RESTORATION STUDIES ON PHASELIS HADRIAN GATE (KEMER, ANTALYA) THROUGH ARCHAEOMETRY

ABSTRACTThe Phaselis Hadrian Gate locating Kemer (Antalya, Turkey) has become the subject

matter of the archaeometrical examinations conducted within the scope of the restoration& conservation project. The archaeometrical methods of physical, chemical andpetrographical were applied to the samples from the monument that were examined toget their raw material characteristics (basic physical properties, binder/aggregate ratio,particle size distribution in aggregate, total soluble salt and types of salt), mineralogicaland chemical compositions, and microstructural properties (Optical Microscopy and XRF).The physical conditions of the building stone samples were determined by means of basicphysical tests. Limestone samples were physically very weak in condition and also affectedby past forest fires. Conductometric analyses were conducted to find out about the solublesalt content of the stones and their pH values. The total soluble salt contents of stones inweak basic condition had very high rate caused by environmental impacts.Aggregate/binder in mortar and the grain size distribution of aggregate were found bymeans of aggregate granulometric analysis. The total binder and sand sized aggregatecompositions of the mortar samples were quite similar and 1:4 and 2:3 in ratio. Thepetrographical characteristics of the stone and mortar samples were determined by thinsection optical microscope analysis. Ancient gate were limestone of the main rock groupof local formation. The binder type of the mortars were lime and classified into three maingroups petrographically. Micro-XRF analysis was carried out to determine the chemicalcomposition of two ancient metal clamp pieces as iron and lead. The element analysis forstone, mortar as well as the soil sample was undertaken applying the PED-XRF analysisin order to characterize and determine the raw material origin of limestones and mortars.The types of the lime mortar, which makes up the binding structure of mortar samples,were assessed in terms of their hydraulic properties by the Cementation Index data.

RESTORATION STUDIES ON PHASELIS HADRIAN GATE (KEMER, ANTALYA)

THROUGH ARCHAEOMETRY

Ali Akın Akyol1 and Yusuf Kağan KadioĀlu2

1 Ankara University, Başkent Vocational School, Material Research and Conservation Laboratory(MAKLAB), TR-06110, Dışkapı, Ankara, Turkey.

2 Ankara University, Faculty of Engineering, Department of Geological Engineering, Earth Sciences Application and Research Center (YEBİM), TR-06100, Beşevler,

Ankara, Turkey

Corresponding author: Ali Akın Akyol ([email protected])Received: 28/5/2012Accepted: 31/3/2013

KEYWORDS: Phaselis, Hadrian Gate, Stones, Limestone, Mortars, ArchaeometricalAnalyses, XRF, Thin Section Analysis

Mediterranean Arhaeology and Archaeometry, Vol. 13, No 1, pp.89-105Copyright @ 2013 MAA

Printed in Greece. All rights reserved.

INTRODUCTION

The ancient city of Phaselis, today locatedin Tekirova of the Kemer district at a 35 kmdistance from Antalya, was an importantport that was situated between the Lycia andPamphylia of the ancient period. The citywas founded by Rhodian Colonists at thebeginning of 6th century BC. It has threeports: in the north, in the northeast and in thesouthwest. The structures, which can still beseen in the archaeological site, get denser inthe narrower pass of the peninsula betweenthe northeastern and southwestern ports.The very-well-laid street/road connects thesetwo ports. The ancient street starts fromaround the southwest port and at the start ofthe street, a gate/arch was built in memoryof the Emperor Hadrian’s visit to the city. ThePhaselis Hadrian Gate dates back to the 2nd

Century AD and it is very important forLycia. Actually, it is the main entrance gate

from the port and the most importantmonument of the city (Akurgal, 1986).

