What is the proper ratio of cement, sand, and aggregate for concrete?

The correct choice outlines a widely recognized formula for creating concrete, specifically the mix design of 1 part cement, 2 parts sand, and 3 parts aggregate. This ratio is commonly referred to as a 1:2:3 mix and is foundational in construction, particularly for structural concrete.

This mix provides a good balance between strength and workability. The cement serves as the binding agent, while the sand fills gaps and provides workability to the mix. The aggregate, which can be gravel or crushed stone, gives the concrete its bulk and structural integrity. Maintaining this proper ratio ensures that the concrete can achieve its desired strength while remaining manageable for pouring and setting.

Using this formulation helps ensure the durability and longevity of structures, as it allows for adequate bonding between the materials, resulting in a strong, resistant final product. Additionally, this mix can be easily scaled and adjusted for different project sizes while retaining the essential properties of concrete.

Other ratios may not provide the same structural integrity or workability necessary for effective concrete applications, which is why they are generally less preferred in standard practice.