Assessment of reliability of natural limestone cladding material

Abstract

The goal of research was identifying possible application of natural limestone samples as a cladding material for facades by means of evaluation of physical and chemical properties and inclusive of external aggressive factors. As the object of research, there were used the samples of naturally occurring limestone, of Afanasyevskiy deposit, Moscow region, designated for face slabs manufacturing of ventilated facades. In compliance with the All-Union Standard (GOST) 30629-2011, the samples have been exposed to the following testing, namely determination of mean density and true specific gravity, kg/m3, pore-saturation coefficient with water; ultimate compressive strength, MPa, water fastness (lowering of compressive strength in the water-saturated state, %); ultimate bending strength, MPa; freeze-thaw resistance, cycles, acid fastness. Chemical (elemental) analysis was carried out by the method of scanning electron microscope investigation. The tests were implemented on the electronic microscope FEI Quanta 200. The microscope is equipped by X-ray spectrometer that is designated for elemental analysis (EDAX). Both masonry units have satisfactory freeze-thaw resistance. As far as acid fastness is concerned, only marmorized limestone has demonstrated satisfactory performance. Thus, only the second group of samples presented by marmorized limestone could be recommended as a reliable material for façade cladding.