NHL 3,5 is a pure white high-resistant ST ASTIER Pure Natural Hydraulic Lime, produced using the use of selected siliceous limestones. The baking of the limestones is carried out in vertical ovens at a temperature below 1250°C and reduced in powder by only the breakdown of calcium oxide, without the need for grinding. NHL 3,5 is totally free of pozzolanic materials, blast furnace slags, flying ash or hydraulic binders of any kind (clinker, cement, etc.), VOCs and according to Standard UNI EN 459-1.
The use, as the only binder, of the Pure Natural Hydraulic Lime NHL 3,5 for the production of mortars and plasters make these products biocompatible in full respect for man and the environment. The complete absence of salts, chemicals, volatile organic compounds combined with the total mineral nature of the components, guarantees the purity, non-toxicity, non-harmfulness and the total recyclability. The specific characteristics of Pure Natural Hydraulic Lime NHL 3,5, such as the slow hardening process, the continuous increase in mechanical strength, coupled with a low elastic modulus, give elasticity to the manufactured articles, making them different from those laid with lime or cement based products. The use of NHL 3,5 allows working in perfect affinity with the building rules of the ancient art of the Restoration as well as in Green building.
The porosity of Natural Hydraulic Lime NHL 3,5 guarantees high water vapour diffusion, gives breathability to the substrate, allows the disposal of absorbed water and regulates environmental humidity avoiding the formation of dangerous condensation and moulds. The high basicity of the mixture whose pH is equal to 12.5 makes the surfaces impregnable from biodeteriogenic agents and prevents their proliferation, generating hostile conditions for the survival of pathogenic micro organisms (bacteria, fungi, viruses) causing infections, diseases or allergic reactions. Products obtained with the only NHL 3,5 binder, being totally mineral; do not constitute "special waste".