VALE, W. L. O.; http://lattes.cnpq.br/2590918858332629; VALE, Walker Luiz de Oliveira do.
Resumo:
The work here presented it is part of a group of researches regarding quality
of the materials used by the professionals of the civil construction of our area. That
group of researches, that he/she stops in the phenomenon efflorescences, he/she
has as study object the present soluble salts in these materials. Those salts produce
the calls efflorescences and subcfflorescences, whose occurrences bring I get great
damages to the structures of the civil works.
The soluble salts, that they create the efflorescences and subcfflorescences,
they can be originating from of the raw materials, of the construction materials and
its components, of the existent water in the underground and/or of the own soil in
which the work is located. The efflorescences and subefflorescences result of the
crystallization of the soluble salts, in the surfaces and/or in the internal pores of the
materials and in the construction pieces, in the form of saline deposits, these
resultants of the migrations and posterior evaporation of saline solutions aqueous.
The efflorescences brings in itself a more problem of aesthetic order than of
structural order, unlike the subefflorescences, that due to the internal tensions
produced by those, they cause more harmful structural effects.
In our study, we studied samples of coarse aggregate, it sands and sand-clay
mixtures, marketed in the city of Campina Grande, in the state of Parafba, with the
objective of studying its potential efflorescences; the samples of material were
collected at sixteen commercial stores of materials of construction of the referred
city. The samples performed a total of forty eight, subdivide in sixteen samples of
coarse aggregate, sixteen samples of sand and sixteen sand-clay mixtures, properly
beneficiaries, stored and classified.
They were used, in the development of that research, the Methodologies
2.34 to 2.40, of EMBRAPA (1979), with the objective of quantification of the ionic
composition of the extracts of saturation of the forty eight studied samples. Besides the methodologies, above mentioned, the one of determination of
the solid residues were used and of the electric conductivity (EMBRAPA), and of
the sulphates determination (APHA) of the respective samples.
The determination of the electric conductivity (CE) and of the total solid
residues serve to the elaboration of an equation that correlated electric conductivity
and percentage of total soluble salts (% Total Soluble Salts). Through statistical
studies, of simple lineal regression, based on the work accomplished by Figueircdo
and adaptation of the equation developed by Richards, such correlation was gotten.
In the development of the work, two loamy materials were used for die making of
the "efflorwicks", that they tested the efflorescences degree in ambient conditions
of the analyzed samples, based on the study developed by Nascimento (1998) and
recommendations of Amberg & Washburn (1946).
Based on the Brazilian norms NB-1/78, of ABNT and Spanish HEY - 80,
indicated by Canovas (1988), it can be developed the analysis and discussion of the
results.
The obtained results indicate to be possible the determination of the total
percentage of soluble salts through the electric conductivity and that the studied
samples of coarse aggregate, it sands and sand-clay mixtures do not present harmful
text of salinity. Of the accomplished study, it cannot him still to end that, the
possible efflorescences and subefflorescences are not originating from of the
samples coarse aggregate, of sand or of sand-clay mixtures used in the civil works,
and that through a good drainage and of a good drainage the problem can be
avoided, because, the largest influence factor is the presence of water.