Experimental study on flexural behaviour of prefabricated concrete beams with double-grouted sleeves

•Prefabricated beams with double-grouted sleeves were developed.•Flexural behaviour of beams under three-point and four-point bending was explored.•Prefabricated beam and monolithic beam have a similar load bearing capacity.•The beam with double sleeves shows a higher ductility than the monolithic beam.•Stress concentration is reduced with increasing transition bar diameter.•The maximum crack width increases with increasing filler length.