Experimental and analytical investigations on shear behaviour of reinforced geopolymer concrete beams

Geo polymer materials are inorganic polymers synthesized by reaction of a strongly alkaline silicate solution and an alumino silicate source. Geo polymer is used as binder to completely replace the ordinary Portland cement in producing Geo polymer concrete(GPC). They possess the advantages of rapid strength gain, elimination of water curing, good mechanical and durability properties and are additional ecofriendly and sustainable alternative to Ordinary Portland Cement (OPC). While substantial research work has been reported on behaviour of reinforced concrete structural elements, similar studies have not been reported on GPCs. This paper describes an experimental and analytical investigation on shear behaviour of reinforced GPC and OPCC beams. The aim is to study the shear behavior of reinforced GPC and OPCC beams. Three GPC mixes and one OPCC mix were considered for the study. All the beams were provided with the same flexural and shear reinforcement and the beams were tested under two point loading with two shear span to depth ratios of 1.5 and 2 for each of the mixes. This paper presents the details of the mix designs of GPC mixes, parameters investigated, preparation of RGPC beams, testing and evaluation of structural behavior with respect to cracking, service load, deflections at various stages and failure modes. Comparison of shear design procedure of beams was made by conventional IS 456 2000 approach and Modified compression field theory. Non linear finite element analysis of beams by 3D modelling of concrete (solid65 element) and discrete modeling of reinforcement (Link8 element) was carried out using ANSYS software. For shear span to depth ratio of 1.5, load shear capacity, load deflection characteristics and failure modes and crack patterns obtained from the experimental and analytical study were compared for both RPCC and RGPCC beams. The results of the study indicate that the performance of RGPC is similar to that of RPCC beams and the ultimate loads are in the same order. The failure modes and crack patterns are also similar.