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IS 1126:1974 is the Indian Standard (BIS) for method of test for determination of durability of natural building stones. IS 1126 prescribes the testing procedure to evaluate the durability of natural building stones. It primarily uses a sodium sulphate crystallization test to simulate natural weathering, freeze-thaw cycles, and salt attack to determine the stone's resistance to disintegration over time.
Method of test for determination of durability of natural building stones
! Maintain the density of the sodium sulphate solution precisely at 1.055 kg/litre, as variations heavily impact the severity of the simulated weathering.
! Ensure loose particles are carefully brushed off the specimens after the final drying cycle before weighing to accurately calculate mass loss.
! This test is critical for stones intended for exterior cladding or use in harsh, exposed, or coastal environments.
EN 12370:2019CEN (European Committee for Standardization), Europe
HighCurrent
Natural stone test methods - Determination of resistance to salt crystallisation
Directly equivalent test method for determining stone durability via sodium sulfate crystallization.
ASTM C88 / C88M - 23ASTM International, USA
MediumCurrent
Standard Test Method for Soundness of Aggregates by Use of Sodium Sulfate or Magnesium Sulfate
Similar crystallization test principle, but primarily intended for aggregates, not dimension stone blocks.
DIN 52111:1982-10DIN (German Institute for Standardization), Germany
HighWithdrawn
Testing of natural stones; weathering test, crystallization test
Former German national standard for salt crystallization testing, now superseded by the European standard.
Key Differences
≠IS 1126 specifies 30 test cycles, whereas EN 12370 requires 15 cycles and ASTM C88 requires only 5 cycles, leading to significant differences in test duration and severity.
≠IS 1126 allows the use of either a 14% Sodium Chloride (NaCl) solution or a saturated Sodium Sulfate (Na2SO4) solution. EN 12370 strictly specifies Sodium Sulfate, and ASTM C88 allows Sodium Sulfate or Magnesium Sulfate, but not Sodium Chloride.
≠The specimen size in IS 1126 is a 40 mm cube, which is smaller than the 50 mm or 100 mm cubes typically specified in EN 12370. ASTM C88 deals with graded aggregate sizes, not solid cubes.
≠The immersion time in the salt solution is 4 hours in IS 1126, while it is 2 hours in EN 12370, affecting the potential saturation level of the specimen in each cycle.
Key Similarities
≈All standards are based on the same fundamental principle: inducing salt crystallization within the pores of the stone to simulate and accelerate natural weathering processes.
≈The core test procedure is analogous across all standards, involving repeated cycles of immersing the stone specimen in a salt solution followed by oven drying to force crystallization.
≈The primary method for evaluating durability is consistent, relying on the quantitative measurement of mass loss (as a percentage) after the completion of all cycles.
≈The drying phase in all standards is conducted at a similar temperature, typically 105 ± 5 °C, to ensure complete water evaporation and salt crystallization.
Parameter Comparison
Parameter
IS Value
International
Source
Test Solution
14% Sodium Chloride (NaCl) or saturated Sodium Sulfate (Na2SO4)
Saturated Sodium Sulfate (Na2SO4)
EN 12370:2019
Number of Test Cycles
30
15
EN 12370:2019
Number of Test Cycles (for aggregates)
30
5
ASTM C88 / C88M - 23
Specimen Size (Cube)
40 mm
50 mm or 100 mm
EN 12370:2019
Drying Temperature
105 ± 5 °C
105 ± 5 °C
EN 12370:2019
Immersion Time per Cycle
4 hours
2 hours
EN 12370:2019
Cooling Method after Drying
In a desiccator to room temperature
In the laboratory atmosphere for at least 4 hours
EN 12370:2019
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
specimen dimensions50 mm cylinders or cubes
number of test specimens3
sodium sulphate solution density1.055 kg/litre
immersion duration16 to 18 hours per cycle
oven drying temperature105 ± 5 °C
total test cycles30 cycles
Key Formulas
Percentage change in weight = [(W1 - W2) / W1] × 100 — where W1 is original dry weight and W2 is final dry weight after test cycles