Experimental and numerical study on the determination of masonry compressive strength by means of cores

A novel moderately destructive method for assessing masonry compressive strength, using small diameter cores, has recently been proposed by the authors. The method involves completing cores with two mortar castings, one below and one above the core, so that cores can be tested in the same direction as they are loaded in the wall. In this study, the method reliability was investigated in laboratory conditions. Four masonry panels were constructed, using solid bricks and a lime-cement mortar. Three panels were subjected to compression test, as reference. The fourth panel was core-drilled and the resulting cores were completed with cement mortar castings and then subjected to compression test. The results of the study show that masonry compressive strength found by testing cores generally overestimates the actual strength by about 20%. The overestimation was ascribed to the confining effect exerted by the mortar castings, whose influence was specifically investigated by FEM modeling