What is the Difference Between Lime Mortar and Cement Mortar

Lime mortar and cement mortar are two types of construction materials, but they have different properties that make them suitable for different applications. Understanding the difference between lime mortar and cement mortar can help determine the best choice for various construction and restoration projects.

What is the difference between lime mortar and cement mortar? Lime mortar uses lime as the binder whereas cement mortar uses cement as the binder.

Key Areas Covered

1. What is Lime Mortar  
      – Definition, Features, Uses
2. What is Cement Mortar
      – Definition, Features, Uses
3. Similarities Between Lime Mortar and Cement Mortar
      – Outline of Common Features
4. Difference Between Lime Mortar and Cement Mortar
      – Comparison of Key Differences
5. FAQ: Lime Mortar and Cement Mortar
      – Frequently Asked Questions

Key Terms

Lime Mortar, Cement Mortar

What is Lime Mortar

Lime mortar is a traditional building material made with a simple recipe: lime, sand, and water. Lime acts as the binder, holding everything together. There are different types of lime, each with its own properties. Sand provides structure and strength. Water activates the lime and helps it form a paste for application.

Lime mortar allows moisture to pass through, preventing water buildup in walls. It can accommodate slight movement and expansion within the structure. It takes longer to cure than cement mortar.

Another property is that it is weaker (compared to cement mortar) but gains strength slowly over time. Furthermore, lime mortar production has a lower environmental impact than cement.

Lime mortar has different uses. It is used for foundation work, plastering and rendering, and chimney repairs. It is also ideal for preserving the integrity of older buildings.

What is Cement Mortar

Cement mortar is a mixture of cement, fine sand, and water that hardens over time. It acts as a kind of glue, binding bricks, stones, and concrete blocks together in construction projects. There are many uses of cement mortar, especially in the construction industry.

One of its most common applications is in bricklaying. Cement mortar acts as the binding agent between bricks, blocks, or stones, creating sturdy walls, foundations, and chimneys. Its strength ensures the structural integrity of these elements, allowing them to withstand significant loads.

It is also used to cover unevenness and imperfections in the walls, floors, and ceilings. This protects the underlying structures from weathering and damage caused by moisture. It also enhances the visual appeal.

Furthermore, cement mortar plays a role in creating a damp-proof course, a vital layer that prevents moisture from rising from the ground into the building.

Adjusting the proportions of its ingredients and adding pigments can achieve different textures and even incorporate color. This allows for creative freedom in architectural design, adding a decorative touch to building elements.

Similarities Between Lime Mortar and Cement Mortar

• Both use a binding agent to hold sand and water together.
• They bond well with bricks, stones, and other masonry materials.
• Both are used in similar applications, such as bricklaying, pointing, plastering, and rendering.

Difference Between Lime Mortar and Cement Mortar

Definition

• Lime mortar is a traditional building material made with a simple recipe – lime, sand, and water, whereas cement mortar is a mixture of cement, fine sand, and water that hardens over time. 

Binder

• Lime mortar uses lime, a more natural and flexible binder made from limestone, whereas cement mortar relies on cement, a stronger and more rigid binder.

Strength

• Lime mortar is less strong than cement mortar.

Curing Time

• Lime mortar takes longer to cure, while cement mortar sets and hardens relatively quickly.

Flexibility

• Lime mortar is more flexible and can accommodate slight movements and expansions in a structure, while cement mortar is more rigid.

Breathability

• Lime mortar is more breathable, allowing moisture to move through the material. Meanwhile, cement mortar is less breathable, creating a more waterproof barrier.

Uses

• Lime mortar is better suited for older buildings and historic structures due to its compatibility with traditional materials, while cement mortar is often preferred for modern construction.

Conclusion

Lime mortar and cement mortar are essential building materials. However, there is a distinct difference between lime mortar and cement mortar. Lime mortar, with its flexibility, breathability, and historical preservation benefits, remains ideal for older structures. On the other hand, cement mortar’s strength, waterproofing capabilities, and adaptability to various architectural designs make it indispensable in modern construction.

FAQ: Lime Mortar and Cement Mortar

1. Why not use lime mortar?

Lime mortar is not as strong in compression as cement-based mortar. Moreover, lime mortar does not adhere as strongly to masonry as Portland cement. This is why some people choose not to use lime mortar.

2. What are the disadvantages of lime mortar?

Lime mortar has several disadvantages compared to other types of mortar. One major drawback is its longer curing time, which can delay construction projects. Additionally, lime mortar is generally weaker than cement mortar. It can also be more sensitive to weather conditions during application.

3. Does lime damage concrete?

When lime compounds leach into or come into contact with concrete, they can react with other materials and form calcium carbonate or calcium sulfate. This is called efflorescence. This results in a powdery, white deposit on the surface of the concrete, which can lead to deterioration and weakening of the concrete over time.

4. When did cement replace lime mortar?

Cement began to replace lime mortar in the construction industry in the 19th century with the introduction of Portland cement. Cement offered faster setting times and greater strength compared to lime, making it a popular choice for building projects.

5. Does lime mortar crack?

Yes, lime mortar can crack under certain conditions. If the pointing or application of lime mortar dries out too quickly before adequate carbonation occurs, cracking may happen. Carbonation is the process by which lime mortar hardens and gains strength as it reacts with carbon dioxide in the air, so proper drying conditions are required to avoid cracks.

Reference:

1. “Lime Mortar.” Science Direct.
2. “Cement Mortar.” Science Direct.

Image Courtesy:

1. “Enduit Chaux” By Berrucomons – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Mortar mixed inside bucket” By Tomwsulcer – Own work (CC0) via Commons Wikimedia