Concrete Yield Calculator: Fresh Density Test
Check whether a concrete batch made the volume it was designed to make, from the batch weights and the weight of a measured container of fresh concrete.
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How this calculator works
Add up the weights of cement, water, sand, stone and any admixture. Weigh fresh concrete in a container of known volume to get its density. The batch weight divided by that density is the volume the batch really made. The yield is the actual volume divided by the design volume.
A yield near 1 is right. Below the tolerance (under-yield) the batch made less than designed, and above it (over-yield) it made more, so each cubic metre holds less cement than the mix design intended. The calculator also gives the cement content per cubic metre and the water to cement ratio.
Formulas used
- \rho = W_c/V_c
- V_a = W_t/\rho
- Y = V_a/V_d
Worked example
With the default numbers in the calculator above:
- Total weight of the batch: 2460 kg
- Measured density of the fresh concrete: 2500 kg/m³
- Actual volume of concrete made: 0.984 m³
- Yield (actual volume over design volume): 0.984
- Allowed range: 0.98 to 1.02
- Cement content in each cubic metre made: 406.5 kg/m³
- Water to cement ratio of the batch: 0.4
Change the numbers in the calculator to see the full working, every step, for your own case.
Common questions
What tolerance should I use?
Use your concrete specification. Plus or minus 2 percent is a common figure and is the default here, but it is an assumed value.
What does under-yield mean?
The batch made less concrete than designed. The measured density is higher than the mix calculation assumed, so check the batch weights, the aggregate moisture and the proportions.
Is this the standard test?
It is the calculation that follows the fresh density test. The test itself, including how the container is filled and compacted, is set by the concrete testing standard that applies to your job.
Related calculators
Further reading: The mass per unit volume test for fresh concrete in the AS 1012 series (Methods of testing concrete); your concrete specification.
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