LAUSR

In this study, the main purpose was the mineralogical and thermal characterization of clayey siltites sampled in a quarry located near Viracopos Airport, Campinas city, São Paulo State, Brazil. The sedimentary rocks are fissile and expansive and are therefore easily disaggregated. These characteristics make the rock of difficult geomechanical characterization, because it undergoes defragmentation very easily. Mineralogical considerations about the composition of this rock were carried out by petrography analysis, scanning electronic microscopy (SEM), X-ray diffraction pattern and energy-dispersive spectroscopy. Thermal characterization of powdered rock was carried out by thermogravimetry (TG/DTG) under synthetic air and nitrogen purge gases. The dehydration kinetics of this rock was studied by a non-isothermal method. The mineralogical results show that this rock had quartz, feldspar and kaolinite as the major components and pyrite and chlorite as the minor constituents. The presence of organic matter was verified as fragments present in the rock and seen by SEM. The amount of organic matter was also determined by the gravimetric method, and the results showed a loss of 3.27%. The differential thermal analysis results under nitrogen purge gas exhibit the transition phase of quartz at 575 °C. The kinetic evaluation was made with two dehydration stages obtained from DTG curves, which show that the dehydration stage occurs with two behavior patterns.