The first scientific excavation in Phaseliswas carried out through a World Bankfunded project between 1981 and 1985 byProf Dr Cevdet Bayburtluoğlu. The aim wasto use the site as a tourist attraction center. Inthe last 15 years, owing to the excavationsmade by the Head of Antalya Museum, thesite has been visited by tourists. In 2011,Antalya Surveying and MonumentsDirectorate awarded a contract for theDocumentation, Restitution and RestorationProject for Phaselis (implemented byCumhur Gürel Architecture Ltd.). Thus, theHadrian Gate has become the subject matterof the archaeometric examinationsconducted within the scope of the project.

Stone, jointing and rubble filler mortarsamples taken from the stone blocks fromthe Hadrian Gate – piled on the east of thegate – soil from the vicinity and metal

90 ALi AKiN AKYOL AND YUSUF KAğAN KADiOĞLU

Figure 1. (a) Phaselis Hadrian Gate (September 18, 2011) and (b) sampling from Hadrian Gate.

(a)

(b)

clamp samples were first evaluated visuallyand classified. Then, they werephotographed and coded (Table 1 and Fig.1). Within the scope of the archaeometricalinvestigations, the physical conditions ofthe building stone samples weredetermined by means of physical tests(Table 2 and Fig. 2). Conductometricanalyses were conducted to find out aboutthe soluble salt content of the stones (aniontypes and total salt quantity) and their pH

values (Table 3 and Fig. 3). Aggregate/binder in jointing and rubble

filler mortar and the grain size distributionof aggregate were found by means ofaggregate granulometric analysis (Table 4and Fig. 4). Furthermore, the petrographicalcharacteristics of the stone and mortarsamples were determined by thin sectionoptical microscope analysis (Tables 5, 6 andFig. 5). To determine the chemicalcomposition of a metal clamp piece

RESTORATiON STUDiES ON PHASELiS HADRiAN GATE (KEMER, ANTALYA) 91

Table 1. Phaselis Hadrian Gate archaeometrical studies sample set.

Figure 2. Schmidt hardness test devices (upper left), ultrasonic velocity measurement (upper rightand down left) and limestone (sample APK-T7) exposure to fire.


Fig 3. Long term official atmospheric and meteorological data for Antalya region; seasonal variationsof rain water of (a) pH, (b) sulphate concentraion, (c) nitrate concentration and (d) long term (1975-

2008) official meteorological data (sampling was in September, 2011) (http://www.meteor.gov.tr).

Table 2. Basic physical test for stones; wet & dry unit volume weight (UVW), water absorptioncapacity (WAC), porosity (P), ultrasonic velocity (SV) and Schmidt hardness (SH).

(obtained by chance from stone block codedT-269), Micro-XRF analysis was carried out(Table 7). The element analysis for stone,jointing and rubble filler mortar as well asthe soil sample was undertaken applyingthe PED-XRF method (Tables 8, 9). Thetypes of the lime mortar, which makes upthe binding structure of mortar samples,were assessed by the Cementation Indexdata (Table 10).

METHOD AND ANALYSES

By using various archaeometricmethods, the construction materials of thePhaselis Hadrian Gate were identifiedphysically, chemically and petrographically,and the results were documented.

Basic physical properties of constructionmaterials show their current physicalcharacteristics (competent / incompetent)within certain standard limits (RILEM,1980). To determine the competency ofmaterials, it is necessary to know theirphysical properties (unit volume weight,water absorption capacity, porosity andhardness). The basic physical properties of

the stone samples are provided in Table 2.The Uniaxial Compressive Strength

(UCS) values of rocks are frequentlyreferred to in designing both above andunder the ground structures (Başarır, 2004;ASTM, 1984). Tests such as the SchmidtHammer (SHV) and sonic speed tests arewidely used to predict the uniaxialcompressive strength values. The Schmidthammer is used to determine the hardnessvalue of rocks precisely (Fig. 2). Thehardness values are used to predict UCSand to classify rocks. Especially in situhistorical rock material analysis, theportable digital Schmidt hammer is apractical tool used to determine the uniaxialcompressive strengths of rocks indirectly. Inthis purpose both in situ application and thelimestone rocks taken from the PhaselisHadrian Gate were hit at 5 points and theaverage hardness values were found overall measurements (Table 2 and Fig. 2).During the measurements, a Proseq digitalSchmidt hammer was used.

