IMPROVEMENT IN HARDENING BEHAVIOUR OF MICRO FIBER REINOFRCED CEMENT MORTAR

G. Avinash, SaptarshiSasmal

Abstract: Concrete is a quasi-brittle material which is weak in tension. Inconsistent behaviour due to excessive heterogeneity, extremely low tensile strength and absence of strain hardening has made the concrete the brittle and fast deteriorating material. It exhibits a tension softening behaviour when subjected to tensile loading. Strain hardening is the property of the material to take up the load even after initiation of crack. Pseudo strain hardening is an induced property which can be achieved through incorporation of the fibers suitable for crack bridging. It involves activation of large number of microcracks that develop normal to tensile loading direction, which results in increase in ductility and damage tolerance of the composite. Pseudo strain hardening behaviour of a cement matrix depends on many parameters such as fiber length, fiber diameter, tensile strength of fiber, Young’s modulus of fiber, Young’s modulus of matrix, etc. and any change in the above parameters will result in change in the nature of fiber bridging stress with respect to the corresponding crack opening displacement. This behaviour thus relates the microstructural parameters to the mechanical behaviour of the composites. In the present study, improvement in the pseudo strain hardening behaviour due to addition of the micro fibers is studied. Experimental investigations have been carried out to understand the influence of different fiber parameters on the hardening behaviour. The study is useful in understanding the microstructural behaviour of fiber reinforced cement matrix and serves as a tool to progress further towards developing damage resilient concrete with greater durability and ductility.

Keywords: HARDENING

DOI: https://doi.org/10.15623/ijret.2015.0425042