The basic tests that allow the mechanical properties of grained material to be evaluated are tests of an aggregate’s resistance to crushing - the Los Angeles coefficient, and resistance to abrasion - the micro-Deval coefficient. These parameters primarily depend on the physical and mechanical properties of the raw material from which they are produced. The available literature widely describes the relationship between these parameters and bulk density, porosity, ultrasonic wave velocity, compression strength, tensile strength and point strength. This paper presents the relationship between the mechanical properties of aggregates and their geometrical properties. The analysis was carried out for the relationship between the Los Angeles and micro- Deval coefficients and the flatness and shape indices. As a result of the conducted considerations, the influence of the aggregate assortment on the analysed coefficients was also noted. All of the tests were carried out for aggregates (arch stones and mixtures) produced from sandstones from the Magura, Cergo and Krosno layers.

This article presents the results of laboratory tests of the physical and mechanical properties of various types of sandstone selected from ten quarries from Carpathian flysch. The parameters were used to evaluate the quality of the sandstone and its suitability for use as armourstone in accordance with applicable standards and quality guidelines. The requirements of the BN-79/8952-31, EN 13383-1:2003 and the CIRIA, CUR, CETMEF (2007) standards were compared. Sandstone can display a large variability of parameters depending on its origin. This, in turn, results in a varying degree of its susceptibility to the destructive effects of water and climate.

The article presents the problem of selecting the correct type of limestone for producing paving stones used to renovate the surface of Mariacki Square in Krakow. Due to using up local limestone deposits, imported limestones began to be used. The first one was a Turkish limestone with the trade name Lotus Beige. Despite substantial physical and mechanical parameters (compressive strength 134 MPa, water absorption 0.26%), after several years of use, the paving stone cracked and, as a result, fell apart into smaller fragments. Hauteville limestone from France has been selected for the following reconstruction of the surface. This limestone in the air-dry state was characterised by even higher parameters, i.e. compressive strength of 157 MPa, flexural strength at 16.9 MPa, Bohme Abrasion test at 15275 mm3, and water absorption at 0.23%. The tests also showed absolute frost resistance and high resistance to thermal shock. Unfortunately, after several years of using the surface of Mariacki Square, cracks and flaking of the rock material have been observed in terms of some paving stones. These cracks appeared within the so-called stylolite seams, which are a natural feature of limestone. Despite a very strict selection of materials, unfortunately, problems with the surface’s durability could not be avoided.