Compósitos para construção civil a partir de resíduo de minério de ferro da cidade de Mariana, lodo de dragagem do porto de Paranaguá e resíduo de produção de cal

Abstract

Currently, there is a strong tendency to reduce the exploitation of natural resources with the reuse of waste from material industrialization processes. In the present work, new composites for manufacturing construction materials using iron ore tailings (IOT) from Mariana city, dredging sludge (DS) from Paranaguá Port, and lime waste (LPW) were developed. The raw materials were collected, oven-dried, and characterized regarding their chemical, mineralogical, morphological and granulometric features. The specimens’ preparation technique consisted of drying, sieving, weighing, mixing, compacting, and curing. The proportion of raw materials ranged from 10 to 30 wt.% IOT, 40 to 75 wt.% DS and 15 to 30 wt.% r LPW. The developed materials were analyzed according to linear shrinkage, specific mass, axial compressive strength, water absorption, water resistance coefficient, leaching, and solubility. The new materials were also characterized through Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD) in order to analyze the physicochemical interaction processes of the structure formation processes of new materials. The developed composites showed axial compressive strength values of up to 22.66 MPa. Composites 4 (10 wt.% IOT, 60 wt.% DS e 30 wt.% LPW) and 8 (15 wt.% IOT, 55 wt.% DS, 30 wt.% LPW) were the ones that obtained the best strength values for all curing periods evaluated. All these materials can be used in general civil engineering applications, as foundations or sub-bases of roads, airfields and dams, replacing natural gravel, crushed stones, sand, and in the production of bricks, tiles and other products. The improved strength of the materials is attributed to the new amorphous gel formations. Using the three residues together for material production for civil construction is an innovation not reported in the literature só far.