Experimental evaluation of mechanical properties of RTB masonry

This study investigates experimentally the structural performance of Rat-Trap Bond (RTB) masonry. It focuses on assessing the load-bearing capacity and lateral resistance of RTB construction, with comparisons drawn against conventional English bond masonry. Key mechanical properties evaluated include compressive strength, Young’s modulus, diagonal tensile strength, shear modulus, cohesion, and the friction coefficient. The results revealed that compressive strength is primarily governed by brick strength, while diagonal tensile strength depends on strength of both brick and mortar. The coefficient of friction exhibited a direct correlation with total absorption of brick, conversely cohesion was observed to decline with increasing initial rate of absorption of bricks. Although RTB masonry offers benefits such as reduced material usage and improved thermal performance, it has notable structural limitations—particularly in lateral load resistance. These weaknesses stem from reduced interlocking due to the absence of frogs in bricks and smaller contact areas between units. As such, the study underscores the importance of design adaptations when employing RTB masonry in seismic-prone regions. To support engineering applications, predictive equations were developed linking key mechanical properties to the compressive strengths of both bricks and mortar. These equations serve as practical tools for engineers, for prediction of RTB masonry key mechanical properties. Overall, the findings highlight both the sustainable potential and structural challenges of RTB masonry, encouraging a balanced approach in optimizing its use in low-rise construction.