The Roman cements in
Bohemian and Moravian historical buildings
Gregerová M., Masaryk University, Faculty of
Science, Department of Mineralogy, Petrography and Geochemistry, Kotlářská 2,
611 37 Brno, Czech Republic, mirka@sci.muni.cz
Pavel Pospíšil P., Technical University of
Brno, Faculty of Civil Engineering, Department of Geotechnics, Veveri 95, 662 37 Brno, Czech Republic, pospisil.p@fce.vutbr.cz
Abstract:
Natural historical
analytical methods are for conservators irreplaceable source of information.
Expert – petrologist or mineralogist is able to determine specific material
composition and in some cases also determine the source locality. These methods
were applied during the study of Roman cements from several historical
monuments in
Figure 1 - Location of objects
in
1. Introduction
Conservation
works on many historical structures uncover very well preserved samples of
original mortars and plasters. This material was applied during the formation
of many “stucco” elements, ornamental ledges, columns and handrails. Many of
conservators say about so called “Italian stones” or discuss about the import
of so called “Roman cements” and their application in structures. Sometimes
final products were probably imported to Czech Republic (up to 1918 part of
former Austria).
Mortars,
plasters and ornamental elements were by authors studied on many historical
structures in Czech Republic. The most interesting results were obtained during
the study of 3 selected objects – Lednice castle, church on Zelená hora hill
near Zdár nad Sázavou and fountain in Valtice.
Because
application of comparative method of study is the best method of identification
of material for natural historical branches comparative samples were carried
from Tuscania in Italy.
2. The history of Roman cement
The term
“cement” is derived from Latin word “caemente”, which Romans used as term for
masonry constructed of irregular stone blocks and some binding material. At the
beginning of 18th century it was translated to French language as
“ciment”. This term is used for material solidifying under the water up to now.
The Romans
applied above mentioned hydraulic materials very often. They made up concrete
for vaults, bridges and another structures with binding material made up of
slack lime and 20 – 75 % of volcanic ash of Puzzuola vicinity. The significant
structure constructed by Romans of this material is the bridge Port du Gard
near Nimes in southern France during the 1st century. The blocks are
bound by mortar made up of mix of lime and Puzzolana soil. The ration was
probably 1:2 up to 1:5. Application of this material was significantly reduced
during the medieval times.
Puzzolana
is hydraulic active matter with volcanic origin. They are tuff, volcanic ash,
pumice etc. In its broader sense Puzzolana also includes some of sedimentary
rocks as radiolarite, diatomite, spongilite, sandy marlstone etc.
The
original Puzzolana is volcanic ash. The most famous Puzzolana are “santorin”
(Roman and Neapolitan Puzzolana, Rhinish, Bavarian and Romanian trasses[1].
Similar
mortars were used during the history also in Czech territory. It is the
technological analogy to so called “Romanesque cement”. The hydraulic lime from
Zlíchov lime works known as “Pasta di Praga” belongs to this group too. This
lime was famous in the Europe during the 18th century and was
applied also within the construction of moles and some structures in Venice,
Amsterdam and London. As a part of Austrian monarchy Czech territories imported
hydraulic lime from Kufstein in Austria. This one was baked of marls or clay
limestones occurring in the Kufstein vicinity. It was high quality hydraulic
lime used for plasters of significant structures in Prague.
Romanesque
cement is component of historically used hydraulic mortars. It was baked of
“hydraulic” limestone (composition is similar to mixture for production of
Portland cement) – clay limestone. These limestones often occur in many regions
in Italy (Tuscany, Calabria, Emilia-Romagna) and abroad. They often occur also
in the Czech Republic. These limestones are used for production so called
“natural cement”. The difference between the Romanesque cement and natural
cement is in the baking temperature. Romanesque cement is baked below the
temperature 900 – 1100°C. Hydraulic active materials
contain higher content of reactive SiO2, which at the standard
temperature (20°C) reacts with Ca(OH)2
while calcium-silicate phase is formed.
1.
Brief
overview of studied objects
Design of the church on Zelená hora
hill near Zdár nad Sázavou and its vicinity constructed in Baroque style is
unique. Therefore was the church written to the list of UNESCO. The architect
of the church Santini – Aichl (1677-1723) belongs to the most famous Baroque
artists in the Central European region. The complex was built during the
extremely short time – two and half years (1719-1722) and it was several times
burnt down and reconstructed again. The plasters were according to records
repaired in 1828 and the cloister in 1829. The latest reconstruction before the
Second World War was realized in 1937.
