Calcined clay processed and used as a supplementary material has gained wide acceptance in recent times in many parts of the world. However, varying chemical and mineralogical compositions of clay significantly impact the performance of calcined clay concrete. Therefore, this makes research on clays vital if researchers are to achieve acceptance of calcined clays into the local market for construction. In this study, commercial Ghanaian calcined clay was acquired and used to replace 50 wt.% of Portland cement to produce calcined clay concrete with characteristic strength (fc) of 30 MPa. Mechanical properties in terms of compressive and flexural strengths, as well as chloride penetration, were investigated on the concrete samples. The compressive strength results showed that the calcined clay concrete met the characteristic strength of class 30 concrete though strength values were lower than the control concrete on all the testing days of 3, 7, 28, 56, and 90 days. The flexural strength values were all lower at the various periods of testing at 28, 56, and 90 days. For chloride permeability, the control concretes tested at 28, 56, and 90 days were characterized within the moderate region (2000–4000 Coulombs) whereas the calcined clay concrete was also identified as within the low region (1000–2000 Coulombs) according to the ASTM C1202.