Ultrasonic techniques are used todetermine the dynamic characteristics of


Table 3. Water soluble salts/anions (SS), anion types and pH determinationtests for stones and soils.


Fig 4. Total agregate/binder distribution (upper) and particle size distribution in aggregate(Agregate Granulometry) analyses of mortars.

Table 4. Acidic aggregate (TA) and binder (TB) rate and particle size distribution analyses results of the mortars.


Fig 5. The thin section microphotographs of stone (upper) and mortar samples (lower).

Table 5. Petrographical thin section optical microscopy analysis of the stones.

rocks. These techniques have been usedincreasingly as they are easy and non-destructive. The dynamic elasticitycoefficients of rocks are determined byanalyzing the ultra sound measurementvalues obtained from cylindrical or cubictest samples prepared (in historicalsamples, both surfaces have been cleared).By applying vaseline on the lower andupper surfaces and by placing a transmitterin between the seismic analyzer(receiver/transmitter), the instrument iscalibrated/adjusted through a seismicvelocity measurement dependent on thecrossing time of impulses. Then, testsamples (limestones in this case) are placedbetween the ends of bothreceiver/transmitter, net required crossingtimes for the P and S wave velocity samplesare determined and then recorded (Fig. 2).The values found are used to calculate thewave velocities:

V = L / T (1)[V : P and S wave velocity (m/s), L :

Sample thickness (m), T : Crossing time ofthe wave (s)]

A Matest brand (High PerformanceUltrasonic Tester) C372N Model ultrasonicvelocimeter has been used in the analysis oflimestones from the monument (Table 2 andFig. 2).

Salts, which are naturally contained invarious construction materials or dissolved

in water and carried to the surfaces andpores of materials as a result of capillaryaction, provide information on chemicalchanges that may occur in materialstructures of both the material itself andother materials that they contact with (Blacket al., 1965; Feigl, 1966; Means, and Parcher,1963). The total amount of the soluble saltcontained in the stone and soil samplesfrom the Hadrian Gate, their average pHvalues and anion types were determined byusing a pH-temperature-conductometer(Neukum Serie 3001 brand) (Table 3). Thesalt contents of the samples were alsoevaluated by official meteorological datafrom the Antalya city center andenvironments (Fig. 3).

To detect the aggregate and bindingparts of the samples from the Hadrian Gate,samples were first weighed. Then, theywere treated with dilute acid (5 % HCl) toremove the binding carbonate content(CO32-) from the sample. Samples wereseparated from their lime and all carbonatecontent by means of filtration, washing anddrying, and thus, the aggregate part wasobtained. Then, the samples were dried atroom temperature. Later, they wereweighed again to obtain the weight of thetotal amount of binder and aggregate (Table4 and Fig. 4). Systematic sieving wasperformed on the aggregates obtained fromthe acidic analysis of samples.


Table 6. Petrographical thin section optical microscopy analysis of the mortars.

Consequently, aggregate grain distributionratios were calculated (granulometricanalysis) (Table 4 and Fig. 4) (TS 3530 EN933-1/April 1999).

Thin cross sections of stone and mortarsamples were prepared – so that all thelayers could be seen from exterior towardsinterior – and examined under an opticalmicroscope (Tables 5,6 and Fig. 5). In theexaminations, the optical microscopeLEICA Research Polarizan MicroscopeDMLP Model was used. Photographs weretaken by the digital camera Leica DFC280,connected to the microscope andassessments were made by using the LeicaQwin Digital Imaging Program (Kerr, 1977;Rapp, 2002).

The element contents of the metal piece,obtained from a clamp cavity on one ofstone blocks (Code T-269) from the PhaselisHadrian Gate, were determined by usingthe X-Ray Fluorescence Analysis Method(non-destructive point Micro-XRF Analysis)(Table 7). In the analysis, Spectro MidexModel Micro-XRF (M-XRF) spectrometerwas used.

