10.6092/issn.1973-9494/17301
application/pdf
1973-9494
17301
en
Mona M.E. Khalil
https://creativecommons.org/licenses/by/3.0
Conservation Science in Cultural Heritage
Luxor
Non-destructive testing of nano-silica for enhancing the durability of limestone structures in the Valley of the Kings, Luxor, Egypt
Text.Serial.Journal
https://conservation-science.unibo.it/
22
Articles
2023-07-20
2023-06-20
2023-07-20
2023-07-20
51-60
CSCH
Mona M.E. Khalil
2022
10.6092/issn.1973-9494/17301
51
Conservation Department, Faculty of Archaeology, Aswan University Aswan, Egypt 
1973-9494
Luxor
en
60
Non-destructive testing of nano-silica for enhancing the durability of limestone structures in the Valley of the Kings, Luxor, Egypt
https://conservation-science.unibo.it/article/download/17301/16517
22
N    ON-DESTRUCTIVE TESTING OF NANO-SILICA
     FOR ENHANCING THE DURABILITY OF LIMESTONE
     STRUCTURES IN THE VALLEY OF THE KINGS,
     LUXOR, EGYPT

   Ahmed Sallam * , Mona M.E. Khalil
   Conservation Department, Faculty of Archaeology
   Aswan University, Egypt

   Sayed Hemeda
   Conservation Department, Faculty of Archaeology, Cairo University, Giza, Egypt
   Liberal arts and culture centre (LACC)
   Egypt-Japan University of Science and Technology (E-JUST)
   New Borg El-Arab city, Alexandria, Egypt

   Moustapha Hassan
   Department of Laboratory Medicine, Karolinska Institutet
   Solna, Sweden

   Keywords: CT Scan, nanomaterials, limestone, consolidants, Luxor


   1. Introduction

    The Valley of the Kings is a UNESCO world heritage site with more than thirty
tombs that have been opened. Since the first tombs were constructed, at least 24 his-
torical flash flood events have been identified, each of which has contributed to the
destruction and deterioration of the tombs.
    After the floods of 1994, most of these tombs were inundated and damaged. The-
ban Tomb 109 (or TT 109) is an example of one of these significant tombs. This study
presents a novel technique ‒ computer X-ray tomography (CT scan) ‒ as a non-de-
structive method to capture the morphology of the limestone’s internal structure at Tomb
109 (TT 109), as well as the stone’s grain texture and the surface features, through 3D
images and videos. Additionally, this research examines the ability of a nanomixture
consisting of tetraethoxysilane (TEOS) and nanosilica to consolidate the limestone,
which is also a novel approach that this study introduces. It is worth noting that the
limestone of Tomb 109 has suffered harsh weather conditions, such as groundwater
and has been in an unfavourable burial environment, causing geostatic stress which in
turn has led to stone abrasion and weakness in its mechanical properties.
    The study, moreover, presents a comprehensive morphological and spectroscopic
study to confirm the efficiency of the nanomixture in the consolidation of the limestone
structures. A cross-examination method using CT scanning, SEM, and XRF analysis
before and after consolidation was employed. The final result shows that the nanomix-
ture significantly enhanced the physical and mechanical properties of the limestone.



   * Corresponding author: dr_ahmedsalam@aswu.edu.eg
                                                                                                                                        1.1. Archaeological context
A. Sallam, M.M.E. Khalil, S. Hemeda, M. Hassan - Non-destructive testing of nano-silica for enhancing the durability of limestone




                                                                                                                                        The Theban Tomb (TT 109) is located on Luxor’s West Bank, in the Necropolis of
                                                                                                                                    Sheikh Abd-el-Qurna, and dates back to the XVIII Dynasty, specifically to the reign of
                                                                                                                                    Thutmosis III. In the Valley of the Kings (tomb number KV TT 109), Min, was the Mayor
                                                                                                                                    of Tjeny (Thinis), and the Tutor of Amenhotep II.
                                                                                                                                        The tomb has some beautiful funerary scenes of everyday life and scenes where
                                                                                                                                    Min is teaching Amenhotep II as a child, but unfortunately, they are not well preserved.
                                                                                                                                    The hall and the chambers of the New Kingdom rock-cut tombs were carved into a
                                                                                                                                    limestone hill. The entrance facade, on the left side, has been reconstructed from frag-
                                                                                                                                    ments of limestone and cement (red). The entrance to the tomb has also been rebuilt
                                                                                                                                    with the same materials (blue).
                                                                                                                                        This reconstruction work, done between 1889 and 1920 has helped protect the tomb
                                                                                                                                    from the weather and looting, and also blocks a window that could lead to further dam-
                                                                                                                                    age caused by water entering the tomb in the case of major storms and floods (Figure 1).