The Lednice
castle was built before the year 1585 in Renaissance style on the place of
Gothic fortress from 13th century. Architect J. B. Fischer from
Erlach during the second half of 17th century reconstructed it. The
riding-school was preserved from these times. Architect J. Wingelmüler realized
the latest reconstruction in the English neo-Gothic style. Facade plastic
ornaments represent romanticism style.
Materials
applied during the construction and reconstructions were various. Architects
used the combination of natural and artificial materials. The necessity or
intention of application of artificial materials, which imitate natural ones by
architects, is discussable. Perhaps for financial costs were preferred
artificial materials, which can be easily formed.
Special
prepared sculptural stone was used during the construction of sculptural
fountain ornaments in Valtice. It was constructed in the half of 18th
century.
The
comparative samples of plasters and mortars were taken by conservators in
Tuscania in 1999 (Tuscany region in Italy) (Tab. 3).
2.
Results
of study
Optical
research
Samples of
material were studied in thin sections (about 0.03 mm) under the polarization
microscope.
Zelená
hora hill
Micropetrographic
analyses of selected samples of mortars and plasters from the Zelená hora hill
complex have discovered follows: The essential sandy component is formed mostly
of rounded quartz grains. Another components are feldspars, biotite, muscovite,
pyroxen, amphibole, olivine and fragments of scorias. These components occur in
micritic carbonate matrix. Rock fragments of metamorphic, igneous and
sedimentary rocks were also identified. Description of individual samples is in
Tab. 1.
|
Sample
No.: |
Extraction
place |
Colour |
Microstructure |
Composition |
|
1 |
O1 –
mortar |
gray |
psammitic
with micritic cement |
quartz,
biotite, vitreous scoria with mullite, scoria with olivine |
|
2 |
Vz002
IIK – ground floor, stucco from the initial part of vault near altar, left of
main entrance |
white |
basal,
micritic |
quartz,
plagioclase, biotite, muscovite, olivine, pyroxene, amphibole, garnet,
calcite? rock
fragments: bitite mica-schist, gneiss, marble, scoria with olivine, pyroxene,
vitreous scoria |
|
3 |
S01 –
stucco in the vault B4 |
light
brown |
basal,
micritic |
quartz,
K-feldspar, plagioclase, carbonates, pyroxene, biotite, muscovite, olivine, rock
fragments: biotite mica-schist, metaquartzite |
|
4 |
005 –
right of main entrance |
light
brown |
basal,
micritic |
quartz,
muscovite, biotite, plagioclase, amphibole, staurolite, calcite? rock
fragments: gneiss, mica-schist, scoria with olivine, pyroxene, vitreous
scoria |
|
5 |
r.
1793 – stucco |
white |
basal,
micritic |
quartz,
K-feldspar, plagioclase, biotite, muscovite, pyroxene, rock
fragments: gneiss, mica-schist, scoria with olivine, vitreous scoria |
|
6 |
K II
009 – core |
light
brown |
basal,
micritic |
quartz,
plagioclase, K-feldspar, biotite, muscovite, pyroxene, amphibole, carbonates rock
fragments: tonalite, biotite-sillimanite gneiss, metaquartzite, mica-schist,
vitreous scoria, scoria with pyroxene, olivine and relicts of slack lime |
|
7 |
S
0011 stucco cloister of ledge K1 |
light
brown |
basal,
micritic |
quartz,
biotite, muscovite, olivine, pyroxene, amphibole, apatite rock
fragments: metaquartzite, marble, biotite mica-schist, scoria with olivine,
pyroxene, vitreous scoria |
|
8 |
K III
0011 sample of wall with lettering -
r. 1793 Nikolas Tomas |
light
gray |
basal,
micritic |
quartz,
K-feldspar, biotite, muscovite, olivine, pyroxene, rock
fragments: gneiss, biotite mica-schist, metaquartzite, marble, scoria with
olivine, pyroxene, vitreous scoria |
|
9 |
O2 –
mortar of cloister |
light
brown |
psammitic
with micritic cement |
quartz,
plagioclase, K-feldspar, biotite, muscovite, olivine, pyroxene, amphibole,
carbonates, garnet, apatite, high temperature baked minerals rock
fragments: metaqurtzite, gneiss, silica shells, scoria with olivine,
pyroxene, vitreous scoria |
|
10 |
K I
006 |
light
gray |
basal,
micritic |
quartz,
plagioclase, biotite, muscovite, K-feldspar, carbonates, portlandite,
pyroxene rock
fragments: sillimanite gneiss, metaquartzite |
Table 1 -
List of selected samples of mortars and plasters of Zelená hora hill complex.
