Experimental investigation on the behavior of composite laminates bonded on masonry

This paper investigates the bonding behavior of carbon- and glass-fiber reinforced polymers (FRP) glued on various kinds of masonry elements. Clay-bricks as well as some natural masonry elements (i.e., tuff or limestone) have been used for preparing a series of specimens for double shear pull-out tests. A preliminary experimental work has been carried out on some samples of the masonry blocks for identifying the basic features of their mechanical behavior. Then, twenty-four pull-out tests have been carried out. The discussion of the results of those tests focuses on the ultimate strength of the FRP-to-masonry joints. Finally, the experimental results will be utilized for assessing the theoretical formula for the ultimate strength of composite laminates glued on masonry provided by a recently issued Italian Code for Structural Strengthening. Since all the relevant mechanical properties of the masonry materials are available, a consistent relationship between such mechanical properties and the observed strength of the FRP laminates failing in delamination is finally proposed.