The use of fibre-reinforced polymers for repair and retrofit is growing at an unprecedented rate. This technique has been used for strengthening and rehabilitation of columns, beams, masonry, joints, etc. and has also found significant suitability for seismic applications. All research to date has focused, however, on wraps and jackets with continuous, unidirectional fibres. Within the auspices of Network of Centers of Excellence on Intelligent Sensing for Innovative Structures (ISIS) program, an entirely new method of fibre reinforced polymer coating is being developed. In this method, the composite with short, randomly distributed fibres is sprayed on the surface of concrete to be repaired. Composite gets pneumatically compacted on the application surface and develops a strong bond with concrete during the hardening process. In this paper, the effectiveness of the spray technique is compared with wraps carrying continuous fibres when applied to concrete cylinders under compression. To assess size effects, a companion test series involving larger cylinders was carried out. It was found that sprayed composites with randomly distributed short fibres performed equally well as or even better than wraps with continuous fibres. Within the continuous fibre wraps, those with a 0-90° fibre orientation are far more effective than those with a ±45° orientation.Key words: concrete, repair, glass fibre, polymer matrix, spray, wraps, deformability, size effects.
A new bio-based fibre-reinforced polymer obtained from sheep wool short fibres and PLA