                                                                                                                                    Figure 1. The entrance to the tomb rebuilt with the same materials (blue); enclosure with limestone
                                                                                                                                    and cement (red).




                                                                                                                                    Figure 2. The building materials of limestone and samples cut into cubes (3x3x3 cm) from boulders
                                                                                                                                    detached from the tomb of TT 109; red marks refer to the number of each sample.


                                                                                                                       52
                                           The limestone that was used to build the tomb
                                       which dates back to the XVIII Dynasty and specifi-
                                       cally to the reign of Thutmosis III [1], shows that
                                       it has been exposed to high temperatures and
                                       groundwater. Both factors are common deteriora-
                                       tion agents in this area; Figure 2 shows the physical
                                       impact of the deterioration on the limestone [2-6].
                                           The study provides an evaluation of the lime-
                                       stone before and after applying the nanomixture
                                       consolidant, while the SEM-EDX analysis [5-6] re-
                                       veals the change in the surface morphology and
                                        stone properties; the CT scan, as a non-destruc-
Figure 3. The CT image shows the        tive method, provides fine details of the surface
morphological features of the lime-     morphology and the internal structure [7-9]. This
stone at the tomb (TT 109) on the       cross-examination, using CT scanning and SEM
West Bank, Luxor.                       confirm the result of this study (Figures 3 and 4).




                                                                                                     CONSERVATION SCIENCE IN CULTURAL HERITAGE
 Figure 4. The 3D CT image shows the morphological features of the limestone after treatment.


   2. Materials and Methods

   2.1. Sample Collection

    The limestone samples were collected from the archaeological site and were cut
into cubes measuring 3 × 3 × 3 cm, as required for the analysis instruments. CT scan-
ning, SEM and XRF analyses were used to examine the grain texture, material struc-
ture, and the morphological features of the sandstone before and after treatment. The
samples were treated using the nanomaterial mixture, which includes tetraethoxysi-
lane (TEOS), nanosilica, and TEOS polymer.


   2.2. Preparation of the nanomaterials for consolidation

    The nanosilica (average size 40-50 nm) was dispersed in an ethanol concentration
of 1% mixed with TEOS in a 1:1 ratio. The nanomixture was then treated using the
sonication technique by dispersing 10 gm wt% of nanosilica powder in 1000 mL of
ethanol for 20 min using an ultrasonic mixture and magnetic stirrer.


                                                                                                53
                                                                                                                                       2.3. Consolidation samples
A. Sallam, M.M.E. Khalil, S. Hemeda, M. Hassan - Non-destructive testing of nano-silica for enhancing the durability of limestone




                                                                                                                                       The samples were dried at 108 °C for 24 hours [2,5], after which the nanomixture
                                                                                                                                    was applied on the limestone surface via multiple brushing once per day for five con-
                                                                                                                                    secutive days. The stone surface was also covered with sheets of polyethylene to
                                                                                                                                    prevent evaporation of the consolidant.


                                                                                                                                       2.4. CT scanning imaging

                                                                                                                                         Generally, the nature of CT images allows the reconstruction of high-resolution 2D
                                                                                                                                    and 3D images. In this study, CT scanning, as a non-destructive technique, gave an
                                                                                                                                    accurate analysis of the surface morphology and assessed the substrate before and
                                                                                                                                    after consolidation. The analysis also helped to evaluate the penetration of the nano-
                                                                                                                                    mixture inside the limestone. To our knowledge, this is the first study in heritage con-
                                                                                                                                    servation that uses CT scanning for investigation of limestone treated with nanomate-
                                                                                                                                    rials. The scans were made using a tube voltage of 90 Kv, a tube current of 160 µA, a
                                                                                                                                    field of view (FOV) at 20 mm, and a scan time 4.5 min. The CT scan investigation of the
                                                                                                                                    sandstone samples was prepared at the Institute of Karolinska, Sweden.


