Stress-Strain Characteristics of Steel Fibre ...

Stress-Strain Characteristics of Steel Fibre Based Hybrid Fibre Reinforced Self-Compacting Concrete

Author Name : Meena, T., Elangovan, G.

ABSTRACT Self-Compacting Concrete (SCC) is a special kind of concrete, capable of flowing freely and filling the form-work without the need for vibration. This feature of SCC enables a reduction in the usage of fossil fuel. As a result of adding more powder, segregation of aggregates is also avoided. So as to reduce the use of cement, suitable supplementary cementitious materials could be used as partial replacements. This enhances the sustainability of concrete as a construction material. Further, discrete fibres could also be added to SCC, either individually (mono) or in combination (hybrid). When mono fibres are incorporated in to SCC, it gives rise to Fibre Reinforced SCC (FRSCC). The process of adding more than one fibre to SCC mix, termed as hybridization, leads to the formation of Hybrid Fibre Reinforced SCC (HFRSCC). The current research work endeavours to employ two industrial wastes, namely fly ash (FA) and silica fume (SF), as powder materials, and to optimize their proportions in the SCC mixture. Initially, an M-30 grade SCC was realized - with the required levels of properties like passing ability (confined flowability), filling ability (unconfined flowability) and segregation resistance (stability) - as per the guidelines prescribed by The European Federation of Specialist Construction Chemicals and Concrete Systems (EFNARC). Further, through a series of experiments conducted by the authors previously, three different fibres, viz., hooked-end steel fibre, polypropylene (PP) fibre and AR glass fibre were identified as most suitable for hybridization. Keeping steel fibre as the base, two different combinations of hybrid fibre SCC, i.e., steel fibre–AR glass fibre (SG-HFRSCC) and steel fibre–PP fibre (SP-HFRSCC) were formulated, by suitably varying the volume fractions of the individual fibres, while keeping the total volume fraction constant. Mechanical properties and stress-strain behaviour of these concrete mixes were experimentally studied. The results of these experiments indicate that the various mechanical properties were enhanced due to the synergy of hybrid fibres. Both SCC with FA and/or SF as well as HFRSCC have made concrete more sustainable.