Amin Abrishambaf

The influence of fibre orientation on the post-cracking tensile behaviour of steel fibre reinforced self-compacting concrete

Adding fibres to concrete provides several advantages, especially in terms of controlling the crack opening width and propagation after the cracking onset. However, distribution and orientation of the fibres toward the active crack plane are significantly important in order to maximize its benefits. Therefore, in this study, the effect of the fibre distribution and orientation on the post-cracking tensile behaviour of the steel fibre reinforced self-compacting concrete (SFRSCC) specimens is investigated. For this purpose, several cores were extracted from distinct locations of a panel and were subjected to indirect (splitting) and direct tensile tests. The local stress-crack opening relationship (?-w) was obtained by modelling the splitting tensile test under the finite element framework and by performing an Inverse Analysis (IA) procedure. Afterwards the ?-w law obtained from IA is then compared with the one ascertained directly from the uniaxial tensile tests. Finally, the fibre distribution/orientation parameters were determined adopting an image analysis technique.

Time-Dependent Flexural Behaviour of SFRSCC Elements

This work presents and discusses the long-term behaviour of pre-cracked steel fibre reinforced self-compacting concrete (SFRSCC) laminar structures of relatively small thickness. One hundred and twelve prismatic specimens were extracted from a SFRSCC panel. These specimens were notched with different orientations regarding to the expected SFRSCC flow direction, and were tested under four-point flexural sustained loading conditions. The influence of the following parameters on the creep behaviour was studied: initial crack opening level (0.3 and 0.5 mm), applied stress level, fibre orientation/dispersion, and distance from the casting point. Moreover, to evaluate the effect of the long-term residual crack opening on the flexural post-cracking strength, as well as on the secondary stiffness, a series of instantaneous monotonic and cyclic tests were carried out, and the corresponding force vs crack tip opening displacement (F–CTOD) curves were compared to the ones obtained by assembling the F–CTOD curves determined in the pre-crack monotonic tests, creep tests and post-creep monotonic tests. Finally, based on the results obtained from the creep tests, an equation was proposed to predict the creep coefficient for the developed SFRSCC.