Behaviour of Hybrid Fiber Reinforced Geopolymer Concrete Beams under Flexural Loading

This paper presents the behaviour of GPC beams with and without fiber under flexural loading. The work is presented in two parts. In the first part tests were conducted for mechanical properties of plain and hybrid fiber reinforced Geopolymer concrete to determine maximum strength characteristics of concrete. In the second part of the program two types of under-reinforced beams were cast with plain GPC and hybrid fiber reinforced GPC (HFRGPC) and tested under two points loading. The percentage of tensile rebar ratio is kept constant for two types of beams. The hybrid fiber reinforced GPC is prepared with 1.5%(1%Steel+0.5% Polypropylene) of fibers and used to cast the under reinforced beams .The cast specimens are tested after a specified curing period to determine first crack load, ultimate load, load-deflection behaviour and crack patterns. The results are compared with the theoretical values. From the test results, the fiber volume fraction has a compelling effect on the cracking load, ultimate load, crack pattern and failure mode. The flexural behaviour of the beams including the induced cracks, failure pattern, load deflection capacity and ductility index were compared. The ductility index of hybrid fiber reinforced beams is greater than that of GPC beams. The HFRGPC beams showed superior performance than that of GPC beams for parameters considered in this experimental study.