Banca de DEFESA: TARCÍSIO SANTIAGO GOMES FILHO

ANALYSIS OF THE INFLUENCE OF THE INCORPORATION OF GESSOALFA, FROM SALINE INDUSTRY WASTE, AND BETA RECYCLED PLASTER PASTE FOR CIVIL CONSTRUCTION COVERAGE

Plaster; recycling; mechanical properties, workability, civil construction coating.

Gypsum is a material widely used by various industries, ranging from cement to dental, construction being the largest consumer. The search for the technical and economic feasibility of recycling their waste, as well as for new mineral sources that can alleviate the intense exploitation of the soil resulting from this activity, has become increasingly important. In this context, it has been studied in recent years the possibility of recycling their waste through recalcination and to obtain the calcination of waste generated by the saline industry, known as “carago crú” or malachacheta. The objective of this work is to evaluate the influence of recalcined plaster and the plaster produced from the calcination of "carago". The experiments involved chemical and mineralogical characterization through the following techniques: X-ray diffraction (XRD), X-ray fluorescence (FRX), thermogravimetric analysis (TG / DTG) and scanning microscopy (SEM). The mechanical and workability properties of the plaster were evaluated from the analysis of initial and final adhesion time, mini-stroke, axial compressive strength, tensile strength and mass constancy. The STATISTICA 7.0 software in the design of the experiments and in the analysis of the obtained results. The recycled plaster was obtained by calcination under atmospheric pressure, temperature of 150 ° C and cycle time of 1.5 hours. Carago was autoclaved at 1.8 Bar, 129 ° C and a 2 hour cycle. The analyzes showed that the paste formulated with 33% alpha salt and 67% commercial plaster presented satisfactory results in all the performed analyzes, although it was also found that the highest values of direct tensile strength were found in recycled plaster paste. composition.