An experimental study of the bond behavior of twisted steel bars embedded in mortar cylinders and in the joints of masonry wallettes.

• Pull-out tests of steel bars inserted in mortar cylinders were conducted. • Pull-out tests of steel bars inserted in masonry wallettes were conducted. • Different bonded lengths were considered. • Bar rotation during extraction was observed. Among the different strengthening techniques available to reinforce masonry buildings, the near-surface mounted technique consists in inserting reinforcing elements of high-strength material in grooves realized by removing part of the mortar in the horizontal bed joints of a masonry wall. The present study deals with two experimental campaigns on pull-out tests conducted on twisted steel bars embedded concentrically in mortar cylinders and in the mortar bed joints of masonry wallettes as in in-situ applications. In order to compare the results between cylindrical and masonry specimens, the same bonded lengths are considered. [ABSTRACT FROM AUTHOR]