                                                                                                                                       2.5. Morphological study using the Scanning Electron Microscope (SEM)

                                                                                                                                       The surface morphology of the limestone samples was observed using SEM
                                                                                                                                    (JEOL/JSM-5500LV). The Acel. Volt. was 30 kV. The samples were examined at the
                                                                                                                                    Central Laboratory, South Valley University, Qena, Egypt.


                                                                                                                                       2.6. XRF analysis

                                                                                                                                       X-ray fluorescence (XRF) was used to identify the limestone minerals. Samples were
                                                                                                                                    prepared at the Central Laboratory, South Valley University, Qena, Egypt.


                                                                                                                                       2.7. Compression Test

                                                                                                                                        A compression test was used to measure the compressive strength of the treated
                                                                                                                                    limestone and helped determine the maximum compression load that compels the
                                                                                                                                    specimen to fail. During the test, the sample was placed precisely in the center of the
                                                                                                                                    loading platen. The compression test was carried out using a Universal Testing Ma-
                                                                                                                                    chine at the Central Laboratory, South Valley University, Qena, Egypt.


                                                                                                                                       3. Results and discussion

                                                                                                                                       3.1. CT scan imaging

                                                                                                                                        CT scan imaging shows that the consolidant covered the stone surfaces and was
                                                                                                                                    effectively dispersed in the pores. The homogeneous distribution on the surfaces and
                                                                                                                                    between the stone grains led to increasing the stone’s mechanical properties. Moreover,
                                                                                                                                    the CT scan images revealed the homogeneity between the nanocomposite nanosilica/
                                                                                                                                    TEOS polymer and the composition of the limestone (Figure 5).


                                                                                                                   54
    The CT scanning rotated 360 degrees around a stationary sample, allowing a more
in-depth investigation of the samples from different angles. This process is especially
helpful in giving a better evaluation of the consolidants.




Figure 5. 3D CT images showing the limestone morphological features after treatment from dif-
ferent angles and CT sections showing nanocomposite cover dispersed homogeneously within the
pores, which leads to improvement in the mechanical properties of the limestone.


   3.2. Observation by SEM

    SEM results confirmed that the morphological surface and grain texture changed
after the consolidation (Figure 6).




                                                                                                       CONSERVATION SCIENCE IN CULTURAL HERITAGE




                                                Figure 6. SEM showing the sample before
                                                consolidation (A), and nanocomposite nanos-
                                                ilica/TEOS clogging surface pores after consol-
                                                idation and interaction with the stone grains
                                                (B and C).


                                                                                                  55
                                                                                                                                       3.3. XRF analysis
A. Sallam, M.M.E. Khalil, S. Hemeda, M. Hassan - Non-destructive testing of nano-silica for enhancing the durability of limestone




                                                                                                                                        The X-ray fluorescence analysis aimed to identify the elemental composition of the
                                                                                                                                    limestone. Results showed the presence (as a percentage) of aluminum (Al), chlo-
                                                                                                                                    ride (Cl), quartz (Si), iron oxide (Fe), calcium (Ca), and sulfur (S), and are presented in
                                                                                                                                    Figure 7; a summary is also given in Table 1.




                                                                                                                                          Figure 7. XRF spectrum of a sample taken from tomb 109 of the West Bank, Luxor



                                                                                                                                    Table 1. XRF composition in wt. of a sample taken from tomb 109 of the West Bank, Luxor.

                                                                                                                                     Element       Al       Si        S       Cl       Ca       Fe       Na        In      Total

                                                                                                                                     Weight%     0.73     3.25     1.04     15.79    52.32     1.70     24.81    0.33     100



                                                                                                                                       3.4. Mechanical properties and mechanical testing ‒ uniaxial compressive
                                                                                                                                            strength (UCS)

                                                                                                                                         Of all the tests carried out, that of establishing the compressive strength of the stones
                                                                                                                                    is very important, as the resulting value is used by structural design engineers to assess
                                                                                                                                    stability and structural conditions. Future research could consider combining the scratch
                                                                                                                                    test coupled with the on-site recoil hammer test which would give greater reliability in
                                                                                                                                    evaluating the stones on site without disturbing/destroying existing structures.
                                                                                                                                         The compressive strength of stone is the maximum load per unit area that it can
                                                                                                                                    bear without crushing. A higher compressive strength indicates that the stone can
                                                                                                                                    withstand a higher crushing load. The required values range from 7569 psi (52 MPa)
                                                                                                                                    for marble (ASTM C 503) to 19,000 psi (131 MPa) for granite (ASTM C 615). To de-
                                                                                                                                    termine the compressive strength, according to the ASTM 170 at least 5 specimens
                                                                                                                                    must be tested for cubes of at least 2″ to 3″ on each side. Each face must be perfect-
                                                                                                                                    ly flat, and they must be parallel or perpendicular with each other; in addition, the
                                                                                                                                    faces must be smooth with no tool marks and there should be no nicks at the corners
                                                                                                                                    [10-13].


