Natural Hydraulic Lime (NHL) 5 Eminently Hydraulic lime is used for applications such as building or repairing wall head copings, pointing and parging the water table or foundation of a building and making lime concrete. Sea-bearing walls can be built and repaired with NHL 5 since it has only trace amounts of soluble salts such as Potassium Oxide, Sodium Oxide and tri-calcium aluminates. This diminishes sulphate attack which normally happens in mortars prepared with Portland cement or where white cement has been introduced into synthetically created hydraulic lime at the time of manufacturing to ensure a hydraulic set. When Portland cement is present, you will find a high percentage of tri-calcium aluminates which will react with the sulphates thus producing an overall expansion and the eventual disintegration of the mortar or concrete especially in marine environments.
St. Astier's Pure and Natural Hydraulic Lime is formed naturally by the presence of reactive silica which is caught up into the limestone deposit making it a truly pure naturally occurring siliceous hydraulic lime. Portland cement is an extreme form of "Hydraulic Lime", whereby it will also set with water and under water. Portland cement however is known to have many of the adverse chemical reactions as noted above, a brittle nature and releases tremendous amounts of Carbon Dioxide into the environment in its production over the equal amount of NHL 5. Specifiers should be aware of Argillaceous Hydraulic Limes where clay is naturally occurring or added to make these limes become hydraulic and what consequences may result from their inappropriate applications.
Comes as a 55 lb bag.
Choose this product when you have your own sand to mix in.
This is a natural color, untinted version. Contact us for tinted or custom color options.
Natural Hydraulic Lime, although it is basically of the same chemical composition as Hydrated Lime, has its initial set with water, much like cement, and a second set by absorption of CO2. Being "hydraulic" allows for simplicity in many applications. Hydraulic Lime, like Hydrated Lime and cement requires some basic care such as minimizing the amount of mixing water, using good sand and tarping the work. The cost of labor when using NHL is therefore comparable to normal cementicious mortar and stucco installations which have been carried out correctly.
The hydraulicity, (which in true form is the ability to set with water and under water), for the St. Astier lime range is achieved only by the nature of the raw material. The St. Astier raw material is a naturally occurring hydraulic lime which is low-temperature fired. Nothing else is added to St. Astier NHL, therefore it is known as "Natural" Hydraulic Lime. It has known and measurable performance criteria which is both comforting and predictably dependable.