IS 4634

: 1991

Methods for testing the performance of batch-type concrete mixers

CurrentSpecializedTesting MethodMaterials Science · Cement, Concrete, Aggregates and RCC
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This standard lays down the methods for testing the performance of batch-type concrete mixers to ensure they produce a uniform mix. Mixing efficiency is evaluated by comparing concrete samples taken from the beginning and end of a batch discharge across parameters like slump, unit weight, air content, coarse aggregate content, and compressive strength.

Methods for testing the performance of batch-type concrete mixers

Quick Reference Values
max difference unit weight16 kg/m3
max difference air content1.0%
max difference slump below 50mm10 mm
max difference slump above 50mm20 mm
max difference coarse aggregate6.0% by mass
max difference compressive strength 7days7.5% from average
Key Formulas
Percentage variation = [ (Value 1 - Value 2) / Average ] × 100
Practical Notes
Always collect performance test samples from approximately the 15% and 85% points of the batch discharge to properly assess uniformity.
Ensure the mixer drum is clean and wetted before starting the performance test to prevent mortar from adhering to the drum.