The aim of this study is the conservation and restoration of the valley conical arch of ancient structure - Alamparai fort, India. Restoration and conservation of the ancient buildings need a careful choice in the use of restoration mortars suitable with the original materials of the existing building. The research comprises of three major stages viz., characterization, development of material and testing of the material. To evaluate the properties of the material used in the ancient structure, tests such as Acid loss analysis, Laser particle size distribution, XRD, XRF, FTIR, SEM-EDX, TG-DTA, and organic analysis were performed to identify the type of materials and proportions used. Air lime binder and river sand (1:3) were used primarily with the organic additives of kadukkai and jaggery with the dosage of 12.5% to improve the properties of the restoration mortar. Bricks were also prepared in accordance with the original structure in terms of shape, size, water absorption and compressive strength. It was concluded that the prepared bricks and mortar can be well suited in adopting as a restoration material, fulfilling the criteria of organic, physical, chemical and durability aspects.