Los Angeles coefficient calculator
Enter the mass retained on the 1.6 mm sieve after the drum and get the Los Angeles coefficient per EN 1097-2 - the aggregate’s resistance to fragmentation - with the lowest LA category it meets. No sign-up.
EN 1097-2 specifies 5000 ± 5 g.
Result
Enter the retained mass to see the coefficient.
For guidance only. A test report must follow the full procedure of EN 1097-2, including the test portion preparation and the drum and charge checks.
How the Los Angeles coefficient is calculated
A 5000 g portion of the 10/14 mm fraction is turned 500 times in the Los Angeles drum with eleven steel balls. The material is then washed and sieved on 1.6 mm, and the retained mass m is dried and weighed. The coefficient is the share of the portion that broke down below 1.6 mm:
LA - Los Angeles coefficient · M - test portion (g) · m - mass retained on the 1.6 mm sieve (g)
With the standard 5000 g portion this is the same as (5000 − m) / 50. The result is rounded to the nearest whole number. A lower coefficient means a harder, tougher aggregate.
Worked example
A 5000 g portion leaves 3870 g on the 1.6 mm sieve: (5000 − 3870) / 5000 × 100 = 22.6, so LA = 23 - category LA25.
Questions engineers ask
What is a good Los Angeles coefficient?
It depends on the use. Concrete and base-course aggregates are often specified at LA30 to LA40, asphalt surface courses tighter - LA20 to LA25 is common for wearing courses. The required category is set by the national annex and the project specification.
Which size fraction is tested?
The reference test uses the 10/14 mm fraction. EN 1097-2 allows other fractions in its annex, but the result is then reported with the fraction and is not directly comparable.
What is the difference between LA and micro-Deval?
Los Angeles measures resistance to fragmentation by impact and grinding in a dry drum; micro-Deval (EN 1097-1) measures resistance to wear by abrasion in water. Specifications often ask for both.
Running aggregate tests every week?
LabFlow keeps every weighing with the sample it belongs to, calculates the coefficient as it is entered, and puts it on an approved report your client downloads from their own portal.