『Abstract
Surficial and bulk samples of historical bricks of different
age (from XII to XVIII centuries) recovered from a campaign of
archaeological excavations recently carried out at the site of
a medieval monastery in the S.Giacomo in Paludo Island in the
Venice Lagoon have been characterised by FT-IR, TGA-DTG, and DTA,
XRD, SEM + EDS. The samples belong to a particular brick type
commonly used in the Venice region: the “altinella brick”.
The bulk relative abundance of primary (i.e. calcite and dolomite)
and secondary firing minerals (i.e. diopside and wollastonite)
in the bricks coupled with their relative geometrical dimensions
allows placing the samples in a chronological sequence according
to known historical changes in brickmaking firing temperatures
and practices. Most of the bricks were used as paving material
and have been exposed to the action of seawater salts (chlorides
and sulphates) due to periodical submersion following high tide
episodes. Salt-laden (gypsum, halite,mirabilite) surficial patinas
are indeed present but salt weathering does not appear to have
affected the overall structural soundness of the bricks in this
now abandoned island as it is the case with brickwork located
in other more populated (and polluted) areas in Venice and its
lagoon.
Keywords: Historical bricks; Venice Lagoon; Altinella brick; Salt-weathering』
Introduction
Materials and techniques
Results
Samples: area 1000
Samples: area 3000
Samples: area 7000
Discussion
Conclusions
References