Efficiency of RC square columns repaired with polymer-modified cementitious mortars

This paper regards the axial behavior of reinforced concrete columns repaired by polymer-modified cementitious mortars. Tests were performed on eight columns with square cross-section: six were repaired with three types of polymer-modified cementitious mortars on all faces, two were in non-damaged and non-repaired condition (control elements). Tests were repeated varying mechanical properties (elastic modulus and compressive strength) of repair materials, maintaining the same repair thickness, including the reinforcement bars. Comparisons between repaired and control elements showed that polymer-modified cementitious mortars cannot restore the original load-bearing capacity of columns. In spite of this, selection of mortar mechanical properties plays a significant role. Among the three types of repair mortar tested in this experimental study, using the material with the most similar elastic modulus and higher compressive strength than that of the concrete substrate is recommended.