This standard outlines the laboratory test method to determine the weathering resistance of natural building stones. It utilizes an accelerated crystallization test involving repeated cycles of immersion in sodium sulphate solution and oven drying to simulate the long-term degradation caused by natural environmental exposure.
Method of test for determination of weathering of natural building stones
Quick Reference Values
specimen dimensions50 mm cubes or cylinders (50 mm dia x 50 mm height)
number of specimens3
drying temperature105 ± 5 °C
immersion duration16 to 18 hours per cycle
number of cycles30 cycles
drying duration per cycle4 to 5 hours
Key Formulas
Percentage change in mass = [(M1 - M2) / M1] x 100 (where M1 = initial dry mass, M2 = final dry mass after 30 cycles)
Practical Notes
The sodium sulphate crystallization test is highly accelerated; 30 cycles in the lab simulate many years of natural environmental weathering.
Handle specimens very carefully during the final weighing process, as heavily weathered stones become extremely friable and any lost fragments will skew the mass loss calculation.
Ensure the drying oven maintains 105 ± 5 °C consistently, as lower temperatures can leave residual moisture and salt, affecting final mass accuracy.