Concrete Calculator Sand Gravel Cement Ratio

Standard Concrete Mix Ratios:

M15 Grade: 1:2:4 (Cement: Sand: Gravel)

M20 Grade: 1:1.5:3 (Cement: Sand: Gravel)

Cement Required:

Sand Required:

Gravel Required:

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1. What Are Concrete Mix Ratios?

Concrete mix ratios specify the proportion of cement, sand, and gravel in concrete. Standard ratios like M15 (1:2:4) and M20 (1:1.5:3) ensure proper strength and workability for different applications.

2. How Does the Calculator Work?

The calculator uses standard mix ratios and accounts for material wastage:

For M15: 1 part cement : 2 parts sand : 4 parts gravel

For M20: 1 part cement : 1.5 parts sand : 3 parts gravel

Calculation Steps:

Calculate total parts in the ratio
Multiply desired volume by 1.54 to account for dry volume
Divide dry volume by total parts to get quantity per part
Multiply by individual ratio components

3. Importance of Correct Mix Ratios

Details: Proper ratios ensure concrete has the right strength, durability, and workability. Incorrect ratios can lead to weak structures or excessive cracking.

4. Using the Calculator

Tips: Select the appropriate grade (M15 for general work, M20 for structural work) and enter the volume needed in cubic meters.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between M15 and M20?
A: M15 has a compressive strength of 15 MPa, while M20 has 20 MPa. M20 is stronger and used for structural elements.

Q2: Why multiply by 1.54?
A: This accounts for voids in dry materials and wastage during mixing (54% extra volume needed).

Q3: How many cement bags per m³?
A: Approximately 6.5 bags for M15 and 7.5 bags for M20 per cubic meter of concrete.

Q4: Can I use this for large projects?
A: For large projects, consult an engineer as other factors (admixtures, aggregate size) may need consideration.

Q5: What about water content?
A: Water-cement ratio is typically 0.4-0.6, but this calculator focuses on dry materials.