The construction sector is a major consumer of non-renewable resources and a significant contributor to CO2 emissions. Reusing entire components or their parts, rather than recycling at the material level, preserves embodied energy and reduces landfill construction waste. In this study, we reclaimed concrete demolition waste units of random shape and constructed masonry wallets and walls, employing a construction technique reminiscent of traditional stone masonry with mortar. This technique applies to any reinforced concrete structure marked for demolition, not just those designed for reuse. Since this typology is untested, we performed ten experimental tests to assess mechanical properties, including uniaxial, diagonal, and cyclic shear compression tests on large-scale walls. Results show that higher axial loads increase shear capacity but reduce collapse drift, providing critical data for collapse risk analysis of concrete demolition waste masonry (CDWM) buildings. The mechanical properties obtained are comparable to those of hollow clay brick masonry, opening up diverse applications, especially in the construction of residential buildings.