Development of an Express Method for Assessing the Dynamic Strength of a Stone Depending on the Geometric Dimensions of the Slabs

When installing floors, stairs, overpasses, it is necessary to determine the values of resistance to stone impact. Determining this parameter when the material arrives at the object is not always possible promptly, due to the discrepancy between the thickness of the plates and the required thickness of the test specimens. An express method for determining the dynamic strength of facing slabs made of natural stone, taking into account their geometric dimensions, is proposed. Based on the proportional ratio of the forces of dynamic and static impact, correction factors are calculated and given to the values of the impact strength of the stone, depending on the thickness and length of the samples. In cases where there are no laboratory data on the impact strength of the stone, an analytical method for determining this parameter is given, based on the functional dependences of the dynamic strength of the stone on the speed of propagation of the ultrasonic pulse through the stone, compressive strength and average density. Based on the approximation of the point values of the functions by the least squares method, the polynomials describing the function of the dependence of the impact strength on the ultrasound velocity, average density and compressive strength for limestones, marmorized limestones and granitoids are calculated. According to such polynomials, the reduced values of the impact strength of natural stone slabs can be determined by calculation as the average given, taking into account the significance of the indicators obtained for each of the polynomials for the same type of stone. In conclusion, the calculated values of impact strength are determined taking into account the correction coefficients introduced on the basis of deviations of the calculated values from the laboratory ones. Verification of the calculated data was carried out by laboratory tests and comparison of the data obtained by calculation with the data of laboratory tests. Such a comparison shows a close convergence of the results. The mathematical dependences given by the authors, as new laboratory data become available, can be improved. The information presented in the article will be useful to organizations designing stone cladding, construction organizations carrying out work on the installation of stone cladding, specialists conducting research in the field of quality assessment of stone materials.

N.I. MOTORNY, Candidate of Sciences (Geology and Mineralogy) (This email address is being protected from spambots. You need JavaScript enabled to view it.),
G.L. LEVKOVSKY, Candidate of Sciences (Engineering)

Research and Design and Survey Institute for Problems of Extraction, Transportation and Processing of Mineral Raw Materials in the Industry of Building Materials (VNIPIIstromsyre) (1, building 1, Volokolamskoe Highway, Moscow,125080,Russian Federation)

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