Flexural response of ECC strengthened reinforced concrete beams

Abstract

This paper reports the results of an experimental study conducted on the flexural behaviour of steel reinforced concrete beams partially strengthened with Engineered Cementitious Composite (ECC). A total of twelve beams were cast and tested. Six beams were tested to study the effect of the length of plastic hinge while four beams were tested to study the effect of thick layers of ECC provided in the tension zone of beams. The remaining two beams acted as control beams. Two variations in reinforcement detailing, corresponding to the under and over-reinforced beam sections, were used for the expected flexural tension and compression failures. Along with beam specimens, tensile coupons, compressive cylinders and cubes specimen were also cast and tested to evaluate the tensile and compressive characteristics of both ECC and concrete. All beams strengthened using ECC plastic hinges and layers were capable of taking more load than the corresponding control beams. The load capacities of over-reinforced and under reinforced RC beams strengthened with ECC plastic hinges were 2.85 - 6.34 times and 1.55 - 4.83 times more than those of the corresponding control beams respectively. Similarly, over reinforced and under reinforced RC beams with ECC layers were even better, having load capacities 5.71- 8.45 times and 5.37 - 8.31 times more than the normalised load capacity of the corresponding control beam, respectively. In general, ECC application increased the ductility of RC beams.