42

The petrographic analysis of the natural building stones, bricks and the mortars

Stone 1 ; The sample is a microcrystalline limestone which contains 99 % micrites and

cryptocrystalline carbonate mud, and, 1% opaque ironoxide (Fe2O3) minerals. The pellets,

indicates the ripple medium, and the size differentiated particle zonning and pseudo oolites

were observed in the thin section, Figure 3.52.

Stone 2 ; The sample is similar with stone 1. It additionally has 1 % quartz, 1-2 % opaque

iron oxide minerals and 1-2 % pores, Figure 3.53.

Stone 3 ; The sample is a microcrystalline limestone that contains calcites with

cryptocrystalline-microcrystalline size, 1-2 % of opaque minerals, and, large amount pores.

Most of the pores were filled with the secondary calcite minerals and lesser amount of the

pores were filled with secondary clay and chlorite minerals, Figure 3.54a, Figure 3.55b.

Stone 4 ; The sample is a microcrystalline limestone which contains 99 % micrites and

cryptocrystalline carbonate mud, and, 1% opaque ironoxide (Fe2O3) minerals. The pellets,

indicates the ripple medium, and the size differentiated particle zonning and pseudo oolites

were observed in the thin section, Figure 3.52.

Stone 5 ; The sample is a fossiliferous microcrystalline limestone that contains 70 % of

micrites and fossils. Approximately 30 % of the secondary large calcite crystals formed in the

pores of the mass, and, at the boundaries and inside of the shell fragments, Figure 3.55.

Stone 6 ; The sample is a marble that contains mainly calcite and seldom dolomite crystals.

The sizes of calcite crystals ranged in 0.1-2.0 mm and cumulated between 0.1-0.6 mm. The

sizes of the dolomite crystals were even smaller than the calcite crystals, Figure 3.56.

Stone 7 ; The sample is a cryptocrystalline calcitic and fossiliferous microcrystalline

limestone. The secondary large calcite crystals which different from the calcite binder, at the

pores and at the boundaries of the fossils. The sample contains 1 % chlorite and iron oxide

spots at the boundaries of the shell fragments, and, 1 % opaque minerals, Figure 3.57.

Stone 8 ; The sample is a fossiliferous microcrystalline limestone with excessive amount of

fossils. It has also another amorphous zones with excessive amount of fossils and some stone

particles (limestone particles with and without clay and sand, altered granite particles),

feldspar (orthoclase) and quartz in an organic binder. The stone totally has 2 % of opaque

minerals, Figure 3.58, Figure 3.59, Figure 3.60, Figure 3.61.

Stone 9 ; The sample is a limestone that contains microcrystalline calcite, lesser amount shell

fragments, 0.5-1 % opaque minerals, and, 3-5 % pores. The calcite crystals in the sample were

well crystallized, homogenously distributed, and, had no alteration. The sizes of these calcite

crystals were below 0.3 mm, Figure 3.62.

Stone 10 ; The sample is a microcrystalline limestone that contains calcites with

cryptocrystalline-microcrystalline size, 1-2 % of opaque minerals, and, large amount pores.

Most of the pores were filled with the secondary calcite minerals and lesser amount of the

pores were filled with secondary clay and chlorite minerals.

43

Brick 1 ; The brick sample has 15 % stone and mineral particles. Most of the particles with

the sizes smaller than 0.1 mm were quartz and feldspar minerals. A few ones having the sizes

around 0.5 mm were quartz, partly altered feldspar, mica minerals and limestone particles,

Figure 3.63, Figure 3.64, Figure 3.65.

Brick 2 ; The brick sample has 25 % of stone particles and minerals in the whole thin section

, 75 % is the clay. The stone particles, which are smaller than 0.5 mm, except a few 2.0 mm

sized, ones were cryptocrystalline and microcrystalline limestone, granite and quartzite. Only

some of the limestone particles and the feldspars partly altered. The minerals were orthoclase,

plagioclase, quartz and very few amphiboles such as hornblende, Figure 3.66.

Brick 3 ; The brick sample has mostly granitic stone particles and lesser amounts of quartzite,

limestone and sandy limestone particles. The minerals were orthoclase, quartz and a few

partly altered muscovite.

Brick 4 ; The brick sample has similar properties with brick 2 sample. It has mostly granitic

particles and lesser amounts of quartzite, limestone and sandy limestone particles. The

minerals of the brick were quartz, a few muscovite and partially altered orthoclase, Figure

3.67, Figure 3.68.

Brick 5 ; The brick sample has 20-22 % stone particles and minerals, 3 % opaque minerals,

and, a few pores. The sizes of the stone particles were mostly cumulated in between 0.5-2.0

mm were granite, gneiss granite, quartzite, and sandstones with and without clay and

carbonate inclusions. Most of the particles are smaller than 0.5 mm and only a few alkaline

feldspar particles were around 3.0 mm. All of the types of the particles, except the quartzite

were mostly or partially altered. The minerals were mostly orthoclase and a lesser amounts of

plagioclase, Figure 3.69.

Brick 6 ; The brick sample has 20-25 % stone particles, 2-3 % of opaque minerals and very

little amount pores in the binder (72-78 %). The sizes of the stone particles were mostly

between 0.3-1.8 mm, they were granite, gneiss granite, quartzite, sandstone, sandy limestone

and a few igneous stone particles. All the types of the particles, except quartzite were mostly

or partially altered. Most of the particles were smaller than 0.3 mm. A few alkaline feldspars

around 5.0 mm were also observed in the sample. Most of the minerals were partially altered

orthoclase and lesser amounts of quartz and plagioclase, Figure 3.70, Figure 3.71.

