A influência da temperatura, resistência, método de resfriamento e reidratação na frequência de vibração de amostras de argamassa estrutural

Abstract

The fundamental resonance frequency of parts is directly linked to the dynamic and static elasticity modulos, which are fundamental factors in the analysis and design of structures, and to the Poisson's coefficient, which directly influences the shear effects. It’s in this context that the present work aims to investigate the influence of heating temperature, nominal reference resistance of mortars, cooling and rehydration method on the fundamental resonance frequency of rectangular bodies of structural mortar. In the Acoustics Laboratory of the Federal University of Santa Maria, 240 specimens were tested with mortars of 3 different resistances, submitted to 10 different temperature ranges, 2 cooling methods on two dates, the first on the day after the heating and the second, 28 days after the first, following the guidelines present in ASTM C215 - 19, that has as objective the evaluation of resonant frequencies in concrete specimens. Through the elaboration of graphs, it was found that the nominal resistance has a direct relationship with the transverse natural frequency of vibration, the heating temperature has an inverse relationship, while the cooling methods showed the same result for the samples without rehydration, but for rehydrated samples, the sudden cooling method showed higher frequencies than samples submitted to slow cooling. Finally, the rehydration of the samples showed an increase in the natural transverse frequency of vibration of the samples.