Concrete Mix Designer
Calculate concrete mix designs for structural concrete. Select standard nominal grades (C10 to C40) or input custom design ratios to get cement, sand, gravel, and water weights and volumes.
Concrete Volume & Grade
Material Mix Proportions
Total volume calculated: --
Dry Mix Volume equivalent: --
Concrete Mix Material Estimate
Project Bill of Quantities (BOQ) Supporting Schedule
Date Generated:
--
Required Quantity: --
Concrete Grade: --
Wastage Margin: --
Cement Bag Size: --
Material Schedule Summary
| Material Description | Required Quantity (Weight) | Volume (CFT / Liters) |
|---|---|---|
| Cement (Dry Mix) | -- | -- |
| Sand (Fine Aggregate) | -- | -- |
| Gravel (Coarse Aggregate) | -- | -- |
| Mixing Water | -- | Liters (approx.) |
Calculated Volume (Wet):
--
Equivalent Volume (Dry):
--
Estimation Method: Standard Shrinkage Factor (1.54) & Bulk Densities
Prepared By: Estimator / Project Engineer
Concrete Mix Calculation Formula & Grade Rules
Concrete reduces in volume by about 35% to 36% when mixed with water due to voids filling up. Therefore, we use a dry volume conversion factor of 1.54:
1. Nominal Ratios (C10 to C25):
• C10 (1:3:6): Sum = 10. Cement = V_dry/10, Sand = 3×V_dry/10, Gravel = 6×V_dry/10.
• C15 (1:2:4): Sum = 7. Cement = V_dry/7, Sand = 2×V_dry/7, Gravel = 4×V_dry/7.
• C20 (1:1.5:3): Sum = 5.5. Cement = V_dry/5.5, Sand = 1.5×V_dry/5.5, Gravel = 3×V_dry/5.5.
• C25 (1:1:2): Sum = 4. Cement = V_dry/4, Sand = V_dry/4, Gravel = 2×V_dry/4.
• Material densities used: Cement = 1440 kg/m³, Sand = 1600 kg/m³, Coarse Aggregate = 1500 kg/m³. Water-cement ratio = 0.50.
2. Design Mix Weights per m³ (C30 to C40):
• C30: Cement = 380 kg, Sand = 680 kg, Gravel = 1200 kg, Water = 185 kg.
• C35: Cement = 410 kg, Sand = 640 kg, Gravel = 1210 kg, Water = 185 kg.
• C40: Cement = 440 kg, Sand = 600 kg, Gravel = 1220 kg, Water = 180 kg.
• Design mixes bypass dry shrinkage calculations because they are based directly on established batch-weight parameters for compaction.
How to use Concrete Mix Designer
- Select the concrete grade (e.g. C15, C20, C25, C30, C35, C40) or enter a custom mix ratio.
- Input the total target concrete volume in cubic meters or liters.
- Read the detailed material breakdown in weights (kg) and volumes (liters/bags).
What is Concrete Mix Designer?
Concrete mix design is the process of selecting and proportioning the ingredients (cement, fine aggregate/sand, coarse aggregate/gravel, and water) to produce concrete of specified strength and durability. Standard grade mixes (like C20, C25, C30) designate the compressive strength in megapascals (MPa) after 28 days.
This calculator determines the quantities of materials required for nominal and design mixes based on standard volume shrinkage (1.54 dry volume factor). It outputs weights and volumes for cement, sand, aggregates, and water to let you prepare batch runs accurately.
FAQ
- What do concrete grades like C25 and C30 mean?
- The letter 'C' stands for Compressive strength. The number represents the characteristic compressive strength in Newtons per square millimeter (N/mm² or MPa) when tested on concrete cubes after 28 days of curing.
- What is the dry volume factor of concrete?
- Fresh concrete shrinks when mixed with water. To produce 1 cubic meter of wet concrete, you need about 1.54 cubic meters of dry ingredients. This is known as the dry volume factor.
- What are standard concrete grade proportions?
- Common nominal ratios (Cement:Sand:Gravel) are: C15 is 1:2:4, C20 is 1:1.5:3, C25 is 1:1:2, and C30 is 1:0.75:1.5.
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