ESTUDO LABORATORIAL DE MISTURAS DE FOSFOGESSO, SOLO TROPICAL E CAL PARA FINS DE PAVIMENTAÇÃO
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Data
2009-08-21
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Universidade Federal de Goiás
Resumo
The phosphogypsum, subproduct of the manufacture of the phosphoric acid, became the
objective of studies, due that it requires the availability of large areas to be stored. The
disposal this waste increases the cost of generating company and can even cause a series of
environmental problems. In this context, It has been arisen the interest to study the application
of phosphogypsum in pavement construction, to minimized environmental damage caused by
its storage and to obtained low-cost pavement with satisfactory performance. The objective of
this research was analyzed the behavior of mixtures composed of phosphogypsum (produced
in Catalão-GO region), regional tropical soils and lime, to the implementation of waste in
pavement. Laboratory tests of specific gravity of solids, consistency limits, grain size,
compaction in the intermediate energy, expansion and California Bearing Ratio - CBR,
Methodology Miniatura Compactada Tropical - MCT, were performed for evaluation of the
soil, phosphogypsum, soil-mixtures of phosphogypsum, soil-lime and soil-phosphogypsumlime
behavior. Additional tests of simple compression strength, permeability and chemical
analysis were also performed. The mixture was called Mixture 1 (90% soil + 10%
phosphogypsum), Mixture 2 (80% soil + 20% phosphogypsum), Mixture 3 (70% soil + 30%
phosphogypsum) Mixture 4 (97% soil + 3% limestone lime CHIII), Mixture 5 (94% soil + 6%
limestone lime CHIII), Mixture 6 (91% + 9% limeston lime CHIII), Mixture 7 (81.9%
Catalão-GO soil + 9.1% phosphogypsum + 9% lime CHIII), Mixes 8 (81.9% Catalão-GO soil
+ 9.1% phosphogypsum+ 9% dolomitic lime), Mixes 9 (84.6% Goiânia-GO soil + 9.4%
phosphogypsum + 6% lime CHI). The results are valid for phosphogypsum generated through
the dihydrate process obtained in Catalão-GO city. The results were concluded that between
the soil-phosphogypsum mixtures, the mixture 2 showed the best performance and can be
used in sub-base of pavements. For the lime-soil mixtures, the mixture 6 showed the
possibility to be use on base of pavement with low traffic volume, by presenting CBR greater
than 60%. Soil, lime and phosphogypsum mixtures showed no resistance to be used in layers
of pavement due to the occurrence of chemical reactions between the three materials. These
reactions cause the appearance of mineral etringita. They increase the plasticity and the values
of expansion. In principle, the risk of contamination occurs in the subsoil or groundwater if
the soil-phosphogypsum mixtures are used in works is minimum. However, when waste is
used in pavement construction is necessary to adopt preventive measures and carry out
monitoring. The use of unconventional materials, i.e. phosphogypsum and tropical soil
mixtures, can be considered an interesting alternative from a technical, environmental and
economic point of view
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Citação
RUFO, Rosely Costa. Laboratory study of mixtures of gypsum, lime and tropical soil for paviment. 2009. 153 f. Dissertação (Mestrado em Engenharias) - Universidade Federal de Goiás, Goiânia, 2009.