Conservation & restoration of historic mortars at Alamparai fort with valley conical arch, Tamilnadu, India

Lime mortar has been a primary binding material in ancient mortar, and is one of the main reasons behind solid and stable constructions that remain stable even after thousands of years. The benefits of lime are innumerable: it is minimally processed and used with a lesser carbon footprint and embodied energy and, most crucially, it is a carbon absorbent. This research experiments with the strength properties (compression) of lime at 28, 56, and 100 days of air curing. The investigation studies the durability using water absorption, UPV test, and carbonation parameters after 100 days of exposure to air. The tested materials are subjected to SEM analysis to find the morphology of the reaction that takes place and the products that are formed. We also performed a comparative study of two different fermented additives by the duration of fermentation (1 day and 10 days) and two different doses of additives (Jaggery and Kadukkai) with air lime. The bio-additives were experimented with using gas chromatography and mass spectroscopy for the formation of new enriching compounds, which improved the qualities of traditional lime mortar. The formation of fat and protein in the additives was found using IS 7219-1973 (a method for the determination of protein in foods and feeds). Using the AOAC method, the presence of fat confirms the improvement in strength and durability properties. The phytochemical analysis details the alkaloids, terpenoids, steroids, phenols, flavonoids, tannins, glycosides, and saponins. Quantification of phenols and flavonoids adds to the beneficial aspects of the fermented additives. The experimental results indicate that using naturally fermented organic materials in the lime has made the structures stronger with the stable build of calcite and vaterite components. The self-healing capacity of lime mortar makes it time resistant.

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Properties of Air Lime Mortar with Bio-Additives

Living mortars-simulation study on organic lime mortar used in heritage structures

Restoration of an ancient temple at Parvathamalai in Tamil Nadu to preserve cultural heritage

The scientific investigation performed on the different mortar typologies of the Padmanabhapuram Palace mortars in a previous study led to the formulation of a similar traditional mortar. The outcome of the study was an increase in the carbonation action and mechanical strength of the mortar compared to conventional lime mortar, primarily due to the fermented organics such as aloe vera, cactus, kadukkai, hibiscus, jaggery, and neelamari. The transformation of portlandite crystals to calcite, along with the early developed C-S-H and C-A-S-H hydrated products reported by the XRD analysis. The bio-organic spectral peaks for compounds such as carbohydrates, polysaccharides, and fatty acids were observed in the FT-IR investigation, which corroborates the XRD mineralogical results. The calcite decomposition is detected in the TGA analysis in the temperature range of 700–750 °C, with a maximum weight loss of approximately 35–37% for the aloe vera lime mortar. The addition of fermented organic extracts to the extent of 5% was found to increase the internal and external carbon absorption of the aloe vera and cactus mortars compared to conventional lime mortars. The mechanical strength of the organic lime mortar reported as 2.5 MPa, and 1.5 MPa for the reference mortar. The carbonation and hydraulic reactions due to the presence of polysaccharides, fatty acids, carbohydrates, and proteins in the formulation enhanced the compressive strength of the compatible mortar. The prepared compatible mortar will support the revival of the 400-year-old practice of the application of Palace mortars.

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Production of the Traditional Organic Mortars of Padmanabhapuram Palace—A Characterization Study on the Simulated Mortars for Their Compatibility

The study aims at preparation and characterization of six organic lime putty (hydraulic Lime + fermented plant extract) using regionally available plants namely Terminalia Chebula (kadukkai), Rosa Sinensis (hibiscus), Palm jaggery (refined sugar), Xanthorrhoeaceae (aloe vera), and Indigofera Tinctoria (neelamari) as per the methods given in the ancient palm leaf of Padmanabhapuram Palace, India. Advanced analytical techniques like Gas chromatography-mass spectroscopy (GC–MS), UV-Spectrophotometer and carbon dioxide quantification were used to study the fermented plant extracts and Fourier transform-infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), Field emission-scanning electron microscopy (FESEM) to study hydrated phases and microstructure of organic lime putty. GC–MS recorded the phytochemical compounds like fatty acids, traces of proteins, polysaccharides and carbohydrates. Fermented kadukkai and neelamari extracts reported as fatty acid, palm jaggery as carbohydrate, hibiscus as polysaccharide and aloevera rich in all the biomolecules. The detection limit of Quantification:0.013 and limit of detection:0.067 for polysaccharides, 0.026 and 0.088 for unsaturated fatty acids was reported through a U.V spectrophotometer for all the herbs. Aloevera and neelamari fermented extracts recorded the CO2 release around 96,000 and 90,000 ppm on 4th day of fermentation, whereas for other herbs it ranged below the recorded readings. Supply of CO2 has initiated the internal carbonation of the lime putty and precipitation of calcite in three different forms aragonite, calcite and vaterite minerals. The addition of organics resulted in high-intensity portlandite peaks and calcium carbonate polymorphs as reported in XRD graphs in agreement with FT-IR analysis. FESEM morphology validated the early formation of carbonate polymorphs, and EDX. has shown that kadukkai lime putty, jaggery lime putty and reference lime putty. mixes have calcium around 35–45%. From the overall results, 3% addition of eco-friendly biopolymers has altered the properties like setting time, water repellency and higher carbonation rate, which is the main reason behind longevity of the structure.