Because of the heterogeneous structureof the stones and mortars as distinct fromhomogeneous structure of metals, theelement contents of these samples were

identified by means of X-Ray FluorescenceSpectroscopy (XRF) (Pollard and Heron,1996; Shackley, 2011). In this study, aSPECTRO X-LAB 2000 model PED-XRF(Polarized Energy Dispersive-XRF)spectrometer was used. The analysis usedthe USGS (United States Geological Survey)standards and referred to GEOL, GBW-7109and GBW-7309. The precision limit of thedevice is 0.5 ppm for heavy elements and 10ppm for light elements. In this study, about50 elements were identified and the mainelements were evaluated (Table 8,9 and Fig.6).

RESULTS AND DISCUSSIONS

The samples reflecting the constructioncharacteristics of the Phaselis Hadrian Gatehave been examined by using variousarchaeometric methods. The archaeo-metrical methods of physical, chemical andpetrographical were applied to the samplesfrom the monument that were examined toget their raw material characteristics (basicphysical properties, binder/aggregate ratio,particle size distribution in aggregate, totalsoluble salt and types of salt), mineralogicaland chemical compositions, andmicrostructural properties (OpticalMicroscopy and XRF).


Table 7. Chemical composition of the ancient metal clamp samples (Micro-XRF analysis).

Basic tests have been applied on thestone/rock samples from the masonry of theancient gate in order to determine theirphysical characteristics as well as unitvolume weight, water absorption capacity,porosity, hardness and ultrasonic velocitymeasurement (Table 2 and Fig. 2). As theamount of the samples was little, thecompetency properties have been assessedusing cementation index instead of directstandard physical tests (Table 10).

The physical properties of the limestonesamples from the Phaselis Hadrian Gaterange as follows. Wet unit volume weight:2.56 – 2.71 g/cm3 (average 2.66 g/cm3); dryunit volume weight: 2.27 – 2.69 g/cm3

(average 2.57 g/cm3); total water absorptioncapacity: 0.26% – 5.08% (average 1.32%);and total porosity: 0.71% – 11.51% (average3.17%) (Table 2). The examination of thestone samples according to their rock typesshow that they are samples of limestonewith the same rock structure (sparitic andbreccia) (Table 5). Stones have differentphysical properties based on their naturalrock structures and environmental

properties. Samples with low density andhigh porosity are more incompetent.Among the stone samples, the one with thelowest competency is APK-T7 (limestone) –which has a low unit volume weight andhigh porosity; it has burnt so its outerpatina has deteriorated. The samples withhighest competency are APK-T1, APK-T3,APK-T5 and APK-T6 (limestone) samples(Fig. 2).

Among the seven main stone samples,four allowed for the Schmidt hardness testand all four are from the same rock type(limestone). The hardness value of thesample with code APK-T2 is much lowerthan others (Table 2).

The ultrasonic velocity measurementsyielded the following values (over averagevalues) in an increasing order: APK-T7 <APK-T6 < APK-T5 < APK-T4 < APK-T2 <APK-T1 < APK-T3. Furthermore, it wasmeasured that the samples with codes APK-T6 and APK-T7, which have burnt layers,have lower competency properties thanother samples. The APK-T3 sample, on theother hand, has the highest competency


Figure 6. Triangle plotting of main element compositions of the limestone and lime mortar samples by PED-XRF analysis.

(Table 2 and Fig. 2). Some of the limestonemust have been directly affected by forestfires that have been happening in time. Thisis clear from the disintegration that isparticularly seen in APK-T6 and APK-T7samples. With the effect of fire (increasingheat), the stones (CaCO3) are converted intoquicklime (CaO) and easily disintegrated

due to humidity.Efflorescence in construction materials

can be due to many reasons such asstructural (porous limestone or mortar withcement), periodical/climatic (cyclonicprecipitation, temperature changes, freezingand melting processes), andenvironmental/atmospheric (proximity to


Table 8. Chemical composition of the stone samples (PED-XRF analysis).

