characteristics. EBS is an easier test method to perform and allows the evaluation of toughness in cores extracted in real structural elements.

Barcelona test; toughness; fiber reinforced concrete; test method