(1) Except as provided elsewhere in this Part, the compressive strength of unreinforced concrete after 28 days shall be not less than,
(a) 32 MPa for garage floors, carport floors and all exterior flatwork,
(b) 20 MPa for interior floors other than those for garages and carports, and
(c) 15 MPa for all other applications.
(2) Site-batched concrete used for garage floors, carport floors and exterior flatwork shall have air entrainment of 5 to 8%.