Mechanical Performance of Coal Ash based Interlocking Bricks Wall Panel: A Sustainable and Viable Solution

The use of interlocking brick incorporating waste coal ash (CA) in masonry construction is an innovative, sustainable and viable solution to address the consequences associated with burnt clay bricks. In this research, the main focus was to study the double interlocking brick incorporating CA for its potential use in masonry construction. The studied dosages of CA were 30%, 35%, 40%, 45%, 50% and 55%. Cement was varied between 5% to 30% in order to make the total binder (cement and CA) contents equal to 60%. Moreover, wall panels using developed interlocking bricks were casted and tested for out-of-plane loading. It was observed that the incorporation of higher dosage of CA decreased the compressive strength owing to porous nature of used CA. However, interlocking bricks having 30% of CA exhibited compressive strength higher than 8 MPa, satisfying the local building code requirement. Higher water absorption was observed for interlocking bricks having higher dosage of CA compared to identical bricks with lower CA. Interlocking bricks exhibited higher shear strength due to mechanical anchorage provided by the keys and notches in comparison with the conventional bricks. Maximum double key shear strength of 2.34 MPa was observed for developed interlock bricks incorporating 30% of CA. Interlocking brick wall panel exhibited flexural strength of 1.05 MPa compared to 0.81 MPa for wall panel constructed using conventional burnt clay brick. Higher flexural strength of interlock CA based brick wall panel was due to the higher mechanical anchorage provided by the projected keys and grooves in between various courses of the wall panel. The cracking patterns of interlocking brick wall panel exhibited diagonal failure rather than the horizontal slide shear failure observed for conventional burnt clay brick wall panel. The experimental cracking load values were comparable with the theoretically predicted cracking loads for the tested wall panels. This study highlights the use of water cured interlocking brick incorporating waste CA for eco-friendly and economical construction leading to avoid the devasting effects of manufacturing process of conventional burnt clay bricks and deposition issues of CA. Moreover, this study motivates the construction stakeholders to employ double interlocking bricks of similar conventional size bricks to be used in a similar manner for masonry construction.