Monitoring the carbonation front progress in a cementitious composite having its pore structure analyzed through µ-CT imaging

• Autor(a) principal: Evando de Lacerda
• Data de Publicação: 2017
• Outros Autores: Aldo Giuntini de Magalhães, Elen E. Bernardes, Eduardo Henrique Martins Nunes, Wander Luiz Vasconcelos
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: https://doi.org/10.1590/S1983-41952017000300006; http://hdl.handle.net/1843/57009; https://orcid.org/0000-0003-1574-8284; https://orcid.org/0000-0002-8133-9043; https://orcid.org/0000-0002-4640-7944
• topic: Mortar; Carbonation; pH; Xray microtomography; Argamassa; Raios X.

The carbonation process is one among the primary factors that cause a reduction in the hydrogen ionic potential (pH) of cementitious composites that may lead to a depassivation of the reinforcement structures, thus furnishing conditions for corrosion processes to begin. In this paper, the research sought to monitor the advancement of the carbonation front in compliance with the European standard, EN 14630, whilst concurrently measuring the pH variation on the surface of the cementitious composite. Cylindrical mortar specimens of (2x4) cm were placed in a carbonation chamber, keeping up the humidity 65%, temperature 28° C and a CO2 concentration of 5%. The structure of voids in the matrix was assessed with the µ-CT imaging technique. The pH reading enabled the monitoring of the carbonation front progress as a function of the loss of alkalinity, before the process established by standard EN 14630. The images obtained by µ-CT did not enable the visualization of the densification of the material found in the outer layer of the specimen.