Lehigh Masonry Type N

Masonry cement consists of portland or blended cement, plasticizers, and an air entraining agent. Air-entraining agents protect mortar from freeze-thaw damage and provide additional workability. The specific components of masonry cement may vary depending on the manufacturer and local construction practices. ASTM C91 defines masonry cement by physical requirements and performance properties rather than ingredients.

For consistency and convenience, most portland-lime blends are premixed and added to sand and water at the job site to produce mortar. However, some contractors prefer to mix all ingredients at the job site.