What is the correct ratio of concrete to sand to coarse aggregate in a concrete mixture?

• A. 1:2:3
• B. 1:1:2
• C. 1:1:1
• D. 1:2:4

Answer: (D)

The correct ratio of concrete to sand to coarse aggregate in a concrete mixture is 1:2:4. This ratio indicates the proportion of materials used to create concrete, where one part is cement, two parts are sand (fine aggregate), and four parts are coarse aggregate.

This specific mix design is commonly used for general-purpose concrete that requires good workability and strength. The 1:2:4 ratio balances the components to ensure adequate strength and durability, making it a standard choice for many structural applications. It allows for sufficient aggregate to create a stable and firmly packed concrete mix, which is essential for preventing shrinkage and ensuring that the concrete can support the loads it will encounter once cured and set.

Other ratios, while useful in different contexts, do not offer the same balance for general construction purposes. For instance, a 1:1:2 ratio would lead to a denser mix, which may increase strength but could result in workability issues and higher costs. The other ratios like 1:2:3 and 1:1:1 may also be suitable for specific applications but do not provide the same characteristics that make 1:2:4 widely accepted in typical construction projects.