Conservation of Machu-Picchu Archaeological Site [II] : Investigation and Experimental Restoration Works of "Temple of the Sun"

The Machu-Picchu archaeological site, called the "Ancient Capital in the Sky," is one of the most important and famous world heritage sites. It was the special place of the Inca Empire in the fifteenth century and is located on a high ridge in Peru. There are about 200 remaining structures built of stones (granite) in the 13km² site. Systematic conservation measures for the structures have not been conducted, except for emergency measures by the regional office. Thus, the authors have started a project for the conservation of the remaining structure with the cooperation of the Ministry of Culture in Peru, especially for the preservation and restoration of "Temple of the Sun," which is one of the most important structures in the site. There are three conservation problems related to the Temple of the Sun. One problem is that the stones of the structure have cracks caused by the high temperature of the fire used for burning the cut trees at the site while excavating. Another problem is that the structure became instable because some of the joint parts among the stones have been opened since the excavation. The other one problem is that the color of the structure has changed recently because of the lichens growing on the surface of the stones. The main activities of this project as to the treatment of stones are as follows: -Injection of epoxy resin under pressure into the cracks of the stones. -Consolidation of the fragile parts of the stones by impregnation with silicone resin and acrylic resin. -Setting the detached parts of the stones back to their original places by mortising and gluing these parts with epoxy resin. -Filling the open spaces among the stones with a mixture of clay and lime. -Killing and eliminating the lichens on the stones using a special chemical. -Making the stone structure waterproof by impregnation with hydrophobic silicone resin. The investigation and experimental restoration work, conducted in the summer of 2012, is reported in this paper.