The
structure was several times reconstructed and burnt down. It is clear that the
exterior of the structure is heterogeneous from a point of view of age and
material composition. For historical and conservators needs they were compared
parts of plasters of the same epoch. Samples were extracted from walls of
cloister and chapel. They were assessed according to binding and filling
materials and pores. Results of analyses (Fig. 2) present mostly preponderance
of binding material over filling material. Samples can be divided into three
basic groups. Within the group A is ratio binding to filling materials 1:1,
within the group B 1,5:1 and within the group C 2:1. The porosity of Sample
No.: 1 is higher than another ones. This is the sample of mortar from brick
joint, which differs also macroscopically. The granulometric study has
determined that applied sandy fraction was within fine grained plasters in the
range from 0,1 to 0,5 mm and within the medium grained plasters in the range
from 0,5 to 1,5 mm. Mineral composition represents Fig. 2.
Figure 2 - Mineral composition
of mortars and plasters in Zelená hora complex
Lednice
and Valtice complex
Within the
Lednice and Valtice historical complex was studied so called "Italian
artificial stone" a sculptural elements of fountain in Valtice.
Italian
artificial stone is significantly altered by carbonates. Sandy fraction is
composed of fragments of biomicritic and biosparitic limestones and quartz
grains. Remains of high temperature baked minerals were found in relicts of
shells. According to castle archive were elements of artificial stone imported
from Italy (made probably of baked calcareous clays and limestones occurring
near Vesuvius?. Climatic conditions caused that the surface of construction
elements is very hoary and gray in colour. Inner parts are generally light brown
in colour with red fragments of tuffs. Material is medium grained. Table 2
shows characteristics of selected samples of Italian artificial stones. Modal
composition shows Fig. 3. Microstructure of artificial stone is very fine in
granularity with significant part of microfossils and fragments of biomicritic
and biosparite limestones. The porosity of material is also significant.
Surface parts are in comparison to inner parts more porous. The mineral
monticellite was identified by optical methods and EDAX analysis as accessory
mineral.
Valtice
Material of
sculptures of fountain in Valtice is
very interesting by its bluish colour. Petrographic study was focused on
discovering of causes of bluish colour. Optical research and EDAX analysis
identified fragments of bluish marbles and blue mineral lazurite[2]
|
Lednice |
|||||
|
Sam.
No.: |
Extraction
place |
Colour |
High
temp. miner. |
Microstucture |
Mineral
composition |
|
(1L) |
Ornamental
column |
gray |
- |
basal
micritic |
quartz,
feldspars, portlandite, fragments of carbonates (biomicritic, sparite),
monticellite |
|
(2L) |
Ledge |
gray |
+ |
basal
micritic |
quartz,
plagioclase, pyroxene, calcite rock
fragments: marble, tuff?, gehlenite group |
|
(3L) |
Ornamental
head |
gray |
+ |
basal
micritic |
quartz,
K-feldspar, plagioclase, pyroxene, calcite rock
fragments: biomicritic and biosparite limestones, marble, tuff, gehlenite
group |
|
(4L) |
Column
pedestal |
gray |
+ |
basal
micritic |
quartz,
plagioclase, pyroxene, calcite rock
fragments: tuff, biosparite and biomicritic limestones |
|
(5L) |
Plaster |
light
gray |
- |
psammitic
with micritic cement |
quartz,
K-feldspar, plagioclase, muscovite, biotite, amphibole rock
fragments: gneiss, mica-schist |
|
Valtice |
|||||
|
(1V) |
Centre
of the fountain |
gray-blue,
surface of sample and cleavage planes coated with gypsum |
- |
homogeneous,
micritic to microcrystalline with mostly angular fragments of sandy fraction |
Calcite
forms angular fragments, mostly in rhombohedron shape reflected deformation.
Calcite fragments are from marbles formed probably by contact metamorphism
with Si contribution or from marl rocks. Rare are phlogopite, quartz,
tremolite and diopside. rock fragments:
marble, biomicritic and biosparitic limestones |
|
(2V) |
Basin |
gray-blue |
+ |
basal
micritic |
quartz,
pyroxene, calcite rock
fragments: marble tuff?, gehlenite Blue
colour caused by: -
bluish marbles, -
presence of lazurite |
Table 2 -
Characteristics of studied samples of Italian artificial stone from Lednice
castle and Valtice fountain.
