Bond Strength Tests under Pure Shear and Tension between Masonry and Sprayed Mortar

Abstract

Sprayed mortar or shotcrete is a construction technology that could enhance existing masonry buildings’ resilience by reinforcing low-safety load-bearing walls. Many factors affect the resistance of shotcrete-reinforced structures. One of the most important is the bond strength at the interface between the shotcrete and the reinforced wall. According to previous technical literature, bond strength usually has two evaluation criteria: shear and tensile strength. The experimental campaign described in this article focused on the bond strength between sprayed mortar and three masonry materials without the influence of normal force or constraint, as well as the roughness of these materials. The analysis of these tests focused on determining the relation between bond strength, roughness, and material strength. The analyses revealed that material strength has a more significant effect on bond strength than roughness, and bond strength is related to shrinkage of the materials. On the basis of previous theories, these researchers found that when there is no obvious influence due to normal force and constraint, the shear strength and tensile strength are different, and the shear strength is likely to be the cohesion force of the two materials. Finally, this article concludes with a novel logarithmic relationship between these strengths.

Influence of Mixing Water Content and Curing Time on Bond Strength of Clinker Masonry: The Wrench Test Method

“…There were also propositions of torsion in the plane of two masonry units connected to each other by mortar as proposed Khalaf [ 17 ]. In addition, nowadays, the axial tensile test is sometimes used to determine bond strength or, actually, adhesion between a masonry element and mortar [ 18 ]. On the other hand, the flexural strength of masonry in a plane perpendicular to its surface is determined on medium-sized panels in a four-point bending test, for example, according to EN 1052-2:2005 [ 19 ].…”