Table 9. Chemical composition of the mortar samples (PED-XRF analysis).

sea, industrial regions and waste sites,exhaust gas emissions, effect of airpollution). The salt contents of stone/rocksamples taken from the Phaselis HadrianGate range between 0.25% -1.92% (average1.28%). The salt content of the single soilsample analyzed is 0.71% (Table 3). A highrate of salification was identified in alloriginal stone samples. The main reason forefflorescence was determined to beenvironmental impacts (due to proximity tosea, salts were carried to constructionmaterials by humidity). The soil sample,which reflects the characteristics of the soilreservoir, is an example of the salifereous soilcategory (>%0,15) with a high ratio of watersoluble salt (0.71%) (Dursun et al., 2008).

The examination of the stone samplesfrom the Hadrian Gate according to theirrock types and physical properties showthat they are samples of limestone with thesame rock structure (sparitic and breccia).The samples have come under efflorescencedepending on structural, functional andlocation differences. As the samples are ofporous/cavity involving nature (~1-12%)depending on the origin of their formation,such stones are more advantageous in termsof efflorescence. Efflorescence in stones mayresult in occurrences such as disintegration,especially due to weakness happening in its

inner structure after a new patina forms onthe outer layer (breakings/cracks are formedwith the effect of the crystals in pores). Thissituation may yield constructional results(static). It is notable that the salt content ofthe APK-T3 sample, which is quite porous,is lower than others’ (Tables 2, 3).

Within the scope of archaeometricstudies on the Hadrian Gate, samples werecollected in September, 2011. Long-termmeteorological data (http://www.meteor.gov.tr) pertaining to this date are as follows(official data for Antalya andenvironments): (all values are average):temperature: 24.5°C, day time sunlightduration: 9.9 hours, number of rainy days:1.7 days, and precipitation amount: 12.3kg/m2 (Fig. 3d). Anions which dissolve insuch a period – i.e., mild climate, beginningof rainy season and in a hot climate zone –are carried into construction materials andfrom the first months when precipitationfalls (May and June), they can be observedin the form of crystallization. This conditionalso leads to lichenification under humidconditions as the stone blocks of themonumental structure have directconnection with soil. Moreover, an intensedeterioration takes place starting from thesurfaces and advancing to the porous innerstructure (causing disintegration from loss


Table 10. Lime type determination of the mortar samples by Cementation Index values.

of pieces) (Fig. 3d).Additionally, anions such as sulphates

and nitrates carried by seasonalprecipitation also increase the destructiveeffects on materials. The pH, sulphate andnitrate values of rain water of Antalya areknown for the fall months (Fig. 3a-3c). Theacidic effect of rain water in Antalya (pH<7)results from its salt content (such assulphates causing acid rains) (Fig. 3b); andin construction materials of limestone typecontaining carbonates, such as those in themonument, this effect causes destruction(Fig. 3a). In Antalya, meteorological datavary according to months. Compared toother months, the acidic effect increases inSeptember (Fig. 3a). Sulphate and nitratetype of anions are lower in fall months (Fig.3b,3c).

The anions that dissolve in water andcarried to the material are groups such assulphates, phosphates, nitrates, nitrites,chlorides and carbonates which are salts ofsodium, potassium and magnesium. Thestandard (Merck) spot anion tests (chloride,phosphate, sulphate and carbonate) appliedto the stone and soil samples from thePhaselis Hadrian Gate and the pHdistributions of the medium are presentedin Table 3. The pH values of the examinedstone / rock (limestone) samples variedbetween 7.56 – 8.28, and the pH value of thesoil is 7.93. All samples have weak basicquality (pH≥7) (Table 3). All of the stones ina weak basic environment (pH≥7) involvecarbonation at varying ratios, as well as saltsulphate at a low ratio, phosphate at anaverage ratio and chloride at a high ratio.

