Renato Veronese, Guilherme Parsekian, and Armando Moreno
i PhD Candidate, Federal University of São Carlos, São Carlos, SP, Brazil, renatoveronese@estudante.ufscar.br
ii Associate Professor, Federal University of São Carlos, São Carlos, SP, Brazil, parsekian@ufscar.br
iii Associate Professor, State University of Campinas, Campinas, SP, Brazil, armoreno@unicamp.br
ABSTRACT
In the event of a fire, the detachment of the mortar applied to the substrate compromises the performance of rendered structural masonry walls. The wall surface is often protected by a layer of cement-lime mortar, which helps to delay the temperature rise within the concrete block section. While fire rating tests of masonry walls with rendering mortar have revealed instances of debonding over time, the behavior of rendering mortar at elevated temperatures remains insufficiently understood. A key question is how the high temperatures affect the tensile bond strength of rendering mortar, and there is no standard method that allows obtaining this parameter. The standard method commonly used for room temperature cannot be used for determining tensile bond strength at high temperatures, and a new method must be developed. This study proposes a procedure for determining the tensile bond strength of rendering mortar applied to a concrete masonry substrate when exposed to high temperatures. This information, along with other material properties, is critical for evaluating the fire resistance rating of walls constructed with various material combinations of block and render, and for facilitating numerical modelling of concrete block masonry under elevated temperature conditions. To conduct the investigation, hollow concrete block prisms were manufactured, rendered, and subjected to different test scenarios, varying factors such as the force application mechanism, the sample area and the heating curve. Preliminary results indicate a favorable response in terms of failure mode, and these findings are presented herein. This work may contribute to future research on materials exposed to high temperatures or fire conditions, and the proposed method could be adapted for studies involving different substrates and rendering materials.
KEYWORDS: Fire situation, high temperatures, rendering mortar, structural masonry, tensile bond strength, test procedure.
105-Veronese.pdf
