Characterisation of Ancient Mortar and Simulation of New Mortar at Naganathaswamy Temple, Kumbakonam and Thanjavur Palace for Restoration

CHARACTERISATION OF ANCIENT MORTAR AND SIMULATION OF NEW MORTAR AT NAGANATHASWAMY TEMPLE, KUMBAKONAM AND THANJAVUR PALACE FOR RESTORATION

Submitted to

The Member Secretary State Planning Commission Ezhilagam, Chepauk Chennai – 600005

Dr. S.K. SEKAR Senior Professor and Dean & Dr. S. THIRUMALINI Associate Professor School of Civil and Chemical Engineering VIT University, Vellore- 632014

July 2016 CONTENT

Chapter Description Page No.

1 Introduction 2

2 Methodology 13

3 Results and Discussions 29

4 Conclusions 72

Chapter 1

INTRODUCTION 1.1 GENERAL

India has a finite number of very rich, and assorted cultural heritage in the form of built structures and architectural monuments. Any structure that is of historical, archaeological or artistic interest and existing for more than 100 years is called as an ancient monument. They include different types of structures such as temples, palaces, domes, forts, ports, aqueducts, prayer halls, cemeteries, step-wells, rock-cut temples and excavation sites. They are the proof of ancient habitation and represent indigenous traditional architecture of India. They not only represents the cultural face and growth but also articulate the knowledge of our ancestors about building design, construction materials, building technology, creative and decoration and artistic capabilities of the craftsmen (Nene2012).

Out of 125 heritage sites declared by UNESCO, 29 are in India. Currently, 3650 ancient monuments and archaeological sites have been declared as remains of national importance. In Tamil Nadu alone, there are 248 structures and 163 prehistoric archaeological sites. They are distributed in different geographical locations and belong to different periods, ranging from early historic period to the colonial period. They also contribute to the prosperity and economic wealth of our country. Only a small number of monuments are under the protection of the state and central archeological survey of India and the remaining left unnoticed.

As a result of this, finite, non-renewable and irreversible resources of our country are fast disappearing without any record for the posterity. The main factors which lead to the non- existence were lack of fundamental knowledge, understanding of construction of monuments, interest in our past, lack of public awareness, industrial revolution and rapidly transforming lifestyle, etc.

1.2 REASONS FOR THEIR NON – EXISTENCE

 Lack of fundamental knowledge  Understanding of construction of monuments  Interest in our past, lack of public awareness  Industrial revolution  Rapidly transforming life style  Finite, non-renewable and irreversible resources of our country is fast disappearing without any record for the posterity

1.3 NEED FOR THE STUDY

 The difficulty in understanding the old mortar could be attributed to the variety of raw materials and organics used for their production and their application techniques.

 Other parameters include the environmental conditions such as climate, humidity etc which could influence their strength and durability.

 It is the need of the hour to investigate the traditional construction material characteristics and construction techniques for effective simulation, conservation, protection and to safe guard our ancient monuments.

 The present study could serve a great source of information regarding the type and proportion of raw materials used (binder, aggregate and organic additives), their application technology, as well as their resistance to ageing and environmental conditions in the temples and also to prepare the compatibility mortar for conservation.

1.4 OBJECTIVES AND SCOPE OF THE STUDY

 To identify the technology of production and characterize the raw materials of the mortar used at Naganathaswamy Temple and Thanjavur Palace, Tamil Nadu.  To simulate the similar mortar by trial and error in the laboratory.

 To find out the scientific reason beyond the durability over centuries and to evaluate its compressive strength, water absorption, curing period carbonation and porosity for the preparation of compatibility mortars for repair works.

 To validate the results of controlled and ancient samples by advanced analytical techniques like X- Ray Diffraction, Scanning Electron Microscope with energy dispersive X- Ray spectroscopy, Thermal Gravimetric Analysis, Fourier Transform- Infra Spectroscopy.

1.5 ABOUT THE NAGANATHASWAMY TEMPLEAND THANJAVUR PALACE 1.5.1 Naganathaswamy Temple The temple (Fig. 1) is 1000 years old is located in Manambadi near Kumbakonam. It is said that the temple was built in tenth century by RajendraChola.The State government has ensured the protection of 1,000-year old Naganathaswamy temple near Kumbakonam.

Fig.1 Naganathaswamy Temple

1.5.2 Thanjavur Palace Thanjavur Palace (Fig. 2) with its architectural beauty reflects the ‘Marathas’ and ‘Nayaks’ patronage towards art and culture. The tower is currently having seven storeys, but originally it was having many number of storeys, which were damaged by thunder and rain. A research note informs that there was a novel clock of sizable dimensions, forming part of the structure in which the figure of a monkey used to strike the gong every hour. The tower is fashioned in the style of Gingee Nayaks. It’s a protected monument by the State ASI department, located at Thanjavur. It was constructed during the Nayaka and Maratiya periods.

Fig.2 Thanjavur Palace

DESCRIPTION OF HERITAGE STRUCTURE

NAGANATHA SWAMY TEMPLE

INTRODUCTION

Naganatha swamy temple is a thousand years old temple built by Rajendra chola in Tanjavur District. Rajendra Chola-I, was known as much for building temples as for extending his empire to the banks of the Ganga in the north and to Srilanka and Maldives in the south. One such small temple was the Naganathaswamy temple in Manambadi village near Kumbakonam which has now virtually disappeared. The temple’s main deity is Lord Siva was initially known as Sri Kailasamudaiyar temple.

The stone temple was built around 1016 CE, much before the king's masterpiece, the Gangaikondaan temple, was raised. The temple is one of the 88 protected monuments in the state under the control of the state department of archaeology. A sculpture in the Naganathaswamy temple, where the Chola king along with his family is seen worshipping Lord Nataraja, signifies the consecration of the temple during his period.

Epigraphist and historian Kudavayil M Balasubramaniam noted the temple has sculptures depicting a story of an elephant and a spider that worships and protects a 'sivalinga' from leaves falling on it. "A sculpture shows the Cauvery as a woman holding a lotus. The temple's flower garden was called Rajendra Cholan.

The deities were called Sri Kailasamudiyar, while the village was called Ilachchikudi. The sculptures depict dance dramas that used to be conducted during festivals in the Tamil month of 'Chithirai'. The State government's Archaeology Department declared it a protected monument 30 years ago. The stone structure below the vimana, with intricate sculptures, and the sanctum sanctorum with a Siva lingam are intact. The temple has an entrance without a gopuram. The prahara has flower plants.

According to Kudavayil Balasubramanian, epigraphist and historian, this temple was constructed by Rajendra Chola (1012-1044 AD). During Chola rule, the village was called ‘Elaichikudi’, and ‘Veeranarayanapuram’. The temple’s name was ‘Sri Kailasam’.

The temple possesses more than ten inscriptions of the Chola period. Some of the sculptures on the walls of the main structure are those of Nataraja, which is an outstanding one. Another sculpture depicting Rajendra Chola worshipping the Lord with his wives is seen. Other sculptures depict Ganapathi, Dakshinamurthy, Ligotpava, Vishnu, Brahma, Gangadharamurthy, Durga and Arthanari. Among Chola sculptures, they are the unique ones.

A) THANJAVUR PALACE

INTRODUCTION

The Thanjavur Maratha Palace Complex, known locally as Aranmanai, is the official residence of the Bhonsle family who ruled over the Tanjore region from 1674 to 1855.The Thanjavur Maratha palace was originally constructed by the rulers of Thanjavur Nayak kingdom. After the fall of the Thanjavur Nayak kingdom, it served as the official residence of the Thanjavur Maratha. When most of the Thanjavur Maratha kingdom was annexed to the British Empire in 1799, the Thanjavur Marathas continued to hold sway over the palace and the surrounding fort. The Bhonsle family continued to hold on to the palace even after the last king Shivaji II was deposed as per the Doctrine of Lapse.

The palace complex consists of the Sadar Mahal Palace, the queen's courtyard and the Durbar Hall. The Raja Serfoji Memorial Hall and the Royal Palace Museum are situated in the Sadar Mahal Palace. There is also a small bell tower. The Saraswathi Mahal Library is situated with the Thanjavur palace complex.

The original name of Thanjavur Palace is Sivaganga Fort, which is rarely used these days. If you observe carefully, there is even a small moat around it which provided security against enemy access. Often mistakenly called the "Thanjavur Maratha Palace" was not built by Maratha Kings, but by Thanjavur Nayaks. However, the Marathas made some enhancements to suit their needs.

Thanjavur, formerly Tanjore, is a city in the south Indian state of Tamil Nadu. Thanjavur is an important center of South Indian religion, art, and architecture. Most of the Great Living Chola Temples, which are UNESCO World Heritage Monuments, are located in and around Thanjavur. The foremost among these, the Brihadeeswara Temple, is located in the centre of the city. Thanjavur is also home to Tanjore painting, a painting style unique to the region.

GEOGRAPHY AND HISTORICAL DEVELOPMENT OF THE LOCATION

The Thanjavur Maratha Palace is located in Thanjavur. Thanjavur is the headquarters of the Thanjavur District. The city is an important agricultural centre located in the Cauvery Delta and is known as the "Rice bowl of Tamil Nadu". Thanjavur is administered by a municipal corporation covering an area of 36.33 km2 (14.03 sq mi) and had a population of 222,943 in 2011. Roadways are the major means of transportation, while the city also has rail connectivity. The nearest airport is Tiruchirapalli International Airport, located 59.6 km (37.0 mi) away from the city. The nearest seaport is Karaikal Port, which is 94 km (58 mi) away from Thanjavur.

