Final answer:
Repair garage floors should typically be made of concrete or similar non-combustible and nonabsorbent materials. Concrete is widely used for its fire resistance and lack of absorption capabilities.
Step-by-step explanation:
The question 'Repair garage floors shall be of ____ or similar non-combustible and nonabsorbent materials' falls under the category of engineering, specifically related to building standards and materials used in construction.
The blank in the question should be filled with a suitable material that meets the criteria of being non-combustible and nonabsorbent. These properties are important in a garage floor to prevent fires and to avoid the floor from absorbing any liquids, such as oils, which may be present in a repair garage.
Concrete is commonly used for this purpose due to its durability and resistance to fire and absorption. Other potential options could include certain types of epoxy coatings or tiled surfaces made of materials like ceramic or porcelain, which would also satisfy these requirements.