Innovative solution to retrofit RC members: Inhibiting-Repairing-Strengthening (IRS)

• Performance of a novel Steel Reinforced Geopolymeric Matrix (SRGM) system.
• IRS technique includes three operations in one: Inhibiting-Repairing-Strengthening.
• Experimental tests on RC beams strengthened with eco-friendly SRGM composite.
• Effectiveness of the IRS technique in terms of strength/ductility/failure modes.
• IRS-SRGM provided greater load carrying capacity and ductility than EB-SRGM.

The work aims to experimentally and theoretically investigate the structural performances of an innovative solution, alternative to Externally-Bonded (EB) technique, for retrofitting of Reinforced Concrete (RC) structures with deteriorated cover concrete and/or corroded bars: Inhibiting-Repairing-Strengthening (IRS) technique. It consists in the installation of a stainless steel fabric in the cover concrete, restoring the latter with a geopolymeric matrix (Steel Reinforced Geopolymeric Matrix, SRGM). This solution includes three operations in one: corrosion inhibition, cover concrete repair and flexural strengthening.Two groups of large-scale RC beams with different geometrical properties, low concrete strength, corroded smooth round/ribbed bars, were strengthened with IRS-SRGM/EB-SRGM systems and tested under four-point bending. Test results showed that the IRS-SRGM system provided greater load carrying capacity and ductility than the EB-SRGM system. Comparing the results of the two groups the scale effect on the ultimate load was not affected. Furthermore, a theoretical prediction of the tested beams and analytical/experimental comparisons were performed.The proposed IRS solution could be an effective alternative to EB technique, reducing the time and costs of intervention with an eco-friendly technology.