Similar International Standards
ASTM C67 / C67M-23aASTM International (US)
HighCurrent
Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile
Specifies procedures for sampling and testing clay bricks for various properties, including compressive strength.
EN 772-1:2011+A1:2015CEN (European Committee for Standardization)
HighCurrent
Methods of test for masonry units - Part 1: Determination of compressive strength
Defines the method for determining the compressive strength of various masonry units, including clay bricks.
AS/NZS 4456.4:2003 (R2018)Standards Australia / Standards New Zealand (AU/NZ)
HighCurrent
Masonry units and segmental pavers and flags — Methods of test — Method 4: Determining the compressive strength of masonry units
Provides the method for determining the compressive strength of masonry units used in Australia and New Zealand.
BS 3921:1985BSI (UK)
MediumWithdrawn
Specification for clay bricks
Previously specified requirements and test methods for clay bricks in the UK, including compressive strength.
Key Differences
≠IS 3495 uniquely requires placing the brick specimen between two 3mm thick, 3-ply plywood sheets during testing. International standards like ASTM C67 and EN 772-1 mandate direct contact between the prepared specimen and the steel platens of the compression machine.
≠The specimen surface preparation in IS 3495 involves filling the frog with a 1:3 cement-sand mortar and a multi-day curing process (1 day damp, 3 days in water). ASTM C67 primarily uses fast-setting gypsum or sulfur-based capping compounds, while EN 772-1 allows for grinding or specialized mortar capping, both with much shorter preparation times.
≠IS 3495 specifies a fixed stress-based loading rate of 14 N/mm² per minute. In contrast, ASTM C67 uses a performance-based rate intended to cause failure within 1 to 2 minutes, and EN 772-1 specifies a stress rate that varies based on the expected strength of the unit (e.g., 15 ± 6 N/mm²/min for lower strength bricks).
≠IS 3495 mandates testing in a saturated condition (24-hour immersion) and a specific mortar capping cured under water. While ASTM C67 has a saturated test as its referee method, it also permits dry testing. EN 772-1 is more flexible, allowing testing in air-dried, oven-dried, or saturated conditions, provided the state is reported.
Key Similarities
≈The fundamental objective across all standards is to determine the ultimate uniaxial compressive strength of a single brick unit by applying a gradually increasing load until failure.
≈All standards specify that the compressive load must be applied perpendicular to the bed faces of the brick, simulating its orientation and loading condition in a typical masonry structure.
≈The final compressive strength value is universally calculated by dividing the maximum load sustained by the specimen at failure by the gross cross-sectional area of its loaded face.
≈All mentioned standards require the use of a properly calibrated compression testing machine that includes a spherical-seated upper bearing block to ensure uniform load distribution and accommodate minor non-parallelism of the specimen faces.