44

Figure 3.52. The micritic limestone with pseudo oolithes, (Stone 1 and 4).

Figure 3.53. The micritic limestone which contains large calcite crystals, (Stone 2).

45

Figure 3.54a. Smaller calcite and opaque minerals (single nicole), (Stone 3).

Figure 3.54b. Double nicole, (Stone 3

46

Figure 3.55. The cryptocrystalline fossiliferous limestone with micrites and secondary

calcites, (Stone 5).

Figure 3.56. The large calcite crystals in marble, (Stone 6).

47

Figure 3.57. A limestone with micrites and recrystallized part, (Stone 7).

Figure 3.58. The limestone particle with numilite fossils, (Stone 8).

48

Figure 3.59. A different numilite fossil, (Stone 8).

Figure 3.60. The limestone, fossil, and, sound and altered orthoclase particles,

(Stone 8).

49

Figure 3.61. The rounded limestone particle, (Stone 8).

Figure 3.62. The tough calcite crystals and opaque minerals, (Stone 9).

50

Figure 3.63. The quartz and feldspar particles in clay matrix, (Brick 1).

Figure 3.64. The slightly altered feldspar particle, (Brick 1).

51

Figure 3.65. The altered orthoclase particle, (Brick 1).

Figure 3.66. Feldspar particle which is mostly altered, (Brick 2).

52

Figure 3.67. Partly altered alkaline orthoclase (off light), (Brick 4).

Figure 3.68. On light, (Brick 4).

53

Figure 3.69. The plagioclase mineral altered at the firing process, (Brick 5).

Figure 3.70. Sound and altered plagioclases (the black material can be hematite formation) ,

(Brick 6).

54

Figure 3.71. The feldspars as plagioclase, and opaque minerals as iron oxide,

(Brick 6).

55

Table 3.4. Visual and petrographic properties and composition of the mortar samples

Sample

No Century Colour Condition Particles and Minerals * Coarse Aggregates (%)

Approximate

Composition (%)

BP (%) S (%) Binder:BP:S

M1 5th Pink Weak- BP,LS,Mr,Qz,Gr,OrC,Q,Pr 21.02 (10-15 mm) 30-35:30-35:30-35

Century Crumbling 100 0

M2 5th Grey- Sound BP,LS,SS, Q,OrC, Q 32.23 (10-12 mm) 25:50:25

Century White 100 0

M3 Medieval Pink Sound BP,LS,F,Q,OrC 16.48 (12-15 mm) 25:50:25

Age 100 0

M4 Medieval Pinkish Sound BP,LS,Qz,Gr,OrC,Q,B,PC 13.09 (12 mm) 25:50:25

Age White 100 0

M5 Medieval Light Crumbling BP,LS,Qz,OrC,PC 14.33 (13 mm) 15:55-60:25-30

Age Pink 100 0

M6 Medieval Pinkish Sound BP,Qz,LS,OrC,Q 12.19 (15 mm) 25:60:15

Age White 100 0

M7 5th Dark Crumbling BP,LS,Qz,OrC,PC 0 30-35:40-45:25

Century Pink

M8 5th Dark Sound BP,LS,Qz,OrC,PC 0 30:40-45:25

Century Pink

M9 5th Pink Sound BP,LS,M,Qz,Gr,OrC,PC,Q 0 25-30:20-25:50

Century

M10 5th Pink Sound BP,Qz,LS,Q,OrC 17.41 (13 mm) 30:40:30

Century 100 0

M11 5th Light Sound BP,LS,Qz,Gr,OrC,PC,Q 24.62 (15-20 mm) 20-25:40:40

Century Pink 100 0

M12 5th Light Sound BP,LS,Qz,Gr,OrC,PC,Q 12.03 (12-15 mm) 20-25:40:40

Century Pink 75-80 20-25

M13 5th Pink Sound BP,LS,Q,OrC 10.20 (10-12 mm) 25-30:40-45:25-30

Century 100 0

M14 15th Cream Quite LS,Qz,Q,OrC,PC 7.92 (8 mm) 30-35: - :65-70

Century Sound 100 0

M15 Medieval Light Sound BP,Q,LS,OrC 34.4 20-25:70:5-10

Age Pink 100 0

M16 Medieval Pink Sound BP,LS,SS,Gr,OrC 31.04 (12-18 mm) 30:40-45:25-30

Age 100 0

M17 Medieval Pink Sound BP,LS,SS,Gr,OrC 21.03 (7-10 mm) 30:30-35:35-40

Age 100 0

M18 Medieval Grey Quite LS,Qz,Q,PC 45.02 (5 mm) 30-35:3-5:65

Age Sound 0 100

* The amounts are from more to less.

M : Mortar Qz : Quartzite pieces B : Biotite pieces S : Sand particles Q : Quartz pieces PC : Plagioclase pieces SS : Sand stone pieces Gr : Granite pieces LS : Limestone pieces BP : Brick pieces AlF : Alkaline Feldspar pieces Mr : Marl pieces

OrC : Orthoclase pieces Pr : Pyroxine pieces

56

Continued from the table 3.4,

Mortar

Samples Notes

M1 Gel formation was observed around the brick pieces. The feldspars were partially

altered.

M2 Adhesion between the binder-brick piece was very good. The gel formation was

only observed around some quartz particles.

M3

Adhesion between the binder-brick pieces was very good while the binder-limestone pieces adherence was poor. The gel formation was observed around the

alkaline feldspars (orthoclase) and quartz particles.

M4

Adhesion between the binder-brick pieces was good. The gel formation was

observed around the brick pieces. There was also some gel formation around some quartz particles.

M5

Adhesion between the binder-brick pieces and binder-sand particles was poor.

