Since 1924



The range of tolerances listed below do not represent ASTM C90-02 in its entirety. If you have questions regarding C90-02 specification information not found below, please visit the NCMA TEK, ASTM link, or Contact Us.

Weight– Oven Dry

    8” Block Weight
Lightweight Less than 105 lbs. per cubic ft. (Less than 29.25 lbs.)
Medium Weight At least 105 lbs. per cubic ft. but less than 125 lbs. per cubic ft. (At least 29.25 lbs.)
(Less than 34.83 lbs.)
Normal Weight At least 125 lbs. per cubic ft. or more (34.83 lbs. or more)

Compressive Strength

(Average of 3 blocks)
Minimum of 1900 lbs. per square inch on the net area
No individual block may be less than 1700 lbs. per square inch

Water Absorption

(Average of 3 blocks)
Lightweight 18 lbs. per cubic ft. maximum
Medium Weight 15 lbs. per cubic ft. maximum
Normal Weight 13 lbs. per cubic ft. maximum

Linear Shrinkage

Shall not exceed 0.065%

Moisture Content

NOTE: Former requirements for moisture content have been eliminated from C90-02. All former ASTM C90 “type” classifications for moisture content i.e. “Type I Moisture Controlled Units” and “Type II Nonmoisture Controlled Units” have been eliminated from ASTM C90-02.




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