Posted on 6 Comments

Rapid Setting ‘Prompt Natural Cement’

Vicat Prompt and Tempo on harbour wall

This fast setting waterproof cement is so versatile that it is constantly finding new uses throughout New build and Restoration Projects. Using the addition of measured amounts of Tempo Retardant, it’s setting time can be controlled from as little as 90 seconds.

About Prompt

Prompt is a unique binder produced by the Vicat Company at their Voreppe works very close to the French alpine city of Grenoble. The Vicat Company was established in 1853 by Joseph Vicat (1821-1902) the son of Louis Vicat (1786-1861) a French military engineer who is credited for his pioneering work with artificial cements. The Vicat Company is the third largest cement producer in France and now the only manufacturer of Natural Cement sold as Prompt, a name synonymous with its unique properties, as Hoover is for vacuum cleaners.

Prompt is an entirely natural cement, produced from a single geological layer of Argillaceous (clayey) limestone, a sedimentary rock formed during the formation of the Alps. It is mined then fired at the same relatively low temperature as that for lime production, 800 -1200º C and then finely ground; it contains no other additives whatsoever. Whilst fully compatible with other types of lime binder Prompt Natural Cement cannot be referred to as a lime binder as it contains no free lime Ca(OH)2 however its primary uniqueness comes from the rapid set that Prompt exhibits, which can be controlled with the addition of Tempo (citric acid) which can delay the set in a Prompt mortar by 10 to 30 minutes depending on the ambient temperature at the time.

Where to use Quick Setting ‘Prompt Cement’

Prompt Natural Cement can be used in countless applications on its own, with sand or gauged with traditional lime mortars and plasters, lime putty or NHL mixes, along with many other applications in building conservation where accelerating or achieving a rapid set would be beneficial. Prompt is the only commercially available and appropriate material for repairing Roman Cement applications. The following is but a small selection for a myriad of uses for Prompt.

Some Applications for ‘Prompt Cement’

WATERPROOFING * LIME RENDERS * CASTING * “ROMAN” CEMENT * DIY AND HOBBY * BUILDERS AND TRADESMEN * FIXER MASONS (STONE CLADDING) * MONUMENTAL MASONRY * CONCRETE & MORTAR REPAIR * SHOTCRETING * SECURING FIXINGS & STREET FURNITURE *FLOORING * ROAD, STREET, MOTORWAY & RUNWAY REPAIRS * WINDOW FITTERS * MARINE & HARBOUR WORKS * UNDERWATER ENGINEERS * * AGRICULTURE * WATER AND SEWAGE SYSTEMS * SOIL STABILISATION * POND CONSTRUCTION * LANDSCAPE GARDENERS * FISH FARMING.

Examples of Use

Accelerated building operations, emergency repairs, rebuilding of openings, quick build up of any type of masonry, quick or rapid (use of Tempo), very useful for fitting doors and windows. Underpinning operations, with a higher compressive strength than NHL based lime concrete or mortars, and with a much quicker set allowing for safer and improved productivity, all without the need for OPC. Casting ring beams. Roman Cement repairs. Tanking works where appropriate i.e. a 10 mm base coat render mixed at 1:1 in vulnerable locations such as window reveals to mitigate damp ingress at such a location. Water stopping in basements or drainage works. Concrete repairs, high alkalinity helps protect rebar from corrosion. Storage bunds especially sewerage or other areas where aggressive chemical leachates would attack repair mortars. Underwater engineering where divers can carry out instant repairs using neat prompt. Harbour works within the tidal zone, Prompt has been used in saltwater marine environments for more than 150 years.

Benefits of Prompt Cement

COMPATIBLE WITH LIME * FAST, CONTROLLABLE SET * LOW SHRINKAGE * LOW REACTIVITY * HIGH ALKALINITY.

Comment On This Article
Ask a Question on our Forum
Get In Touch

Ask a Question on our Forum

6 thoughts on “Rapid Setting ‘Prompt Natural Cement’

  1. Is there a use-by-date for Prompt Natural Cement?
    If stored dry, how long after purchase will the material remain useable?

    1. Thanks for your enquiry – Prompt has a 12 month shelf life.

  2. Can prompt lime mortar be used on lath applications on an exterior wall .
    Thanks

    1. Hi Kevin

      We wouldn’t recommend a pure prompt mix as this will be too strong for the lath background, also given the rapid set the mixing and working time is reduced. We do have a premixed product for lath – http://cornishlime.co.uk/cornerstone-woodlath-render – this contains a small percentage of prompt to help increase the set, whilst maintaining the virtues of an NHL 2 mortar.

      If you have any questions or would like any further information please contact us.

      Kind Regards

      Adam

  3. Hi guys
    I was considering ordering and using this for my koi fish pond. Is this safe to use for fish after curing? Many thanks

    1. Thanks for your enquiry.
      There are several different variables to consider when using Prompt on a fish pond.
      If you want to keep the water in the pond on a repair; in a small pond (a few cubic meters) the pH will increase as small amounts of calcium hydroxide will be released. However if your pond is 10 cubic meters or more the effect is limited and unless you have certain types of very pH sensitive fish it’s usually fine.
      If you’re draining the pond to do the repairs/works then leave the water out for a few days (preferably a week) after the work has been done and clean the new sections down well before you fill the pond. Regardless of pond size in this case the pH increase should be limited enough not to be a problem.
      If you wanted a belt and braces approach for an empty pond; washing the surface of the render with Tartaric acid shortly after application (after the Prompt has set) will neutralise any potential alkaline release, this is what they do in France for wine storage tanks. Unfortunately we do not stock Tartaric acid so you would need to source this elsewhere, I can give you more specific information on this method if you decide it’s the way you want to go.
      Either way you should always monitor the pH of the water after any work is complete regardless of which product you decide to use.
      Prompt has been certified for use in drinking water so it’s better than OPC based cements in that sense, however it still does need a bit of care when dealing with fish. If you needed any further information please don’t hesitate to get in touch.
      Kind regards, Justine

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.