Limited gel formations were observed around the both brick pieces and the sand

particles.

M6

Adhesion between the binder-brick pieces and binder-sand particles was poor, clay

and gel formations were observed around both the brick pieces and the sand

particles.

M7 Adhesion between the binder-brick pieces and binder-sand particles was poor. The gel formation were observed around both brick pieces and the sand particles.

M8 Same as M7.

M9

Adhesion between the binder-brick pieces and binder-sand particles was poor. The clay and gel formation were observed around both the brick pieces and the sand

particles.

M10

Adhesion between the binder-brick pieces was good and there was partial gel

formation while binder-sand particles adherence was poor. There were partially siliceous, sericite and carbonate formation alterations behind the partial gel

formation.

M11 Adhesion between the binder-brick pieces and binder-sand particles were good.

Orthoclases were partially altered.

M12 All properties were similar to the M11, except M12 contains less limestone pieces

in a small amount.

M13

Adhesion between the binder-brick pieces was good, binder-sand particles

adherence was poor. Partial gel formation was observed around both brick pieces and the sand particles. Orthoclases were partially altered.

M14 Sample has partially yellow spots. Plagioclases were partially altered.

M15 Binder-brick pieces adherence was good, binder-sand particles adherence was poor.

Orthoclases were partially altered.

M16

Adhesion betwwen the binder-brick pieces and the binder-sand particles was good.

Partial gel formation was observed around the brick pieces. Orthoclases were

partially altered.

M17 All properties were similar to the M16 except crushed brick : sand ratio was different.

M18 Adhesion between the binder-sand particles and the binder-brick piece was good. Some fossiliferous limestone pieces and plagioclases were partially altered.

57

Table 3.5. The sieve analysis and the grading of the aggregates (%) of the mortar samples

Sample Acid Coarse Aggregates (8 - 1mm) %

Approximate ratios (8 - 4mm) %

of the 1-8 mm agg.

(4 -1mm) % (1 - 0,125 mm) %

Remains

%

No Insolubles

(%) BP (%) S (%) BP (%) S (%)

BP (%)

Coarses

S(%)

Coarses

BP (%)

Medium

S (%)

Medium

BP (%)

Fines

S (%)

Fines ( > 0,125)

M1 56.4 21.02 (10-15 mm) 54.26 20 (4-7 mm) 80 (1-4 mm) 21.5 3.23

5thC 100 0 45-50 50-55 100 0 30-35 65-70 30-35 65-70

M2 52.95 32.23 (10-12 mm) 55.83 60-65 (4-8mm) 25-40 (1-4 mm) 9.55 2.39

5thC 100 0 60 40 100 0 50 50 75-80 20-25

M3 49.41 16.48 (12-15 mm) 66.94 60 (4-8 mm) 40 (1-4 mm) 12.74 3.83

Med 100 0 80 20 100 0 60 40 30-35 65-70

M4 57.28 13.09 (12 mm) 67.79 60 (4-10 mm) 40 (1-4 mm) 15.76 3.36

Med 100 0 80 20 100 0 55-60 40-45 30-35 65-70

M5 50.11 14.33 (13 mm) 63.76 45-50 (4-10 mm) 50-55 (1-4 mm) 16.88 5.03

Med 100 0 65 35 100 0 30-40 60-70 40-50 50-60

M6 47.87 12.19 (15 mm) 66.37 40 (4-10 mm) 60 (1-4 mm) 14.46 6.98

Med 100 0 80 20 100 0 65 35 50 50

M7 39.47 0 57.33 60 (4-10 mm) 40 (1-4 mm) 34.94 7.73

5thC 80 20 95 5 30 70 40-45 55-60

M8 52.75 0 65.5 40 (4-12 mm) 60 (1-4 mm) 28.47 6.04

5thC 50 50 95 5 20-25 75-80 25 75

M9 38.71 0 51.82 30-35 (4-8 mm) 65-70 (1-4 mm) 42.39 5.80

Med 35 65 85 15 15-20 80-85 30 70

M10 65.62 17.41 (13 mm) 48.94 75 (4-8 mm) 25 (1-4 mm) 31.32 2.33

5thC 100 0 40 60 50 50 35 65 15 85

M11 56.33 24.62 (15-20 mm) 54,09 25-30 (4-9 mm) 70-75 (1-4 mm) 18.28 3.01

5thC 100 0 50 50 50 50 50 50 50 50

M12 64.93 12.03 (12-15 mm) 51 40 (4-8 mm) 60 (1-4 mm) 32.83 4.14

5thC 75-80 20-25 40-45 55-60 40-45 55-60 40-45 55-60 30-35 65-70

M13 43.11 10.20 (10-12 mm) 47.12 25 (4-8 mm) 75 (1-4 mm) 36.72 5.97

5thC 100 0 50 50 50 50 50 50 50 50

M14 11.39 7.92 (8 mm) 13.77 15 (4-8 mm) 85 (1-4 mm) 67.67 10.65

15thC 100 0 5-8 92-95 5-8 92-95 100 0 0 100

M15 54.19 34.4 (13 mm) 53.4 45-50 (4-7 mm) 50-55 (1-4 mm) 9.94 2.27

Med 100 0 85-90 10-15 85-90 10-15 85-90 10-15 30 70

M16 59.84 31.04 (12-18 mm) 52.95 20-25 (4-8 mm) 75-80 (1-4 mm) 13.62 2.39

Med 100 0 65-70 30-35 65-70 30-35 65-70 30-35 30 70

M17 44.18 21.03 (7-10 mm) 61.04 40 (4-8 mm) 60 (1-4 mm) 15.9 2.04

Med 100 0 50 50 50 50 50 50 50 50

M18 44.41 45.02 (5 mm) 49.22 5-10 (4-8 mm) 90-95 (1-4 mm) 5.04 0.71

Med 0 100 3-5 95-97 3-5 95-97 3-5 95-97

58

Table 3.6. The results of the acid loss+ sieve analysis and the ignition loss analysis of the

mortar samples

Sample

No

Humid

%

550o C

%

CaCO3

%

Acid

Lost

%

Acid

Retained

%

Coarse + (*)

