Yüksek gözenekli yapı taşlarında su itici kimyasal kullanılmasının tuz kristalleşmesine etkisinin araştırılması

Abstract

Porously building stone  Changes due to salt crystallization  Surface protection chemicals One of the main factors which cause the decaying of the structures is the existent water in natural stones which are used in constructions. After the effect of water damage, the most decomposition occurs by salt crystallization. Soluble salts are transported to the capillary cavities along with water and crystallize. In this study, salt crystallization experiments with sodium sulphate and sodium chloride solutions were conducted to examine the resistance of the tested tuff and andesite samples to the salts. Figure A. In the salt crystallization experiment of tuff and andesite, the (sodium sulphate) normal and water repellent chemical applied samples, the mass change graph (Dotted lines are samples coated with water repellent chemicals) Purpose: In this research, water repellent chemical influence on salt crystallization in high porously andesite and tuffs were investigated. Theory and Methods: Main technical values and parameters such as mineralogical-petrographic (polarize microscope, XRD and SEM), chemical (XRF) and mechanical-physical properties were studied. Moreover, this study also included pore size distribution of the tested building stones. In the second step, their durability was investigated by means of salt crystallization test according to TS EN 12370. Finally, the structural changes of building stones after salt crystallization tests were investigated by SEM observations and ultrasonic wave measurements, while strength properties were determined by uniaxial compressive strength test. Results: With the application of water repellent chemicals, it has been found that the ultrasound wave velocities increase by more than 60%. It was found that water-repellent chemical-treated samples were less affected than the destructive effect of salt crystallization compared to non-chemical-treated samples. Conclusion: According to the results of this study, salt crystallization will not be a problem for deterioration of andesite which will be used in new buildings or restoration projects. But Ayazini tuff was not durable in the environments of containing salt solution.