ESTUDO LABORATORIAL DE MISTURAS DE FOSFOGESSO, SOLO TROPICAL E CAL PARA FINS DE PAVIMENTAÇÃO

• Autor(a) principal: RUFO, Rosely Costa
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/0013000009mwp
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/632
• topic: Resíduo; Fosfogesso; Cal; Solos tropicais; Pavimentaçã; . Ensaios laboratoriais; 1. Resíduos 2. Fosfogesso 3. Cal 4. Solos tropicais 5. Pavimentação; Subproduct; Phosphogypsum. Lime; Tropical soil; . Pavement; Laboratory tests; CNPQ::ENGENHARIAS::ENGENHARIA SANITARIA::RECURSOS HIDRICOS

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