Aggregates

A, %

Coarse + (**)

Aggregates

B,%

(***)

1000

%

(***)

500

%

(***)

250

%

(***)

125

%

(***)

<125

%

M1 1.81 4.17 45.59 51.35 48.65 15.08 26.74 57.34 4.84 28.63 3.61 5.58

M2 4.27 4.97 27.96 63.35 36.65 25.73 48.59 66.39 3.44 20.98 2.46 6.72

M3 16.02 15.21 26.96 56.22 43.78 10.02 20.27 75.28 3.58 13.43 2.00 5.72

M4 0.71 5,53 25.19 46.83 53.17 8.78 15.33 74.09 5.56 14.04 1.75 4.56

M5 6.11 13.42 18.53 54.57 45.43 8.58 17.12 69.29 3.84 16.70 3.13 7.05

M6 1.33 6.58 35.54 55.95 44.05 6.83 14.27 71.65 2.34 14.21 2.56 9.23

M7 4.58 9.12 40.43 60.53 39.47 0.00 0.00 57.33 2.76 28.00 4.18 7.73

M8 1.05 4.23 55.76 47.25 52.75 0.00 0.00 65.50 3.61 22.42 2.44 6.04

M9 2.28 5.89 51.86 61.29 38.71 0.00 0.00 51.82 3.64 32.70 6.05 5.80

M10 4.41 6.94 28.28 39.95 60.05 13.95 21.26 48.37 3.42 42.31 2.31 3.58

M11 5.13 6.20 26.14 53.55 46.45 18.45 32.75 58.05 6.23 27.44 2.36 5.93

M12 6.93 7.93 24.35 38.43 61.57 8.75 13.47 51.32 2.93 36.40 3.90 5.45

M13 5.30 8.07 34.50 59.82 40.18 4.90 11.37 46.38 5.11 35.95 5.06 7.49

M14 0.41 4.21 80.36 89.50 10.50 0.99 8.70 6.94 4.01 61.73 14.66 12.65

M15 2.15 9.61 26.25 64.29 35.71 28.74 53.05 60.89 6.15 23.00 2.70 7.26

M16 1.68 3.37 41.01 55.41 44.59 27.52 45.99 57.77 7.67 24.66 3.59 6.31

M17 8.04 8.72 37.53 63.44 36.56 12.01 27.19 69.06 5.34 17.51 4.57 3.52

M18 1.80 3.04 80.83 87.45 12.55 36.42 82.03 42.12 3.15 40.40 7.16 7.16

(*) :Proportion of the coarse aggregates vs the amount of the mortar sample

(**) :Proportion of the coarse aggregates vs total aggregates.

(***) :Sieve distribution of those aggregates do not include the coarse ones.

59

3.1.2.1. The results of the analysis of natural stones, brick and mortars

Natural Stones;

Petrographic analysis of the natural stones indicated that the samples S1, S3, S4, S9 and S10

were microcrystalline limestones with calcite, samples S5, S7 and S8 were fossiliferous

microcrystalline limestones and sample S2 was an oolitic limestone. All of them were organic

limestones (with calcites, oolithes and fossils ), and they were locally named as “Küfeki

Stone”, all of them were extracted from the Merter and Bakırköy region close to the land

walls of Constantinople. The sample S6 is a marble which probably was quarried from the

Marmara Island (Proconnesses).

The DTA curves (Figure 3.41) of limestones indicated that the main components of the

samples are CaCO3.

The semi-quantitative analysis of the water soluble salts indicated that the stone samples S1,

S2, S9 and S10 included considerable amounts of Cl- salts, while samples S2, S7, S8, S9 had

SO4-2

salts.

The results of the ICP analysis gave the general compositions of the limestone samples, the

Cl- and SO

-24 (as S) contents seem to support the data derived from the semi-quantitative

analysis. The samples S7, S8, S9 which was taken from the altered evaporation front of a

limestone from T4 of landwalls of Constantinople contained 2-9 times more SO4-2

salt when

compared to the samples which were taken from the sound core of those limestone blocks.

The SO4-2

salt was accumulated as a black gypsum crust on the surfaces of the limestone

samples which were exposed to the polluted air. Dust, soot and clay were trapped during the

surface condensations. Consecutively the SiO2 contents of a contamined samples, S7, S8, S9

were increased on their surfaces. The sample S10 showed a contrary result where it was

sampled from the sound core of the same limestone block. Also no

SO-2

4 salt was detected in the clean and sound core. The Cl- salt content was doubled because

the stone sample was in contact with the joint mortar, as stone laying and pointing mortars

included more Cl- salt. The production, migration and crystallisation of the Cl

- and SO

-24 salts

during the wetting and drying cycles had caused efflorescence and surface erosion in the

forms of fissures, flaking and crumbling. The results of the ICP analysis also indicated that

the stones S2, S4, S5 and S10 included Cr salt ranging between 0.003-0.006 %.

Contamination due to the Cr salt was originating from the leather manufacture (tanning)

processes which took place in the factories which were adjacent to the T4 and the adjoining

rampart for the last four decades before the urban clearance.

In regard to the results of the ICP analysis, the Cr salts contamination was limited and since

Cr salts are not water soluble they do not cause physico-chemical deterioration processes,

whereas they create aesthetic problems.

