The biomineralisation process exploits the natural capacity of certain non-pathogenic bacteria to produce limestone.
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Saint
Maximin limestone cleaned but untreated. This coarse limestone is
essentially composed of an accumulation of shells cemented together
by an ancient bacterial carbonate. This is particularly clear in
this photograph. |
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Treated Saint Maximin limestone: the high magnification (x 3,300) shows that even the small grains are covered with calcifying bacteria. Furthermore although the porosity of the stone is reduced by the calcified bacterial organisms the micro-pores are not totally obstructed, thus enabling the rock to breath. |
After
preventive or restorative treatment of the surface, the rapid formation
of this natural calcin by a reversible and compatible process hardens
the stone and provides long-term protection without modifying the appearance,
texture or colour of the original material. The porosity of the material
is reduced, thus limiting water infiltration, and the exchange of gases
between the stone and the atmosphere is unaltered.
In the case of particularly porous surface, allowing the deep penetration
of the calcifying bacteria, the CALCITE Bioconcept process can lead to
a reinforcement of the internal cohesion of the material and a resulting
consolidation of the stone.
Like a skin, the biocalcite produced by the micro-organisms forms a protective
crystalline structure which is identical to that of the original stone
and which matures in total harmony with the support. In addition, the
observation of the destruction of certain pathogenic micro-organisms in
the stone (biological pollution) by the CALCITE Bioconcept process has
highlighted the inhibiting effect of this new stone protection treatment
on harmful flora.
The first full scale application of this revolutionary process was carried
out on the church of Saint Médard in Thouars, France, under the supervision
of the French Laboratoire de Recherche des Monuments Historiques.
