Investigation of lime mortar characteristics for the conservation of the Ottoman Baths in Seferihisar-Urla region

Abstract

Lime mortars are among the binding agents used in binding masonry units such as brick and stone in many historic buildings. Their physical, mechanical strength and durability properties, raw material compositions can play significant roles in structural behaviour of historic buildings. Their production technologies may be also different according to their specific use in the structural layout. Therefore, the characteristics of lime mortars are of particular interest in the evaluation of structural characteristics of the historic buildings. Besides, determination of characteristics of the lime mortars is also important for the production of intervention mortars to be used in the restoration of historic buildings.In this study, lime mortars used in the walls and domes of some historic Ottoman baths in Seferihisar-Urla region near İzmir were analyzed in order to understand their characteristics for the purpose of conservation of these buildings. It is also aimed to investigate characteristics of the lime mortars in relation to their specific use in the structural elements of the walls and domes. Therefore, several laboratory studies were carried out on the collected mortar samples. Their basic physical and mechanical properties, raw material compositions, pozzolanic activity of aggregates used in the mortars, soluble salts in the mortars, their mineralogical and chemical compositions, and microstructural and hydraulic properties were determined. In addition, basic physical properties and pozzolanic activity of bricks used in the construction of domes were also determined in order to evaluate their contribution to the structural stability of the domes.Stone masonry mortars used in the walls and brick masonry mortars used in the domes of the Ottoman baths are lime mortars. Lime ratios of the stone masonry mortars are relatively higher than those of the brick masonry mortars. Some differences have been identified in the aggregates used in the mortars. Particle size distributions of the aggregates used in each mortar are almost the same. Fine aggregates used in each mortar have similar mineralogical and chemical compositions with their coarse aggregates. However, the fine aggregates have higher pozzolanic activity than their coarse aggregates due to high contents of amorphous materials, silicon dioxide and aluminium oxide in their compositions. Either of high-calcium lime and lime containing silica at high ratios was used as binding material in the stone and brick masonry mortars. All brick masonry mortars and some of the stone masonry mortars have hydraulic properties owing to the use of pozzolanic aggregates and lime containing silica at high ratios. These pozzolanic aggregates have good adhesion with the lime used in these mortars. Hydraulic lime mortars used in all domes have higher mechanical strength properties than non-hydraulic lime mortars used in the walls built of stone. Such differences in the stone and brick masonry mortars have been explained with a mortar technology developed consciously in relation to the difference in structural behaviour of the wall and dome. Even though the bricks used in the domes have poor pozzolanicity, they are tightly adhered to the lime mortar. This contributes to the structural strength of the domes.All these results indicate a lime mortar technology developed according to the use of the lime mortars in structural layout and its traditional character peculiar to the Ottoman baths in Seferihisar-Urla region. The first part of the study defines its subject and aim, limits and method. The second part deals with the subject of lime mortars in respect to their general characteristics and production process. In the third part, method of the study composed of sampling and experimental study is presented. In the fourth part, the results of the experimental studies are evaluated and discussed in respect to results of the related studies in the literature. The fifth part is devoted to the conclusions of the study.