The compressive strength of standard mortar cubes made with Ordinary Portland Cement (OPC) after 7 days of curing should not be less than:

Explanation

According to standard specifications (such as IS 269), OPC mortar cubes (1:3 cement-sand mortar) must achieve a minimum compressive strength of 22 N/mm² at 7 days and 33 N/mm² at 28 days.