Caracterização geotécnica de um resíduo da produção de sal (carago)

Abstract

The large consumption of natural resources in the construction industry has generated interest in new ways to reduce these damages to the environment. One of the ways to solve this problem can be through the use, in geotechnical works, of carago, a residue composed of calcium sulfate dihydrate discarded in nature during the production of salt. This solution would reduce the need to extract new resources from nature during geotechnical works, which sometimes requires techniques to improve soil strength, as well as reduce the irregular disposal of carago in nature. Throughout this work, geotechnical characterization tests of carago were carried out. For the compaction tests, optimum water content between 6.93% and 9.30%, and maximum dry density of 1.78g/cm³ and 1.95g/cm³ were obtained. Its granulometry was predominantly sandy, in addition to being non-plastic. It was necessary throughout this work not to adopt the oven at 100ºC for the determination of moisture in the samples throughout the tests, since at this temperature chemical reactions occurred in the material. Then the methods of Speedy-Test and oven regulated at 60ºC were adopted. When analyzing its granulometric composition, it was classified according to the SUCS as SM-SW and by the HRB Classification System adopted by AASHTO in A-1-a, which characterizes it as a material that presents a general behavior as a subgrade from excellent to good. Other results of interest to civil engineering were those obtained by direct shear, permeability and CBR tests, which found that carago is a material with high shear strength, with friction angle values, without flooding, greater than 45º, as well as presenting a low permeability, having a minimum value in the molded samples of 1.558 x 10^(-4) cm/s, in addition to presenting values of 27.30% and 54,11% for CBR.