                                                                                                                    56
    Five samples were equipped with electric strain gauges measuring 100 mm in
length. Vertical pressure was gradually increased until failure. Table 2 shows the
compressive strength results of the five backing limestone samples collected from the
tomb. The compressive strength (σc) of the weathered / untreated specimens was
between 21 to 22 MPa, indicating medium to poor geochemical characteristics. The
average elastic modulus obtained for the five tested cubes was 21 GPa. By comparing
the mechanical properties before and after treatment, as shown in Table 2, we can
conclude that the nanocomposite nanosilica/TEOS polymer, which was effectively
dispersed within the pores, enhanced the mechanical properties of the limestone and
added a protective layer on the surface, where the uniaxial compressive strength (σc)
of the treated/consolidated specimens was 27.4 MPa.

Table 2. Compressive strength value before/after consolidation of the limestone

    Limestone specimens        Ultimate     Cross-     Compressive strength       Enhancement
                                 load      sectional         (Mpa)                   value
                                 (kN)        area                                     ( %)
                                            (mm2)

    Untreated specimens          19.4        900                21.1                   -

  Treated specimens (with        24.7        900                27.4                  30
 Nanosilica/TEOS polymer)



   4. Conclusions

    This study presented a novel approach to consolidate limestone using a nanocom-




                                                                                                     CONSERVATION SCIENCE IN CULTURAL HERITAGE
posite mixture. It also introduces CT scanning as a non-destructive method to ana-
lyze the limestone structure and the effectiveness of the nanocomposite consolidant.
Therefore, this research shows that CT scanning can be a helpful instrument for restor-
ers to investigate internal structures and evaluate treatments. The nanocomposite
based on a mixture of TEOS polymer with nanosilica (dispersed in ethanol) was suit-
able for consolidation to increase the mechanical properties of the limestone used in
tomb 109 of the West Bank, Luxor, Egypt.
    The SEM post-treatment images show that the nanocomposite (nanosilica/TEOS)
has successfully interacted with the stone grains and clogged the surface pores. XRF
was able to identify the major and minor compositions of the limestone. More specifi-
cally, Calcite (Ca) was identified as the main element and Chloride (Cl) as a minor ele-
ment. This study recommends applying nanocomposites in the treatment of the lime-
stone at tomb 109 of the West Bank, Luxor, Egypt.
    Our future research will build upon these findings, using MATLAB, to strengthen
and retrofit intervention plans.


   Acknowledgments

   The authors wish to express their thanks to Prof. Farag Khodary, Faculty of Engi-
neering, South Valley University, Egypt.


                                                                                                57
                                                                                                                                          References
A. Sallam, M.M.E. Khalil, S. Hemeda, M. Hassan - Non-destructive testing of nano-silica for enhancing the durability of limestone




