INVESTIGATION OF JOINT THICKNESS & MORTAR STRENGTH ON THE MECHANICAL BEHAVIOUR OF BRICK MASONRY

Abstract

The knowledge of brick masonry structures is essential to advance our understanding of their behaviour, performance, and design principles. The unique characteristics and challenges associated with brick masonry, such as material heterogeneity, mortar properties, and structural complexities, necessitate dedicated research efforts. Although there has been significant research conducted on masonry structures, limited attention has been given to the influence of mortar thickness. The lack of comparative studies simultaneously examining the effects of both mortar type and thickness on compressive and shear strength is evident. Most research has primarily focused on the compressive strength of masonry structures, neglecting other important parameters such as shear strength and diagonal tension. This study aims to address the existing research gap by focusing on the following objectives. Firstly, it seeks to examine the influence of different types of mortar on the strength of clay brick masonry. Secondly, the study aims to investigate the influence of joint thickness on the strength of masonry constructed with clay bricks. Lastly, the study aims to evaluate the shear response of brick masonry. Understanding the shear behaviour is crucial for accurately assessing the structural performance of masonry elements. The methodology for this research project involved several essential steps. Initially, basic materials such as bricks, sand, lime, and cement were procured and v evaluated for their properties through various tests. The next phase encompassed the careful construction of specimens including brick masonry prisms, brick triplets, and a wall. These specimens were cured under specific conditions to ensure proper hydration. Once the curing period concluded, the samples underwent testing using a Universal Testing Machine (UTM) and a hydraulic jack to assess their compressive capacity, bond strength, and diagonal tension resistance. The study reveals that mortar strength has a significant impact on the compressive and shear strength of brick masonry. Cement mortar exhibits higher strength compared to lime mortar, with differences of approximately 253% in compressive strength and 255% in shear strength. Increasing mortar thickness initially improves compressive strength, but exceeding the optimal range leads to a decline. Similarly, shear strength decreases with increased mortar thickness. The diagonal tension test demonstrates the superior shear strength of cement mortar compared to lime mortar at a thickness of 13 mm. These findings underscore the importance of mortar strength and optimal thickness in determining the mechanical behaviour of brick masonry structures.