Figure 3 -
Modal composition of studied “Italian stones” of Lednice castle
Tuscania
and
Overview of
samples extracted in Italy for comparison with studied mortars and plasters of
Czech historical structures shows Table 3.
|
Tuscanie |
||||||
|
No |
Mark |
Extraction
place |
Age |
Colour |
microstructure |
Mineral
composition |
|
La
chiesa – S. Francesco (XIV. Sec.) |
||||||
|
1 |
T/1F |
Core-
stucco |
XIV.
century |
brown |
micritic,
slight recrystalization |
Tuff,
volcanic glass, trachyte, pyroxene, gehlenite, titanite, feldspar, nepheline |
|
2 |
T/2F |
Core |
|
rusty
brown |
micritic |
Tuff,
volcanic glass, trachyte, pyroxene, gehlenite, titanite, feldspar, nepheline
(usually altered to zeolites) |
|
3 |
T/3F |
Paving
stone |
|
brick
red |
slightly
parallel |
ceramics
baked of calcareous clay with tuff |
|
La
basilica di S.Pietro (XI.-XV. Sec) style romanico-lombardo |
||||||
|
4 |
T/1P |
Stucco |
krypta
XI-XII. century |
gray |
micritic |
Nepheline,
feldspar, leucite, pyroxene, amphibole, glass, tuff, trachyte, leucitic rocks |
|
Castello
della Badia I.-XII.sec. |
||||||
|
5 |
B/1C |
Plaster |
Historical? |
gray-brown |
micritic |
Volcanic
glass, altered nepheline, analcite[3],
leucite, pyroxene, zeolites, tuff,, trachyte |
|
6 |
B/2C |
Plaster
– interior of tower |
XII.
century |
ochre-white |
micritic |
Baked
clay limestone with fragments of leucitic crystalloclastic tuff, rarely
feldspar, gehlenite |
|
7 |
B/3C |
Bridge
near castella – inner plaster |
I.
century |
rusty-brown |
micritic |
Acidic
glass, lithoclastic and crystalloclastic trachyte tuff, pyroxene, lazurite,
sodalite, |
|
8 |
B/4C |
Bridge
near castella – lime plaster |
VII.
century? |
light-brown |
microsparite |
Volcanic
glass, tuff with leucite, pyroxene, alkali feldspar, sodalite, biotite,
nepheline, baked clay limestone |
|
9 |
B/5C |
Binding
material assumption of Etruscan material from bridge in Badia |
Castello
della Badia I.-XII. century |
gray-brown |
micritic, locally microsparite |
Vitreous
nepheline trachyte, pyroxene, alkali feldspar, tuff |
|
Rome |
||||||
|
Rome
– Circo Massimo |
||||||
|
10 |
R/1 CM |
Coarse
grained mortar |
Historical? |
gray-brown |
micritic |
Modern
plaster with addition of cement, biomicritic, biosparite limestone, quartz,
feldspar, silicite, zeolites |
|
11 |
R/2 CM |
shard |
Fragment
of dish |
dark-brick
red |
slightly
parallel |
Fragments
of quartz, feldspar, metaquartzite and micas, binder heterogeneous |
|
Rome
– Tempio di Vesta |
||||||
|
12 |
R/1TV |
Surface treatment between columns |
Fragments
near the wall, authentic material |
light
rusty brown |
micritic |
Tuff,
volcanic glass, leucitic rocks, pyroxene, feldspar |
|
Rome
– Ostia Antica |
||||||
|
13 |
R/10A |
Sample
with painting |
(fragments
from ground) Reg, V.IS.VL Caseggio del sole |
brown-white |
micritic |
Lime
plaster with clasts of limestones, quartz, feldspar, pyroxene |
|
14 |
R/20A |
Two
layer plaster (two modification) |
1.
older lighter, finer, red and ochre painted |
brown-white |
micritic |
Lime
plaster with clasts of limestones, quartz, feldspar, pyroxene |
|
15 |
R/30A |
Coarse-grained |
2.
younger red and ochre painted |
gray-brown |
microsparite |
Fragments
of leucitic crystalloblastic and lithoclastic tuff, volcanic glass, clastic
limestone, biotite, pyroxene, nepheline and alkali feldspar |
|
16 |
R/40A |
Plaster
of the same wall as samples No.: 14 a 15. |
|
gray-brown |
sparite |
Fragments
of clastic limestone, leucitic rocks, tuff, bitite, volcanic glass, pyroxene,
nepheline and alkali feldspar |
Table 3 - Overview
of mortar and plaster samples from Tuscania and Rome in Italy.
