PSI - Issue 11

Stefanie A. Campos et al. / Procedia Structural Integrity 11 (2018) 145–152 Stefanie A. Campos et al./ Structural Integrity Procedia 00 (2018) 000–000

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seeks strategies to minimize the arising impacts from production systems activities, which generate solid, liquid and gaseous wastes, impact the physical-ecological system and compromises the equilibrium of the planet (Calmon, 2007). Among natural resource exploration sectors, we highlight steel industry, that occupies a prominent role in Brazilian economy. There are 28 mills, of which 13 are integrated (production from iron ore) and 15 semi-integrated (from the pig iron process) that make Brazil an average producer of 33 million tons of crude steel. The steel slag is a co-product with volume generation in range of 100 kg to 150 kg per ton of steel produced, depending on technological route and raw materials used. In the processing stage, we always look for those that provide the most noble applications for the co-product (CGEE, 2010). CGEE (2008) recommends the use in production of concrete, primary coating for vicinal roads, use as an aggregate for hot-rolled asphalt concrete, soil use and as fertilizer for agriculture, among others. For other uses, the investigation of possibilities for reuse of waste must be adopted, noting the opportunities and limitations according to necessary requirements. According to Jonh (2000), the high volume of natural resources consumed in construction causes great environmental impacts. Thus, the use of steel slag in this sector can minimize this demand, but it is necessary to carry out studies that go beyond use of blast furnace slag by cement industry, enabling alternative product’s development for use in civil construction. The incorporation of waste into productive cycle of civil construction can be an alternative of reducing costs in production, since recycling and reuse are part of main alternatives that seek sustainable development. There are studies looking for alternatives to insertion of residues, where depending on characteristics such as chemical composition and particle size distribution, they can be used as a small aggregate in mortars for civil construction (Menezes et. al, 2009). In this paper, it will be developed a study for evaluation of steel slag as an aggregate in coating mortars by partially replacing the fine aggregate with proportions of 10%, 20% and 30%, analyzing its physical, chemical, mechanical, mineralogical, morphological and based on existing standards. The volume replacement percentages were up to 30% because it was an initial study to investigate the influence of steel slag as a fine aggregate in mortar coatings systems. The objective is to provide a volume reduction of steel production tailings, with the partial substitution of natural resources from non-renewable sources, contributing to sustainable development. According to NBR 13281 (ABNT, 2005), the mortar is composed of a homogeneous mixture formed by fine aggregates, inorganic binders and water, where it is possible to contain additives, having properties of adhesion and hardening. The coating mortar of internal and or external walls can be industrialized, dosed on site or in a metering plant, provided they meet the specific conditions required. For the manufacture of the mortar, the Portland cement CP II Z 32 - RS of Companhia Industrial de Cimento Apodi was adopted. This material has pozolane addition, good performance and resistance to aggressive agents. The fine aggregate came from the Curu River, located in the city of São Luiz do Curu. The steel slag used to replace the fine aggregate in the coating mortar was obtained by Companhia Siderúrgica do Pecém (CSP), where it is the result of a process for the use of new technologies and state-of-the-art equipment in the adoption of Baosteel Slag Short Flow (BSSF). In this process, according to CSP, the net slag of steelworks is tilted in a rotary drum, where the cooling takes place with water jets, with consequent granulation, followed by magnetic separation. The experiments were started three months after the collection of steel slag and they remained packed in bags. Fine aggregate and steel slag were characterized for granulometry, specific mass, absorption and powder content. The high specific mass is related to the high content of iron contained in the slag and the studies indicate the great abrasion because of the great hardness (Gumieri, 2002). The slag was also analyzed for abrasion and the result is in the same table. The results obtained from the sand and slag characterization are presented in Table 1. The grain size curve of the materials is shown in Figure 1. 2. Materials and methods 2.1. Materials