Self leveler applicationLafarge Prestia supplies Alpha S NR to a growing number of companies manufacturing screeds and technical mortars for the construction industry.

Prestia Alpha S NR is a pure Alpha hemi-hydrate (CaSO4, ½H2O) made out of the purest natural gypsum.

It is used as a chemical in a wide range of applications for the construction industry, mostly in combination with other compounds; therefore we designed it to be :

  • additive-free
  • very consistent (ISO 9002 certification)
  • very reactive (fineness and grinding process specially adapted to maximize the particles surface tension)

It is widely used in construction products such as self-levelers, tile adhesives, repair mortars, in combination with aluminous cement (Fondu Lafarge, Ternal Lafarge), portland cement and some additives (plasticizers, resin,…), to yield :

  • high early and long term mechanical strengths
  • shrinkage compensation (no cracks)
  • rapid drying (ettringite cristallizes water)
  • no efflorescense (trapping of free lime)
  • NB : Fondu and Ternal are products of Lafarge Aluminates.
    Contact in Singapore : tel : 65 839 42 70; fax : 65 734 85 16
    Tile installation on tile adhesive 

Alternative sources of calcium sulfate (CaSO4) are gypsum and anhydrite , but gypsum causes cracks, and anhydrite is not as efficient as alpha-hemihydrate for shrinkage compensation. Moreover, anhydrite is very unstable and not produced in Asia-Pacific.
Therefore, Prestia Alpha S NR makes formulation easier and safer.

Technical tip : when using Alpha-hemihydrate with aluminous cement and Portland cement, use of a retardor is necessary (sodium citrate, sodium tartrate, citric acid, boric acid can be recommended).
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Quality control of Alpha S NR:

Plaster/Water Ratio (P/W) = 200%
Water/Plaster Ratio (W/P) = 50%

With those ratios and a manual mixing:

  • Slump (Schmidt Ring)  = 160-250 mm
  • Initial Setting Time (Knife Set) = 6-25 min.
  • Final Setting Time (Shore A)      45 min.
  • Granulometry :
    Over 100 µm (dry screen)   0.5%
    Over 63 µm (under water)   1%
  • Expansion at two hours     0.42%Rheological measurement

Gauging and mixing for those Laboratory tests:

  • Use correct plaster/water ratio
  • Use clean bucket and blade.
  • Sprinkle plaster into water slowly
  • Allow it to soak for one minute
  • Stir gently by hand or clean mechanical mixer for 1 to 4 minutes maximum.

Blade type (size, shape), stirring time and speed, water purity and plaster/water ratio have an influence on working time, mechanical strength and porosity of the hydrated plaster.

SOur loading areatorage

  • Bags must be kept dry in a closed room and  must be stored so as to avoid direct contact with the ground, protected from moisture and condensation.
  • For the best protection, the plastic wrapping surrounding each pallet should be kept as long as possible
  • It is recommended that the product be used within 4 months of manufacturing date.

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Our standard payment terms are Telegraphic Transfer before delivery or irrevocable Letter of Credit. We are currently preparing the possibility for customers who find it more efficient to pay through internet with credit card.

 We will be glad to give you a price quotation. Please contact us.

 Meet our team on our Customer Assistance page

Do you have any other question ? Please contact us.

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Components

Qty %

Function

Fondu Lafarge
Prestia Alpha S NR
 Portland cement

20
7
4

Early strength, rapid set,
fast drying and
shrinkage compensation

Lime flour
Sand

28
38

Fluidity and compacity
 

Resin

3

Adhesion and flexibility

Casein
Ca(OH)2

0.2
0.5

Fluidity
pH regulator for casein

Cellulose

0.06

Prevents sedimentation

Anti-foaming agent

0.05

Suppresses bubbles

Citric acid
Lithium carbonate

0.2
0.1

Controls setting time and
hardening kinetic

This formulation is only given as an example; any change of component in this formulation might require an adjusment of the formula.

Would you like to discuss the results you get with our Prestia Alpha S NR ? Please contact us now.

We will be glad to send you data sheets upon request. Please contact us.

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Australia

12 to 15 days

Bombay

10 to 15 days

Jakarta

7 to 9 days

Kuala Lumpur (by truck)

3 days

Manila

9 to 14 days

New Dehli

18 to 20 days

Seoul (Inch'on)

11 or 12 days

Shanghai, Guangzhou

7 to 12 days

Singapore

3 or 4 days

Sri Lanka

10 to 15 days

Taiwan

7 to 9 days

Tianjin

7 to 12 days

Tokyo, Nagoya, Osaka

10 to 12 days

Viet Nam

3 to 4 days

Our logistic know-how, our flexibility in production and our location very close to Bangkok harbor (Laem Chabang) enable us to offer short delivery time to Asian countries. Examples of shipping time between Laem Chabang and…

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Example 1 : Fondu cement-Prestia Alpha S NR mix :

To obtain a high early strength mortar with no cracks, a typical formula could be :

  • 30% Fondu cement, 7% Prestia Alpha SNR, additives (retardor, plasticizer) and sand/fillers.
  • Usual strengths will be : 20 MPa at 4 hours, 40 MPa at 24 hours and 60 MPa after 28 days.

Technical tip : the ratio Alpha/Fondu should not exceed 20% (otherwise, some expansion will occur).

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Example 2 : Prestia Alpha S NR in Self-Leveller

The following formulation, assessed by Lafarge Aluminates technical services, provides a crack-free, high early strength self-leveller

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Purchasing conditions

  • Standard packaging is 35kg bags, specially designed to preserve the plaster the longest and resist even tough handling.
  • We supply the bags on strong pallets.

For export markets, we prefer to ship 21 tons per containers (except in Korea where maximum container load is 17 tons and Tokyo harbor where maximum load is 20 tons)

The data presented in this document are in accordance with the present state of our knowledge, but do not absolve the user from carefully checking all supplies immediately on receipt. We reserve the right to alter product constants within the scope of technical progress or new developments.

The recommendations made here should be checked by preliminary trials, because of conditions during processing over which we have no control, especially where other companies' raw materials are also being used.

Prestia is a registered trademark of Lafarge Prestia

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