Bricks;

The DTA curve and the XRD patterns (Figure 3.39) brick of (Figure 3.41) indicated that the

main component of the sample is SiO2.

60

Petrographic analysis of the 5th

C and the medieval bricks indicated that the minerological

compositions of all of them were similar to each other. But the amounts of the minerals and

their porosities changed from one sample to another. Sample B1 (yellow coloured medieval

brick) had smaller particles than the others. The other minerals of the brick samples were

similar to each other.

The alteration of the limestone particles in the exhibited similar deterioration processes as the

limestones. These results which were derived from the petrographic analysis were correlated

to the results of the ICP analysis. All of the samples included SO4-2

salt in amounts between

0.02-0.08%. Sample B3 and B4 (medieval) included small amounts of Cl- salt, while B1

included almost no Cl- salt. The brick samples B2 and B5 and the surface stratum of the

sample B3 (all medieval brick) had larger amounts of Cl- salt, B6 which is a 5

thC brick had

excessive amount of Cl- salt, which can originate from the production technology or the

accumulation of the Cl- ions by means of sea spray coming from Marmara sea, percolating

rain water, since the sample was taken from the ground level of T4, from the passageway

from the city to the ground floor, (Figure 2.1) where the stones, bricks and the mortars were

exposed to weathering processes for centuries.

Bricks for the conservation works :

The 5th

C and the medieval bricks were 38/38/4-5 cm sized, where the Late Byzantine bricks

were sized 35/35/3.5 cm, and 32-34/32-34/2.5-3.5 cm bricks were also found in the landwalls

of the city. The physical and the mechanical properties of Byzantine bricks were heterogenous

due to the production techniques and their state of conservation. The average values for

Byzantine bricks of the 5th-14

th centuries can be summarized as follows:

Density : 1.55-1.89 g/cm3

Water Absorption (by weight,%) : 14.7-22.05

Table 3.7. The physical and the mechanical properties of the bricks which were produced in

the brick kiln Kılıçoğlu in Eskişehir

Dimensions Density

(g/cm3)

Water Absorption

(by weight, %)

Coefficient of

Capillary (cm.min)

Compressive Strength

(N/mm2)

38/36/5.5 1.97 10.7 0.112 27.6

30/15/3 1.95 11.5 0.116 25.7

32/17/3.5 1.96 10.7 0.073 28.5

*The results were the average of 5 samples, the tests were conducted in 1993 during the conservation works in the land walls of Constantinople at Yedikule, Sulukule Kapı (Porta Pempton) and Topkapı

(Porta Romanus).

Mortars

The DTA curves (Figures 3.30, 3.3) and the XRD patterns (Figure 3.2) of the mortars

indicated that the main component of the samples are both SiO2 and CaCO3. The results of the

petrographic analysis (Table 3.4), the ignition loss (Table 3.6) and the acid loss and the sieve

analysis (Table 3.5 and 3.6) of the siliceous aggregates and the crushed brick particles had

given the binder : aggregate ratios of the original samples. Also additives and their some

physical and chemical properties were determined (Table 3.11 and 3.12). The acid insoluble

61

aggregates presented an important data in regard to their grading, especially gravel sized brick

particles which were mostly 8-20 mm sized were calculated as their ratio to the sum of the

aggregates (first method) and to the weight of the mortar sample (second method) as a whole

for characterisation purposes. In the second method the ratio of the gravel sized coarse brick

aggregates to the sample weight was between 1-36 %. In the first method, it was observed that

the ratio of the coarse brick particles to the total amount of the aggregates (by weight) led to

incorrect conclusions. Because these brick particles which were 8-16 mm mesh size and

above, were scattered in large amounts of mortar and when sampled in 40-50 g lumps, the

binder : aggregate ratios were deviating from the real values. The ratio of the coarse

aggregates in the total of the aggregates were as much as 82 %. Because of these diversity in

the total aggregate ratio, the ratio of the gravel sized brick particles, were evaluated separately

the binder : aggregate ratios do not include the 8-16 mm and >16 mm mesh size brick

particles. Instead they were included to the total sum of the aggregates in the calculations in

regard to total aggregate : binder ratios of the mixes. As a result this method the binder :

aggregate ratios were generally 1:3 (samples M1, M7, M8, M10, M14, M16, M17 and M18),

and 1:4 (M2, M3, M4, M6, M11, M12 and M15). Sample M5 had a 1:6 ratio, where samples

M9 and M13 had 2:7. Samples could not be categorized according to binder : aggregate ratios

in the historic timeline, since ratios were randomly detected in all ages. Petrographic analysis

of the mortar samples showed that all of them had crushed limestone (limestone chips and

pieces) aggregates with or without fossils as afore mentioned. Limestone pieces were mostly

crushed local limestone which was used in the construction, and should be the chips which

were left by the stone masons during their stone dressing for the ashlar blocks which were

used for the facework. (Figure 3.72, 3.73, 3.74, 3.75, 3.76, 3.77). Lesser amount was provided

from natural sources which were rounded. The amount of the limestone aggregates differed

from sample to sample. The other aggregates were mainly quartz, quartzite (Figure 3.78, 3.79)

feldspar (Figure 3.80, 3.81, 3.82), granite (Figure 3.83). Other igneous rock particles which

can be accepted as impurities were plagioclase (Figure 3.84), pyroxene, biotite and opaque

iron oxide minerals (Figure 3.85). The crushed brick and the brick powder was used both as a

artificial pozzuolanic additive and as aggregates, where fines of the brick powder reacted with

Ca(OH)2.