In stone and soil samples (supportingthe meteorological data), sulphate iscontained at a low ratio (20 and 40 mg/L).Phosphate is found in all of the stonesamples (between 0.200-1.200 mg/L), and inAPK-T5 sample, the amount was higher(1.20 mg/L). Salification occurs due to thesalts carried from the soil reservoir (APK-D1) in humid environment throughvegetation (lichenification). Dissolved

carbonate was generally identified in thestone samples at average and high ratios(19.2-59.2 mg/L), and in stone samples withcodes APK-T4 and APK-T6, as well as thesoil sample with code APK-D1 at a highlevel (40.0 and 59.2 mg/L). In all of the stoneand soil samples, due to proximity to sea,chloride was identified at a quite high ratio(60.0-220.0 mg/L) (Table 3). Regarding watersoluble salts, the samples from the PhaselisHadrian Gate involve anions of thefollowing types: carbonates, low level ofsulphates, average levels of phosphate andhigh levels of chloride. In the samples, thesource of salification was found to be thesalts carried to the structure from the soildue to environmental impacts (proximity tothe sea) (Table 3).

Mortar samples from the PhaselisHadrian Gate were treated with acid. Theaggregates obtained after the analysis wereweighed and the total aggregate/binderratios of the samples were found (TA% / TB%) (Table 4 and Fig. 4). The total aggregatecontents of the examined mortar samplesvary between 19.08-46.37% (average27.89%). The jointing mortar samples wereexamined for non-carbonated aggregatecontent and it was identified that theiraggregate/binder compositions were quitesimilar and at low levels, except the rubblefiller sample APK-H3. The original jointingmortar samples did not comply with the 2:1(aggregate:binder) ratio seen intraditional/standard applications. The ratiois 1:4 and 2:3 in jointing mortar sample andin rubble filler sample (APK-H3),respectively (Table 4 and Fig. 4).

Systematic sieving was performed on theaggregates obtained from the acidicanalysis of mortar samples (sieves between63-1000 μm were used). Consequently,aggregate grain distribution ratios werecalculated (Table 4 and Fig. 4). The ratio ofaggregates with very coarse sand-sizedgrains (1-3 mm grain size) ranges between9.73-63.01% (average 36.63%), and that ofthe clay/silt-sized grains (<63 μm) changes


between 2.06-27.40 % (average 7.02%). Theremaining are silt/sand-sized grains (63-1000 μm) (Table 4). Of the six mortarsamples examined, the aggregate structureof three (APK-H1, APK-H3 and APK-H6) isvery coarse sand size (>1000 μm); in sampleAPK-H2, very coarse silt and average /coarse / very coarse sand sized (125-1000μm) aggregates together; in sample APK-H4, average / coarse silt (<63 μm) and verycoarse silt sized (>125 μm) aggregatestogether; in sample APK-H5, coarse sandsized (500 μm) aggregates form the mainstructure (Wentwort, 1922). The mortarsampled from the jointing of the stoneblocks of the Hadrian Gate and from therubble filler taken from the platform (APK-H3) have different aggregate distributions.In the APK-H4 sample, clay/silt content isdense (<63 μm), whereas the aggregatecontent of the APK-H1 and APK-H3samples are composed of quite coarseaggregates. The aggregate content of theAPK-H2 sample, on the other hand, has arather homogenous distribution (Table 4and Fig. 4).

The macro physical structure of theoriginal jointing and rubble filler mortarsamples from the Gate involves a variety ofheterogeneous aggregates of a type that donot contain the preferred aggregate types asa result of some sieving. The aggregatecontents involve various types of mineralsand rocks that comply with local formation.Pieces of rounded marine rock make up themacro physical structure of the aggregates.Binocular microscopic examinations of themortar samples indicated that the aggregatecontained quite coarse sized brick particlesat varying ratios (Fig. 4; Photographs ofMortar Aggregates).