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Preparation and characterization of ancient recipe of organic Lime Putty-Evaluation for its suitability in restoration of Padmanabhapuram Palace, India.

This research aims at providing the scientific evidence of ancient construction practice and production technology on the use locally available geoearth materials and natural herbs, namely kadukkai (Terminalia Chebula), neelamari (Indigofera tinctoria), hibiscus (Rosa sinensis), palm jaggery (Borassus flabellifer), aloe vera (Aloe barbadenis) as specified in ancient palm leaf texts which were adopted at Padmanabhapuram Palace, India for preparing the traditional lime mortars. Six mortar samples of three different mortar typologies (wall, bedding and floor finish) were taken from the Padmanabhapuram Palace for the study. The sampled mortars were characterized using physiochemical analysis as well as modern analytical techniques including XRD, TG-DTA, FT-IR and FESEM-EDX methods. Different binder-to-aggregate ratios was proportioned for wall plaster (1:3), bedding mortar (1:2) and floor finish (1:1) and was confirmed through acid loss analysis. Wall plaster samples indicated the presence of organic protein and polysaccharide spectral peaks substantiated by FT-IR analysis. Organics have played a significant role in the formation of calcium aluminate silicates and carbonate polymorphs to enhance the crystalline hydrated phases observed through XRD and FESEM analyses. The thermal investigation substantiated that calcite decarbonation mostly occurred between 705 and 730 °C. The results apprised the wide use of hydraulic lime with fine-grained aggregate particles, added with fermented organics to produce an environmentally friendly organic mortar to restore the structure.

A scientific study on the role of organic lime mortars of Padmanabhapuram Palace, Thuckalay, Tamilnadu, India

Characterization study on the influence of limestone and shell lime as a fine aggregate substitute: A traditional approach on lime plaster restoration

Stones surfaces and elevated architectural grillworks of historic buildings, due to their predominantly outdoor location, suffer from deterioration factors, including air pollution, soluble salts, relative humidity (RH)/temperature, biodeterioration and by shelling in 1914. The durability and longevity of the structure can be enhanced on proper restoration techniques are adopted in order to arrest the degradation, contaminants, damages and environmental forces. The mineralogical identification and organic substrates were evaluated using X-ray diffraction (XRD), Fourier transformation-infrared spectroscopy (FT-IR), optical microscopy (OM) and Munsell colour chart for rock identification. Presence of silicates, feldspar, calcite and hornblende confirmed the rock to be sandstone on agreement with Munsell colour specifying the pale soft yellow (quartzose sandstone) and inorganic binding agent of calcite as cementing material was also confirmed through FT-IR analysis. Reduced feldspar peaks affirmed the rock has weathered for ages. The results provided the base for the formulation of repair and restoration work of high court building and for modern conservationist.

M. Shivakumar

Papers

Preparation and characterization of ancient recipe of organic Lime Putty-Evaluation for its suitability in restoration of Padmanabhapuram Palace, India.

A scientific study on the role of organic lime mortars of Padmanabhapuram Palace, Thuckalay, Tamilnadu, India

Characterization study on the influence of limestone and shell lime as a fine aggregate substitute: A traditional approach on lime plaster restoration

Identification of Crystalline Mineral Phases of Ornamental Latticed Jallies of Madras High Court Building, Tamil Nadu