According
to above presented overview is clear that majority of studied mortars and
plasters contents minerals of volcanic rocks of surrounding volcanic region
(leucite, nepheline, alkali pyroxene, sodalite, gehlenite group, lazurite,
monticellite and their tuffs and contact metamorphic rocks). These minerals and
rocks can be used for determination of source locality.
3.
Chemical
composition
Chemical composition is one of very good criteria
for assessment of hydraulic properties of mortars and plasters. Therefore were
selected Italian and Czech samples analyzed (Tables 4 and 5).
|
|
1 |
2 |
3 |
4 |
9 |
10 |
11 |
12 |
13 |
16 |
|
H2O- |
5,36 |
6,23 |
0,41 |
1,53 |
2,64 |
1,61 |
0,37 |
0,72 |
1,33 |
4,16 |
|
H2O+ |
8,03 |
7,8 |
0,86 |
1,95 |
2,14 |
1,55 |
0,69 |
1,06 |
3,5 |
5,18 |
|
SiO2 |
49,59 |
49,5 |
50,11 |
45,3 |
53,85 |
13,76 |
63,67 |
47 |
6,27 |
41,88 |
|
TiO2 |
0,58 |
0,62 |
0,72 |
0,56 |
0,59 |
0,14 |
0,62 |
0,72 |
0,13 |
0,79 |
|
Al2O3 |
15,87 |
15,53 |
14,49 |
12,61 |
17,68 |
2,34 |
13,41 |
14,46 |
1,31 |
12,71 |
|
Fe2O3 |
4,25 |
3,85 |
5,71 |
3,87 |
3,39 |
0,86 |
5,23 |
6,23 |
0,4 |
0,3 |
|
FeO |
0 |
0,41 |
0,2 |
0,11 |
1 |
0,28 |
0,18 |
0,09 |
0,12 |
1,33 |
|
MnO |
0,12 |
0,13 |
0,11 |
0,1 |
0,14 |
0,07 |
0,13 |
0,14 |
0,01 |
0,09 |
|
CaO |
5,08 |
4,95 |
16,92 |
14,31 |
5,15 |
44,82 |
6,98 |
16,83 |
46,31 |
16,35 |
|
MgO |
1,67 |
1,68 |
2,92 |
1,9 |
1,75 |
1,16 |
2,42 |
3,28 |
2,16 |
2,77 |
|
K2O |
6,52 |
6,2 |
2,9 |
6,04 |
7,39 |
0,39 |
2,5 |
1,98 |
0,28 |
2,65 |
|
Na2O |
1,08 |
1,34 |
0,9 |
2,09 |
1,83 |
0,21 |
1,46 |
1,21 |
0,34 |
1,89 |
|
S |
0,07 |
st. |
0,18 |
0,11 |
0,06 |
0,21 |
st. |
0,13 |
0,19 |
st. |
|
CO2 |
1,17 |
1,27 |
3,31 |
9,2 |
1,62 |
32,42 |
1,84 |
5,58 |
37,3 |
9,07 |
|
P2O5 |
0,24 |
0,12 |
0,16 |
0,13 |
0,24 |
0 |
0,11 |
0,3 |
0,04 |
0,32 |
|
Sum |
99,63 |
99,63 |
99,9 |
99,81 |
99,47 |
99,82 |
99,61 |
99,73 |
99,69 |
99,49 |
Table 4 -
Chemical composition of mortars and plasters from Tuscania and
|
|
7zh |
5zh |
8zh |
2zh |
9zh |
10zh |
1L |
2L |
k |
l |
|
H2O- |
1,34 |
1,22 |
0,02 |
0,45 |
0,7 |
1,39 |
5,41 |
4,98 |
6,38 |
0,78 |
|
H2O+ |
3,17 |
2,92 |
4,21 |
2,68 |
12,19 |
7,48 |
7,87 |
7,25 |
0,05 |
1,2 |
|
SiO2 |
51,87 |
53,56 |
45,35 |
37,21 |
1,46 |
5,05 |
30,74 |
32,5 |
55,02 |
71,78 |
|
TiO2 |
0,16 |
0,19 |
0,11 |
0,19 |
|
|
0,31 |
0,3 |
|
|
|
Al2O3 |
8,26 |
8,35 |
3,99 |
4,74 |
0,69 |
0,77 |
5,81 |
7,2 |
|
|
|
Fe2O3 |
1,36 |
1,29 |
0,58 |
1,20 |
|
|
1,25 |
1,35 |
2,69 |
3,68 |
|
FeO |
0 |
0 |
0 |
0 |
0,23 |
1,1 |
|
|
|
0,3 |
|
MnO |
0,03 |
0,03 |
0,04 |
0,03 |
|
|
0,6 |
0,2 |
|
|
|
CaO |
13,32 |
12,53 |
25,21 |
29,52 |
46,2 |
46,04 |
20 |
19,8 |
20,47 |
13,69 |
|
MgO |
4,24 |
3,64 |
1,11 |
1,23 |
0,9 |
0,58 |
1,92 |
1,79 |
2,03 |
|
|
K2O |
3,03 |
3,07 |
1,66 |
1,80 |
0,01 |
0,34 |
1,22 |
1,23 |
|
|
|
Na2O |
1,39 |
1,44 |
0,61 |
0,59 |
0,5 |
0,23 |
0,99 |
2,97 |
|
|
|
S |
|
|
|
|
0,2 |
0,31 |
0,63 |
0,89 |
0,18 |
|
|
CO2 |
11,46 |
11,28 |
16,90 |
20,09 |
36,9 |
36,7 |
15,54 |
19,25 |
16,06 |
8,51 |
|
P2O5 |
0,13 |
0,19 |
0,12 |
0,11 |
|
|
0,16 |
0,16 |
|
|
|
suma |
99,76 |
99,71 |
99,91 |
99,84 |
99,98 |
99,99 |
92,45 |
99,87 |
80,44 |
99,94 |
Table
5 - Chemical composition of mortars and
plasters of Zelená hora hill complex
(2zh, 7zh, 8zh, 9zh, 10zh), Lednice (1L, 2L), Cimperk (k) and Mikulov (l).
