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)
DL (dolomitic lime)
Semi hydrated and hydrated | Calcium
oxide or Calcium Hydroxide
Calcium and Magnesium Oxides OR
Calcium and Magnesium Hydroxides | | | Hydrated
lime | CL or DL resulting from controlled slaking of quicklime. Produced
as POWDERPUTTY 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 1:1.3 binder/sand ratio. |
Natural
hydraulic lime (NHL) |
Eminently Hydraulic
or XHN 100 | NHL 5 | NATURAL
HYDRAULIC LIMES
Argillaceous or siliceous limestone burned and 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 other materials such as ash, fillers etc… N.D.R.) |
|
NOTES:
Artificial hydraulic limes (HL) are not regulated in their overall composition
and the presence of cement is almost certain. A more appropriate definition would
have been HB (Hydraulic Binders) instead of HL. Should be avoided
in restoration and conservation work.
The addition permitted in NHL-Z
of up to 20% of other materials in conjunction with the further allowances made
in the Norm related to the presence of SO3 (3%
AND UP TO 7% subject to soundness test) and the small amount of Available Lime
required in NHL products (3% -15%)* can cause problems. These additions will
consist of cement or other materials (i.e. Gypsum) used in order to achieve constancy
in the performance of otherwise unreliable products. Although in many instances
this will be acceptable in new build, in restoration and conservation work
NHL – Z products could produce unwanted effects.
* Available lime in
St. Astier NHL products: 15% to over 50% |
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