Can a sand that does not meet ASTM C 144 gradation requirements be acceptable for masonry construction?
Sands that do not meet the gradation requirements of ASTM C 144 sometimes can work well. Sands can be classified as meeting ASTM C 144 even without meeting the gradation requirement, provided they can produce mortar that complies with the aggregate ratio, water retention, and compressive strength requirements of the property specifications of ASTM C 270. In some areas, finding sands that meet ASTM C 144 can be difficult. In most cases, however, I recommend using sands that meet C 144. Sands that are too coarse to meet C 144 produce mortars with poor workability. Mortars produced by sands that are too fine are workable, but may be weak and porous.