This standard outlines the methods of test for evaluating concrete admixtures. It provides procedures to assess the effect of an admixture on the properties of fresh concrete (like workability, water content, and setting time) and hardened concrete (compressive strength and drying shrinkage) by comparing a test mix against a control mix.
Prescribed methods for testing the performance and compliance of chemical admixtures for concrete.
Quick Reference Values
Minimum water reduction for water-reducing admixture5% (for same workability)
Minimum 7 & 28-day compressive strength compared to control mix90% of control
Maximum 1-year compressive strength compared to control mix125% of control
Initial setting time deviation from control mixNot more than 30 mins earlier or 90 mins later
Maximum drying shrinkage at 28 days compared to control mix135% of control
Key Formulas
Water Reduction (%) = [ (Water in control mix - Water in test mix) / Water in control mix ] * 100
Practical Notes
This standard is officially WITHDRAWN. The testing methods have been incorporated into IS 9103:1999 'Concrete Admixtures — Specification'. For all current purposes, refer to IS 9103.
The effectiveness of an admixture is highly dependent on the type and brand of cement, aggregates, and ambient conditions. These tests are comparative and results are specific to the materials used.
Test results, especially setting time and strength, are very sensitive to temperature. Maintaining the standard test temperature of 27 ± 2°C is critical.