Factors Effecting Pull Out Behavior of Corrugated Steel Fibres in Cementitious Composites

Pull out behaviour of steel fibres which are not straight and not circular in shape have received little attention compared to the straight steel fibres. Flat corrugated steel fibres are proved to be very effective at interface during pull out, which results into strain hardening and dissipation of significant amount of cold work energy. Such a performance encourages in development of a unique HPFRCC which is well known as Engineered Cementitious Composite (ECC). All such capabilities can be thoroughly explored by performing single fibre pull out test. In the present experimental study, a single fibre pull out test was performed on MTS machine under displacement control with specially designed fixtures to grip any type of fibre. Corrugated flat steel fibres were embedded in cementitious matrices with 6 mm and 12.5 mm lengths. Cement and sand ratios were adopted as 1: 0.5, 1: 1, 1: 1.5 and 1:2 along with replacement of cement by fly ash as 10%, 20% and 30%. Load was recorded at peak and corresponding pull out energy is calculated. De-bonding and pull out behaviour are evaluated qualitatively. Effects of fibre length, cement and sand ratio and fly ash percentage on pull out behaviour of flat corrugated fibre in cementitious composite are discussed in detail. This will help in developing the corrugated steel fibre based ECC.