While the early history of Thanjavur remains unclear, the city first rose to prominence during the reign of Medieval Cholas when it served as the capital of the empire. After the fall of Cholas, the city was ruled by various dynasties likePandyas, Vijayanagar Empire, Madurai Nayaks, Thanjavur Nayaks, Thanjavur Marathas and the British Empire. It has been a part of independent India since 1947.

Thanjavur became the most important city in the Chola Empire and remained its capital till the emergence of Gangaikonda Cholapuram in about 1025 During the first decade of the eleventh century, When the Chola Empire began to decline in the 13th century, the Pandyas from the south invaded and captured Thanjavur twice, first during 1218–19 and then during 1230. During the second invasion, the Chola king Rajaraja III (1216–56) was set in exile and he sought the help of the Hoysala king Vira Narasimha II (1220–35) to regain Thanjavur. Thanjavur was eventually annexed along with the rest of the Chola kingdom by the Pandya king Maravarman Kulasekara Pandyan I (1268–1308) in 1279 and the Chola kings were forced to accept the suzerainty of the Pandyas. The Pandyas ruled Thanjavur from 1279 to 1311 when their kingdom was raided and annexed by the forces of Malik Kafur (1296–1306) and Delhi Sultanate. The Sultanate extended its authority directly over the conquered regions from 1311 to 1335 and then through the semi-independent Ma'bar Sultanate from 1335 to 1378.

Starting from the 1350s, the Ma'bar Sultanate was steadily absorbed into the rising Vijayanagar Empire.

Fig 2.1 Thanjavur Royal Palace courtyard

Thanjavur is an important pilgrim centre and a major tourist destination of Tamil Nadu. South Zone Culture Centre in Thanjavur is one of the regional cultural centres established by the Government of India to preserve and promote cultural heritage of India. There were 2,002,225 Indian and 81,435 foreign tourist arrivals in 2009 to Thanjavur. The Thanjavur Maratha palace was the official residence of the Bhonsle family who ruled over the Thanjavur region from 1674 to 1855. It was originally constructed by the rulers of Thanjavur Nayak kingdom and after their fall, it served as the official residence of the Thanjavur Marathas. When most of the Thanjavur Maratha kingdom was annexed by the British Empire in 1799, the Thanjavur Marathas continued to hold sway over the palace and the surrounding fort. The southern side of the third quadrangle of the palace has 190 ft (58 m) tower like building, called the Goodagopuram.

The Saraswathi Mahal Library, established around 1700 and located in the premises of the palace, contains over 30,000 Indian and European manuscripts written on palm leaf and paper. Over eighty per cent of its manuscripts are in Sanskrit and many of them are on palm leaves. The Tamil works include treatise on medicine, and commentaries on Sangam

literature. The Rajaraja Chola art gallery is located inside the palace – it has a large collection of stone and bronze images from the ninth to 12th centuries. Most of the idols present in the gallery were collected from various temples in the Thanjavur district.

Fig. 2.2 Depicting a Thanjavur painting

Schwartz Church, a historic monument located in the palace garden, was built in 1779 by Serfoji II as a token of affection for Rev. C.V. Schwartz of the Danish Mission. There are five museums in the city namely Archeological Museum, Tamil University Museum located with the Tamil University premises, the Saraswathi Mahal Library Museum located inside the Saraswathi Mahal, Nayak Durbar Hall Art Museum and Rajaraja Chola Museum. Raja Rajan Manimandapam is one of the tourist attractions in Thanjavur, built during the Thanjavur Tamil Conference in 1991. "Sangeetha Mahal" has a permanent handicrafts exhibition centre. Thanjavur is the cradle for many of the arts and crafts in South India. Carnatic musicwas codified in Thanjavur and the art flourished during the Nayak rule in the 16th century.

Brief History of the Palace

After the fall of Cholas in 1279 A.D, and a few centuries of Pandyan occupation, Sevappa Nayak captured Thanjavur and became the King in 1532. The construction of Thanjavur Palace began in 1534 and was completed in 1535, thanks to plenty of local prisoners of war who provided manual labor. The Palace was officially called "Sivagangai Fort" and was held by the Nayak family until April 1674, when the Maratha ruler Venkoji captured it. The Marathas enhanced the original structure and expanded the palace complex. It was used by them until 1799 when British finally annexed the Thanjavur Maratha Kingdom.

Plenty of tourists expect a gigantic, luxurious and ornamented interior and get disappointed. The complex was built as a fort, not a palace. The Nayaks chose the site carefully and there is even a moat around the complex to protect it. Another intriguing feature is the extremely narrow staircases with short steps, sharp turns and low ceilings. Why would a palace have such primitive staircases? This was a measure to prevent enemies' rapid advance. Cavalry advances would be impossible through the stairs, and the foot soldiers cannot climb up with great speed. The enemy foot soldiers would be easy prey to the men waiting for them above. Again: this was built as a fort, not a palace.

Secret Chambers:

There are at least 3 hidden chambers with secret, interconnecting doors. These were used as torture chambers and to have discreet meetings. One hidden chamber, located at the base of the Arsenal tower is acoustically designed in a way that you can hear even the smallest whisper from 3 floors above. This must have been used as a way for sending secret voice signals over multiple floors. Sadly, the Government has completely prohibited all access to these hidden chambers.

Underground Tunnel:

There are two underground passages in the palace, only one of them is partially accessible by tourists. This is a relatively short passage and the Government is renovating it as of 2014. Another secret tunnel which is a mile long, connects the Brihadeeswara temple and the palace. It is wide enough to ride 2 horses in parallel, and was designed as a getaway route by Kings during war times.

Arsenal Tower (Koodagopuram):

This is a 192 feet tall pyramidal structure with eight floors. The initial building was constructed by Nayaks in 1645 with only 2 floors. The Marathas later renovated and finished the tower in 1855, and used it for various military purposes. The top floor was used as a watch tower, and the remaining floors were used to store arms and ammunition. The second floor was exclusively used for the King's martial arts training.

Fig. 3 The Arsenal Tower at Thanjavur Palace

Bell Tower (Maadamaaligai):

Fig. 4 The Bell Tower was once used as a clock tower (just hourly bells) by locals

Chapter 2

METHODOLOGY

2.0 GENERAL The entire experimental works were carried out in two phases:

Part 1: Characterization of ancient mortar for both locations Part 2: Simulation of repair mortar

PART 1: CHARACTERIZATION OF ANCIENT MORTAR FOR BOTH LOCATIONS

2.1 REVERSE ENGINEERING METHODOLOGY

The reverse engineering methodology was followed to characterize the ancient mortars as given in following steps: Step1: Characterization of historic mortars Step 2: Selection of raw materials Step 3: Preparation of mortars Step 4: Experimental investigation Step 5: Optimization – Standardization Step 6: Pilot application of restoration mortars

2.2 CHARACTERIZATION OF HISTORIC MORTARS  Step 1 : Sampling  Step 2 : Chemical analysis  Step 3 : Acid loss analysis  Step 4 : Granulometry of sand  Step 5 : Mineralogical analysis  Step 6 : FT-IR  Step 7 : TGA with DTA  Step 8 : Texture analysis  Step 9 : Organic test  Step 10 : Interpretation of results

2.2.1 Sampling of Mortar The location for sampling was selected. The analyses were carried out in a significant quantity of samples in order to avoid errors caused by heterogeneity. Samples were taken from the upper parts of the temple to avoid such phenomena caused by capillary rise. Altered (decayed) and non-altered material samples were taken from both internal and external portion of the temple. Samples nearer to decay portion and cracks were avoided. Sufficient number of samples (min. 15 samples) shown in Fig. 3 and 4 from temples were taken for the study. Analysis of these samples showed details about the original as well as the degraded mortars. The samples are grouped based on their similar characteristics.Table 1 and 2 lists the sampling points from Naganathaswamy Temple and Thanjavur palace.