                                                                                                                                    [1]     https://camnes.org/min-project
                                                                                                                                    [2]     El-gohary, M., Abo El-Magd, M. (2018) Influence of Acrylic Coatings and nano-
                                                                                                                                            materials on the Interfacial, Physical and mechanical, Properties of Limestone
                                                                                                                                            based Monuments, Case Study AMENEMHAT II TEMPLE. International Journal
                                                                                                                                            of Conservation Science, Volume 9, Issue 2, April-June, pp. 219-234.
                                                                                                                                    [3]     El-gohary, M. (2015) Methodological evaluation of some consolidants interfer-
                                                                                                                                            ence with ancient Egyptian sandstone “Edfu Mammisi as a case study”. Prog-
                                                                                                                                            ress in Organic Coatings, 80, pp. 87-97.
                                                                                                                                    [4]     El-gohary, M. (2013) Evaluation of treated and un-treated Nubia sandstone us-
                                                                                                                                            ing ultrasonic as a non-destructive technique. Journal of Archaeology Science,
                                                                                                                                            40, pp. 2190-2195.
                                                                                                                                    [5]     Kamh, G., Klitzsch, N. (2018) Testing Single and Mixed Resins for consolidating
                                                                                                                                            Moderately Weathered Limestone of Archaeological Sites, New applied Tech-
                                                                                                                                            niques. International Journal of Conservation Science, Volume 9, Issue 3, Ju-
                                                                                                                                            ly-September, pp. 599-610.
                                                                                                                                    [6]     Ahmed, S., Ying, Z., Moustaph, H., Muhammet, T., Mamoun, M., Abdusalam, U.
                                                                                                                                            (2016) Studies on the Deterioration of Coptic Mural Paintings in the Monastery
                                                                                                                                            of Martyrs and the Luxor Temple. International Journal of Conservation Science,
                                                                                                                                            Volume 7, Issue 2, pp. 493-500.
                                                                                                                                    [7]     Ahmed, S., Hemeda, S., Moustaph, H., Muhammet, T., Mamoun, M., Abdusalam,
                                                                                                                                            U. (2019) CT Scanning and MATLAB Calculations for Preservation of Coptic Mu-
                                                                                                                                            ral Paintings in Historic Egyptian Monasteries. Scientific Reports, 9(1): 3903.
                                                                                                                                    [8]     Re, A., Corsi, J., Demmelbauer, M., Martini, M., Mila, G., Ricci, C. (2015) X-ray
                                                                                                                                            tomography of a soil block: A useful tool for the restoration of archaeological finds.
                                                                                                                                            Heritage Science, pp.2:7.
                                                                                                                                    [9]     Hughes, S. (2011) CT Scanning in Archaeology, Computed Tomography - Spe-
                                                                                                                                            cial Applications, ISBN: 978-953-307-723-9, In Tech, Available from: http://www.
                                                                                                                                            intechopen.com/books/computedtomography, pp.57-68.
                                                                                                                                    [10]    Hemeda. S. 3D finite element coupled analysis model for geotechnical and com-
                                                                                                                                            plex structural problems of historic masonry structures: conservation of Abu Ser-
                                                                                                                                            ga church Cairo Egypt. Herit Sci. 2019; 7:6.
                                                                                                                                    [11]    Hemeda. S. Geo-environmental monitoring and 3D finite elements stability anal-
                                                                                                                                            ysis for site investigation of underground monuments. Horemheb tomb (KV57),
                                                                                                                                            Luxor, Egypt. Herit Sci. 2021; 9:17. https://doi.org/10.1186/s40494-021-00487-3.
                                                                                                                                    [12]    Hemeda. S., A. Sonbol. Sustainability problems of the Giza pyramids. Herit Sci.
                                                                                                                                            2020; 8:8.
                                                                                                                                    [13]    Hemeda. S, K. Pitlakis. Serapeum temple and the ancient annex daughter li-
                                                                                                                                            brary in Alexandria, Egypt: geotechnical-geophysical investigations and stability
                                                                                                                                            analysis under static and seismic conditions. Eng Geol. 2010; 113:33-43.


                                                                                                                                          Biographical notes

                                                                                                                                        Ahmed Sallam is an associate professor fellow in the Conservation Department at
                                                                                                                                    the Faculty of Archaeology of Aswan University. He is a visiting researcher at Tsukuba
                                                                                                                                    University, Tsukuba, Japan. He has also received a scholarship from Erasmus Mundus
                                                                                                                                    at the Department of Materials and Nano Physics, Royal Institute of Technology KTH


                                                                                                                   58
Stockholm, Sweden (2014-2015). His research interests are in mural painting, stones
and advanced technologies in the field of cultural heritage.

    Mona M.E. Khalil is an assistant professor fellow in the Conservation Department
of the Faculty of Archaeology at Aswan University. Her research interests are gypsum
masks, stones, advanced technologies, and conservation of museum pieces.

    Sayed Hemeda is a Doctor of Civil Engineering in the same Department, at the
Aristotle University of Thessaloniki, Greece. Currently, he is a Professor in the Basic
and Applied Science Institute (BAS). He is the manager of the Heritage Science Pro-
gram, LACC, Egypt-Japan University of Science and Technology (E-JUST). He is the
First Professor of Heritage Science and Architectural Preservation of Architectural Her-
itage in the Conservation Department at the Faculty of Archaeology, Cairo University,
Egypt. He is also the former manager of the historic buildings Conservation Center in
Cairo University.

