Flexural strength evaluation of Persian clay brick masonry with gypsum mortar

Abstract

This paper addresses the imperative need for understanding the mechanical properties of clay brick masonry with gypsum mortar, the primary construction material in Persian historical buildings, to facilitate accurate restoration efforts. Given the constraints of heritage preservation, destructive tests on large-scale specimens are unfeasible. As a viable alternative, this research employs scaled-down specimens to investigate the flexural strength. For the first time, Persian clay brick masonry with gypsum mortar assemblages have been tested at three scales of 1:2, 1:4 and 1:6 to determine the flexural strength. The paper introduces new relationships between the flexural strength of brick masonry and brick size. Furthermore, it establishes a correlation between the flexural strength of the brick masonry specimens and the flexural strengths of both the brick and the gypsum mortar. Additionally, some specimens incorporate cement mortar instead of gypsum mortar for result comparison. The obtained results reveal the profound influence of mortar type and thickness, along with brick dimensions, on flexural strength. The flexural strength of brick masonry increases with decreasing brick size. By reducing the size of bricks, the ratio of compressive strength to flexural strength decreases, offering key insights for restoration efforts. © 2023 Informa UK Limited, trading as Taylor & Francis Group.