The petrographic characteristics of thesamples were determined by thin crosssection optical microscope analysis; i.e. rockand mineral composition, type, texture,deterioration condition, distribution andgrain size. The thin cross section opticalmicroscopic analysis concluded that all of

the stone samples taken from the stoneblocks constituting the Phaselis HadrianGate can be classified as belonging to twodifferent sub-types of limestone rock(sparitic and breccia) (Table 5 and Fig. 2, 5).The stone samples have been highlyaffected by humidity, forming adeteriorated patina caused by the structuralresolution on the surfaces of stones.Moreover, the crystallization of the saltscarried to the structure with the effect ofhumidity shows that the environment wassuitable for disintegration.

The mortar from the jointing of the stoneblocks of the Hadrian Gate has beenconserved and survived up do date.Samples were taken from it. Furthermore,rubble filler of the platform, on which thegate stands, and mortar sampled fromnearby (Mortar Gr1) were also included inthe sampling set. The thin section opticalmicroscope analysis differentiated thesampling clearly and the mortar sampleswere classified in three groups (Table 6).The total aggregate content of the mortarsamples range as 35%, 40% and 65%. Thebinding structure of the mortar is lime.Brick particles were seen in the aggregatecontent of all mortar samples at ratios of 1%,1.5% and 2.5% of the total aggregate (Table6 and Fig. 5).

Point Micro-XRF analysis has beenapplied to document the chemicalcomposition of the metal piece that form theclamp of one of the stone blocks making upthe Phaselis Hadrian Gate (stone block withcode T-269). It was found that the outer partwas lead (95.87% Pb) surrounding theoriginal iron clamp (92.27% Fe) (Table 7).

The chemical compositions of theoriginal stone and mortar samples werefound by means of PED-XRF analysis(Tables 8,9). The stone samples from theHadrian Gate are limestone type ofsedimentary rock origin. Consistent withthis finding, the main structure of thesamples is composed of CaO (at ratiosbetween 38.02-62.65%) and carbonate (LOI:


Loss on Ignition, at ratios between 36.98-45.72%). Given the main element contents(>%1), rock formation of the same locationis determined (Table 8).

Within the stone sample set, the APK-T7sample has quite different chemicalcontents than other samples (Table 8 andFig. 6). The formation of this stone might bedifferent from the others in terms of itsmain and trace elemental composition. Ithas higher rates of SiO2, Al2O3 and Fe2O3

and lower CaO than other samples.Furthermore, regarding the trace elements(~%1), sulphation (SO3) is four times higherthan other samples and a very high rate ofP2O5, K2O and MnO is contained (Table 8).It is highly probable that the stone has comeunder fire and the elements carried to thestone from the soil reservoir have affectedit. This can be related to the deteriorationand disintegration of the stone structure.

The jointing mortar taken from thePhaselis Hadrian Gate has chemicalcomponents very similar to rubble fillermortar (Table 9). This shows that thesamples were applied in the same period.The chemical composition of the APK-D1soil sample, which can be accepted as areference about the natural structure, hasbeen examined by means of a PED-XRFanalysis (Table 9).

The chemical composition of the mainelement contents (>%1) of the mortarsamples are as follows: CaO between 34.75-48.77%; SiO2 between 6.54-15.81%; Fe2O3

between 1.49-3.20%, Al2O3 between 1.28-3.60%; MgO between 2.56-5.76% and totalcarbonate (LOI) between 34.78-41.89%(Table 9). The variables of mortar samplesare aggregate/binder composition (type andratio), location difference, petrographiccharacteristics, function, and environmentalimpacts. The APK-H2 and APK-H3 samplesare rubble filler and others are jointingmortar. In rubble filler mortar, the mostbasic variable is the high ratio of soilcontaining materials (mainly containingSiO2, Al2O3, Fe2O3, MgO), which is the

natural filling material (Table 9).The competency properties of the mortar

samples were assessed by using theCementation Index (CI) data (Table 10)(Boynton, 1980). In the mortar samples,MHL, WHL and C/NC types of lime, one ineach, were identified. Moreover, in all threesamples, EHL type of lime was identified.With its dense aggregate structure, therubble filler sample APK-H2 had a highercompetency CI value than the jointingsamples.

