Effect of scale on compressive strength of brick masonry with gypsum mortar

Abstract

Abstract A large number of historical buildings of Iran are made of brick masonry with gypsum mortar. For structural assessment of the buildings, information about the mechanical properties of the materials is required in order to analyse the structures and in some cases to propose restoration or strengthening for them. Taking masonry specimens with actual scale from historical buildings is not allowed and also testing on actual scale specimens in the laboratory is costly. Therefore, if the mechanical properties of the materials are obtained from a scaled model, the small scale specimens can be used for full scale structures. This paper investigates the effect of scale on the compressive strength and modulus of elasticity of brick masonry with gypsum mortar. The tests were conducted on two types of specimens at 1:1, 1:2, 1:4, and 1:6 scales based on two different standards. Scaled bricks were cut from full scale bricks. At some scales, cement mortar was used instead of gypsum mortar to compare the results. Obtained results show that the compressive strength and modulus of elasticity decrease by reducing the sizes. Furthermore, the material type, volume, and thickness of the mortar used in the wall considerably affect the compressive strength. Also, using the relationships obtained in this study, it is possible to predict the compressive strength and modulus of elasticity of the samples at any scale.