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We have been analysing mortars since 1989 and have developed a unique
mortar analysis service that now enjoys an international reputation. We
have tested in excess of 5000 samples. We have a particular expertise
in the analysis of historic and traditional mortars, and hold a nationwide
aggregates library.
Traditional mortars are of infinite variety. The binder is normally lime,
but roman cement, early Portland cement, gypsum, clay/earth, animal dung
and combinations and blends were also used. Traditional limes varied depending
on the actual limestone burnt, kiln type, fuel, and temperature achieved.
Aggregate type, particle grading, clay fines content and void ratio affect
mortar performance. Binder: aggregate ratios vary and pozzolanic reactions
may have taken place.
It is now accepted that a detailed understanding of existing mortars
is essential in informing and assisting the specification of replacement
or repair materials, and mortar analysis has become standard practice.
We can determine the constituents and proportions of all mortars, plasters
and renders. Non-hydraulic lime; hydraulic lime; roman cement; Portland
cement; cement/lime blends; gypsum; gypsum/lime blends: and daubs can
all be identified.
Our Standard Analysis Procedure comprises:
Microscopic evaluation of sample
Initial moisture content
Phenolphthalein carbonation test
Laboratory reaction comments
Chemical 'dissolution' tests in accordance with BS4551:2005
Dry-sieving insoluble residue to +/- 150µm (microns)
Microscopic examination of insoluble residue
Interpretation of results and analytical report
Suggested matching mortar recipe on a 'like-for-like' basis
CHEMICAL ANALYSIS & MICROSCOPIC EXAMINATION provide:
- The proportions of calcium, acid and alkali soluble silica, acid-soluble
sulphate, and acid insolubles
- The identification of insoluble sands, aggregates and additives
- The determination of soluble calcareous aggregate
INTERPRETATION OF RESULTS enables the determination of:
- Binder type(s)
- Hydraulicity of binder and pozzolanic reactions
- Sands and aggregates type
- Calculation of original volumetric mix proportions
- Suggestions for a matching repair or replacement mortar mix recipe
- Reasons for failure or poor performance (if applicable)
This Standard Procedure gives sufficient information on the vast majority
of samples. Various additional instrumental techniques can be employed
if necessary. Please note that DTA (Differential Thermal Analysis) is
no longer part of our standard procedure.
A representative sample of at least 40g is required, and contextual information
is always useful.
Mortar analysis costs £195 + VAT per sample and takes two to three weeks.
Please note that for example two-coat plaster is two samples. Orders and
cheques should be made out to Rose of Jericho Ltd and samples sent to
Horchester Farm.
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