Resistance of aggregate to crushing under a gradually applied load (IS 2386 Part 4).
Sieve Analysis (Aggregate)Impact ValueAbrasion (Los Angeles)Specific Gravity & Absorption
Aggregate Crushing Value Calculator: Free Online Tool
The aggregate crushing value measures the resistance of aggregate to crushing under a gradually applied compressive load. A sample passing the 12.5 mm sieve and retained on the 10 mm sieve is placed in a steel mould and loaded in a compression machine to 40 tonnes. The crushed material is then sieved on the 2.36 mm sieve, and the fines are weighed.
Material testing technicians, pavement and concrete engineers, and students use it to judge the strength of aggregate for roads and concrete. A lower crushing value means stronger aggregate. This calculator follows IS 2386 Part 4. It takes the total sample mass W1, the mass passing 2.36 mm W2 and the mass retained W3, computes the crushing value for each trial and the average, and compares it with the IS 383 limits.
When to use this calculator
Use this calculator after a crushing test on coarse aggregate from a quarry, crusher plant or stockpile. It helps when approving aggregate for wearing surfaces and for other concrete, or when comparing different sources. Enter W1, W2 and W3 in grams for up to two trials. The defaults for trial 1 are 3100 g, 640 g and 2459 g. Leave a trial blank to skip it. The result gives the crushing value of each trial, the mass lost, the average and the check against the 30 % and 45 % limits.
How to use the Aggregate Crushing Value Calculator
- Open the calculator above on your phone, tablet or computer. Nothing needs to be installed and no sign-up is required.
- Enter your values in the input boxes: Total sample W1 (g), Passing 2.36 mm W2 (g), Retained 2.36 mm W3 (g). The boxes already hold sample values, so overwrite them with your own.
- Press Calculate. The result appears straight away under the button.
- Change any value and press Calculate again to compare options. Press Reset to go back to the sample values.
- Check the result against your drawings, project specification and local code before you order material or approve work.
How the calculation works
The crushing value is W2 / W1 x 100. W1 is the mass of the test sample, which passes 12.5 mm and is retained on 10 mm, and which is loaded to 40 tonnes in the crushing mould. W2 is the mass passing the 2.36 mm sieve after crushing, and W3 is the mass retained on it. Mass lost, W1 - (W2 + W3), is shown for each trial and should be small. The calculator averages the trials you enter. The average is checked against the IS 383 limits shown: 30 % for wearing surfaces and 45 % for other concrete. The default trials give 20.65 % and 20.99 %, averaging 20.82 %.
Worked example
When you open the page the calculator is filled with sample values. Pressing Calculate with those values gives the result below, which you can use to check that you are reading the output correctly.
| Result of each trial | |
|---|---|
| Trial 1 (mass lost 1.0 g) | 20.65 % |
| Trial 2 (mass lost 1.0 g) | 20.99 % |
| Result | |
| Average value | 20.82 % |
| Check against IS 383 limits | |
| Wearing surfaces (limit 30 %) | Within limit |
| Other concrete (limit 45 %) | Within limit |
Tips and common mistakes
- Sieve the crushed sample thoroughly on the 2.36 mm sieve, so fines are not left with the retained material and W2 is not understated.
- Check the mass lost shown for each trial. A big difference between W1 and W2 plus W3 usually means a weighing or spillage error.
- Load to 40 tonnes as the calculator note states, at a gradual rate. A different final load gives a value that is not comparable.
- Use dry aggregate of the 12.5 mm to 10 mm size fraction, and fill the mould in the same way for every trial.
- Do not confuse this value with the impact value. They test different actions, so keep the results and limits separate in your report.
Frequently asked questions
What does the crushing value tell me?
It shows how much of the aggregate turns into fines under a slowly applied load. A lower value means stronger aggregate. The default sample gives an average of 20.82 %, within the 30 % and 45 % limits.
What do W1, W2 and W3 mean?
W1 is the total mass of the test sample, W2 is the mass passing the 2.36 mm sieve after crushing, and W3 is the mass retained on that sieve. Mass lost is W1 minus the sum of W2 and W3.
What limits are checked?
The average value is compared with 30 % for wearing surfaces and 45 % for other concrete, according to the IS 383 limits listed in the calculator result. It shows whether the value is within each.
How is crushing value different from impact value?
Crushing value uses a slowly applied load of 40 tonnes, while impact value uses 15 blows of a hammer. The formula is the same, W2 divided by W1, but the tests measure different kinds of strength.
Can I enter just one trial?
Yes. Fill in one trial and leave the other blank. The average is taken over the trials you entered, though testing two trials gives a better check on consistency.
Important note
This tool gives estimates for planning, study and quick checks. It does not replace design by a qualified engineer, site-specific testing, or the requirements of your project specification and local building code. Always confirm final quantities, test results and acceptance limits with the responsible engineer before using them for construction or payment.
