Tempo (food-grade citric acid) is the most powerful retardant of Prompt natural cement retardant on the market. It is available in doses of 80 grams, and is dosed in relation to the volume of Prompt natural cement used. It is added to the mortar or concrete preparation.
Depending on temperature and dose, the setting time can be adjusted by a few minutes to more than an hour. Tempo is also used in mortars and concretes based on a mixture of natural lime and Prompt natural cement to bring better resistance to manipulation. In concrete, the Tempo dose alters the time of the onset of setting by around 20 minutes at a temperature of 20°C.
Tempo Dose: Half a capful of Tempo per litre of Prompt natural cement. Beyond the highest dose (one capful per litre), Tempo is not very effective.
Example of delays to Prompt natural cement mortar setting (1:1 volume):
|Temperature of mortar||10°C*||20°C*||30°C*|
|Setting time without Tempo||4 minutes||2 minutes||1 minute|
|Setting time with Tempo (one capful per litre)||30 minutes||15 minutes||10 minutes|
* above 10°C, you can use a half capful of Tempo per litre of natural cement, or even none at all, depending on the open time required.
How to use Tempo:
Mortar: sprinkle the Prompt natural cement with Tempo before mixing it with the sand.
Concrete: Put the Tempo in the concrete mixer at the same time as the Prompt natural cement.
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Adjusting setting .pdf