Microstructural Characterization and Mechanical Properties of Volcanic Tuff (Malatya, Turkey) Used as Building Stone for the Restoring Cultural Heritage

Abstract

Old stone buildings constitute a significant percentage of the residential buildings in many countries. These structures are highly vulnerable, and important losses in masonry structures occur even in moderate earthquakes. Therefore, safety evaluations of these structures have gained significant attention in recent years. In this study, the mechanical, physical and microstructural characteristics of tuff samples used in the old buildings were investigated in Battalgazi within the boundaries of Malatya Province during the Seljuk time. The characteristics of the building materials were examined in detail using in-situ and laboratory tests. Because adequate samples could not be obtained from the historical buildings, quarry areas with the same characteristics were identified. First, original building stone (OBS) used in construction was taken from fallen and unusable blocks. Then, the properties of the restoration building stones (RBS) brought from the quarries were investigated. The RBS samples were also examined using in the laboratory, and the mechanical and microstructural properties of the building components were determined. The dynamic and static moduli of elasticity were determined using ultrasonic pulse velocity and uniaxial compression test. The OBS and RBS samples yielded similar results after the microstructural analyses. Our results showed that the dynamic elastic modulus value was higher than the static elastic modulus value. The results revealed by both methods showed that the static and dynamic elastic moduli were closely linked. The OBS and RBS samples exhibited microlitic porphyritic and vesicular textures and nearly the same mineralogical and textural characteristics.

Seismic Assessment of the Historical Sütlü Minaret Mosque

“…In the determination of elasticity modulus, ultrasound tests are used frequently [25,26]. In this study, ultrasound methods, were used for masonry building elements, and the dynamic elasticity modulus was determined according to ISRM 1978 [27] (Table 2).…”

Impact of Tufa Stone Powder as a Partial Replacement of Aggregate on the Mechanical Performance and Durability of Repair Mortar

“…When the preparation of the mortars was completed, the specimens were kept at a temperature of 20 ± 2 °C and a relative humidity of 75%. The skeletal and bulk densities of mortar M1 were 1.96 g/cm 3 and 1.37 g/cm 3 while the skeletal and bulk densities of mortar M2 were 1.81 g/cm 3 and 1.31 g/cm 3 respectively.…”

“…The mineralogical and physical characteristics of both the air lime and the tufa stone powder appear in Table 1. Silica sand with a particle size of 20-315 μm is utilized in this study as a fine aggregate, and its bulk density is about 1.22 g/cm 3 . The particle size distribution of both the tufa stone powder and the silica sand can be observed in Fig.…”

“…Beside these constituents, the raw tufa stone was quarried at Saint-Cyr-en-Bourg in the region of Maine-et-Loire in France. The major features of this stone are that it is a white stone, it is quite light (bulk dry density of 1.31 g/cm 3 ), and it is an 'easy to sculpt' when used in ancient buildings for repair and rehabilitation purposes. Mineralogically, tufa stone essentially consists of both calcite and silica, as shown in Table 1.…”

“…Also, there are other factors relating to the environment that govern the occurrence of deterioration [1]. In the rehabilitation works, the choice of the repair building materials, in terms of its aesthetic appearance, mechanical behavior, and even chemical and mineralogical composition, ought to be appropriate for use with the older substances used in these ancient structures [2,3]. Accordingly, one of the major requisites in conservation and rehabilitation works is to achieve full compatibility between the ancient stone and restored mortar (i.e., physical, chemical, structural), which should ensure the perfect performance of the repair mortar [4,5].…”