CONCLUSION

The stone blocks of the Hadrian Gate inthe ancient city of Phaselis could notconserve their gate structure and gotscattered in the nearby areas and survivedup to date, without any intervention andexposed to natural destruction.

The construction materials of themonument have been investigated anddocumented by means of variousarchaeometric methods with the aim ofconservation. Thus, the stone and mortarconstituting the ancient gate and the near-surface soil in the environment have beenexamined petrographically and chemically.A metal piece that could have been sampledcoincidentally from a clamp bed has alsobeen identified within this scope.

Stones with similar type of rockstructure (limestone) have competencyvalues varying according to petrographiccharacteristics, location difference andphysical conditions. Ultrasonic velocitymeasurements were made and it wasdetermined that some of the stone blocks inthe sampling kit were quite competent(APK-T1 and APK-T3) while some wereweak (APK-T7). Some of the limestones(APK-T6 and APK-T7) must have beendirectly affected by forest fires that havebeen happening in time.

The high rate of salification in thesamples was similar and they had beencaused by environmental impacts


(proximity to sea, salts carried from the soilreservoir and effect of vegetation) andcarried to the original structural materialsby humidity. Efflorescence in the sampleswas caused by the limestone layer formedby the disintegration and recrystallizationof stones, and the salts easily carried to thestructure from the soil with the influence ofthe humid environment (such as chlorideand phosphate).

The mortar samples were examined fornon-carbonated aggregate content and itwas identified that their aggregate/bindercompositions were quite similar and at lowlevels. The ratio is 1:4 and 2:3 in jointingmortar sample and in rubble filler sample(APK-H3), respectively. Aggregate size inmortar largely varies (average/coarse/verycoarse sand size aggregates). Pieces ofrounded marine rock make up the macrophysical structure of the aggregates inmortar. The aggregate contained quite largesized brick particles at varying ratios.

Original construction stones of theancient gate are limestone. Limestone,which is the construction stone, is in themain rock group of local formation. Themortar samples are classified into threeoriginal lime mortar groupspetrographically. The brick particles werealso identified in the aggregate content ofthe all mortars.

The iron and lead compositions of themetal pieces obtained from the stone clampcavity and were also identified by non-destructive M-XRF analysis.

The elemental composition of limestone,

soil and lime mortar samples wereidentified by means of PED-XRF analysis.The stones, except APK-T7, from themonument had similar elementalcomposition and addressed local formationlike mortars. The type of the lime andcompetency of lime mortar samples wereassessed by the Cementation Index data.The mortars had hydraulic character fromweak to eminent. It was identified that thecompetency of rubble filler mortar is higherthan the jointing mortar that contains ahigher ratio of binder (lime) and a lowerratio of aggregate.

Through the archaeometric studiesconducted on the construction materials ofthe Phaselis Hadrian Gate, it has beenpossible to do research into and documentthe construction technology of the buildingand the changes and transformations(deteriorations) that occurred in time.Furthermore, the characteristics of therepair materials were identified so that thematerials to be selected are in compliancewith the principles and codes of restoration.

ACKNOWLEDGEMENTS

The authors thank to Turkish Ministry ofCulture and Tourism for the permission tothe work of documentation & restorationProject of Phaselis Hadrian Gate; toCumhur Gürel Architecture Ltd. for thefinancial support of the researches; tolaboratory project assistants Gülşen Albuzand Kıymet Deniz for the analyses and totechnician Orhan Karaman for samplepreparations.


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RESTORATION STUDIES ON PHASELIS HADRIAN GATE (KEMER, ANTALYA) THROUGH ARCHAEOMETRY

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