Characterization of sustainable interlocking burnt clay brick wall panels: An alternative to conventional bricks Qasim Afzal, Safeer Abbas, Wasim Abbass ⇑ , Ali Ahmed, Rizwan Azam, M. Rizwan Riaz Civil Engineering Department, University of Engineering and Technology, Lahore highlights  To develop a sustainable interlocking burnt clay brick.  To characterize the interlocking brick incorporating various dosages of waste marble powder.  To compare the out of plane performance of interlocking brick wall panels and conventional brick wall panels. article info Article history: Received 19 December 2018 Received in revised form 17 September 2019 Accepted 6 October 2019 Keywords: Interlocking brick wall Waste marble powder Mechanical performance Out of plane loading abstract The application of interlocking burnt clay brick can be a viable option for conventional brick masonry due to its improved structural performance and ease in construction. Furthermore, the incorporation of waste marble powder (WMP) in interlocking burnt clay bricks can lead to economical and sustainable masonry construction. This research program was mainly categorized into two stages: material characterization of developed interlocking burnt clay brick and mechanical performance of wall panels incorporating inter- locking bricks. Various dosages of WMP (i.e. 10%, 20% and 30% by clay weight) in interlocking bricks were investigated. Results showed that the lighter interlocking bricks can be manufactured with the addition of WMP. It was observed that the compressive strength of interlocking burnt clay bricks decreased with the addition of WMP. However, the compressive strength of burnt clay bricks with 10% of WMP satisfies the local building code requirement for masonry construction. Test results on wall panels revealed that the interlocking burnt clay brick wall exhibited 43% increase in out of plane load carrying capacity com- pared to that of the conventional brick wall panels. Similarly, higher deflection at peak load and improved toughness was observed for interlocking brick wall panels. Moreover, cracking pattern transformed from horizontal slide shear in conventional brick wall to diagonal shear cracks in interlocking brick wall pan- els. The findings of this research demonstrate that the addition of 10% WMP in interlocking burnt clay brick can be a potential option for sustainable masonry wall leading to more eco-friendly and economical construction. Ó 2019 Elsevier Ltd. All rights reserved. 1. Introduction Clay bricks have been employed in construction as a basic building unit since very early civilizations. With advancement in construction techniques, fired clay bricks got popularity and used for load bearing and partition walls [1,2]. It was reported that more than 62% of the residential construction units are made up of burnt clay bricks in South Asia region [3]. The mechanical and durability performance of burnt clay bricks is mainly dependent on its constituents such as clay, water ratio, manufacturing, curing and burning processes [1]. Furthermore, the geometry and size of bricks have a vital role in the mechanical performance of wall panels. The main purpose of masonry wall construction is to transfer vertical loads to the soil underneath. However, the possibility of lat- eral loads cannot be ignored due to frequent earthquakes and wind gusts. This accentuates the concerns regarding performance of masonry wall construction against lateral loads [4]. Conventional bricks have flat surfaces; therefore, their resistance against out of plane loading in wall panels is mainly contributed by the bonding agent (mortar) and friction between the flat surfaces (in between the brick courses). To increase the lateral capacity of brick walls, interlocking burnt clay bricks may be considered a viable option for masonry construction. Interlocking bricks have raised portion called as ridge and recessed part known as bed where the ridge of https://doi.org/10.1016/j.conbuildmat.2019.117190 0950-0618/Ó 2019 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: wabbass@uet.edu.pk (W. Abbass). Construction and Building Materials 231 (2020) 117190 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat