Avaliação de argamassa histórica de revestimento da estação ferroviária de Alegrete – RS

Abstract

Historic constructions are of great importance to society, providing us information about a way of life, construction methods and knowledge about the past. Most of these constructions do not have maintenance and are in an advanced state of degradation, in this way, the coating mortar loses its function of protecting the structure and sealing. In view of this, the present work aims to carry out the characterization of the mortar coating of the Alegrete Railway Station, in Rio Grande do Sul, which is a construction of historical value for the city of Alegrete/RS. Five samples of coating mortar were collected to characterize and identify the components, using the chemical attack technique and granulometric composition, X-ray fluorescence (FRX) and scanning electron microscopy (SEM). The proportions found through chemical attack ranged from 1:1.92 to 1:4.99 (binders:agreggate, in mass), consistent with proportions of mortars in historic buildings found in other scientific works, demonstrating that this technique is effective. The results of the fluorescence tests indicate the probability that the mortar binder is lime-based, according to the percentage of Calcium Oxide (CaO) identified in the samples. The granulometry of the fine aggregates are similar to the natural fine aggregates used in this region and derived from the Ibicuí River. From the images captured in the scanning electron microscope, it was possible to conclude that the mortar has a certain porosity, based on its distribution, consistent with historic mortars. Keywords: historic mortar, characterization of coatings, chemical attack, Alegrete Railway Station, X-ray fluorescence, scanning electron microscopy.