Brick powder was not used in the sample M14 which belonged to the 15th

C repairs. A few

brick particles was of medium size were detected in the mortar in situ, but it did not effect the

colour of the mortar. The amounts of the brick particles differed in between 5-70 % in

different samples regardless to the chronology (Table 3.5).

Many of the feldspar particles were partially altered in different morphologies such as

cracking, crumbling, and, clay (Figure 3.86, 3.87) and carbonate formation (Figure 3.80). In

sample M16 (Figure 3.88, 3.89) orthose was observed. Some quartzite exhibited micro cracks

and some of the plagioclase particles were partially altered. The adherence at the

aggregate/binder interstices of those altered aggregates were weaker than the adhesion at the

brick particle/binder interstices. The gel formation was observed on the surfaces and on the

surrounding areas of the crushed brick particles (Figure 3.90). These pozzuolanic properties

led to a good adhesion between the binder and the crushed brick particles.

The amount of the CaCO3 in the mortars samples which were determined by means of the

ignition loss test were correlated with the results of the ICP analysis. The ICP analysis results

of the mortar samples (Table 3.1) also were correlated with the amount of the crushed brick in

them. As the amount of the crushed brick increased in the samples, the amounts of the Al2O3,

Fe2O3, Ba and Zr contents were increased in direct proportion. When the amounts of the

62

Al2O3 and Fe2O3 in the mortar samples compared with the amount of the crushed brick, it can

be concluded that the results of the acid loss and sieve analysis, ignition loss and petrographic

analysis were correlated with the results of the ICP analysis.

The poor adhesion of the sample M5 depends on the inappropriate composition. Since the

khorasan mortars which was used in the construction of the land walls was produced in large

quantities, it was quiete normal to result with heterogenously mixed batches. Also mortars

were exposed to precesses of weathering and mechanical deterioration under different loads.

Also, their location in the structure determined their state of conservation. The locations of the

samples M1 and M7 (Figure 3.91) were shown in Figure 2.1. Since those samples subjected to

wetting and drying cycles, and, the water soluble salts were not washed away with rainwater,

thus, these samples were deteriorated by crystallisation pressures (efflorecence and

cryptoflorecence) of the water soluble salts. Cl- ions were accumulated in all of the samples

which were sampled from the different parts of the Tower T4 which had originated from the

sea spray. The water soluble salts which were easily soluble were washed away with rain

water as in the mortar samples M4, M6, M14, M16 and M18. The mortars which were

sampled from the interior or relatively sheltered parts included large amounts of water soluble

salts originating from sea spray and polluted air. These were absorbed by the mortar surfaces

during and after surface condensations and had been accumulated in the pores. But when the

wetting-drying cycles were minimum or neglectable in the sheltered parts samples were sound

and were not decomposed by salt crystallisation pressures. Although mortar samples M16 and

M17 were sampled from the same location, the sample M17 which remained dry had 9549

p.p.m Cl- ions, while the one which was washed with rainwater had 562 p.p.m Cl

- ions.

But in

both cases the deterioration due to salt crystallisation was not drastic. And there had been a

gradual and progressive surface erosion process on the ruined parts where the corework was

exposed to weathering, whereas the sheltered parts or the interior of the tower was relatively

well protected.

Figure 3.72. Altered F particle size with ~250µ is in the binder, (Mortar 1).

63

Figure 3.73. The calcerous fossil, (Mortar 5).

Figure 3.74. The calcium carbonate particles, (Mortar 11).

64

Figure 3.75. The limestone and the fossils, (Mortar 14).

Figure 3.76. The limestone and the fossils, (Mortar 17).

65

Figure 3.77. The rounded limestone and quartz particles, (Mortar 9).

Figure 3.78. The slightly altered quartzite particle with approximately 250µ size, (Mortar 2).

66

Figure 3.79. The phase between binder and quartzite particle, (Mortar 6).

Figure 3.80. The altered feldspars due to carbonate formation, (Mortar 4).

67

Figure 3.81. The large amount opaque (ironoxide) minerals together with quartz, feldspar and

carbonate particles, (Mortar 10).

Figure 3.82. The fossil, orthoclase and quartz particles in the binder, (Mortar 10).

68

Figure 3.83. The fossil, the feldspar and the granite particles, (Mortar 11).

Figure 3.84. The phase between the binder and the feldspar particle, (Mortar 4).

69

Figure 3.85. The brick dusts and black particles (probably magnetite or hematite) in the

binder, (Mortar 3).

Figure 3.86. The altered feldspar as clay formation, (Mortar 12).

70

Figure 3.87. Feldspar particle totally transformed to clay and the limestone particles,

(Mortar 12).

Figure 3.88. Altered orthoclase as domorite formation, (Mortar 16).

71

Figure 3.89. The same with Figure 3.44.

Figure 3.90. The phase between the brick piece and binder and the feldspar particles in the

lime paste, (Mortar 2).

72

Figure 3.91. The quartz, calcite and calcerious particles in the binder, (Mortar 7).

73

3.1.3. The physical properties

The physical properties tests conducted on the stone, brick and mortar samples of the T4

landwalls of Istanbul. The tests were conducted according to TSE 699 (ASTM C97-96,

ASTM C20-92, ASTM C 121-90, ASTM E 12-70).

Table 3.8. The results of physical property tests of stone and brick samples

- (*) Unable to determine the property of water vapour transmision

S : Stone sample B : Brick sample

CC : Coefficient of capillary WA : Water absorption

D : Density SG : Specific gravity C : Composity P : Porosity

SD : Saturation degree μ : Water vapour transmission

No of

Samples

CC

(gr/cm2sn)

W A (by weight)

(m/m, %)

WA

(by volume)

(v/v, %)

WA (in boil. wat.)

