1. What is M15 Concrete?

M15 refers to a grade of concrete with a compressive strength of 15 MPa (megapascals) after 28 days of curing. It's commonly used for general construction purposes like flooring, foundations, and pathways.

2. Understanding the Ratio

The standard mix ratio for M15 concrete is:

Where:

• 1 part Portland cement
• 2 parts fine aggregate (sand)
• 4 parts coarse aggregate (gravel or crushed stone)

Explanation: This ratio provides the optimal balance between workability, strength, and economy for M15 grade concrete.

3. Importance of Proper Mixing

Details: Accurate proportioning of materials is crucial to achieve the desired strength and durability. Too much sand makes concrete weak, while too much aggregate makes it difficult to work with.

4. Using the Calculator

Tips: Enter the number of cement bags (50kg each) you plan to use, and the calculator will show the corresponding amounts of sand and aggregate needed.

5. Frequently Asked Questions (FAQ)

Q1: What does M15 stand for?
A: The 'M' stands for Mix and '15' represents the compressive strength of 15 N/mm² after 28 days.

Q2: How much water should be added?
A: Typically 0.5 times the weight of cement (water-cement ratio of 0.5), but this may vary based on conditions.

Q3: Can I adjust this ratio?
A: For structural applications, maintain the standard ratio. For non-structural uses, minor adjustments may be acceptable.

Q4: What type of sand should be used?
A: Clean, well-graded river sand or manufactured sand (M-sand) free from organic impurities.

Q5: What aggregate size is best?
A: 20mm nominal size aggregate is commonly used for M15 concrete.