    Moustapha Hassan currently works at the Department of Laboratory Medicine, Kar-
olinska Institutet, Sweden. Moustapha does research in clinical pharmacology, hematol-
ogy and oncology. He is currently working on a project involving biomedical engineering
and imaging at the Department of Laboratory Medicine, Karolinska Institutet, Sweden.


   Summary

     The Valley of the Kings (KV) is a UNESCO world heritage site with more than thirty
tombs that have been opened. Since the first tombs were constructed, at least 24 his-
torical flash flood events have been identified, each of which has contributed to the
destruction and deterioration of the tombs. After the floods of 1994, most of these
tombs were inundated and damaged. Theban Tomb 109, or TT 109, is an example of




                                                                                                CONSERVATION SCIENCE IN CULTURAL HERITAGE
one of these significant tombs. This study presents a novel technique which uses com-
puter X-ray tomography (CT scan) as a non-destructive method to capture the mor-
phology of the limestone’s internal structure at Tomb 109 (TT 109), as well as the
stone’s grain texture and the surface features through 3D images and videos. Addition-
ally, this research examines the ability of a nanomixture, consisting of tetraethoxysi-
lane (TEOS) and nanosilica, to consolidate the limestone, which is also a novel ap-
proach that this study introduces. It is worth noting that the limestone of Tomb 109 has
suffered harsh weather conditions such as groundwater and has been in an unfavour-
able burial environment, causing geostatic stress which in turn has led to stone abra-
sion and weakness in its mechanical properties. This study also presents a compre-
hensive morphological and spectroscopic study to confirm the efficiency of the
nanomixture in the consolidation of the limestone structures. A cross-examination
method using CT scanning, SEM, and XRF analysis before and after consolidation
was employed. The final result shows that the nanomixture significantly enhanced the
physical and mechanical properties of the limestone.


   Riassunto

   La Valle dei Re (KV) è un sito patrimonio mondiale dell’UNESCO con più di trenta
tombe scoperte. Da quando sono state costruite le prime tombe, sono stati identificati


                                                                                           59
                                                                                                                                    almeno 24 eventi storici di inondazioni improvvise, ciascuno dei quali ha contribuito
A. Sallam, M.M.E. Khalil, S. Hemeda, M. Hassan - Non-destructive testing of nano-silica for enhancing the durability of limestone



                                                                                                                                    alla distruzione e al deterioramento delle tombe. Con l’alluvione del 1994, la maggior
                                                                                                                                    parte di queste tombe è stata inondata e danneggiata. La tomba tebana 109, o TT 109,
                                                                                                                                    ne è un significativo esempio. Questo studio presenta una nuova tecnica che utilizza
                                                                                                                                    la tomografia computerizzata a raggi X (CT scan) come metodo non distruttivo per
                                                                                                                                    comprendere la morfologia della struttura interna del calcare nella Tomba 109 (TT 109),
                                                                                                                                    la grana della pietra e la caratteristica superficie attraverso immagini e video 3D. Inol-
                                                                                                                                    tre, questa ricerca studia la capacità di una nanomiscela, costituita da tetraetossisilano
                                                                                                                                    (TEOS) e nanosilice, di consolidare il calcare: questo è un nuovo approccio introdotto
                                                                                                                                    dallo studio. Vale la pena notare che il calcare della tomba 109 ha subito condizioni
                                                                                                                                    meteorologiche avverse come le acque sotterranee e si è trovato in un ambiente di
                                                                                                                                    sepoltura sfavorevole, causando stress geostatico che, a sua volta, ha portato all’abra-
                                                                                                                                    sione della pietra e all’indebolimento delle proprietà meccaniche. Questa ricerca pre-
                                                                                                                                    senta anche uno studio morfologico e spettroscopico completo per confermare l’effi-
                                                                                                                                    cienza della nanomiscela nel consolidamento delle strutture calcaree. È stato impiegato
                                                                                                                                    un metodo di esame incrociato che utilizza la scansione TC, SEM e l’analisi XRF prima
                                                                                                                                    e dopo il consolidamento. Il risultato finale mostra che la nanomiscela ha notevolmen-
                                                                                                                                    te migliorato le proprietà fisiche e meccaniche del calcare.




                                                                                                             60
