Influence of Coatings on Rebar-to-Mortar Bond in Patch-Repairs

D. DIAS-DA-COSTA Assistant Professor INESCC, Dep. of Civil Eng., Univ. of Coimbra Portugal dcosta@dec.uc.pt

D. Dias-da-Costa received his Ph.D. degree in Civil Engineering in 2010 from the University of Coimbra where he is an assistant professor since then. His main research interests include the numerical modelling of quasi- brittle materials.

E. JÚLIO

Full Professor

ICIST, DECivil IST-UTL,

Lisbon, Portugal

ejulio@civil.ist.utl.pt

E. Júlio is a full professor at the Instituto Superior Técnico of the Technical University of Lisbon. His research interests are in the field of Structural Concrete. He is member of IABSE WC 3, fib Commission 5 and ACI 364 Committee.

Patch repairs are common in the rehabilitation of reinforced concrete structures. This technique includes the following steps: i) removal of damaged concrete; ii) cleansing of corroded steel rebars;

iii) application of anti-corrosive coating; and iv) application of a repair mortar.

Although the application of an anti-corrosive coating is common practice, part of most manufacturers’ guidelines and, moreover, a mandatory step in some countries standards, it is important to assess if it decreases the bond of steel rebars to the repair mortar.

The experimental study herein described includes 72 pull-out tests and it was conducted aiming to characterise the bond strength of the rebar-to-mortar interface and, subsequently, to define the most adequate procedure concerning anti-corrosive protection of the rebars. Conclusions are presented covering all situations considered.