(m/m, %)

WA (in boil. wat.)

(v/v, %)

D (gr/cm

3)

SG (gr/cm

3)

C (%)

P (%)

S D (%)

μ

S1 3.2*10-5 4.25 8.54 9.41 18.76 2.01 2.68 75.18 24.81 34.42 - (*)

S2 6.6*10-5 6.49 11.42 15.47 27.29 1.76 2.72 64.88 35.11 32.53 - (*)

S3 2.8*10-5 3.64 7.93 5.00 10.39 2.18 2.74 79.74 20.26 39.14 77,1942

S4 4* 10-5 7.03 12.87 14.82 27.01 1.83 2.76 66.30 33.70 38.21 81,4251

S5 2.8*10-5 2.36 5.69 3.77 8.99 2.41 2.77 87.00 13.00 43.76 - (*)

S6 0.97*10-6 0.18 0.50 0.28 0.76 2.71 2.79 97.13 2.87 17.33 - (*)

S7

Medieval 2.4*10-4 3.52 7.46 6.23 13.18 2.12 2.67 79.40 20.60 36.22 - (*)

S8 Medieval

6.6*10-4 1.55 3.98 1.90 4.91 2.57 2.67 96.02 3.98 100.00 - (*)

S9 Medieval

3.6*10-4 2.57 5.98 4.71 10.93 2.33 2.68 86.94 13.06 45.79 96,4104

S10 Medieval

6.3*10-4 6.04 11.57 12.04 22.99 1.91 2.64 72.35 27.65 41.84 - (*)

B1 Medieval

3.4*10-4 19.84 33.68 20.74 35.16 1.69 2.62 64.50 35.50 94.88 - (*)

B2 Medieval

1.7*10-4 15,33 27.96 15.68 28.48 1.82 2.66 68.42 31.58 88.54 - (*)

B3

Medieval 2.9*10-4 16,77 29.89 18.30 32.25 1.77 2.74 64.60 35.40 84.43 33,2962

B4

Medieval 2.5*10-4 15,32 27.94 16.23 29.45 1.82 2.74 66.42 33.58 83.21 36,2160

B5 Medieval

1.87*10-4 15,97 27.78 16.49 27.65 1.74 2.68 65.32 34.68 90.10 - (*)

B6 5

th Century

3.09*10-4 22,44 35.68 23.29 36.93 1.59 2.74 56.93 43.07 82.84 - (*)

74

Table 3.9. The results of physical property tests of mortar samples

- (*) Unable to determine the physical properties.

3.1.4. The mechanical properties

No of

Samples Century

W A

(by weight)

(m/m, %)

WA

(by volume)

(v/v, %)

D

(gr/cm3)

SG

(gr/cm3)

C

(%)

P

(%)

S D

(%)

M1 5th Century 21.08 34.02 1.62 2.63 61.60 38.40 88.60

M2 5th Century 13.43 26.86 2.00 2.56 78.14 21.86 100.00

M3 Medieval 35.54 53.16 1.50 2.59 57.91 42.08 100.00

M4 Medieval 20.74 34.80 1.68 2.56 65.62 34.37 100.00

M5 Medieval - - - - - - -

M6 Medieval 31.51 44.44 1.41 2.53 55.75 44.25 100.00

M7 5th Century 21.49 35.50 1.65 2.59 63.70 36.29 97.83

M8 5th Century - - - - - - -

M9 Medieval - - - - - - -

M10 5th Century 15.26 26.50 1.73 2.59 67.05 32.95 80.42

M11 5th Century 19.30 32.42 1.68 2.53 66.40 33.60 96.49

M12 5th Century 18.30 30.56 1.67 2.58 64.73 35.27 86.64

M13 5th Century 18.40 30.54 1.66 2.64 62.88 37.12 82.27

M14 15th Century 18.72 31.10 1.69 2.56 66.02 33.98 86.45

M15 Medieval 28.17 41.65 1.48 2.40 61.66 38.34 100.00

M16 Medieval 28.30 41.60 1.47 2.39 61.50 38.50 100.00

M17 Medieval 28.30 41.60 1.47 2.39 61.50 38.50 100.00

M18 Medieval 28.20 42.30 1.50 2.47 60.73 39.43 100.00

75

The mechanical tests were conducted according to TSE 699 (ASTM C120-90, ASTM C170-

90). The determination of compressive strength tests were conducted by using (Form-Test-

Seidner-Co GMBH, D-7940 Riedlingen West Germany) universal press with 3000KN

capacity. And, the determination of tensile strength tests were conducted by using Mfl

Systeme (GMBH, D-6800 Mannheim) universal press with 100KN capacity.

Table 3.10. The results of mechanical property tests of the stone and the brick samples

- (*) Unable to determine the

mechanical properties.

No of

Samples Century

Compressive

Strength

(c, N/mm2)

Tensile

Strength

(t, N/mm2)

S1 5thC + Med 20.3 3.1

S2 5thC + Med 11.7 1.8

S3 5thC + Med 37.3 7.5

S4 5thC + Med 18.9 4.0

S5 5thC + Med 32.5 0.8

S6 5thC + Med 77.3 8.8

S7 Medieval 21.6 7.0

S8 Medieval 46.0 -

S9 Medieval 25.3 7.06

S10 Medieval 20.7 4.10

B1 Medieval 25.0 -

B2 Medieval 14.3 -

B3 Medieval 16.4 4.8

B4 Medieval 21.04 6.3

B5 Medieval 19.3 5.1

B6 5th Century 14.9 4.3

76

3.2. The choice of the natural stones for replacement and indenting

Two different limestones were chosen for the repair of the original and the subsequent parts,

one being an organic limestone (fosiliferous) quarried at Pınarhisar, Kırklareli and a

chemically precipitated (sedimentary) limestone, with small amount of quartz and

microfossils, the Kandıra stone which is quarried at Kandıra Kocaeli.

