1. What is Concrete Sand Gravel Ratio?

The sand to gravel ratio in concrete determines the workability and strength of the final mix. Different concrete grades (M15, M20, M25) use different ratios to achieve specific strength characteristics.

2. How Are Ratios Determined?

Standard concrete mix ratios are established through extensive testing and engineering standards:

These ratios ensure proper particle packing and binding for each strength grade.

3. Importance of Correct Ratios

Details: Using incorrect ratios can lead to weak concrete (too much sand) or unworkable mixes (too much gravel). Proper ratios ensure optimal strength, durability, and workability.

4. Using This Calculator

Tips: Simply select the concrete grade you're working with to see both the full mix ratio and the specific sand-to-gravel ratio.

5. Frequently Asked Questions (FAQ)

Q1: Can I adjust these ratios slightly?
A: Small adjustments may be made for workability, but significant changes will affect concrete strength and durability.

Q2: What's the difference between M15, M20, and M25?
A: The numbers indicate compressive strength in MPa (15MPa, 20MPa, 25MPa) after 28 days of curing.

Q3: How does aggregate size affect the ratio?
A: Larger aggregates may require slightly more cement paste to coat all particles, but the basic ratio remains similar.

Q4: Should I measure by weight or volume?
A: Weight measurements are more accurate, but volume measurements are common for small projects.

Q5: What about water ratio?
A: Water-cement ratio is separate (typically 0.4-0.6) and critical for strength - not covered in this sand:gravel ratio calculator.