C D

Fig 3 : A) Main Mandabam Top Dome B) East Entrance left side C) Person collecting the sample D) Inner portion of the wall of the Naganathaswamy Temple

Table.1 Sample identification at Naganathaswamy Temple S.No Sample Name Type of Mortar Location 1 N.S-1 Plastered Mortar East Entrance left side 2 N.S-2 Bedding Mortar Entrance wall 3 N.S-3 Bedding Mortar Compound wall East 4 N.S-4 Plastered Mortar Compound wall Out side 5 N.S-5 Bedding Mortar Main Mandabam 6 N.S-6 Plastered Mortar Near Vinayagar statue 7 N.S-7 Bedding Mortar Main Mandabam Back Side 8 N.S-8 Bedding Mortar Small Mandabam SW corner 9 N.S-9 Plastered Mortar West small Mandabam 10 N.S-10 Bedding Mortar Small Mandabam NW corner 11 N.S-11 Bedding Mortar Main Mandabam North facing 12 N.S-12 Bedding Mortar Vinayagar Temple inner Dome 13 N.S-13 Flooring Mortar Main Mandabam inner Flooring 14 N.S-14 Bedding Mortar Main Mandabam Beam 15 N.S-15 Plastered Mortar Main Mandabam Top Dome

Sample identification – Thanjavur Palace

A B

C D

E Fig. 4 A) Museum Outer Wall, B) SaraswathimahalEntrance, C) Collection of the sample by the Investigator, D) Bell tower E) Durbar north side arch wall

Table 2 Sample identification at Thanjavur Palace

S.No Sample Name Type of Mortar Location

1 T.P-1 Mud Mortar Back to Amman Statue

2 T.P-2 Bedding Mortar Near Library

3 T.P-3 Plastered Mortar Durbar entrance

4 T.P-4 Bedding Mortar Arch/Durbar hall

5 T.P-5 Bedding Mortar Bell tower / First floor

6 T.P-6 Bedding Mortar Elephant tieng place

7 T.P-7 Plastered Mortar Arch/Ticket counter

8 T.P-8 Plastered Mortar Museum entrance

9 T.P-9 Plastered Mortar Side wall / JE office

10 T.P-10 Plastered Mortar Bell tower / Outer wall

11 T.P-11 Bedding Mortar Library entrance

12 T.P-12 Bedding Mortar North wall/ Durbar hall

13 T.P-13 Plastered Mortar Inner wall / JE office

14 T.P-14 Plastered Mortar First floor / Durbar hall

15 T.P-15 Plastered Mortar Inside arch / Ticket counter

2.2.2Acid loss Test

The dissolution of the mortar in hydrochloric acid yielded three fractions: Insoluble fraction/soluble fraction from calcium content, clay minerals and volatile fraction.

2.2.3 Organic Test

The presence of fat, protein in both ancient and new mortars were tested using Lane &Eynon method. The presence of carbohydrate was calculated by Kjeldhal method.

2.2.4 Chemical Analysis

Samples (Table 3) were analysed for their chemical composition by adopting traditional method of testing. CaO and MgO were quantified on titration with ethylene diamine tetra acetic acid (EDTA), using eBT as indicator. The amounts of Al2O3and Fe2O3 were determined by Atomic Absorption Spectroscopy (AAS). Gravimetric method was used to find the amount of silica present. The hydraulic index (HI) and cementation index (CI) were calculated [Taylor,1990 Boynton,1980]

Table 3 Tests for Chemical Analysis

S.No Minerals Method employed

1. CaO+ MgO Titration Method

2. Al2O3& Fe2O3 Atomic Absorption Spectroscopy ( AAS)

3. SiO2 Gravimetric Method

4. K, S Gravimetric Method

5. Na and Cl Titration Method

6. LOI Using Muffle furnace

HI = (%Al2O3+ % Fe2O3 + % SiO2) / (% CaO + % MgO) , If 0.3 < HI < 0.5 Weakly Hydraulic, 0.5 < HI < 0.7 Moderately Hydraulic , 0.7 < HI <1.1 Eminently hydraulic

CI = (1.1%Al2O3+ 0.7% Fe2O3 + 2.8 % SiO2) / (% CaO + % MgO)

If 0.3 < CI< 0.5 Weakly Hydraulic, 0.5 < CI < 0.7 Moderately Hydraulic

0.7 < CI<1.1 Eminently hydraulic ,Highly hydraulic Higher the index , more hydraulic properties.

2.2.5 Binder -Aggregate Ratio

The raw material composition was found by dissolving the carbonated lime in 10 % of hydrochloric acid, leaving out fine aggregates.

2.2.6 Electronic Particle Size Analyser

The particle size distribution was carried out and grading was done.

2.2.7 Organic Test

The herbs used in preparation of lime mortar was tested for the presence of carbohydrate, protein and fat.

2.2.8 Analytical Techniques

The analyses of ancient mortars were done using following instrumental techniques.

XRD analysis of finely ground samples was done using Bruker Desktop-Diffracometer working with the Cu Ka radiation and interpretation by Bruker DIFFRAC.SUITEEVA Software.

Thermal Gravimetric Analysis (TGA) was performed to find the hydroscopic and structural bound water content of lime mortar and it is also helpful to determine any possible thermal decomposition of mineral phases. Here weight loss of sample was monitored as a function of temperature. TGA could serve as best tool to characterize and evaluate historic mortars.

DTA reveals thermal transformation of various components heated under controlled conditions. The phase transfers are exothermic or endothermic in nature. DTA was carried out on non- fractioned mortar to find the dehydration, oxidation and decomposition

Infrared Spectroscopy (FT-IR analysis) provides supplementary information to XRD. It is mainly carried out to identify the presence of organics in the mortars.

SEM (FEI Quanta FEG 200) was used to determine the surface morphology of the mortars, specially cracks and pores of the samples. SEM images revealed the mineral morphology of hydrated phases.

EDX was used to unveil the elemental composition of mortars.

PART- II SIMULATION OF REPAIR MORTAR

The objective of the work is to simulate the similar mortar by trial and error in the laboratory and to evaluate its compatibility.

2.3 MATERIALS USED

2.3.1 Lime

Mortars were prepared using commercial natural hydraulic lime. Lime was purchased from Pollachi, Coimbatore that is being used widely in the restoration works. Lime used in the study is a uniform material manufactured by an industrial process. It was obtained by ignition of the regionally available limestone. The lime was slaked in a traditional manner in huge vats. After sieving to remove larger and unslaked particles, it was left to settle for one month before being transferred to 25 Kg plastic bags. The lime has a particle size of 850 microns below to be used in lime mortar.

2.3.1.1 Chemical characteristics of lime

There is a varied geological distribution in India. Hence several kinds of lime stones are available. These lime stone are burnt to obtain building lime. Due to the variability of limestone from place to place, the resulting lime is expected to vary in quality. Hence, chemical characteristics were carried out as per IS: 6932 (Part V) - 1973. The hydraulic lime used for investigation was subjected to preliminary chemical analysis by Atomic Absorption Spectrometry (AAS) and gravimetric method. Oxides such as calcium oxide and magnesium oxide, silica, alumina and ferric oxides were determined to identify the class of the lime and to assess the hydraulicity of lime.

2.3.1.2 Physical characteristics of lime

Field tests on building lime

Lime is a reactive material and constantly undergoes chemical changes on exposure to the atmosphere. Even during manufacture there are chances of variability in the quality. Therefore, it is necessary to check the quality of lime at various stages. For quick and reliable results simple field tests on lime such as visual examination, ball test, and hydrochloric acid test have been done as per IS: 1624- 1986.

(a) VISUAL EXAMINATION

Lime was examined for color and state of aggregation namely lumpy, powdery, soft or hard. Class C lime and class D lime mostly used for white washing are white in color. Lumpy form may indicate quicklime or unburnt limestone. Lime free from coarse and gritty pieces larger than about 2.30 mm may be categorized as Class ‘A ‘ lime.

(b) BALL TEST

Ball test was conducted as per IS: 1624 – 1986, where lime was sieved through 850 microns sieve. Then the lime was mixed with sufficient quantity of water to get a stiff paste and

a ball of 50 mm diameter was prepared and it was left undisturbed for a period of six hours. Then the ball was gently immersed in a jar of water.

The codal guidelines for assessing the class of lime is as follows.

No signs of disintegration - Class A lime

Very little expansion and numerous cracks - Class B lime

Signs of disintegration within few minutes - Class C or Class D lime

The test was conducted as per IS: 1624 - 1986. Lime was examined to find out the presence of inert material. Sufficient quantity of lime was placed into a 50 ml glass cylinder up to 5 ml mark. Twenty five ml hydrochloric acid was added into the cylinder along the glass rod placed inside so that the acid does not get smeared all over the sides of the cylinder. The contents were stirred with a glass rod. The cylinder was left with the contents for 24 hours to observe the gel formation.

SETTING TIME OF LIME

Initial and final setting times of lime have been determined according to IS: 6932 (Part 11) - 1973 by using Vicat apparatus. Initial setting time is defined as the time measured from mixing binder with water to the time at which the needle fails to pierce the binder paste (5 ± 1) mm from the base-plate. Initial setting time needle was replaced by an annular arrangement for the determination of final setting time. The lime is considered as finally set when the needle applied on the surface of test block fails to make an impression.

2.4 SAND

Sand is used as an aggregate in mortars, plasters and renders. The properties of sand used in the mix have a major effect on its workability, final strength and durability.The quality of sand is of primary importance in achieving a high-quality lime mortar. Sand provides the structural

strength, with the lime putty coating and cementing the particles together. In this investigation, clean river sand free from organic and inorganic particles were used as aggregates in mortar preparation.

2.4.1 Grain size distribution

Grain size distribution of sand have been determined as per IS: 2386 (Part 1) - 1963 on mechanical sieve shaker with sieve series (square mesh) of size 2.36 mm, 1.18 mm, 0.6 mm, 0.3 mm, 0.15 mm and 0.075 mm, with sieving time of 10 minutes. Individual fractions were weighed, and the results were plotted.