Figure 4 shows very good conformity of
studied plasters and mortars from Tuscania and Rome with published data of
trasses. But from chemical data is not possible to identify the source
locality. At the same time is clear that some of hydraulic limes are by their
chemical composition similar to natural hydraulic materials.
Figure 4 – Modal composition
of mortars and plasters from Tuscania and
4.
RTG
and electron microanalysis
Results of
RTG analyses and electron microanalyses of studied mortar and plaster samples were
used as complementary method for more accurate analysis of mineral phases (as
monticellite, lazurite, analcime, gehlenite, nepheline, ackermanite and
zeolites. Results verified the method of optical research and its results.
5.
Conclusion
Complex
results verified optical methods and its results and documented the ability of
optical methods reach quickly and cost effective right results. Another
analytical methods serve more accurate results but they are also more
expensive. Optical microscopy study not only porosity of material, character
and microstructure of binder but especially for identification of modern and
historical materials and their source localities and materials. The more marked
is difference between geological conditions of source raw materials and
conditions in the re-deposition place the more reliable results are reachable.
This is applicable especially for imported materials. For example mineral leucite (Photo 1)
documents imported material (within the region of Czech Republic are leucitic
rocks rarely within neovolcanic rocks in České středohoří and Doupovské hory in
northwestern part of the republic). Another reliable source of information is
archive if it exists. The best results are taken by combination of these
methods. Similar example is identification of lazurite “Lapis Lazuli”, which
was identified by optical method and by EDAX in samples of Valtice fountain
(Photo 2). Its presence within the rock is observable already macroscopically
by bluish colours. Another minerals for identification are high temperature
minerals formed during the baking of calcareous raw materials. In this case is
important to differ historical and modern mortars and plasters especially
during first half of 20th century when was used portland cement.
|
Foto 1
Leucite crystal rounded with glass – Sample No.:15, magn. 80x, 1N. Photo M.
Gregerová |
Foto 2
Lazurite in artificial stone – fountain in Valtice. Magn. 120x, 1N. Photo M.
Gregerová |
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(1)
Hošek
J.; Muk J. - „The plasters historical buildings“, SPN, Praha, 1989
(2)
Gregerová,
M. - “The building stone of the historical monuments in
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Gregerová,
M. – “Rocks and technical materials of historical buildings”. Proceedings of
the conference on Life environment for XXIth century,
(4)
Gregerová,
M.; Pospíšil, P. – “The reason of
(5)
Gregerová, M.; Střelcová, E. –
“Petrographical characteristic of building materials of the
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Pohanka,
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Rovnaníková, P.; Gregerová, M.; Krmíčková, N. –
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