The American Society for Testing and Materials (ASTM) publishes standards providing physical properties and test methods for bricks according to their intended use – as facing bricks (in a wall) and as pavements. These properties allow bricks to qualify for various designations (“grades”) at the point of purchase. Bricks manufactured in and/or used in Canada meet standards published by the Canadian Standards Association (CSA). There are no current standards in North America for terra cotta (ceramic) products, and specifiers generally dictate that terra cotta products must meet brick standards.
- ASTM Designation C1405-16, Standard Specification for Glazed Brick (Single Fired, Brick Units).
- ASTM Designation: C652 − 17a, Standard Specification for Hollow Brick (Hollow Masonry Units Made From Clay or Shale)
- ASTM Designation C1272-17, Standard Specification for Heavy Vehicular Paving Brick
- ASTM Designation C 902-15, Standard Specification for Pedestrian and Light Duty Paving Brick
- ASTM Designation: C 216 – 07, Standard Specification for Facing Brick
- CAN/CSA-A83-14, Fired Masonry Brick Made from Clay or Shale (Canada)
- ASTM Designation C67/C67M – Standard Test Methods for Sampling and Testing Bricks
Brick standards provide key physical properties to “qualify” bricks for various exposure conditions. These properties provide a FIRST EMPHASIS in sampling and testing bricks, i.e to characterize or “find out” what the bricks are like as a basis for explaining how they are performing (but not whether they qualified as a certain Grade). These properties include water absorption (an indication of porosity), compressive strength (an indication of bearing capacity), and saturation coefficient (an indication of pore sizes),
Standard C216 and its Commentary explain may of the “whats” and “whys” about brick property limits, Clearly, the properties or test performance provide Grade Qualification when bricks are tested at the point of purchase. Bricks change over time mainly by moisture expansion so GRADE QUALIFICATION cannot be made by tests on bricks stored on a job site or bricks extracted from a structure. Nevertheless, property tests on older or extracted bricks are very useful in interpreting performance or predicting future performance.
AFTER an initial characterization, chemical (analytical) investigations and microscopy may be required in forensic analyses.
Background: ASTM Standards for Masonry Mortar
ASTM C270, Standard Specification for Mortar for Unit Masonry, is usually referenced in job specification when mortar is delineated. In any repair, mortar of the same “stiffness” and color as the original mortar is usually desired. Most buildings built in the United States between 1920 and 1950 employed portland cement-lime-sand (PCL) mortar, while since the 1950’s masonry cements have been increasingly used. Masonry cement is specified in ASTM C91/C91M-2018, Standard Specifications for Masonry Cement. Buildings built in the United States prior to about 1900 usually were built with lime-aggregate mortars or natural cement-sand mortars.
In any repair, “compatible cement” mortars must be used or problems can appear in the brickwork. Most experts consider mortar as the “weakest” or “sacrificial” component of the masonry. Forensic analysis of mortars is carried our following ASTM C1324, Standard Test Method for Examination and Analysis of Hardened Masonry Mortar, as frequently supplemented by techniques using advanced analytical techniques.
Mortar recession in a brick building is due to attack of ground or sea salts. Water leaching techniques are required along with microscopy to determine causes of recession.
Color issues with mortars can develop with repairs using masonry mortars. The mortar color frequently makes the entire wall in a repaired structure look different than the original brick mason
Gallery of ASTM Building Brick Tests
Cold Water Absorption – 24 hr. Soak
Boiling Water Absorption – 5 hr. Duration
Absorption Weight Measurements
The saturation coefficient is the quotient of cold water absorption value and (divided by) the boiling water absorption value.