Brick-Mortar Bond and Masonry Compressive Strength

TLDR

Brick‑mortar bond strength is a key but under‑modeled factor in masonry compressive strength, yet existing failure theories assume the bond remains intact during failure. The study varied brick‑mortar bond strength over a wide range using local bricks and mortars, measured bond via flexure and shear tests while keeping brick and mortar properties constant, and then tested masonry prism compressive strength. Results show a clear positive relationship: increasing bond strength, with mortar strength held constant, raises masonry compressive strength.

Abstract

This paper focuses on some issues pertaining to brick-mortar bond and masonry compressive strength. Failure theories for masonry under compression make the assumption that the bond between brick and mortar remains intact at the time of failure of the brick or mortar. The influence of bond strength on masonry compressive strength is not fully accounted for in these failure theories. In this investigation, the influence of bond strength on masonry compressive strength has been examined through an experimental program using local bricks and mortars. Masonry prism compressive strength has been determined when the brick-mortar bond strength is varied over a wide range without altering the strength and deformation characteristics of the brick and mortar. Brick-mortar bond strength has been determined through flexure bond strength and shear bond strength tests. A relationship between the masonry prism compressive strength and bond strength has been obtained. The results clearly indicate that an increase in bond strength, while keeping the mortar strength constant, leads to an increase in the compressive strength of masonry.