Which grades of concrete are commonly used in construction?

In the context of common construction practices, the correct answer highlights grades of concrete that are more frequently specified in design and construction documents. Grades such as C25, C30, C35, and C40 correspond to the compressive strength of the concrete measured in megapascals (MPa) and are representative of the strength levels typically required for various structural applications.

For example, C25 is often used in standard structural applications, while C30 and C35 are commonly employed in residential and commercial buildings due to their balance of strength, workability, and cost. C40 is commonly specified for structures that require higher strength, such as heavily loaded beams or columns. These grades are adequate for the majority of structural elements, ensuring safety, durability, and overall performance.

Other options include grades that are either not standard or refer to strengths that are not as commonly required in typical construction scenarios. Understanding these common grades is essential for selecting the right material according to project specifications and ensuring that the structural integrity meets the necessary design criteria.