2.5PREPARATION OF MORTAR SPECIMENS

A mix proportion of 1:3 (1 part of hydraulic lime, 3 parts of sand) by weight was chosen which has been considered as the most common mix proportion for restoration works (Moropoulou et al., 2003). Hydraulic lime mortars were prepared as per Indian standards IS: 6932 Part VII – 1973. Equal quantities of hydraulic lime and water were thoroughly mixed for five minutes (lime putty). The hydraulic lime putty so prepared was mixed with sand and then ground for a period of 8 minutes and then left aside for 24 hours. The (water + AN)/lime ratio was adjusted to 0.65 at the time of casting. The prepared mortar mixtures were filled into non-corrosive moulds of dimension 50x50x50 mm cube for compression tests and 40x40x160 mm prism for flexure tests and gently pressed using the thumb. Steel moulds with zinc coating were used for this purpose to avoid corrosion. The filled up moulds were covered with wet cloth and maintained at a temperature of 27±2 º C, and 90 percent RH. Samples were demoulded after 3 days and kept in air for a further period of 4 days at the same temperature and humidity to avoid cracks due to drying shrinkage. Thus the cubes of seven days old were immersed in clean water and left till the prior date of testing for its strength in UTM. The water should be periodically changed for every 3 days and maintained at a temperature of 27 ± 2°C.

Fig 5 Preparation of Mortar Mix

Fig 6 curing of casted specimens

2.6 CONSISTENCY TEST ON LIME MORTAR

The typical consistency of a Lime paste is the consistency, which will permit the Vicat plunger to penetrate to a point 5 to 7 millimeter from the bottom of the mould. Lime and water of weighted quantity is taken and made as paste, taking care that the time of mixing was not less

than three minutes nor more than five minutes and the gauging is completed before any sign of setting occurs. The time should be noted immediately after the water is added to the lime. Then the vicatmould is filled up with this paste in three layers, compacting each layer by keeping the mould on a non-porous glass plate and the top surface is smoothened. This whole set up is then placed under the plunger so that it touches gently on the surface of the paste and it is released at once so that it penetrates into the paste. This operation was repeated for different trial mixes and the consistency was found.

2.7 SETTING TIME ON LIME MORTAR

Initial and final setting times of lime were done as per IS: 6932 (Part 11) – 1973 [11] by using Vicat apparatus. Initial setting time is the time taken for the needle, which fails to penetrate the binder paste (5 ± 1) mm from the base-plate. The final setting time was founded out by replacing the needle by an annular arrangement. The lime was identified as finally set when the needle fails to make an impression on the surface.

2.8 COMPRESSIVE STRENGTH TEST The compressive strength test was conducted as per IS: 6932 (Part VII) – 1973 [12]. Three cubes are taken out from water after 28 days and wiped out so that its surface gets dried. Keeping those cubes in the low capacity compression-testing machine tests the compressive strength of these cubes. The casted face should be facing towards the person. The moulded side should be in contact with the surface through which load is applied. There should not be any packing between the cube and steel plates of the testing machine. The top steel platen is fixed with ball bearing and shall be self-adjusting. The load should be stable and uniformly applied, starting from zero increasing at the rate of 15 kg/min. The average strength of the six specimens shall be taken as the compressive strength of the mortar and the result expressed in N/mm2.

Fig. 7 Compressive strength test for the specimen

2.9 FLEXURAL STRENGTH TEST The determination of flexural strength is undertaken when the test specimens are twenty-eight days old, the testing machine is required to have two supporting rollers and a third roller (the loading roller, located above the test specimen and midway between the supporting rollers). The prism is placed so that one of its faces, which has been cast against the steel mould, is in contact with the supporting rollers. The load is applied to the test specimens at a rate that produces failure in a time period of thirty to ninety seconds. The load at failure was noted.

Fig. 8 Flexural strength test for the specimen

2.10 WATER RETENTIVITY TEST

This test determines the change in the level of consistence when the mortar is subjected to suction and the loss of water from the fresh mortar. The mould of 10 cm internal diameter and 2.5 cm height is weighed and eight discs of filter paper are also weighed. The mould is then filled with lime mortar and the top surface is the leveled with the palette knife. The mould and its contents are then weighed.

The eight discs of filter paper are placed on top of the mortar and a non-porous plate is placed on top of these together with a 2 kg weight. A period of two minutes is allowed to elapse, the weight and plate removed, the cotton gauze discarded and the filter papers weighed to the nearest 0.05 grams.

The mass of water remaining in the mould (i.e. the mass of water originally in the mortar minus the water absorbed by the filter paper) is expressed as a percentage of the original water content of the fresh mortar and reported as the water retentivity.

2.11 BULK DENSITY AND POROSITY INFLUENCE

The bulk density (Rilem TC 203 2009) is the ratio of the mass of the mortar to its bulk volume. It is calculated as ratio of 28th day weight of the sample to its volume. Porosity is indirect measure of water absorption and easy measure of carbonation. It is defined as the fraction of the total volume of a solid that is occupied by pores or empty spaces or voids. It is calculated based on Archimedes principle (RilemTC 25 1980).

The samples were initially dried at 103 ºC for 24 hours and weighed to determine their dry weights (Md). Then the samples were immersed in water for 24 hours and weighed Ms. Also the

Archimedes weight of the mortar sample, immersed in water (Ma) was measured. Bulk density and porosity was calculated using Eqn 3.4 and Eqn 3.5

Equ.3.4

Porosity of the mortar was calculated using Eqn. below

Equ.3.5 Where D - Bulk Density (g/cm3)

Md- Dry mass (g)

Ms- Saturated mass (g)

Ma- Archimedes mass (g)

2.12 CAPILLARY ABSOPTION

Sasse and Snethlage [1997] observed that the water transport characteristics of the mortar and substrate must be similar to avoid differential discolouration over time and strong weathering along the contact zones. In addition to this, these properties exert an influence on deterioration mechanisms such as salt crystallization and freeze-thaw, which are the result of the movement of water into, through and out of stone [Russell et al, 2002]. Bromblet [2000] used these tests to make comparisons between mortars and stones in order to assess compatibility following the Sasse & Snethlage precepts. The presence of large pores confers resistance to freezing since they provide space into which ice crystals can expand without causing damage [Balksten& Magnusson, 2004]. It is found by using

Where, C – Capillary absorption m90 – Weight of sample after 90 min (g) m10 - Weight of sample after 10 min (g)

Chapter 3

RESULTS AND DISCUSSSIONS

3.1 SAMPLE PREPARATION

The collected samples (Fig. 9) are crushed with mild pressure in hand and sieved through 63µm sieve. The lime particles passing thorough sieve will be binder rich content is collected. The acid loss analysis was carried on this portion.

Fig.9 Altered and Unaltered lime mortar samples

Fig. 10 Rich binder less than 63µm

3.2 Acid Loss analysis

The results of acid loss analysis of Naganathaswamy Temple and Thanjayur palace is presented in Table 6 and 7 respectively. Binder to aggregate ratio of 1:3 to 1.6 for Naganathaswamy Temple and in the range of 1:3 to 1: 7 for Thanjayur palace, respectively. The palster of both the structures rich binder to aggregate ratio of 1:3 and bedding mortars have lean ration for 1: 6.

Fig 11: Acid loss Test

Table 6 Acid Loss Analysis of Naganathaswamy Temple

Sample Initial Weight of sand Weight of B/A Ratio weight (gm) retained (gm) binder (gm)

1 28.65 24.29 4.35 1 : 5.6 2 31.41 27.12 4.28 1 : 6.3 3 24.85 19.40 5.44 1 : 3.5 4 26.75 21.67 5.07 1 :4.3 5 28.22 24.40 3.81 1 : 6.4

6 24.46 18.95 5.50 1 : 3.4 7 25.63 21.59 4.03 1 : 5.3 8 21.85 16.48 5.37 1 : 3.1 9 23.40 18.16 5.23 1 : 3.5 10 24.32 18.50 5.81 1 : 3.2 11 32.05 26.71 5.33 1 : 5 12 26.42 19.85 6.56 1 : 3.1 13 28.71 21.96 6.74 1 : 3.3 14 27.32 21.58 5.73 1 : 3.7 15 28.85 23.20 5.64 1:4.1

Table 7 Acid Loss Analysis of Thanjavur Palace

Sample Initial Weight of sand Weight of B/A Ratio retained (gm) binder (gm) Weight (gm)

1 28.66 23.211 5.449 1 : 4.26

2 25.51 20.95 4.56 1 : 4.6

3 27.41 24.115 3.295 1 : 7.32

4 24.98 19.069 5.911 1 : 3.23

5 25.57 20.086 5.484 1 : 3.66

6 26.46 22.559 3.901 1 : 5.78

7 24.75 20.33 4.42 1 : 4.6

8 27.04 23.748 3.292 1 ; 7.2

9 22.82 18.38 4.44 1 : 4.14

10 19.54 16.73 2.81 1 : 5.9

11 26.55 21.587 4.963 1 : 4.35

12 24.68 20.835 3.845 1 : 5.42

13 26.45 22.252 4.198 1 : 5.3

14 26.51 22.991 3.519 1 : 6.5

15 23.46 19.525 3.935 1 : 4.96

3.3 Chemical analysis of mortar samples

The complete characterisation of representative samples from each category is established. Table 8includes the results of chemical analysis of all groups. Calcium carbonate (calcium oxide and calcination loss) and silica were the main components identified. Presence of clay minerals (Al2O3and Fe2O3) along with silica around 30% in the mortar samples indicates the hydraulic nature of the lime. The percentage of silica content is highest whereas magnesium content is minimum. Further, the hydraulic and cementation indices of all the ancient samples are on the higher side and ranged from 1.39 to 1.7 and 3.6 to 6, respectively. As per Taylor (1997) findings, the values proved that the lime powder used is similar to cement.

