Technology, design and applications of steel fibre reinforced self-compacting concrete

Abstract

Steel fibre reinforced self-compacting concrete (SFRSCC) is a composite material that can integrate the benefits of fibre reinforcement with those derived from the self-consolidating characteristics of self-compacting concrete (SCC). SFRSCC can be used in several structural applications with economic and technical advantages. In this paper relevant aspects of the technology of SFRSCC are discussed, mainly those that can influence the fibre distribution and orientation, with consequences in terms of the post-cracking residual strength of this composite material. The evaluation procedures of the constitutive laws that characterize the post-cracking behaviour of a SFRSCC, based on available guidelines and recommendations, are described, and their robustness is discussed based on the results obtained with distinct test setups that highlight some deficiencies of these approaches. The use of SFRSCC is being explored for the construction of slabs supported on columns, where a minimum reinforcement ratio formed by steel bars is placed in the alignment of the columns. A formulation based on the yield line theory is presented to estimate the postcracking residual performance that a SFRSCC needs to have in order to accomplish the serviceability and the ultimate limit design requirements. To analyze in depth the behaviour of a SFRSCC structure up to its local or global collapse, material nonlinear analysis should be executed based on finite element method (FEM). The FEMIX computer program is used to obtain the fracture mode I constitutive law that simulates the crack initiation and propagation in a SFRSCC, by using inverse analysis. FEMIX is also used to explore the potentialities of SFRSCC for underground structures and grid foundations of single family-houses.