An experimental study on the behavior of interlocking masonry blocks manufactured using 3D printed mold

Masonry structure built with mortarless interlocking blocks effectively reduces the construction time and costs and also improves the quality of construction. However, due to the vast variety in the construction methods and geometry of these blocks, their behavior has not been fully understood. In this paper, an experimental study was conducted to understand the in-plane and out-of-plane behavior of interlocking mortarless masonry. Four types of interlocking blocks (namely trapezoidal-shaped, Lego-shaped, cross-shaped, and checkered-shaped blocks) as well as one simple control block with the same size as the interlocking blocks were considered. Innovative 3D printed molds were designed and manufactured to construct the designed interlocking blocks with different shapes. Masonry units were then assembled with and without adhesive paste and were subjected to six different tests including compressive, diagonal shear, in-plane and out-of-plane shear tests, as well as flexural tests in parallel and perpendicular to the bed joints directions. The results were compared in terms of the general behavior, crack pattern, failure mode, and ultimate strength. According to the results, in the flexural test perpendicular to the bed joints and diagonal shear tests, the trapezoidal-shaped and Lego-shaped blocks had the highest strength because of their side shear keys. In the flexural test in parallel to the bed joints, the cross-shaped block had the highest strength due to its highest total locked area. In the in-plane and out-of-plane shear tests, the cross- and checkered-shaped blocks respectively had the best performance due to their high inter-block contact area and out-of-plane effective contact area. This research provides a comprehensive evaluation of the effect of shapes on the behavior of interlocking blocks under different loading conditions. The outcome of this study helps designers to identify the most suitable interlocking shape based on the critical type of loading that masonry needs to be designed for.