Table 8 Percentage of various minerals present in ancient lime mortar (Naganathaswamy Temple)

CaO MgO S cl Fe2O3 Al2O3 SiO2 k LOI Sample Na

NS-1 33.41 27.22 9.51 8.16 10.43 5.18 3.21 2.14 0.74 19.21 11.58 7.51 4.61 31.28 38.46 9.64 2.82 1.12 065 21.63 NS-2 NS-3 34.74 22.95 12.18 9.25 8.54 5.21 3.61 3.13 0.34 18.33 10.68 11.2 6.43 NS-4 39.35 18.51 6.84 3.52 2.89 0.57 18.91 1

NS-5 28.35 23.64 13.51 8.34 11.15 9.83 2.16 1.89 1.08 22.04 12.87 10.6 11.61 NS-6 31.93 19.55 7.22 3.28 2.14 0.68 17.47 9 NS-7 26.27 29.31 9.24 9.37 8.31 7.11 5.92 3.53 0.94 19.07 13.81 11.6 4.62 NS-8 40.15 12.51 9.14 4.33 2.72 1.12 21.73 3 14.29 10.2 6.46 NS-9 33.43 16.65 12.51 4.08 1.83 0.52 20.69 7 8.33 12.1 8.38 NS-10 43.14 10.86 9.43 5.19 1.68 0.79 19.76 7

Table 9 Percentage of various minerals present in ancient lime mortar (Thanjavur Palace)

CaO MgO Fe2O3 Al2O3 SiO2 k LOI Sample S Cl Na

TP-1 44.56 11.51 8.91 11.14 9.09 7.61 5.19 1.39 0.55 31.24

36.32 11.12 9.53 15.89 10.89 9.76 4.65 1.02 0.79 33.61 TP-2 TP-3 42.95 13.25 7.65 11.2 11.57 7.84 4.01 1.27 0.46 25.71 TP-4 49.15 13.38 10.33 6.77 7.28 6.95 4.41 1.11 0.59 29.22 TP-5 37.98 14.07 8.27 15.64 8.71 8.26 5.47 1.05 0.58 35.47 TP-6 36.06 12.68 9.7 14.92 9.45 10.94 4.47 0.99 0.74 21.53 TP-7 39.69 12.56 9.04 15.43 8.59 7.93 4.63 1.554 0.55 23.81 TP-8 41.13 15.14 7.15 9.33 12.01 9.66 3.98 1.37 0.68 28.91 TP-9 43.39 10.38 5.45 18.69 9.27 6.96 4.13 1.12 0.56 26.06 TP-10 47.49 12.55 6.76 14.26 7.81 4.74 4.41 1.27 0.67 31.75

3.3 Organic analysis of mortars

The organic analysis of mortars samples are presented in Table 10 and 11, respectively for Naganathaswamy Temple and Thanjayur palace. The percentage of carbohydrate is high in both mortar with around maximum 3 % of protein and fraction of fats in the ancient samples. Hence the kadukai and jaggery would have been added to the mortars to improve the fresh and hardened properties of the mortar.

Table 10 Organic Tests on Naganathaswamy Temple

Samples Name Carbohydrate Fat Protein

1 N.S-1 5.02 0.07 0.58

2 N.S-3 0.33 0.04 2.69

3 N.S-9 6.16 0.06 0.39

4 N.S-11 6.67 0.08 0.96

5 N.S-17 9.78 0.13 0.26

Table 11: Organic test on Thanjavur Palace

Samples Name Carbohydrate Fat Protein

1. T.P-7 6.81 0.05 0.36

2. T.P-10 9.24 0.28 3.37

3. T.P-13 10.66 0.16 1.43

4. T.P-14 5.43 0.03 0.16

5. T.P-15 12.69 0.18 1.12

Kadukai or TerminaliaChebulashown in Fig.12 contains tannic acid or tannins made up of polyphenoliccompounds which has ability to build very complex chemical structures. The

tannic acid has an estimated chemical formula of C76H52O46.Amala et al (2014) established that the main composition is carbohydrates in the form of tannins.The basic unit of kadukai(tannin) is in the form of gallicacidmay be natural or synthetic. The vegetable tannin or natural organic tannins or sometimes even called as tannoid is a type of bio molecule whereas modern synthetic tannin is an astringent. The polyphenolic compound present in the bitter plant binds with lime and precipicate protein and various other organic compounds including amino acids and alkaloids.

Fig.12 Dry seeds of Kadukai

Jaggery shown in Fig 13 is an amorphous form of unrefined and non-distilled sugar prepared from sap or juice of plants that contains sugar. The addition of jaggery to lime, increases the solubility of lime in water by 84%. Hence, instead of water jaggery extract water can be added during slaking. This helps in more conversion of calcium oxide (lime) into calcium hydroxide (portlandite). Jaggery contains 60 - 85 % sucrose, 5-15% glucose and fructose, 0.4% protein and 0.6 – 1 % of minerals.

Fig.13 Jaggery from sugar cane

3.4 SIEVE ANALYSIS OF NAGANATHASWAMY TEMPLE

Sieve analysis (Table 12 and 13, Fig. 14 to 19) indicates the uniform graded particles unlike well graded particles. Hence grinding was done to overcome the short comings of improper slaking and to improve the pozzolanic activity of lime with clay minerals. Slaking was carried out during manufacturing of lime. The process of adding and mixing of water to lime is called slaking which may be wet or dry. In dry slaking less amount of water is added to lime that cause conversion of partial amount of lime into portlandite. It is preferred when quality of water is poor or insufficient for use. However, in wet slaking in excess of water when carried for long duration lasting up to months, the complete transformation of calcium oxide into portlandite is possible. Moreover, wet slaking will prevent carbonation, the portlandite crystals formed changes its shape, become smaller and flatter. This allows the crystals to move easily on other crystals thus aiding workability (Sangeethabais2007). During the process of slaking, a lot of heat was generated which causes the lime to split. This process will not happen in case of improper slaking as the parameters required for lime production were not standardized resulting in large variations at each source point. Hence, grinding is necessary. Though slaked lime was procured for production, minimum grinding was carried out to ensure the two things to happen. By grinding,splitting of lime takes places and the silica grains become finer in order of nanometers. Fine silica and clay minerals accelerate the reaction rate less than a day to form

CSH phases without changing the microstructure of lime matrix (Moropoulou et al 2004).Without grinding the mortars will take much time to reach the similar extent of reaction. Similarly, micronized lime will result in change in shape of portlandite for good workability.

Fig.14 Sieve analysis of NS – 6

Fig.15 Sieve analysis of NS – 8

Fig. 16 Sieve analysis of NS – 10

Fig. 17 Sieve analysis of TS– 6

Table 12 Sieve analysis of Naganathaswamy Temple

Sample Total 4.86 2.8 2.36 1.4 600 425 300 150 90 75 Pan

N.S-1 24.296 Nil Nil Nil 0.154 3.217 4.347 5.637 8.271 2.173 0.06 0.437

N.S-2 27.124 Nil Nil 0.23 0.6 3.4 5.332 6.714 8.457 1.955 0.09 0.346

N.S-3 19.407 Nil Nil Nil 0.224 1.001 1.485 2.607 5.72 4.725 0.309 3.336

N.S-4 21.672 Nil Nil 0.498 1.655 3.543 2.787 2.936 5.456 3.098 0.366 1.333

N.S-5 24.409 Nil Nil 0.1 0.16 2.026 7.29 7.749 5.155 1.52 0.105 0.304

N.S-6 18.955 Nil Nil Nil 0.042 0.877 2.926 4.917 7.823 1.688 0.105 0.577

N.S-7 21.596 Nil Nil Nil 0.102 1.341 3.627 5.767 7.89 2.183 0.143 0.543

N.S-8 16.48 Nil Nil Nil 0.11 5.04 0.031 4.516 5.004 1.398 0.075 0.306

N.S-9 18.169 1.53 0.356 1.653 2.522 1.834 1.253 1.406 4.448 2.398 0.109 0.66

N.S-10 18.505 Nil Nil 0.208 0.575 1.878 3.381 4.41 6.018 1.533 0.071 0.431

N.S-11 26.719 1.25 Nil 1.102 0.031 1.52 6.242 4.615 8.325 2.612 0.658 0.364

N.S-12 19.855 Nil Nil 0.541 1.022 2.321 3.043 5.168 4.346 1.932 0.246 1.236

N.S-13 21.965 Nil 0.265 Nil 1.406 3.245 2.846 2.845 6.826 3.421 0.365 0.746

N.S-14 21.588 0.85 Nil 0.109 0.184 1.336 5.212 3.965 4.183 2.667 0.614 2.468

N.S-15 23.209 Nil Nil Nil 1.865 3.452 6.328 2.725 7.098 1.064 0.245 0.432

Fig. 18 Sieve analysis of TS– 7

Fig. 19 Sieve analysis of TS– 9

Table 13 Sieve Analysis of Sand (Thanjavur Palace)

