What is hydraulic lime?

hydraulic lime is a type of lime or calcium carbonate used to make mortar and plaster. The lime is heated and then mixed with aggregated material such as sand or stone. Once this mixture is mixed with water to form mortar, it can be used in many types of building projects of masonry. The mortar can be placed between bricks or blocks to connect them together, or even applied to the surface of the masonry to form plaster or stucco application.

For the production of hydraulic lime, a specialized form of limestone is used. The limestone is mixed with clay and then fired in a high temperature oven. This process removes a large part of the lime moisture and also produces mineral by -products known as silicates. The remaining limestone and silicates are combined to form a hydraulic lime.

To understand how hydraulic lime works, it is important to first understand how traditional hydrated lime works. When the hydrated lime is mixed with water fromAnd the creation of mortar, has akonsisation similar to peanut butter. As the mortar reacts with the air, it absorbs carbon dioxide, causing it to harden or cure. Hydraulic lime mortar, or vice versa, begins to harden when it is exposed to water. Over time, it also absorbs carbon dioxide from the air to experience the second phase of hardening or curing. Thanks to these different reactions, hydrated lime and hydraulic lime are very different products and are not interchangeable.

Hydraulic lime offers a number of advantages over the traditional lime mortar mixture. The most important thing is its ability to cure and harden when it is wet, which means it can be used in many applications where other mortar products would fail. It also has low elasticity, resulting in fewer cracks due to expansion and contraction. Hydraulic lime is also very porous, allowing excess moisture to escape rather than collect inside the structurery walls. It makes very popular for historical nature conservation applications, where traditional hydrated lime would burst over time or disintegrated due to captured moisture.

This product is available in a number of different varieties that are selected based on the application. Natural hydraulic lime type 2 (NHL-2) is designed for internal applications and some exterior use, where the mortar will be protected from moisture. NHL-3.5 is suitable for most exterior applications, while the NHL-5 is designed for the most difficult outdoor applications such as floorboards, underground work and chimneys.