M 41-10 Page 9-81 Masonry Units 9-129-12 Masonry Units
9-12.1 Concrete Blocks
Concrete blocks for building construction shall conform to the requirements of ASTM C90.
9-12.2 Concrete Brick
Concrete brick shall conform to the requirements of ASTM C55.
Source: Washington Standard Specifications for Road, Bridge, and Municipal Construction, 2024 Edition. Pages 991–991 of 1,151.