Effect of Brick Prewetting on Masonry Bond Strength

Masonry walls resist both in-plane and out-of-plane forces through the bond between the brick unit and mortar. Moisture content or saturation level of the brick unit at the time of construction is one of the key contributing factors in bond strength. Absorption of water from mortar by brick alters the development of a mechanical key that establishes the bond strength. In this study, the effect of the moisture content of bricks, at the time of construction, on shear and tensile bond strength is investigated for fired clay and fly ash bricks. The results of this study indicate that around a 75% saturation level of the brick unit yields the highest values of shear and tensile bond strength of clay and fly ash brick masonry with cement mortar. Adequate prewetting of brick units at the time of construction will ensure the desired moisture content and subsequently help to achieve a good bond strength.