Compressive Strength
(1) Where dampproofing is not provided, the concrete used for floors-on-ground shall have a compressive strength of not less than 25 MPa after 28 days.
(2) Where dampproofing is provided as described in Article 9.13.2.7., the concrete used for floors-on-ground shall have a compressive strength of not less than 15 MPa after 28 days.
Article 9.16.4.5. Ontario Regulation 332/12 Building Code, Information published by oncodes.ca for educational purposes only.