Novos compósitos para materiais de construção civil com base em solo de bota-fora, lodo e sedimentos de dragagem marinha e resíduo da produção da cal

Abstract

This study explored the development of composites to create civil construction materials using a mixture of discarded soil from mining dolomitic limestone deposits, added sludge and sediments from marine dredging of Port of Antonina in Paraná State, and the residues from the production of lime as a hydraulic agglomerate, with natural time cure, unburning and without the emission of greenhouse gases. Twelve mixtures were prepared, varying the contents of each raw material: sludge and dredging sediments between 20% to 50%, discarded soil between 30% to 60%, and residue from the production of lime between 15% to 30%. Curing times were set at: 3, 7, 14, 28, 60, 90, 180, 365, 730 and 1.095 days. Compressive strength at 28 days of all examples reached strengths between 6.3 and 11.4 MPa, and at 1.095 days with resistance to uniaxial compression between 10.4 and 22.8 MPa. The evolution of compressive strength increased up to 1,095 days of cure, resulting from the alkaline composition and the increase in the elements of calcite, dolomite and quartz. The apparent densities values varied from 2.69 to 3.14 g/cm³ and the expansion coefficient between 0.14% and 1.56%. The values of water absorption after 90 days of cure varied between 8.9% and 15.1% and the coefficient of resistance to water reached 1.17. The results of the afore mentioned composites qualify for use in several areas of civil construction and infrastructure. The evolution of the increased resistance to uniaxial compression during curing came from the chemical reactions of raw materials in an alkaline environment generating new amorphous formations. The materials were analyzed in the MEV methods with EDS and LAMMA, FRX and DRX methods for obtaining the chemical composition and mineralogical formation. Derived thermogravimetry (DTG) and differential thermal analysis (DTA) tests to identify the behavior of the cured composites with the thermal variation. Leaching test of sludge and sediments from marine dredging for the identification of inorganic contaminants. The positive results demonstrated countless possibilities of using these composites and residues to contribute in an environmentally sustainable way and reduce the emission of greenhouse gases.