ENVIRONMENTAL PROPERTIES OF ENVIRONMENTALLY FRIENDLY CONSTRUCTION MATERIALS: RECYCLED LDPE COMPOSITES FILLED BY BLAST FURNACE DUST

ABSTRACT This study focused on creating a sustainable composite material using blast furnace dust of the iron-steel industry and plastic wastes of the plastic industry in order to reduce the embodied energy of the material and generate more sustainable material. In this study, varying amounts of blast furnace dust (BFD), which is the primary iron-steel industry waste and which is used as filler for recycled low-density polyethylene (LDPE), was mixed to create the composite material. The embodied energy, emissions to water and air (volatile organic compounds) of BFD filled LDPE composites were determined. It was found that the composite materials had less embodied energy compared with polymer-based flooring materials such as epoxy, polyurethane (PU) and polyvinylchloride (PVC). In addition, it was determined that the composite material did not release emissions to water and have fewer total volatile organic compounds (TVOCs). These results showed that the produced composite material could be used in buildings as a sustainable floor coating material, thus saving raw materials and supporting indoor air quality and recycling.

Uso de polvo de alto horno para mejorar las propiedades de material granular para pavimentos

The granular base and sub-base materials used in the construction of road surface structures must comply with certain requirements. In some cases, the requirements are not complied with and it is necessary to search for alternatives to improve the properties of the materials and thereby enable the use of these materials in the construction of roadways. Blast furnace dust is a residue from the production of steel that is of little use and is causing a negative environmental impact due to its accumulation. This study was carried out to analyse the possibility of utilizing blast furnace dust to improve the properties of granular materials, as an alternative that mitigates the environmental problems caused by the disposal and accumulation of these residues, which affect the areas of influence of these companies. To achieve this goal, the chemical and physical properties of blast furnace dust were determined and a analysis was carried out on mixtures of granular base and sub-base materials with 0, 2, 4, 6, and 8 percent dust. The analysis took place of determined characteristics including optimum humidity, maximum dry density, resistance, plasticity, and expansion in the presence of water. The results indicate that with the incorporation of 6% of BFD the properties of the granular material are improved and it can be used as an optimal material in road construction.

Behavior of the Dynamic Modulus and Fatigue in Asphalt Mixtures with Blast Oxygen Furnace Slag and Blast Furnace Dust

Slag from a Blast Oxygen Furnace (BOF) is produced during the transformation of cast iron, coming from the blast furnace, into steel during the integrated steelmaking process, just as blast furnace dust (BFD) is produced during the transformation of the iron mineral into cast iron. These residues have generated environmental problems due to the accumulation and inadequate disposal thereof. Consequently, this study aims to analyze the use and behavior of the dynamic modulus and the fatigue in asphalt mixtures with partial (50 %) and total (100 %) substitution of the coarse aggregate for BOF slag and the fine aggregate for BFD. The results are compared with the behavior of a mixture elaborated with conventional aggregates. To achieve this objective, the chemical and physical properties of BOF and BFD were determined along with the optimum asphalt cement content, determined using the Ramcodes methodology. Tests were carried out to evaluate the physical characteristics, the dynamic modulus, and the fatigue of each type of mixture. The results of this study demonstrate adequate fatigue behavior and a slight reduction in dynamic modulus in mixtures with BOF and BFD. This allows us to deduce that the use of these residues is feasible and thereby to contribute to sustainable development and the protection of the environment.

Preparation process of cold bonded pellets with iron-bearing dust and sludge from steel production process

Blast furnace dust (BFD) and converter sludge (CS) were used as raw materials for preparing of cold bonded pellets (CBPs). The results showed that BFD contained high content of C, Fe and harmful element of Zn. Conversely, the CS had more Fe and Ca content and less Zn. BFD particles are mostly large and irregular in shape with poor hydrophilicity, whereas CS particles are generally smaller spherical and could bond together easily. Additionally, the main factors influencing the performance of CBPs are the binder, moisture, and pressing pressure. By controlling the mixing ratio of BFD and CS, selecting the appropriate binder and binder amount, and controlling the moisture and pressure, CBPs with a compressive strength and a falling strength of up to 142.7 N and 8.34 times, respectively, can be prepared, thus meeting the requirements of the rotary hearth furnace and the OxyCup production process.