A Study on the Vertical Pull-off Testing and Horizontal Shear Testing Strength of External Wall Tile Adhesion

Abstract

Most of the exterior wall tiles deterioration appears in the adhesive layer, because of grooves and tile caulking marks on adhesion layer are clearly be seen from the fallen tile scene. The current strength test of adhesive layer is pull-off testing which is vertical to the exterior wall. The author developed a new shear test machine, and carries out the experiment with the universal pull-off testing machine. In this study, pull-off testing and shear testing which is horizontal to the exterior wall were both proceed for a more comprehensive discussion. To understand the relation between adhesive strength and hollow ratio, there are four hollow proportion of adhesion layer be set, 0%, 25%, 50%, and 75%. And the author into a variable with the experiment, if the structure is sprinkled or not. The pull-off testing strength is higher in the structural watering area, and 60% of the tile failure layer appears in the cement mortar layer. According to statistics from shear testing and pull-off testing of watering area, we get 1.62 and 12.77 kgf/cm2 on the 0% ratio of hollow, 0.77 and 5.67 kgf/cm2 on the 25% ratio of hollow, and 0.63 and 5.39 kgf/cm2 on the 50% ratio of hollow. The tiles adhesive strength of 25% ratio of hollow is less than half of the 0%. In the case of 0% ratio of hollow, the ratio of shear testing to pull-off testing is about 1:8. Comparing with current pull-off testing, shear test shows that even small strength can cause damage. It is suggested that the condition need to be aware when external wall tiles are determined to have hollow, their adhesion strength also becomes extremely weaker.