Abstract:
This work presents the results of characterization tests in the coating mortar of a building of 20 floors, which has presented expansion, cracking with crumbling and low mechanical resistance throughout its 12 years. The preliminary observed signs referred to the inappropriate use of pulverized gypsum in the final stage of the coating mortar applying. However, during chemical evaluation tests, it was noted that this was not the precursor to the pathological manifestation observed. For the mechanical characterization, visual inspection was used in conjunction with the qualitative evaluation of percussion and tensile strength tests. X-ray diffraction (XRD), mix proportion analyses, differential thermogravimetric analysis (TG / DTG) and petrographic analysis were performed for chemical and mineralogical characterization. The results of the mechanical analysis indicated that the entire coating mortar is compromised. The data from the laboratory tests indicate the absence of ettringite in the samples and the abundant presence of anhydrous slag grains or without evidence of hydration, and a high amount of incorporated air, with low adhesion of aggregate to the cement paste. Considering the recurrence of the pathologies observed in facade cladding, this work allows to show the relevancy of the data of some characterization techniques associated to the visual inspection, focusing to adequate conclusion of the diagnostic hypothesis.
Reference:
SAHADE, Renato Freua; CHOTOLI, Fabiano Ferreira; LIMA, Sergio Soares de; LEAL, Priscila Rodrigues Melo. Caracterização de argamassa de revestimento de fachada em edifício litorâneo com expansão, fissura com esfarelamento e baixa resistência mecânica: estudo de caso. In: TULIO, Franciele Braga Machado. (Org.) Pesquisa científica e inovação tecnológica nas engenharias. Ponta Grossa, Atena, 2019. Cap.4, p.35-44.
This work presents the results of characterization tests in the coating mortar of a building of 20 floors, which has presented expansion, cracking with crumbling and low mechanical resistance throughout its 12 years. The preliminary observed signs referred to the inappropriate use of pulverized gypsum in the final stage of the coating mortar applying. However, during chemical evaluation tests, it was noted that this was not the precursor to the pathological manifestation observed. For the mechanical characterization, visual inspection was used in conjunction with the qualitative evaluation of percussion and tensile strength tests. X-ray diffraction (XRD), mix proportion analyses, differential thermogravimetric analysis (TG / DTG) and petrographic analysis were performed for chemical and mineralogical characterization. The results of the mechanical analysis indicated that the entire coating mortar is compromised. The data from the laboratory tests indicate the absence of ettringite in the samples and the abundant presence of anhydrous slag grains or without evidence of hydration, and a high amount of incorporated air, with low adhesion of aggregate to the cement paste. Considering the recurrence of the pathologies observed in facade cladding, this work allows to show the relevancy of the data of some characterization techniques associated to the visual inspection, focusing to adequate conclusion of the diagnostic hypothesis.
Reference:
SAHADE, Renato Freua; CHOTOLI, Fabiano Ferreira; LIMA, Sergio Soares de; LEAL, Priscila Rodrigues Melo. Caracterização de argamassa de revestimento de fachada em edifício litorâneo com expansão, fissura com esfarelamento e baixa resistência mecânica: estudo de caso. In: TULIO, Franciele Braga Machado. (Org.) Pesquisa científica e inovação tecnológica nas engenharias. Ponta Grossa, Atena, 2019. Cap.4, p.35-44.