Sample Total 4.86 2.8 2.36 1.4 600 425 300 150 90 75 Pan

T.P-1 23.211 Nil 0.046 0.303 0.817 2.828 3.186 4.931 6.705 2.642 0.203 1.55

T.P-2 20.95 Nil Nil 0.47 2.285 5.142 3.981 2.434 2.622 2.935 0.325 0.756

T.P-3 24.115 Nil 0.098 0.247 0.451 3.284 5.86 7.075 6.477 0.573 0.02 0.03

T.P-4 19.069 Nil 0.154 0.585 1.064 3.433 4.465 4.75 3.596 0.77 0.072 0.18

T.P-5 20.086 Nil Nil 0.103 0.557 2.191 2.906 3.929 7.01 2.983 0.308 0.099

T.P-6 22.559 Nil 0.223 0.756 1.27 3.215 4.578 5.494 6.751 0.24 0.02 0.012

T.P-7 20.33 Nil Nil 0.147 0.725 4.339 5.494 4.84 4.273 0.512 Nil Nil

T.P-8 23.748 Nil 0.416 0.529 1.776 6.332 7.728 4.821 2.142 0.004 Nil Nil

T.P-9 18.38 0.447 0.727 0.791 0.957 1.509 2.598 3.404 7.031 0.916 Nil Nil

T.P-10 16.73 Nil Nil 0.252 1.033 1.81 2.005 3.818 5.889 1.897 0.013 0.013

T.P-11 21.587 Nil Nil 0.356 1.263 4.526 2.462 5.013 6.228 1.373 0.301 0.065

T.P-12 20.835 0.126 Nil 0.165 1.648 5.183 3.486 4.194 5.192 0.841 Nil Nil

T.P-13 22.252 Nil 0.612 0.647 2.615 3.456 5.113 2.644 6.034 0.605 0.361 0.165

T.P-14 22.991 Nil Nil 0.458 2.489 6.874 2.469 3.754 4.586 1.691 0.586 0.084

T.P-15 19.525 Nil 0.542 0.648 1.64 4.157 3.009 2.648 6.338 0.543 Nil Nil

3.5 XRD of Ancient samples

3.5.1 Nagannathaswamy Temple

In the present research, the proportions of binder and aggregate were examined based on XRD pattern.XRD analysis is very useful technique to identify the CaCO3 polymorphs (calcite, aragonite and vaterite) for the investigation of the carbonation reaction of limeOur interpretation is based on the assumption that the aggregate proportion corresponds to the quartz and the binder to the calcite percentage. This assumption was derived from the earlier petrographic study, which demonstrated a granitic origin of the aggregate and showed the presence of calcite only as binder. As XRD can neither distinguish between carbonates in the aggregate and in the lime paste coming from the binder nor amorphous phase like calcium silica gel, the only detection noticed are crystalline phase resulting for carbonation and hardening. In the present work semi quantification obtained through XRD gave an idea about aggregate/binder proportions

Fig.20 XRD of Ancient Samples

Table 14 Minerals present in the XRD of Samples Sample Calcit Ca Quart M C

s e O z g H

NS-1 ++ + +++ + +

NS -2 ++ +++ + - -

NS -3 +++ ++ + - +

From the XRD results of NS-1 it is observed that the main component of the plaster is Quartz, calcite that is present abundant and other components such as calcium oxide, magnesium and CH are in very less quantity. From the sample NS-2 it is observed that calcium oxide is present abundant and calcite is in moderate range. The optical microscopy on the thin section of the plaster sample gave further information about the binder, the type and shape of the aggregate materials and structure of the entire components. The major minerals noticed in the plaster of NS-3 are calcite along with minor minerals such as Calcium oxide and quartz. The results are in complete agreement with XRD data. Hence, the high intense peaks observed in XRD(Fig 20 and Table 14) also indicates the pozzolanic reaction due to addition of shell lime during burning, followed by hot lime technology and subsequent grinding of the mortar mix. However, peaks indicate the formation of degradation products such as syngenite (K2Ca

(SO4)2.2H2O), gypsum (CaSO4) along with major calcite peaks throughout the range.

3.5.1 THANJAYUR PALACE

The XRD graph of TP-1, TP-2 and TP-3isshown in Fig 21. All the peaks are calcite except a major sharp peak which indicates the presence of CSH and CAH phases in complex form of gyrolite, stilbite and nechelyustovite.Stilbite (calcium sodium aluminium hydrate) belongs to zeolite groups that are formed in the presence of sodium and calcium. Complex of CSH and CAH is seen SEM images (Fig 5.7) indicating the hydro thermal products in flattened plate crystals along with aggregates. Nechelyustovite is the hydrated phase of magnesium oxide.These reaction phases are hydro thermal in nature, as shell lime with high percentage of clay mineral would have been fired and slaked in hot water and allowed to mature for 1 to 3 months (Maroti and Kalmar 2006). This will result in micronisation of lime particles and make it workable and reactive. After laying the mortar, simultaneously both hydration (hardening

under water) and carbonation (hardening by carbon- di – oxide) will take place. As the high amount of carbon-di-oxide is available within the mortar due to fermentation of organics, more calcite was formed. The presence of organics favoured the hydraulic reaction leading to the initial formation of CSH and CASH. As the time progresses, all complex formation of CAH and CSH will slowly re-carbonate into calcite. The results of XRD are confirmed with FT-IR, TGA and DTA. In FT-IR (Fig 5.3) shows the wave band corresponding to 712, 874, 1440,1790,2515 and 2854 cm-1 of all samples of the temple indicate the formation of calcium carbonate and co-existence of a small peak around 3430 cm-1 due to portlandite which was not traced in XRD graphs.

Fig.21 Presence of possible minerals in mortars of Padaleeswarar temple

3.6 FT-IR of ancient samples

3.6.1 Nagannathaswamy Temple

Fig. 22 FT-IR of Ancient Samples

The samples of plasters and aggregates were examined under infrared spectroscopy (IR) the analytical investigation was mainly carried to gather qualitative information about the major components present in the plaster. The FTIR spectra were recorded in the region of 3500–500 cm_1 under a spectral resolution of 2 cm_1 for the powdered plaster samples. The aggregates sieved after the digestion of plaster samples in dilute hydrochloric acid were also subjected to similar examination.

A data for the FTIR spectra with spectra for inorganic and organic materials was used to characterize the unknown materials present in the plaster. The characteristic peaks at 3427.11cm_1, 2511.90cm_1, 1794.24cm_1, 874.40cm_1, 715.68cm_1 were noticed to be calcite and the peak at 1036.20 were observes to be aluminum silicates in the sample TS-1 of lime mortar. The characteristic peak at 2513.35cm_1, 1795.09cm_1, 874.44cm_1, 715.64cm_1

arecalcite and were as peak 1631.45 is under group of CSH, the peak 1025.75cm_1 and 477.57 cm_1 were observed as silica and peak at 3442.84cm_1 confirmed the presence of protein in the sample NS-2. The peak at 2514.47cm_1, 1796.47cm_1, 874.06cm_1, 712.79cm_1 were observed to be the presence of calcite and the peaks at 476.77 and 460.12cm_1 are the compounds of silica groups, 778.80cm_1 were observed to be quartz and 2924.28cm_1 were CH-bond stretching groups of organics in the sampleNS-3. In support to organic analysis the peaks 3427.11cm_1, and 3431.88cm_1 in FT-IR corresponds to organics. The peak 3442cm_1 is found to be portlandite. Peak 1033cm_1 is possibility of CSH,The peak indicates the presence of amides (proteins) whereas 2924.28cm_1and indicates carbohydrates or polysaccharides. In confirmation with organic test and FT-IR of samples indicates the presence of the organic matter. It has been observed from the investigation of many of the Indian plasters that the binding calcite is finally crystallized and surrounds the aggregate grains and partly fills the void between the grains. Further, presence of finally crystallized calcite shows the almost total conversion of Calcium hydroxide into Calcium carbonate by atmospheric Carbon dioxide in all the plaster works, which is also the main reason for good tensile strength of those plasters, which have no external contamination.

Additives were found to have transformed into calcium oxalate, revealed through FTIR spectrum. Further, organic fibers and seeds were admixed to improve tensile strength and reduce cracking in most plasters. From the results shown in figure5.5mixed with vegetal fibers and seeds (high CO2 content) had been added to the plaster of along with lime .The proteic materials and lime together have enhanced the binding properties of the earthen plaster.

3.6.2 THANJAVUR PALACE

As there are no vibrations corresponding to1420, 1450-1478 cm-1 and 1480 cm-1, there is no possibility of formation of magnesite or hydromagnesite. However, in XRD, formation of nechelyustovite may be due a small amount of MgO. A special band at 783 cm-1 in all the samples infers the formation of calcite by biological growth that implies that microbial carbonation of lime mortar has taken place(Fig 23).

