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IS 3085:1965 is the Indian Standard (BIS) for method of test for permeability of cement mortar and concrete. This standard outlines the testing method to determine the coefficient of permeability for cement mortar and concrete. It details the preparation of cylindrical specimens, the setup of the permeability cell under applied water pressure, and the calculations based on Darcy's Law once a steady flow state is achieved.
Method of Test for Permeability of Cement Mortar and Concrete
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Cement, Concrete, Aggregates and RCC
! Proper sealing of the specimen using a beeswax and rosin mixture is strictly required to prevent water from bypassing the concrete through the edges (edge leakage).
! Do not record measurements until a steady state of flow is achieved; initial water intake is primarily due to capillary absorption rather than actual permeability.
! Micro-cracks induced during demolding or curing can drastically alter flow results. Specimens must be handled with extreme care.
USACE CRD-C 48-92U.S. Army Corps of Engineers (USA)
HighCurrent
Standard Test Method for Water Permeability of Concrete
Directly measures the coefficient of permeability by collecting water that percolates through a specimen under pressure.
BS EN 12390-8:2019BSI - British Standards Institution (United Kingdom) / CEN - European Committee for Standardization
MediumCurrent
Testing hardened concrete. Part 8: Depth of penetration of water under pressure
Assesses water resistance under pressure but measures penetration depth, not the coefficient of permeability (flow rate).
DIN 1048-5:1991DIN - Deutsches Institut für Normung (Germany)
MediumWithdrawn
Testing concrete; testing of hardened concrete (specimens prepared in mould)
A precursor to the EN standard, it also focused on measuring the depth of water penetration rather than flow-through.
ASTM C1202-19ASTM International (USA)
LowCurrent
Standard Test Method for Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration
Assesses penetrability indirectly by measuring electrical charge passed, which correlates with permeability but is a different physical test.
Key Differences
≠IS 3085 measures the quantity of water that flows completely through the specimen (percolation) to calculate the coefficient of permeability (K), whereas modern standards like EN 12390-8 measure the depth to which water penetrates the specimen without necessarily passing through it.
≠The primary output of IS 3085 is a quantitative value, the coefficient of permeability (e.g., in m/s), based on Darcy's Law. The output of EN 12390-8 is a depth measurement (in mm).
≠The test duration in IS 3085 is variable and continues until a steady state of flow is achieved, which can take over 150 hours. In contrast, EN 12390-8 specifies a fixed test duration of 72 hours.
≠IS 3085 is a direct water permeability test. Other widely used standards, like ASTM C1202 (Rapid Chloride Permeability Test), are indirect methods that measure the movement of chloride ions under an electrical field as a proxy for permeability.
Key Similarities
≈Both IS 3085 and its international counterparts (like EN 12390-8 and USACE CRD-C 48) share the fundamental principle of applying sustained water pressure to one face of a concrete specimen.
≈The standards universally require specimens to be cured for a specified period (typically 28 days) prior to testing to ensure the concrete's microstructure has sufficiently developed.
≈The general apparatus concept is similar, involving a cell that seals the sides of the specimen and allows pressure to be applied to one face while the other face is either monitored for percolation (IS 3085) or inspected post-test (EN 12390-8).
≈All methods emphasize the need to test multiple specimens (typically three) from the same batch to obtain a representative average result and account for the inherent variability of concrete.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Measured Property
Quantity of water percolated (flow rate)
Depth of water penetration
BS EN 12390-8:2019
Test Pressure
7 kg/cm² (approx. 700 kPa), or as specified
500 ± 50 kPa (5 bar)
BS EN 12390-8:2019
Test Duration
Until steady flow is achieved (e.g., 150-200 hours)
72 ± 2 hours
BS EN 12390-8:2019
Primary Result Unit
Coefficient of Permeability (cm/s)
Depth (mm)
BS EN 12390-8:2019
Primary Result Unit (Direct Equivalent)
Coefficient of Permeability (cm/s)
Coefficient of Permeability (m/s or ft/s)
USACE CRD-C 48-92
Typical Specimen Shape
150 mm diameter x 150 mm high cylinder
150 mm cube or cylinder (at least 150 mm high)
BS EN 12390-8:2019
Minimum Age at Test
28 days (unless specified otherwise)
28 days (recommended)
USACE CRD-C 48-92
Test Liquid Specification
Water
Potable water (tap water)
BS EN 12390-8:2019
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Concrete specimen size (max aggregate 38mm)150 mm diameter x 150 mm height
Mortar specimen size100 mm diameter x 50 mm height
Test pressure appliedUsually up to 15 kg/cm2 depending on design head
Standard age for testing28 days
Key Formulas
K = Q / (A * t * (H/L)) — Coefficient of permeability (Darcy's Law)
Tables & Referenced Sections
Key Tables
No tables data
Key Clauses
Clause 2 - Apparatus
Clause 3 - Preparation of Specimens
Clause 4.2 - Sealing of Specimen
Clause 5 - Procedure for testing
Clause 6 - Calculation of Coefficient of Permeability