This chapter investigates the effects of bonding Eco-friendly Ductile Cementitious Composite (EDCC) repair material to the surfaces of plain hollow concrete block masonry walls on the in-plane behaviour of the walls. The EDCC repair material improved the inplane behaviour of the walls. The final mixture-proportioning of the EDCC was determined through extensive experiments at the University of British Colombia. The EDCC is not a very workable material, and this was one of the main challenges. To understand the effectiveness of the proposed technique to increase the shear strength of concrete masonry, nine 1.8 m square specimens were constructed with hollow concrete masonry units of actual size 390 × 190 × 190 mm and type S mortar. The failure mode altered in the strengthened specimens compared to the plain specimens due to the changes in stiffness and ductility resulting from the application of the EDCC repair material.
