RJ2.06 ROMAN CEMENT |
PRODUCT DATA SHEET |
DESCRIPTION: |
Roman Cement is a term used to describe certain hydraulic binders produced by the calcination in a coal or coke fired kiln of limestones containing significant clay minerals (principally iron, silica and alumina). The name was adopted in about 1800 because the typical red/brown colour resembled mortars of the Roman period. Roman cement was most notably produced by James Parker (patented 1794) but similar products including 'Medina' Cement and 'Sheppey' Cement were produced from the septaria (clay-rich limestones) of the Solent and Harwich. Unlike modern hydraulic limes these were not supplied as hydrates, but mixed with water and sand on site when much heat was produced. They were fast-setting materials much used for run and cast mouldings and external renders. As true Roman Cements are no longer available, modern Roman cements are based on a hydraulic lime (RJ 1.05) which is mixed on site with carefully selected and blended aggregate which generally includes brick dust to match the colour and properties of the original. Roman Cements varied considerably in colour, texture, binder: aggregate proportions and degree of hydraulicity. It is normally necessary to analyse the existing material (RJ 6) in order to design an accurate matching mix recipe. |
USES: |
For the repair or reinstatement of Roman Cement
renders and mouldings.
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AVAILABILITY: |
Normally ex stock. It is important to use the correct grade of hydraulic lime. |
SHELF LIFE: |
Hydraulic limes deteriorate with age. Use fresh
material..
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PACKAGES: |
Hydraulic limes are supplied in 25 and 30kg bags depending on type. |
HEALTH & SAFETY |
Alkali pH13. Protect eyes, open cuts, skin. See
Safety Data Ssheet RJ 5.01A.
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OBSERVATIONS: |
Experienced operatives familiar with the use of lime based materials and with experience of their successful use should be employed. Accurate volumetric site mixing is essential. Hydraulic lime mortars do not behave as modern cementitious materials. They set by a combination of the hydration of the hydraulic compounds and carbonation. This 'carbonation' in the presence of moisture is a slow process and the control of the drying and curing by 'tending' and protecting is crucial to success and long term performance. Do not use in temperatures of 5ºC and falling. Protect from frost. |