Lime

Definition

Lime is a material derived from limestone through a process of calcination, where it is heated to high temperatures to produce quicklime (calcium oxide) and then hydrated to create slaked lime (calcium hydroxide). In the context of construction and artistic techniques, lime has been extensively used as a key component in mortars, plasters, and paints, valued for its durability and workability.

5 Must Know Facts For Your Next Test

1. Lime has been used since ancient times in construction, particularly by the Greeks and Romans, who recognized its strength and versatility.
2. Slaked lime is known for its ability to set and harden over time when exposed to carbon dioxide in the air, allowing it to bind well with other materials.
3. The use of lime in art dates back to antiquity; it was often combined with pigments to create durable frescoes and wall paintings.
4. Lime mortars are more flexible than cement-based mortars, allowing for movement in structures without cracking, making them ideal for restoration projects.
5. In addition to construction, lime plays a significant role in agriculture as it helps improve soil quality by raising pH levels in acidic soils.

Review Questions

• How does the hydration process of lime impact its usability in construction materials?
  • The hydration process transforms quicklime into slaked lime, which is more workable and easier to mix with other materials like sand. This process is crucial because it allows the lime to bind effectively with aggregates in mortars and plasters. The resulting slaked lime enhances the properties of these materials, providing better adhesion, flexibility, and durability, making them suitable for various construction applications.
• Discuss the historical significance of lime usage in ancient Greek and Roman architecture.
  • Lime was pivotal in ancient Greek and Roman architecture as it allowed for stronger and more durable construction techniques. The Romans perfected the use of hydraulic lime that could set underwater, enabling monumental structures like aqueducts and amphitheaters. Their mastery of lime-based materials not only facilitated architectural advancements but also influenced later building practices throughout Europe during the Middle Ages and the Renaissance.
• Evaluate the advantages of using lime over modern cement in conservation projects for historical buildings.
  • Using lime instead of modern cement in conservation projects offers several advantages. Lime mortars are more breathable, allowing moisture to escape from historical structures without causing damage. This is essential for preserving the integrity of older buildings that were originally constructed with lime-based materials. Additionally, lime's flexibility accommodates structural movements over time without cracking. By matching original materials closely, conservationists can maintain the authenticity of historical sites while ensuring their longevity.

Related terms

Hydration: The process of adding water to quicklime to produce slaked lime, which enhances its properties for use in construction and art.

Mortar: A mixture used in masonry, typically made from lime, sand, and water, which binds stones or bricks together.

Plaster: A building material made from lime, sand, and water that is applied to walls and ceilings to create a smooth surface.