MC cement, commonly known as Masonry Cement, is a specialized blended cement meticulously formulated for creating durable and aesthetically pleasing mortar for masonry construction. It is a key ingredient mixed in specific proportions with sand and water to form a strong binding mortar, notable for its strength, durability, aesthetic appeal, and resistance to atmospheric and chemical deterioration.
Understanding Masonry Cement
Masonry cement is engineered to simplify the job site preparation of mortar, providing consistent quality and performance. Unlike general-purpose Portland cement, which requires separate additions of plasticizers and air-entraining agents, masonry cement already contains these components, ensuring superior workability and bond strength.
Key Characteristics and Benefits
Masonry cement is designed with specific properties that make it ideal for various construction applications:
- Optimized Blend: It is a special blended cement combining Portland cement with materials like ground limestone, hydrated lime, and other admixtures such as plasticizers and air-entraining agents. This blend ensures a consistent product.
- Superior Workability: The added plasticizers enhance the plasticity and workability of the mortar, making it easier for masons to spread and shape, leading to faster and more efficient construction.
- Enhanced Durability: Mortar made with masonry cement provides excellent bond strength, contributing to the overall structural integrity and longevity of masonry units like bricks, concrete blocks, and stones.
- Aesthetic Appeal: The consistent color and texture offered by masonry cement contribute to the uniform and attractive appearance of finished masonry walls.
- Resistance to Elements: It provides good resistance to freezing and thawing cycles, minimizing cracking and deterioration, and also offers resistance to chemical attack.
- Reduced Efflorescence: Some formulations can help reduce efflorescence, which is the white powdery deposit that can appear on masonry surfaces.
Common Composition
While exact formulations vary by manufacturer and region, masonry cement typically includes:
- Portland Cement: The primary hydraulic binder.
- Mineral Admixtures: Such as finely ground limestone or other inert materials that contribute to plasticity and volume stability.
- Plasticizers: Organic compounds that improve workability and reduce water demand.
- Air-Entraining Agents: Chemicals that introduce microscopic air bubbles into the mix, enhancing freeze-thaw resistance and workability.
Applications of MC Cement Mortar
Masonry cement is predominantly used in the production of mortar for:
- Bricklaying: Mortar for bonding bricks in walls, facades, and other structures.
- Block Work: Laying concrete blocks for foundations, load-bearing walls, and partitions.
- Stone Masonry: Setting natural and manufactured stones.
- Pointing and Repointing: Repairing and finishing mortar joints in existing masonry.
- Stucco and Plaster: In some cases, it can be used for base coats of stucco or plaster applications.
Types of Masonry Cement
In the United States, masonry cements are classified by ASTM C91 into three main types based on their compressive strength and other properties, which align with the mortar types M, S, and N defined in ASTM C270 for proportioning:
| Type | Compressive Strength (7 days) | Typical Uses |
|---|---|---|
| Type M | High (e.g., 2500 psi) | Heavy loads, severe weather, below-grade applications |
| Type S | Medium-High (e.g., 1800 psi) | General use, normal loads, suitable for exterior walls |
| Type N | Medium (e.g., 750 psi) | Non-load-bearing, interior walls, less severe exposure |
Note: The actual strength values are for mortar made with these cement types, not the cement itself.
Mixing Proportions
To form a strong binding mortar, masonry cement is mixed in specific proportions with sand and water. The exact ratio will depend on the type of masonry cement, the desired mortar strength, and project specifications. Typically, a common mix ratio by volume might be 1 part masonry cement to 2.5 to 3 parts sand, with just enough water added to achieve a workable consistency. Always refer to the manufacturer's recommendations and project specifications for precise mixing instructions.
For more detailed information on masonry materials and construction standards, you can consult resources from the Portland Cement Association (PCA) or ASTM International.
