COMUNICAÇÃO TÉCNICA
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Nº 171296
Why use the lab to characterize old mortar coatings?
Claudia Bastos do Nascimento
Mirian Cruxên Barros de Oliveira
Valdecir Angelo Quarcioni
Pôster apresentado no
16th annual
International
Preservation Trades
Workshop ‐ IPTW
2012, Charleston
A série “Comunicação Técnica” compreende trabalhos elaborados por técnicos do IPT, apresentados em
eventos, publicados em revistas especializadas ou quando seu conteúdo apresentar relevância pública.
___________________________________________________________________________________________________
Instituto de Pesquisas Tecnológicas do Estado de São Paulo
S/A - IPT
Av. Prof. Almeida Prado, 532 | Cidade Universitária ou
Caixa Postal 0141 | CEP 01064-970
São Paulo | SP | Brasil | CEP 05508-901
Tel 11 3767 4374/4000 | Fax 11 3767-4099
www.ipt.br
WHY USE THE LAB TO CHARACTERIZE OLD MORTAR COATINGS?
Claudia Bastos do Nascimento1; Mírian Cruxên Barros de Oliveira2; Valdecir Angelo Quarcioni2
1 Instituto do Patrimônio Histórico e Artístico Nacional - IPHAN, Brazil
2 Instituto de Pesquisas Tecnológicas do Estado de São Paulo, IPT, Brazil
4. Results – Study Case of Sobradão Aguiar Vallin (Bananal/SP)
1. Abstract
The present work aims to draw attention to laboratory and human resources available in research institutes laboratories, especially in the IPT-Institute for
Technological Research of the State of São Paulo, Brazil, to subsidize the technical survey of built heritage and its restoration projects, specifically in the case of
inorganic mortar coatings. It also aims to highlight the importance of interdisciplinary work required in these cases. The different stages of laboratory assistance and
the benefits derived are presented in details, always seeking the care and preservation of the built heritage. Thus, it is essential for investment promotion agencies in
project financing laboratory infrastructure, multidisciplinary research projects focused on technical and scientific research applied to cultural heritage..
This study related of the Sobradão Aguiar
Vallin building was requested by the former
Department of Recovery of Cultural Property
in the State of São Paulo, responsible for the
collection of samples sent to our laboratory.
Therefore, only the characterization of the
two samples of mortar coating were
performed, identified as external coating and
internal coating. In both samples the
renderings consisted of mixed cement
mortars, lime and quartz sand with high fines
content (39% in the inner and 30% in the
outer coating). The proportions binder:
aggregate, in mass, is 1: 10.4 for the internal
coating and for 1: 18.7 for the outer coating.
2. Introduction
It is essential to promote technical and political discussion about the necessities of exchange among restorers of built heritage and support laboratories in order to
facilitate financial resource desirable for the development of research technical-scientific nature of the buildings, their building systems and their materials.
This poster will try to answer initially two questions, central to this discussion:
• Why use the laboratory characterization?
• When you use a lab?
Figures 2 to 5 show the grading curve of the
aggregate and the microscopic characteristics
of the mortars coating studied.
Assumptions:
• The principle of minimum intervention
• Research of the heritage property with technical-scientific approach
• Follow up with technical and scientific support for the intervention and the use of appropriate records of all activities.
According to the obtained informations, the
walls of the building are made of rammed
earth and adobe. We considered the
proportions binder: aggregate compatible with
the recommendation of CRATerre (1983)
coverings sealing elements in soil.
3. Working Methods
The Figure 1, based on Lichtenstein (1986), presents a flowchart
with the different stages of a study of historical building which
precede the restoration project.
Cadastral Survey
Technical Survey
- Research of mortar coatings:
Inspection
Critical analysis of technical
documentation
The experience of IPT - Institute for Technological Research of
the State of São Paulo is based on two aspects:
- Inspection-building techniques.
