1 Salt weathering in the Al-Namrud Monuments in Iraq:
characterization of historical stone and fresh stone treated with
accelerated decay tests Al-Mukhtar M. Ali H. E., Khattab S.A., Beck
K., Al-Mukhtar M. Slide 2 2 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 The site Slide 3 3 Al-Namrud city, is located in the north of
Irak Bagdad The site Al-Namrud city Slide 4 4 Mosul Al-Namrud
monuments Eski quarry Bagdad Sampling Historical stone samples
Fresh stones samples Al-Namrud, is located 37 km to the eastern
south of Mosul city, The quarries of the stone elements (marble and
limestone) which used in the construction of the monument were
extracted from Eski-Mosul area. The site Slide 5 5 AL-NAMRUD city
and monuments 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
Slide 6 6 The outer wall fence of the locations was built with the
limestone The city was protected by an outer strong wall (8 km)
built from limestone AL-NAMRUD city and monuments The site Entry of
the city Slide 7 7 Limestone The construction elements of the
monument Construction materials: Clayey bricks - Limestone and
marble 1.Outer wall built with limestone (8 km) 2.Others walls
built with the clayey bricks, then coated with the green marble 3.
The ground covered with a limestone Green marble Clayey brick wall
The site Slide 8 8 Rain and wetting drying factors, Freezing and
thawing, salt effect, Acid effect from bird waste,.. Al-Namrud
monument stones suffered from many decay factors In-situ
observations: sever signs of damage of the building structure and
stones of the city The site Slide 9 9 The 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
Slide 10 10 fresh X-Ray Diffraction analysis of fresh limestone
historical X-Ray Diffraction analysis of historical limestone major
mineralogical compositions calcite (CaCO3) about 93% and silica
(SiO2)- Quartz XRD & TGA show similar mineralogical composition
Results Analysis RESULTS AND ANALYSIS Characterization of the
historic and fresh limestone This may reflect the correct selection
of the quarry Slide 11 11 More amount of water fill the pore of the
historical limestone More big pores in the historical limestone
than in the fresh one! RESULTS AND ANALYSIS Characterization of the
historic and fresh limestone samples Results Analysis Slide 12 12
RESULTS AND ANALYSIS Characterization of the historic and fresh
limestone samples 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 m 25 % of pores
having < 6 m 75 Average pore diameter (m) 0.28 Historic
limestone 34 0.19 65 35 0.73 Results Analysis Dissolution water
transfer Incremental pore volume ml/g Slide 13 13 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
RESULTS AND ANALYSIS Characterization of the historic and fresh
limestone samples Results Analysis Slide 14 14 EXPERIMENTAL PROGRAM
Aging tests: wetting-drying decay test Slide 15 15 Results of tests
carried out with distilled water and with saline water (10% and 20%
of NaCl) Decay tests: accelerated wetting drying cycles 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 Results Analysis dry wet
** Normalized Weight of samples = weight of the sample divided by
its initial dry weight Slide 16 16 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 In-situ: many
decay factors However, laboratory tests give preliminary
indications about the mechanisms of degradation of this limestone.
Water transfer- dissolution Results Analysis Mercury intrusion
porosimetry curves Incremental pore volume ml/g Slide 17 17
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 Results Analysis Capillary - imbibition tests
Slide 18 18 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 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 Orlans - France
CONCLUSIONS In the field (In-situ), T varies from -2C to +50C,
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. Slide 19
19 Thank you for your attention
