| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 169.6 KB | Adobe PDF |
Advisor(s)
Abstract(s)
As argamassas de reboco, aplicadas em reabilitação de edifícios antigos, devem
ser essencialmente diferentes das utilizadas atualmente em edifícios contemporâneos.
Isto porque estes materiais devem ter compatibilidade física, química e mecânica com
o suporte, o que é conseguido utilizando argamassas à base de cal. Este estudo desenvolveu
três composições diferentes de argamassas à base de cal com pigmentos,
sendo a primeira livre de aditivos, a segunda adicionada de metacaulim e a terceira de
cimento, buscando, através de ensaios laboratoriais, evidenciar a compatibilidade com
aplicações de reabilitação ou a falta dela. Todas as composições foram submetidas a
ensaios de envelhecimento natural e artificial, sendo expostos às condições climatéricas
da primavera do ano de 2019 no município de Bragança e a 1008 horas de ciclos de
intemperismo artificial em um equipamento QUV Accelerated Weathering Tester, respetivamente.
A caracterização da durabilidade de materiais diretamente expostos ao ar
livre tem vantagens económicas e permite a melhoria da qualidade do material, atendendo
aos requisitos do mercado de forma mais eficaz. Os resultados obtidos mostram
justamente a incompatibilidade da utilização de altos teores de materiais pozolânicos
e cimento, já que estes resultam em valores inadequadamente altos de resistência à
flexão e compressão para alvenarias antigas. Os ensaios de envelhecimento apresentam
duas linhas de tendência, sendo a degradação dos materiais maior em um fator 1:2
na metodologia artificial; porém, em termos de resistência as mesmas são acrescidas
nesta metodologia, provenientes de uma aceleração e potencialização no processo de
carbonatação da cal presente em todas as composições.
When applied to the rehabilitation of buildings, rendering mortars are essentially different from those used in contemporary buildings. This is because these materials must have physical, chemical and mechanical compatibility with the substrate, which is achieved using lime-based mortars. This study developed three different compositions of lime-based mortars with pigments, the first free from additives, the second added from metakaolin and the third from cement, seeking, through laboratory tests, to show the compatibility with rehabilitation or not. All compositions were submitted to natural and artificial aging tests, being exposed to the spring of 2019 in Bragança city and 1008 hours of artificial weathering cycles in a QUV Accelerated Weathering Tester equipment, respectively. Characterizing the durability of materials directly exposed to the open air has economic advantages and allows for improved material quality, heeding market requirements more effectively. The results show precisely the incompatibility of the use of high contents of pozzolanic materials and cement, as these result in inadequately high values of flexural and compression strength for old masonry. Aging tests have two trend lines, the degradation of materials being greater by a factor of 1:2 in the artificial methodology, but. in terms of resistance, they are increased in this methodology, resulting from acceleration and potentiation in the lime carbonation process present in all compositions.
When applied to the rehabilitation of buildings, rendering mortars are essentially different from those used in contemporary buildings. This is because these materials must have physical, chemical and mechanical compatibility with the substrate, which is achieved using lime-based mortars. This study developed three different compositions of lime-based mortars with pigments, the first free from additives, the second added from metakaolin and the third from cement, seeking, through laboratory tests, to show the compatibility with rehabilitation or not. All compositions were submitted to natural and artificial aging tests, being exposed to the spring of 2019 in Bragança city and 1008 hours of artificial weathering cycles in a QUV Accelerated Weathering Tester equipment, respectively. Characterizing the durability of materials directly exposed to the open air has economic advantages and allows for improved material quality, heeding market requirements more effectively. The results show precisely the incompatibility of the use of high contents of pozzolanic materials and cement, as these result in inadequately high values of flexural and compression strength for old masonry. Aging tests have two trend lines, the degradation of materials being greater by a factor of 1:2 in the artificial methodology, but. in terms of resistance, they are increased in this methodology, resulting from acceleration and potentiation in the lime carbonation process present in all compositions.
Description
Keywords
Argamassas Reboco Reabilitação Pigmento
Pedagogical Context
Citation
Obrzut, Lauren; Luso, Eduarda; Medeiros, Arthur (2019). Experimental characterization of colored lime mortars subjected to aging tests. In VI Encontro de Jovens Investigadores do Instituto Politécnico de Bragança. Bragança: IPB
Publisher
IPB