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IS 1124:1974 is the Indian Standard (BIS) for method of test for determination of water absorption, apparent specific gravity and porosity of natural building stones. This standard prescribes the laboratory testing methods for determining the water absorption, apparent specific gravity, and porosity of natural building stones. These properties are critical for engineers to assess the durability, density, weathering resistance, and overall quality of stones used in masonry and monumental construction.
Method of test for determination of water absorption, apparent specific gravity and porosity of natural building stones
! Ensure test specimens are completely dry by heating in an oven to a constant mass before recording the initial dry weight (W1).
! Carefully remove all trapped air bubbles from the specimen surface when recording its weight while suspended in water (W3).
! Wipe off surface water with a damp cloth immediately before recording the saturated weight in air (W2) to ensure true saturated mass is measured without excess surface water.
Standard Test Methods for Absorption and Bulk Specific Gravity of Dimension Stone
Covers water absorption and bulk specific gravity, but uses a 48-hour cold soak instead of boiling for saturation.
EN 1936:2006CEN (European Committee for Standardization), Europe
MediumCurrent
Natural stone test methods - Determination of real density and apparent density, and of total and open porosity
Covers apparent density (specific gravity) and porosity but uses a more advanced vacuum saturation method.
EN 13755:2008CEN (European Committee for Standardization), Europe
MediumCurrent
Natural stone test methods - Determination of water absorption at atmospheric pressure
Covers water absorption but uses a lower drying temperature and saturates until constant mass without boiling.
ISO 10545-3:2018ISO (International Organization for Standardization)
LowCurrent
Ceramic tiles — Part 3: Determination of water absorption, apparent porosity, apparent relative density and bulk density
Covers identical properties (absorption, porosity, density) but the standard is for manufactured ceramic tiles, not natural stone.
Key Differences
≠Saturation Method: IS 1124 requires immersion for 24 hours followed by 5 hours of boiling to achieve saturation. ASTM C97 uses a 48-hour soak at room temperature, while EN 1936 uses a more rigorous vacuum saturation method. Boiling forces water into smaller pores, typically yielding higher absorption and porosity values than a simple soak.
≠Drying Temperature: IS 1124 specifies drying at 105 ± 5 °C, similar to ASTM C97. However, European standards like EN 13755 and EN 1936 mandate a lower temperature of 70 ± 5 °C to prevent altering clay minerals present in some types of stone.
≠Drying Criterion: IS 1124 specifies a fixed drying time of 72 hours. Modern standards like ASTM C97 and the EN series require drying until 'constant mass' is achieved, a more performance-based and accurate method that accounts for variations in stone type and sample size.
≠Sample Size: IS 1124 specifies a relatively small sample size (40-50 mm cube/cylinder). EN standards prefer slightly larger specimens (50 mm or 70 mm), and ASTM C97 has a more general requirement for a minimum dimension of 50 mm and minimum volume of 180 cm³.
Key Similarities
≈Fundamental Principle: All standards utilize the Archimedes principle, relying on the determination of three key masses: oven-dry, saturated surface-dry (SSD), and immersed (suspended) in water.
≈Calculation Formulae: The mathematical formulas used to calculate percent absorption by mass, apparent specific gravity (bulk density), and porosity from the three measured weights are functionally identical across the standards.
≈Saturated Surface-Dry (SSD) Condition: The procedure for obtaining the SSD weight is consistent, involving wiping the surface of the saturated specimen with a damp cloth to remove the surface film of water without drawing water from the pores.
≈Core Apparatus: The basic equipment required, including a ventilated drying oven, a balance with a minimum precision, and an apparatus for weighing the specimen suspended in water, is common to all methods.
Parameter Comparison
Parameter
IS Value
International
Source
Drying Temperature
105 ± 5 °C
70 ± 5 °C
EN 13755:2008
Drying Duration
Fixed for 72 hours
Until constant mass is achieved (weighing at ≥24h intervals)
ASTM C97 / C97M - 21
Saturation Method (Absorption)
24h immersion + 5h boiling
48h immersion at 22 ± 2 °C
ASTM C97 / C97M - 21
Saturation Method (Porosity)
24h immersion + 5h boiling
Saturation under vacuum
EN 1936:2006
Sample Size (Cube)
40 mm to 50 mm
50 mm or 70 mm
EN 1936:2006
Number of Test Specimens
At least three
Not less than three
ASTM C97 / C97M - 21
Calculation of Apparent Sp. Gravity
A / (B - C), where A=dry, B=saturated, C=immersed mass
Wd / (Ws - Wi), where Wd=dry, Ws=saturated, Wi=immersed mass
ASTM C97 / C97M - 21
⚠ Verify details from original standards before use
Key Values5
Quick Reference Values
Specimen dimensions50 mm cubes or cylinders of 50 mm diameter and 50 mm height