Fig.23 FT-IR analysis of historic mortar at Thanjayur palace

3.7 Thermo gravimetric Analysis Results

3.7.1 Naganathaswamy temple

TG and DSC ( Fig 24 to 26) of sampleNS-1 curve of common lime mortar showed that there were two obvious weight loss processes which belong to the decomposition of Ca (OH)2 and CaCO3, respectively. The broad endothermic decomposition 650.0 to 780.0 characterizes amorphousand crystalline solids from CaCO3 calcite. The region bit 20 to 330 corresponding to loss of absorbed water and dehydration of C-S-H phase.The DSC of ancient mortar showed that there is a weight loss process, which belongs to the decomposition of calcium carbonate temperature range of calcium carbonate from the peak of 650.0 to 780.0. Italso reveals complete transformation of calcite from complex forms of CSH. The CSH gel can be stable in natural form of gyrolite and okenite.Hence, the high intense peaks of CSH and CAH observed in XRD also indicates the pozzolanic reaction due to addition of shell lime during burning, followed by hot lime technology and subsequent grinding of the mortar mix. All carbonation peaks are endothermic and around 730°c in these samples two types of reactions is done

hydration and carbonation. Exothermic peaks between 200 to 400 which indicates the presence of organics

Fig.24 TGA Graph of NS-1

Fig.25 TGA Graph of NS-1

Fig. 26 TG-DSC Graph of NS-1

Fig.27 TG-DTG Graph of NS-2

Fig.28 TGA Graph of NS-2

Fig. 29 TG-DSC Graph of NS- 2

From sample TN-2 it is observed that the portlandite CSH, CAH and MgO is observed more.The presence of organic admixtures enhances the formation of CSH, and CAH.The board endothermic decomposition in the region of 650.0 to 780.0 characteristic of amorphous and crystalline form of Caco3 and calcite. The region bit 20 to 330 corresponding to loss of absorbed water ad dehydration of C-S-H phase. Hence in confirmation with XRD, the TGA

results indicates the shell lime rich in clay impurities along with limestone dehydroxylate during burning process and acts as a pozzolan imparting early strength to the mortar. Also, the dehydration of magnesia between 250 °C and 550 °C is seen in all the mortar samples that substantially contribute to desirable plasticity. It is found that the co-existence of amorphous and crystalline calcite enhances the hydration process as more amounts of free lime has been available for reaction. As the age processes the complex forms of CAH and CSH phases re- carbonate and forms CaCO3. Early decomposition of CaCO3 to CO2 between 600 °C and 770 °C and the major weight loss in this range shows that the hydraulic components (CSH like gyrolite and okenite and CAH are completely transformed into CaCO3.

Fig.30 TG-DTG Graph of NS-3

Fig.31 TGA Graph of NS-3

Fig.32 TG-DSC Graph of NS-3

TG-DSC curves of ancient mortar displayed another weight loss process temperature ranges from 120-400°c. This could be associated with the decomposition of organic in lime mortar.It also reveals complete transformation of calcite from complex forms of CSH. TGA (Table 15) data indicates the major weight loss in the range of 600–800 °C and it is due to decomposition of calcite and release of CO2. It is definitely hydraulic in nature due to higher reaction of carbonation. When heated up to 120 °C, the mortar containing less than or equal to 2% of

absorbed water demonstrate the absence of hygroscopic character, indicating lesser amount of portlandite. Table 15: Results of Thermal Analysis (Naganathaswamytemple )

Weight loss over temperature range (%) CO2 / Total Inference Structurally H2O weight 600- 800- Sample < 120 120 - 400 - bound Loss 800 1000° ° C 400°C 550°C water % ° C C (%) 1.43 6.31 11.21 New NS -1 0.55 0.88 0.55 9.03 0.2 mortar 9.04 0.93 20.24 Old NS -2 3.48 5.54 2.8 8.42 1.61 mortar 4.5 3.75 23.68 Old NS -3 0.78 3.72 2.29 16.89 - mortar

3.7.2 TGA at Thanjavur palace

TGA is in agreement with XRD. In the analysis of weight loss based on TGA results (Table 16), four ranges of temperature are considered. In the range of 0 to 120°C, the weight loss percentage of TP-1, TP-2 and TP-3 samples are 0.125, 0.41 and 0.67, respectively. In this range, weight loss is associated with hygroscopic water.As percentage is very less for both exterior walls TP-1andTP-2 indicating that they are totally carbonated compared to inner wall TP-3 whichhas more water content. In the temperature range 200oC – 650°C weight loss is because of structural bound water which is due to dehydration of hydraulic compound. Structural bound water of all the samples were in the range of 5 – 14 % that implies that natural pozzolans have been added to the mortars. As observed by Moropoulou et al (1995) and o Moropoulou et al (2000) the percentage of CO2 due to decomposition in the range of 600 C -

800° C is in the range of 12-20.The value of CO2 / H2O which inversely expresses the level of hydraulicity is less than 3, hence the mortars are hydraulic in nature. The hydraulic mortars with high clay as pozzolanic materials were used as a binder and the high level of CO2 in mortars as possible because of the addition of cocktail of herbs added to improve the properties of mortar.

Table 16: Results of Thermal Analysis(Thanjavur Palace)

Weight loss per temperature Range (%) Sample < 120 ° C 120 -400°C 400 -550°C 600 - 800° C

TP-1 0.125 0.48 0.55 16.73

TP-2 0.41 1.02 0.70 11.01

TP-3 0.67 0.53 0.53 11.04

In DTA analysis of samples TP-1, TP-2andTP-3 shows a very narrow endothermic peak near 868.9oC, 806.6°C and 823°C, respectively. This is due to the formation of calcite in the recarbontion zone of 800o-900°C. The CSH and CASH are initially formed due to hydration and after long exposure to carbon-di-oxide, it will further completely transformed into calcite. The formation of more amounts of CSH and CASH is due to presence of the clay minerals. Elsen (2006) has expressed that there is a traditional practice of using the clay minerals fired at 600° C to 900°C to gain a distinct pozzolanic activity in India or lime with high clay minerals is used. The clay minerals are nano materials whose particle size is less than 2 µm. Because of thetiny size of the particle, clay minerals have a larger surface area with string electrostatic interactions (Singh and Arbad 2014).

The fired clay minerals are alumina silicate with rich calcium content which will act as zeolites. This improves the workability and reduces chlorine permeability is much suitable for the marine environment. This proves the main aim of our ancestors to produce hydrated phases similar to natural minerals and had reqiured properties like strength and long term stability (Stefanidouet al 2013). Similarly in all samples the exothermic reaction in the range of 300oC to 400°C infers that organics is added to the mortar. They may be rich in carbohydrate as the

TGA indicated a high level of CO2. In Tamil Nadu, fermented jaggery and kadukai juice are added in lime mortar construction. For the weatherproof course for houses, addition of surthi, limestone, shell lime along with jaggery and kadukai extract is still prevalent in south India.

Borges et al(2014) has discussed that the recarbonation of CSH and CAH is only possible in hydraulic lime mortars. As the recrystallisation of calcium carbonate takes place, the crystals

formed will occupy the pores that will contribute to the compactness of the mortar matrix by fulfilling the porous structure.

The exothermic peaks near 400°C in all samples show the decomposition of organic matter or aluminium hydroxides. The endothermic peaks of 571.8, 574.1 and 571.6°C for TP-1, TP- 2andTP-3, respectively show the presence of quartz phase change. In all the samples, the peaks 62.3, 106.1 and 74.1° C show the dehydration of CSH and CAH confirms the hydraulic character of lime. (Mertenset al2009). Figures 33,34 and36 show TGA and DTA of samples TP-1, TP-2 and TP-3, respectively.

Fig.33 TGA and DTA of TP-1Samples

Fig. 34 TGA and DTA of TP-2 Sample

Fig.35 TGA and DTA of TTP-3 Sample

3.8 SEM INTERPRETATION

3.8.1 Naganathaswamy Temple

SEM images are presented from Fig.36 to 38. The images clearly support the other analytical techniques and shows the formation of calcite crystals. The amorphous form of calcite is also present.The lime sand matrix is very compact in all the images. The complete carbonation on external surface is evident. The presence of organics is confirmed by simultaneous presence of amorphous and crystal calcite.

Fig. 36 Lime sand matrix

Fig. 37 Compact strutures of lime mortar

Fig. 38 Crystal forms of calcite

3.8.2 SEM images at Thanjavur palace

In SEM images as represented in Fig. 39, aragonite fibrous form of calcite develops ring texture around sand grains. The big grains show calcium silicate hydrate (CSH), which is the prime ingredient in hardening hydraulic lime. Aragonite is formed due to addition of clay

minerals at higher temperature similar to the presence of zeolites (Andrejkovicaetet.al 2012). They are seen along the long voids as in Fig 40. The Fig. 41 shows the formation of calcite crystals. Further there is a formation of nano clusters of calcite which are polydispersed and compact. They have specific crystallographic orientation that contributes to an agglomeration process. The Fig. 42 shows the white layer heaped on the top of sand grain and rhombohydral forms of calite in Figure 43.There are no cracks in the mortar sample on further magnification. As the mortar is in good condition still after many centuries exposed to the marine environment may be due to the presence of organic matter that acts as an inhibitor to crystallization.

Fig. 39 Aragonite formation of calcium carbonate

Fig. 40 Long voids in between the mortar

Fig. 41 Calcite crystals

Fig. 42 White layers heaped on the top of sand grain

Fig.43 Formation of rhomhedral crystals of calcite

3.9 NEW MORTAR SIMULATION 3.9.1 Characteristics of lime Chemical characteristics of lime such as oxides of calcium and magnesium, silica, alumina and iron are determined, and their significance on the behavior of lime are discussed to ascertain the class and hydraulicity of lime. Field tests are conducted on lime, and the observations are correlated to classify the lime. Influence of admixtures on the setting time of lime is also discussed in this section.

