Mortar plays a crucial role in masonry construction, acting as the binding agent that holds blocks, bricks, or stones together. It creates a seamless surface, fills gaps, distributes weight evenly, and sometimes even adds decorative touches. Here’s a detailed breakdown of what mortar is and its various aspects:
Composition:
- Mortar is a workable paste typically made from:
- Binder: The main ingredient that hardens and binds the mix together. Common binders include Portland cement, lime, or a combination of both.
- Fine aggregate: Provides texture and body to the mix. Sand is the most common fine aggregate, but other materials like crushed stone or fly ash can also be used.
- Water: Activates the binder and allows the mix to be workable. The quantity of water is crucial for proper setting and strength.
- Additives: Sometimes used to improve specific properties like workability, water retention, or frost resistance.
Types of Mortar:
- Several types of mortar exist, each suited for different applications:
- Portland cement mortar: Strong and durable, ideal for load-bearing walls and structural applications.
- Lime mortar: More flexible and breathable, suitable for historical restorations and non-load-bearing walls.
- Masonry cement mortar: Combines the properties of Portland cement and lime, offering good strength and workability.
- Lightweight mortar: Contains lightweight aggregates like perlite or pumice, reducing weight for specific applications.
Properties and Performance:
- The quality of mortar significantly impacts the overall performance of a masonry structure. Key properties to consider include:
- Strength: Ability to withstand compressive and tensile forces.
- Bond strength: Adhesion between the mortar and masonry units.
- Workability: Ease of mixing and placing the mortar.
- Durability: Resistance to weather, moisture, and other environmental factors.
- Water retention: Ability to hold water for proper hydration and setting.
Application and Techniques:
- Applying mortar involves preparing the mix, spreading it on the masonry units, and ensuring proper bedding and filling of joints. Techniques vary based on the type of mortar and desired finish.
Beyond Strength: Decorative Possibilities
- Mortar can be used creatively for aesthetic purposes too:
- Color pigments: Add color to the mortar for visual interest.
- Textured finishes: Create unique Oberflächen with specialized tools.
- Jointing techniques: Different jointing styles like raked or flush joints can enhance the look.