You typically add cement, sand, and water to create brick mortar. These ingredients combine to form a workable paste that binds bricks together.
Components of Brick Mortar
Brick mortar is more than just glue; it's a crucial structural element. The specific mix of ingredients determines the mortar's strength, durability, and workability. Here's a breakdown of the key components:
- Cement: Cement acts as the binder. Portland cement is the most common type used. It hydrates and hardens, adhering to the bricks and sand.
- Sand: Sand serves as a filler and aggregate. It provides bulk, reduces shrinkage, and improves workability. The type and grading of sand are important for mortar performance.
- Water: Water is essential for the hydration of the cement, initiating the chemical reaction that leads to hardening. The amount of water affects the mortar's consistency and strength.
Optional Additives
While cement, sand, and water are the core ingredients, other materials can be added to modify the mortar's properties:
- Lime: Adding lime improves workability, water retention, and elasticity. It also contributes to the mortar's ability to self-heal minor cracks. Historically, lime was a primary binder in mortar.
- Pigments: Pigments can be added to color the mortar to match or complement the bricks.
- Admixtures: Various admixtures can be used to enhance specific properties such as water resistance, freeze-thaw resistance, or setting time. These might include air-entraining agents or water-reducing agents.
Mortar Mix Types
Different mortar mix types are designated by a letter-number combination, such as Type M, Type S, Type N, and Type O. Each type has a specific proportion of cement, lime, and sand, resulting in varying compressive strengths and intended applications. Consult building codes and project specifications to determine the appropriate mortar type.
Here's a general overview:
| Mortar Type | Compressive Strength (PSI) | Recommended Use |
|---|---|---|
| M | 2500 | Heavy loads, below-grade applications |
| S | 1800 | High wind or seismic areas, pavers |
| N | 750 | General use, above-grade applications |
| O | 350 | Interior, non-load-bearing applications |
Mixing Mortar
Proper mixing is critical for mortar performance. The ingredients should be thoroughly combined to create a consistent, workable mix. Mortar can be mixed by hand or with a mechanical mixer.