3.9.2 Chemical characteristics of lime The results of chemical composition of lime determined as per IS: 6932 (Part V) - 1973 are given in Table 17. Total binder content (calcium and magnesium oxides) is 64.6 %, which is greater than the minimum requirement of 60% for Class A structural lime as per Indian Standards, IS: 712 - 1984. Total clay content (silica, alumina and ferric oxide) is equal to 28.33% which is greater than the minimum requirement of 10% for Class A lime as per IS: 712 - 1984. From the results the lime can be classified as class A lime that could be used for the construction of structural elements.

Table 17 Chemical composition of lime Sl. Composition Limits as per IS: 712-1984 Chemicals No. (%) for Class A Lime 1. Calcium and magnesium oxides 64.90 60 % minimum (on ignited basis) 2. Magnesium oxides 1.21 6 % maximum (on ignited basis) 3. Silica, alumina and ferric 28.33 10 % minimum oxides.(on ignited basis) 4. Ferric oxides 2.29 - 5. Unhydrated magnesium oxide Nil - 6. Insoluble residue in dilute acid 12.90 15% maximum and alkali (on ignited basis) - Limits are not specified in IS 712-1984

3.10 HYDRAULICITY OF LIME

Hydraulic Index (HI) is an indication of the hydraulicity of lime. It is based on the oxides content in lime. Hydraulic index of the lime used in the study is equal to 0.43. Eminently hydraulic lime have values greater than 0.4 (Cowper 2000).Hence, the lime used is categorized as eminently hydraulic.

3.11 FIELD TESTS ON LIME

The outcome of the field tests conducted as per IS: 1624 - 1986 are presented in Table 18. The inferences are discussed to assess the nature of lime. Lime is examined visually for the colour, texture, fineness and the presence of grit particles. On visual examination, the lime used for the investigation is light grey and does not contain coarse and gritty lime pieces larger than 2.30 mm. Hence, it could be categorized as Class A lime.

In the hydrochloric acid test, a thick gel formation is observed and did not flow out of the glass tube when tilted, which shows signs of Class A Lime.

Results of the ball test infer that there are no signs of disintegration after six hours observation of the prepared lime ball (50 mm diameter). Hence, the lime is categorized as Class A, structural lime.

Table 18 Field tests on lime Test Observation Inference Conducted Visual Does not contain coarse and gritty lime pieces Class A, structural lime examination larger than about 2.30 mm Ball test Sign of disintegration in the ball of 50mm Class A, structural lime diameter after six hours Hydrochloric A thick gel formation observed and did not Class A, structural lime acid Test flow out of the cylinder when tilted

Table 19 Sample Description Category Description Category 1 12.5% of jaggery and 2.5 of kadukkai Category 2 12.5 of kadukkai and 2.5 of jaggery Category 3 6.25 % jaggery and 6.25 % of kadukkai

3.12 TEST RESULTS OF CONSISTENCY AND SETTING TIME OF LIME

The results of consistency and setting time of reference lime and admixture-modified lime are presented in Table 20. It was observed that the consistency of admixtures lime mortar of categories1, 2,3 gradually increases with the reference.The initial and final setting time of lime was found to be increased in admixture lime in comparison to the reference lime mortar. 1st category is of 12.5% of jaggery and 2.5 of kadukkai, 2nd category of 12.5 of kadukkai and 2.5 of jaggery and 3rd category is of combinations of both category of percentage 12.5%.

Table 20 Consistency and Setting Time of Lime Category Consistency (%) Initial setting time Final setting time (In minute) (In minute) Reference 64% 300 900 1 70% 330 1500 2 69% 430 1430 3 70% 410 1400

3.13TEST RESULTS ON COMPRESSIVE STRENGTH OF HYDRAULIC LIME MORTAR

The compressive strength of hydraulic lime mortar of admixture modified was comparatively lower and more or less equal to the normal conventional lime mortar. Though the compressive strength of admixture modified lime mortar is low it had a good flexural strength.

Table 21 Compressive strength of hydraulic lime

Sample Compressive Strength in MPa

28 Days 90 Days

Reference 1.52 2.70

HL1 1.01 1.85

HL2 1.87 2.52

HL3 1.95 2.67

3.14 Test results on Compressive strength of Air lime mortar

The results of compressive strength of Air lime mortar and admixture modified at 28, and 90 days are presented in Table 22. The compressive strength of Air lime mortar of admixture modified was comparatively higher than the normal conventional lime mortar. The strength gradually increases with the category 1,2 and 3. The category 3 has an increasing compressive strength of 53% than the reference lime mortar.

Table 22 Compressive strength of Air lime Sample Compressive Strength in MPa 28 Days 90 Days Reference 1.38 2.10 AL1 1.19 1.63 AL2 1.58 2.45 AL3 2.56 3.21

Fig. 44 Mode of failure of cube specimen

5.10.4 Test results on Flexural Strength of hydraulic lime mortar

Table 23 Flexural Strength of Hydraulic Lime

Sample Flexural Strength in MPa

28 Days 90 Days

Reference 0.48 1.98

HL1 0.56 2.51

HL2 0.45 1.68

HL3 0.39 0.78

It is observed that good increase in Flexural strength of admixture modified lime mortar than the conventional lime mortar. The flexural strength of category 1 added lime mortar had a peak value of 2.51 N/mm2 at 90th day and 0.56N/mm2 at 28th day. The category 1 has an increasing flexural strength of 60% to the reference mortar. Then the flexure strength gradually decreases with category 2 and 3.

5.10.5 Test results on Flexural Strength of Air lime mortar

Table 24 Flexural strength of Air lime Sample Flexural Strength in MPa 28 Days 90 Days Reference 0.22 0.12 AL1 0.45 0.18 AL2 0.34 0.56 AL3 0.60 0.16

The results of flexure strength of the air lime mortar on reference lime concrete and admixture modified concrete at 28 and 90 days are presented in Table 24. The flexure strength of concrete was found to be increased gradually of 64%at 28 days in three categories than the reference mortar. Lime with admixtures dosage increases the flexural strength of the mortar with age, in comparatively with the reference mortar.

Fig.45 Mode of failure of prism specimen

5.10.6 Water Retentivity test

The percentage of water retended in the admixture modified lime mortar varies for every 5min. Since the admixture modified lime mortar had a good water retentive capacity it will have low shrinkage, good workability and also it enhance the hydration process. The water retention capacity of various proportions of admixtures modified lime mortar is expressed in percentage

and is given in the Fig.46, 47 and 48. WATER WATER RENTENTIVTY(%)

TIME (IN MIN)

Fig.46 Water Retentivity test Results of category No.1(HL1) WaterRententvity (%)

TIME (in min)

Fig. 47 Water Retentivity test Results of category No.2(HL2)

WATER WATER RETENTIVITY(%)

TIME (IN MINUTES)

Fig. 48 Water Retentivity test Results of category No.3 (HL3)

5.10.7 PHYSICAL PROPERTIES

The bulk density of admixture modified lime mortar was gradually increasing and hence there is an increase in unit mass. The percentage of water absorption and porosity decreases gradually for increasing percentage of admixtures with water. Since there was a decrease in percentage of water absorption and porosity it enhances the durability characteristics and also resist the rainwater penetration.

Table 25 Physical properties of hydraulic lime

Sample Bulk density Water Porosity Capillary (g/cm3) absorption (%) (%) absorption

1 1.568 19.38 30.40 1.4x10-3

2 1.736 10.40 18.05 1.5x10-3

3 1.775 11.12 19.54 1.6x10-3

Table 26 Physical properties of Air lime

Sample Bulk density Water Porosity Capillary 3 (g/cm ) absorption (%) (%) absorption

Reference 1.692 19.38 21.53 1.8x10-3

1 1.696 12.5 21.12 1.6x10-3

2 1.765 6.194 10.93 1.5x10-3

3 1.693 10.47 17.74 1.3x10-3

Chapter 4

CONCLUSIONS

The properties of characterized and simulated mortars required for Naganathasamy Temple and Thanjavur Palace is summarized in Table 27.

Table 27 Properties of characterized and simulated mortars

Naganathaswamy Temple Thanjavur Palace

Description Characterization Simulated Characterization Simulated mortar study mortar study

B/A ratio 1: 3 to 1: 7 1: 3 1: 3 to 1: 6 1: 3

Lime mortar Limestone Hydraulic lime classification Hydraulic lime with artificial Lime stone ( HL) ( HL) pozzolans

Organic 6.25 % 12.5 %Kadukai and Carbohydrates Carbohydrates Kadukai and 2.5% Jaggery with materials and proteins and proteins 6.25% Jaggery brick dust

Compressive 3-5 2.66 1.37-4.60 1.8 strength(N/mm2)

Flexural strength 0.394 0.5-1.0 0.563 Less than 0.5 (N/mm2)

Bulk density 1.7 1.5-1.9 1.56 (g/cm3) 1.7-2.1

Porosity 18-20 19.54 40 30.4 (%)

Based on the study output the restoration of the both structures can be carried out. The results of the experimental investigation will be much helpful for the Department of Archaeology both for conservation of the ancient monuments and for preparation of restoration mortars which will make our Country’s Monuments to stand rigid for further centuries.

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