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Globally, concrete is the most widely used man-made construction material. This is due to its combination of flexibility of form, wide availability, and balance of cost and strength when compared to alternative materials (P. Kumar Mehta et al, 2006). The low  tensile  strength  and  strain  capacity  are  some  of  the  undesirable  properties  of concrete as they can cause failure to occur shortly after the formation of the first crack (Amir Alani et al, 2013). These properties of mass concrete have led to the use of steel reinforcement (rebars)  to  improve  its  tensile  properties.  However,  the  use  of  steel reinforcement  carries  durability implications  such  as  the  corrosion  of  the  embedded steel  among  others  (Per  Jahren  et  al,  2014).  An  alternative  method  of  concrete reinforcement  has  been  the  introduction  of  short-fibre  into  the  concrete,  examples include steel, polypropylene and glass fibres. The addition of these fibres to concrete influences  the  manner  in  which  cracks  develop  (Amir  Alani  et  al,  2013)  as  well  as increasing the strain capacity at peak load, and provides significant energy absorption in the post-peak portion of the load vs. deflection curve (L.N.Vairagade et al, 2015).

A number of research studies have looked at how the introduction and dosage of fibres in a  concrete  mix affect  mechanical  properties, and  there  exists a  body of  guidance documents  on  the  use  of  short-fibre  steel,  polymer  and  glass  reinforced  concrete. However,  only  a  limited  amount  of  research  has  considered  the  effect  of  mixing different  fibre  types  to  form  mixed  fibre  composites.  To  date  there  has  been  no coherent   study   of   the   “hybrid”   effect   of   using   combinations   of   short-fibre reinforcement  with  significantly  different  stiffness  and  strength  in  order  to  identify combinations  that  yield  the  best  properties  (toughness,  bond  strength,  etc.) and the potential  structural  benefits  of  such  hybrid  composites.  Hence,  an  investigation  into the  benefits  of  hybrid,  short-fibre  reinforced  concrete  and  its  use  for  structural advantage needs to be conducted. The research focus on short fibres thus requires that these materials be optimized for use in large engineering components and structures to commercial and engineering advantage.  To  adequately  perform  structural  element optimization, extensive material testing will be conducted comparing the performance of  plain  concrete  and  concrete  containing  short  fibres  such  as  steel,  polypropylene, glass, etc. In addition to this, testing of large elements will be conducted to investigate component property. In terms of the material properties of the concrete the samples tested will be of the scale 10–20 cm whereas a scale of about 1–3 m will be used for structural elements.  The experimental results will be compared with the output of finite element models to gain a further understanding of the structural implications of short fibre additions.

The  outcome  of  this  study will provide  a  better  understanding  of  the  structural performance  of  short-fibres  and  their  potential  for  cost  optimization  in  construction through a reduced requirement for link reinforcement, a faster construction cycle and also a better structural performance.