Rehabilitation of reinforced concrete axially loaded elements with polymer-modified cementicious mortar

Abstract The aim of the paper is to investigate the compatibility and the efficiency of the rehabilitation intervention on reinforced concrete columns with polymer-modified cementicious mortar. This paper presents the results of experimental tests on axial behaviour of reinforced concrete columns, with square cross-section, repaired by polymer-modified cementicious mortar. Tests were repeated varying repair thickness, which included or did not include the steel reinforcement on one face of the square column. Despite this type of intervention is quite common in practice, the effect of repair thickness on the intervention efficiency, in relation to the existing steel reinforcement configuration, had not been previously studied in detail for axially loaded elements. Results were discussed and compared with those from control columns, which were tested in non-damaged, non-repaired conditions. The main findings of this work can be summarized as follows. The repair cannot restore the load-bearing capacity of non-damaged control columns, although they give acceptable results. Repairs that include the longitudinal reinforcement show good properties, with stable behaviour, sharing of loads, and plasticization of the material before failure, whereas thin repairs that do not include the reinforcement do not have adequate performance due to premature debonding. Non-linear numerical models also confirmed the different behaviour of the two types of repair.