- Characterization of materials to formulate repairing materials.
visual assessment
monitoring
essays in loco
Survey geometric / spatial
Characterization of architectural style
and construction techniques
Historical Survey
Bibliographical Survey
Sampling
Characterization and laboratory evaluation
INVESTIGATION
Identification of anomalies and
deterioration mechanisms
The goals of these aspects are:
a) Evaluation of the state of conservation and investigation of the
causes of pathological manifestations for specifying corrective,
preventive measures and direct sampling, which is derived
fundamentally from tactile and visual inspection of the building,
complemented when necessary with tests to verify in situ the
bond strength, and laboratory analysis, such as verification of
soluble salts and microorganisms (fungi / algae). The pathologic
manifestations commonly found in the coatings of buildings of
historical value studied by our lab are: presence of moisture
(ascending, accidental) presence of biofilm (fungi, algae)
and higher plants, soluble salts, shrinkage cracking by thermal
variation or by presence of higher plants.
The presence of cement is an evidence that it
was incorporated coating after construction,
since the building is from 1860, and the start
of production of cement in Brazil dates from
1888, and culminated in 1924 with the
implementation of a industrial plant in Perus
in São Paulo State by the Companhia de
Cimento Portland. We don’t
have any
registers about imported cement used in this
building.
Identification of agents and
deterioration mechanisms
Recommendations for intervention
5. Conclusions
Simulation Laboratory
Performance evaluation
Physical compatibility
lower mech. resist.
Chemical Compatibility
Restoration Project
Figure1 - Flowchart of the stages of the restoration project.
b) Identification of materials and construction techniques in order to understand the history of the building and supporting the attribution of value.
Multidisciplinary scientific studies should be provided in phase of fundraising and planning activities
in order to provide the financial resources and the time needed to research activity.
The labs experience, added to the restorer, minimizes the risks of inappropriate interventions and
promotes the search for solutions that respect the principle of minimum intervention.
Thus, it is essential for investment promotion agencies in project financing laboratory infrastructure,
multidisciplinary research projects focused on technical and scientific research applied to cultural
heritage.
activities.
6. References
In this case, the characterization of isolated
samples, no further details of the building
obtained in situ, as modifications or repairs
performed in over a hundred years, makes it
difficult to do precise suggestions. So, our
recommendations
were based in the
literature for buildings constructed of earth
(CRATerre, 1983).
7. Acknowledgements

IPT - Institute for Technological Research
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
The Getty
Foundation
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APT - Association for Preservation
Technology International
• The selection of instrumental techniques depend on the goals, as mentioned, however, there is a tendency among the technical community to perform physical,
chemical, mineralogical and microstructural. Generally we use: mineralogical analysis by X-ray diffraction, petrographic analysis (optical microscopy), particle size
analysis of the aggregate by sieving and sedimentation and mix proportion determination (by chemical analysis). A natural consequence of the characterization of
mortars is the formulation of repair mortars, but it is not an activity performed routinely.
The formulation of mortar should be the object of careful study, especially when the mortar presents specific aesthetic characteristics, which require greater care. The
formulation of mortar repair occurs from the characterization of mortar building and characterization of materials available in the market. The selection of the
formulation is linked to the evaluation of the appearance and texture similar to the original coating and evaluation of physical performance (water absorption, no
shrinkage cracking) and mechanical (bond strength).
CRATerre. CENTRE DE RECHERCHE ET D’APPLICATION TERRE. 1983. Construire em Terre. 2 ed.
Paris: Ed. Alternatives. 286 p.
INSTITUTO DE PESQUISAS TECNOLÓGICAS DO ESTADO DE SÃO PAULO (IPT). Caracterização
de duas amostras de argamassa de revestimento do Sobradão Aguiar Vallin. Relatório Técnico no 54816 .
São Paulo. SP. 2001.
LICHTENSTEIN, N. B. Patologia das construções. São Paulo: EPUSP. (Boletim técnico 06). 1986.
activities.