The Pınarhisar limestone quarries are located around the Erenler village of the Kandıra

province and they are consisted of oligocene aged fossiliferous limestones and marls. These

quarries were used throughout the Byzantine and the Ottoman eras. The beds of the

sedimentation is approximately 70 cm thick and are composed of sparitic limestones and

marls. Blocks of 0.5-1 m3 fossiliferous limestone can be extracted, marly parts are

alternatively bedded, consequently stone to be used for conservation works should be selected

in the quarry.

Figure 3.92. The map of Marmara Region

Kandıra limestone has a wide area of quarrying, this different samples extracted from

different quarries exhibit heterogenous physical and mechanical properties. The most durable

samples are quarried at Akçaova, Örentepe region at west Kandıra. There are several actively

managed quarries at Örentepe. The paleocene unit has random beds of pale yellow and brown

siliceous limestones and pale grey marls. The beds have an average thickness of 0.4-0.6m,

exceptionally 5-6 m3 blocks could be extracted due to the increasing thicknesses of the beds.

The physical and mechanical properties of the Kandıra stone was given in tables 3.11 and

3.12.

77

Table 3.11. The physical and mechanical properties of Pınarhisar, Erenler Organic

(fosiliferous) limestone

Physical and

Mechanical Properties

Maximum Minimum Mean

Density (g/cm3) 2.29 2.25 2.27

Saturated Density (g/cm3) 2.33 2.27 2.30

Specific Gravity (g/cm3) 2.65 2.65 2.65

Porosity (%) 15 14 14.40

Water Abs. (By Weight) % 4.57 3.96 4.33

Water Abs. İn Boiling Water

(By Weight) % 5.28 4.98 5.03

Coefficient of Capillarity

(cmmin.) 0.0508 0.0308 0.0384

Coefficient of Water Vapour

Transmission Resistance 16 8 12

Compressive Strength (MPa) 45.67 19.9 30.4

Tensile Strength (MPa) 1.10 1.01 1.07

Elasticity Modulus (GPa) 17.25 8.90 13.4

Table 3.12. The physical and mechanical properties of Kandıra Limestone

Physical and

Mechanical Properties

Maximum Minimum Mean

Density (g/cm3) 2.56 2.38 2.51

Saturated Density (g/cm3) 2.58 2.48 2.57

Specific Gravity (g/cm3) 2.58 2.58 2.58

Porosity (%) 10.11 4.96 6.17

Water Abs. (By Weight) % 4.25 1.94 2.49

Water Abs. İn Boiling Water

(By Weight) % - - -

Coefficient of Capillarity

(cmmin.) - - 0.01437

Coefficient of Water Vapour

Transmission Resistance - - 70

Compressive Strength (MPa) 103.29 58.51 79.20

Tensile Strength (MPa) 3.83 2.35 2.95

Elasticity Modulus (GPa) 13.59 10.08 12.25

The petrographic analysis of the stones :

Pınarhisar Organic (fosiliferous) Limestone; The rock is creamy white, the grains are

medium sized, peloids, mollusus and bentonitic foraminifers, oolites and ecinoderm

particles were detected. The peloids were almost spherical and partially replaced by

78

microcrystalline calcite. These particles were most probably bioclasts or oolites in the

original phase. The grains were cemented with fine crystalline sparicalcite cement. This

natural cement was formed during the sedimentation early and late consolidation phases

in the intergranular pores. The other diagenetic alteration was the formation of the

siliceous minerals. The porosity was small and the pores were mostly secondary and

formed by dissolution. Considerable amounts of compactions and consecutive micro

cracks were observed. The micro cracks were filled with sparicalcite. Also

recrystallisation was widely detected.

Kandıra (sedimentary) Limestone : Kandıra limestone has a creamy-yellowish hard

rock. The grains were mostly rounded and the dimensions of the grains were

homogenous, and the polished thin section did not exhibit a porous structure. Partially

minor amounts of mafic minerals were detected, no alteration was observed. The sample

had a crystalline structure, plagioclases and remains of fossils were also detected.

Secondary formations and recrystallisation was the general character of the texture.

Partially oolitic structures and siliceous formations were seen between the calcite crystals.

X-Ray Diffraction analysis of the Pınarhisar and the Kandıra Limestones :

Pınarhisar (Erenler), organic limestone had high amount of calcite and a minor amount of

quartz.

Kandıra (Akçaova), limestone had high amount of calcite and less than quartz.

ICP analysis of the Pınarhisar Organic Limestone and the Kandıra Limestone :

Table 3.13. The results of the ICP analysis for the Pınarhisar and the Kandıra Stones

Composition of

the Stones

Pınarhisar

Organic Limestone Kandıra Limestone

SiO2 % 2.06 2.95

AL2O3 % 0.36 0.72

Fe2O3 % 0.33 0.72

MgO % 0.18 0.40

CaO % 54.93 53.09

Na2O % 0.03 0.06

K2O % 0.11 0.13

TiO2 % 0.01 0.02

P2O5 % 0.08 <0.01

MnO % 0.02 0.05

Cr2O3 % <0.001 <0.001

Ba ppm 25 15

Ni ppm 34 37

Sr ppm 145 590

Zr ppm <10 <10

Y ppm <10 <10

Nb ppm <10 <10

Sc ppm <1 1

Loss of Ignition 41.9 41.8

Total C 11.66 11.56

Total S 0.01 0.01