1. Salt weathering in the Al-Namrud Monuments in Iraq:
characterization of historical stone
and fresh stone treated with accelerated decay tests
Ali H. E., Khattab S.A., Beck K., Al-Mukhtar M.

2. The
site
In the north of Iraq, beginning in the second millennium B.C.,
the Assyrian Empire developed great cities such as Nineveh, Korsabad, and Calah (Al-Namrud).
Assyria imperial map

3. Al-Namrud city, is located in the north of Irak
site
Al-Namrud city, is located in the north of Irak
Al-Namrud city
Bagdad

4. Al-Namrud, is located 37 km to the eastern south of Mosul city,
site
Al-Namrud, is located 37 km to the eastern south of Mosul city,
Sampling
Eski quarry
Mosul
Fresh stones samples
Al-Namrud
monuments
Historical stone samples
Bagdad
The quarries of the stone elements (marble and limestone)
which used in the construction of the monument were
extracted from Eski-Mosul area.

5. The site AL-NAMRUD city and monuments
Ancient city of Assyria: founded in the 13th century BC by Shalmaneser I
At 9th century BC Ashurnasirpal II made it the capital of Assyria
It was the site of a religious building founded in 798 BC by Queen Sammu-rema
The
site

6. The outer wall fence of the locations was built with the limestone
site
AL-NAMRUD city and monuments
The city was protected by an outer strong wall (8 km) built from limestone
Entry of the city
The outer wall fence of the locations was built with the limestone

7. The construction elements of the monument
site
The construction elements of the monument
Construction materials:
Clayey bricks - Limestone and marble
Clayey brick wall
Outer wall built with limestone (8 km)
Others walls built with the clayey bricks, then coated with the green marble
3. The ground covered with a limestone
Green marble
Limestone

8. The
site
In-situ observations:
sever signs of damage of the building structure and stones of the city
Al-Namrud monument stones suffered from many decay factors
Rain and wetting drying factors, Freezing and thawing, salt effect, Acid effect from bird waste,……..

9. Characterize the two stones: fresh stone – quarry and
study
Studies carried out on the stones coming from Al-Namrud site and from the quarry
Characterize the two stones:
fresh stone – quarry
and
historical stone – Al-Namrud site
Determine the effect of
accelerated weathering tests
on the fresh stone
The aim of the preliminary study
Verify the origin
of the stone!
Evaluate the degree
of degradation
understand the main
reasons and mechanisms
of the damages observed
* Fresh samples in order to construct a database for the studies

10. correct selection of the quarry
Results
Analysis
X-Ray Diffraction analysis of historical limestone
RESULTS AND ANALYSIS
Characterization of the historic and fresh limestone
XRD & TGA show similar mineralogical composition
major mineralogical compositions
calcite (CaCO3) about 93% and
silica (SiO2)- Quartz
X-Ray Diffraction analysis of fresh limestone
This may reflect the
correct selection of the quarry

11. Characterization of the historic and fresh limestone samples
Results
Analysis
RESULTS AND ANALYSIS
Characterization of the historic and fresh limestone samples
More amount of water fill the pore of the historical limestone
More big pores in the historical limestone than in the fresh one!

12. Characterization of the historic and fresh limestone samples
Results
Analysis
RESULTS AND ANALYSIS
Characterization of the historic and fresh limestone samples
Incremental pore volume ml/g
Mercury intrusion porosimetry: historical and fresh limestone showing cumulative pore volume & incremental pore volume
Fresh limestone
Porosity by mercury intrusion (%) 21
Total volume of pores
0.11
% of pores having > 6 µm 25
% of pores having < 6 µm 75
Average pore diameter (µm)
0.28
Historic limestone 34
0.19 65 35
0.73
Dissolution water transfer

13. Properties of fresh and historic limestone
Results
Analysis
RESULTS AND ANALYSIS
Characterization of the historic and fresh limestone samples
Properties of fresh and historic limestone
Fresh limestone
Bulk density (gm/ml)
2.04
Skeletal density (gm/ml)
2.66
Porosity by hydrostatic method (%) 26
Water content at saturation (%)
13.5
Porosity by mercury intrusion (%) 21
Historic limestone
1.71
2.58 38
23.8 34

14. Aging tests: wetting-drying decay test
EXPERIMENTAL PROGRAM
Aging tests: wetting-drying decay test

15. Decay tests: accelerated wetting – drying cycles
Results
Analysis
Decay tests: accelerated wetting – drying cycles
dry
wet
** Normalized Weight of samples = weight of the sample divided by its initial dry weight
Results of tests carried out
with distilled water
and
with saline water (10% and 20% of NaCl)
The normalized wet and dry weights reduce with cycles. water absorption followed by insufficient drying temperature and duration
Changes in the weight is function of (% of salt): As % salt increases – changes in the NW reduces
Dissolution CaCO3 of limestone is very low (0.2 mg/L) but affect samples aged with distilled water.
&
Reduction in the absorption due to incomplete drying

16. Mercury intrusion porosimetry curves
Results
Analysis
Mercury intrusion porosimetry curves
Curves of the altered stones are located between the two limit curves: fresh stone and historic stone with
an increasing in the values of total porosity and
the nature of pore structure toward the historic stone
Incremental pore volume ml/g
In-situ: many decay factors
However, laboratory tests give preliminary indications about the mechanisms of degradation of this limestone.
Water transfer- dissolution

17. Capillary - imbibition tests
Results
Analysis
Capillary - imbibition tests
Increasing pore diameter as shown previously leads to decrease the Capillary front height
The more reduction occurred in the samples submitted to wetting-drying process and especially with saline water.
The effect of NaCl salt seems to accelerate the dissolution and hence increase the diameter of the pore giving a bigger range for precipitation

18. CONCLUSIONS
Results show weathering effects on the historic stone in comparison to the fresh stone.
The salt weathering seems to be the main factor of the physico-chemical reactions (dissolution, crystallization), structural, textural changes and deterioration in the Al-Namrud monuments
In the field (In-situ), T° varies from -2°C to +50°C, numerous mechanisms contribute in the degradation of the monument: dissolution of carbonate, NaCl salt solubility, salt penetration in the pore space and mechanical, thermal and hydric behaviour mainly shrinkage and expansion inducing the fatigue of the stone.
A lot of laboratory and field work must be carried out
to firstly evaluate the state of the degradation of different stones and
to determine a proper method to repair or/and to stabilize the degradation
in order to insure the stability of the different structures of this very old city - Al-Namrud - constructed in the second millennium B.C. by the Assyrian Empire.
Research started at the University of Mosul - Irak and continued in collaboration with our research centre in Orléans - France

19. Thank you for your attention