Environmental Alternative for the Stabilization of Amazonic Soils

The typical superficial soils of Amazonas present, in general, low technical quality for use in paving, being necessary to adapt them to the geotechnical requirements. As one of the alternatives, there is chemical stabilization, which minimizes the participation, as a rule, of natural materials. In this way, the compositions of two soils (red and white) characteristic of the Petroleum Base Pedro Geologo de Moura (Coari-AM) were analyzed, in the presence of chemical additives, Portland cement and Roadcem. Soils were characterized in terms of chemical and mineralogical aspects, additives and compositions according to X-ray diffraction mineralogy (XRD). The mechanical behavior of the formulations was also determined. The results of the chemical analysis showed very acid soils with a low organic matter content, and according to mineralogy, kaolinite and ilite clay minerals were identified. As for the additive, Portland cement, the presence of the main constituents of the product (CP II E-32), dicalcium silicate (C2S), tricalcium silicate (C3S), tricalcium aluminate (C3A) and ferro-aluminate (C4AF), in addition to gypsum and calcite, was evident. Regarding Roadcem®, the presence of the minerals halite (NaCl) and silvite (KCl) was observed. The results of the Portland-Roadcem® cement and Portland-Roadcem® cement-soil compositions showed the presence of halite and silvite. It should also be noted that the chemical additive Roadcem® developed a crystalline structure, when added to the natural soil, in the studied formulations. In mechanical performance, according to indirect tensile strength test and four-point bending test, an increase in soil resistance was observed when additives participated.