Flexural Response of Double Cast Concrete Beam: Experimental Investigation by Aftab Mehmood
Abstract
During past few decades, steel fibers reinforced concrete and fly ash has been increasingly used in structural engineering applications. Due to the steel fibers (SF) and fly ash (FA) additions there is significant increase in shear strength and flexural strength of beam. The cement consume high energy which emit a huge amount of greenhouse effect (100 kg of cement emits approximate 100 kg of CO2) so reduce these environmental problems use some quantity of fly ash replace with cement increase the specimen strength. That should be economical and safe environmentally. In this research work, the steel fiber were used below the neutral axis (NA) of beam and some quantity of fly ash replace with cement in the whole beam to find the flexural response of concrete beam. The four point loading test arrangement used to test the beam in flexural. To check the influence of beam size, the beam having the dimensions 200×250×750 without steel reinforcement are taken only steel fiber is added below the neutral axis to developing the flexural strength in absence of steel reinforcement. The cubes were casted (minimum 3 specimen) to check the compressive strength using steel fiber. Four different volume fraction contents ranging from (0%, 1%, 1.5%, 2%) are used to test the cubes. but in beams, 15% of fly ash replace by weight of cement constantly used for all beams and steel fiber 0%, 1%, 1.5%, 2% is used in beams. the aspect ratio kept constant which is 80. The design mix used is M25 for all beams to check the flexural response of beams and compressive strength of cubes. The maximum compressive strength is at 1.5% of steel fiber with 15% fly ash that is 36.22N/mm2 and increased 16.42% when comparison with conventional concrete. Therefore the value of conventional cube is 31.11N/mm2. The maximum flexural strength was found 3.5 Mpa in beam having 1.5% of SF and 15% of FA and also increased 42.36 % when compared to the normal beam.
