EU Norm (EN 459) Summary of terminology
for building limes
| Building limes | ||
|---|---|---|
|
AIR
LIMES |
Hardening only in contact with CO2 in the air (Carbonation) Classified according to their Calcium oxide/magnesium oxide content (90,85,80,70) |
|
|
OLD
Quicklime |
NEW
Quicklime |
Main components
Calcium Oxide + Magnesium Oxide
calcinated and producing an exothermic
reaction in contact with water |
|
CAEB |
CL (calcium lime) |
Calcium oxide or Calcium Hydroxide |
|
|
DL (dolomitic lime)
Semi hydrated and hydrated |
Calcium and Magnesium Oxides OR
Calcium and Magnesium Hydroxides |
|
|
Hydrated lime |
CL or DL resulting from controlled slaking of quicklime. Produced as POWDER, PUTTY or SLURRY (milk of lime). |
Hydraulic Lime – Setting and hardening in contact with water. Air setting also present. Classified according to Compressive Strength expressed in N/mm2 measured @ 28 day in mortars prepared with a 1:1 binder/sand ratio
| OLD | NEW | Natural hydraulic lime (NHL) |
|---|---|---|
|
Eminently Hydraulic
or XHN 100 |
NHL 5 |
NATURAL HYDRAULIC LIMES Argillaceous or siliceous limestone burnedand slaked . Reduced to powder with or without grinding. NO ADDITION ALLOWED |
|
Moderately hydraulic
or XHN 60 |
NHL 3.5 |
|
|
Feebly hydraulic
or XHN 30 |
NHL 2 |
|
|
IF ADDITIONS OF SUITABLE POZZOLANIC OR HYDRAULIC MATERIALS (up to 20%) ARE MADE THE ABOVE PRODUCTS MUST BEAR THE DESIGNATION OF NHL-Z |
||
|
ARTIFICIAL HYDRAULIC LIME
or XHA |
Hydraulic Limes
HL |
A blend of calcium hydroxide, calcium silicate and calcium aluminates (and possibly othermaterials such as ash, fillers etc… N.D.R.) |
Notes: Hydraulic limes (HL) are not regulated in their overall composition and the presence of cement is almost certain. A more appropriate definition would be HB (Hydraulic Binders) instead of HL.
Formulated lime (FL), is lime with hydraulic properties consisting mainly of aerial lime (CL) and/or natural hydraulic lime (NHL) with added hydraulic and/or pozzolanic materials. It has the property of setting and hardening when mixed with water and by reaction with carbon dioxide, i.e. the carbon present in air. This is called carbonation.)
The EU norm permits the addition of other materials in HL and FL such as cement, filler, metakaolin, gypsum or others. It also allows a SO3 presence up to 3,5%. Additions are used to improve the performance and convenience of lime products when there are constraints such as time, weather, environment. For conservation and restoration these lime products should be used under skilled supervision. They are suitable for new build.