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- Safe use of electric arc furnace dust as secondary raw material in self compacting mortars productionPublication . Lozano-Lunar, Angelica; Raposeiro Da Silva, Pedro; De Brito, Jorge; Fernandez Rodriguez, Jose Maria; Jimenez, Jose RamonThis research contributes to the development of the Circular Economy concept by managing waste through its use as a construction material. A novel process in which two samples of industrial waste Electric Arc Furnace Dust collected from two different steelwork plants are used as secondary raw material in the production of self-compacting mortars is proposed. At a previous stage, a characterisation of mortar material components was carried out. Then, self-compacting mortars with replacement ratios of 25%, 50% and 100% of siliceous filler with Electric Arc Furnace Dust were designed. The feasibility of Electric Arc Furnace Dust use was analysed by means of the study of mechanical strength, mineralogical, capillary properties and leaching behaviour in monolithic and granular state. The environmental classification of mortars, according to their leaching behaviour, was carried out in accordance with European Directive 2003/33/EC (2003). Electric Arc Furnace Dust incorporation modified the self-compactability and common hydration reactions. Mechanical strength decreased with Electric Arc Furnace Dust incorporation, although the mortar with 25% of replacement with one of the Electric Arc Furnace Dust's showed a negligible loss compared to the self-compacting reference mortar. Water absorption by capillarity increased with Electric Arc Furnace Dust content, consistently with the mortars' mechanical behaviour. The leaching behaviour analysis in a monolithic state revealed that all mortar releases were below the permitted limit. In a granular state, the mortar with the best mechanical behaviour was environmentally safe, leaving all the elements encapsulated by the self-compacting matrix. The results of this study contribute to Electric Arc Furnace Dust management through its valorisation as secondary raw material in the production of self-compacting mortars, addressing an unprecedented line of research.
- Safe use of electric arc furnace dust as secondary raw material in self-compacting mortars productionPublication . Lozano-Lunar, Angélica; Raposeiro Da Silva, Pedro; De Brito, Jorge; Fernandez Rodriguez, Jose Maria; Jimenez, Jose RamonThis research contributes to the development of the Circular Economy concept by managing waste through its use as a construction material. A novel process in which two samples of industrial waste Electric Arc Furnace Dust collected from two different steelwork plants are used as secondary raw material in the production of self-compacting mortars is proposed. At a previous stage, a characterisation of mortar material components was carried out. Then, self-compacting mortars with replacement ratios of 25%, 50% and 100% of siliceous filler with Electric Arc Furnace Dust were designed. The feasibility of Electric Arc Furnace Dust use was analysed by means of the study of mechanical strength, mineralogical, capillary properties and leaching behaviour in monolithic and granular state. The environmental classification of mortars, according to their leaching behaviour, was carried out in accordance with European Directive 2003/33/EC (2003). Electric Arc Furnace Dust incorporation modified the self-compactability and common hydration reactions. Mechanical strength decreased with Electric Arc Furnace Dust incorporation, although the mortar with 25% of replacement with one of the Electric Arc Furnace Dust's showed a negligible loss compared to the self-compacting reference mortar. Water absorption by capillarity increased with Electric Arc Furnace Dust content, consistently with the mortars' mechanical behaviour. The leaching behaviour analysis in a monolithic state revealed that all mortar releases were below the permitted limit. In a granular state, the mortar with the best mechanical behaviour was environmentally safe, leaving all the elements encapsulated by the self-compacting matrix. The results of this study contribute to Electric Arc Furnace Dust management through its valorisation as secondary raw material in the production of self-compacting mortars, addressing an unprecedented line of research.
- Ternary blends for self-compacting mortars production composed by electric arc furnace dust and other industrial by-productsPublication . Lopez-Uceda, Antonio; Cantador, David; Raposeiro Da Silva, Pedro; De Brito, Jorge; Fernandez Rodriguez, Jose Maria; Jimenez, Jose RamonThis study is framed within the circular economy model through the valorisation of industrial by-products. This research shows the results of producing self-compacting mortars (SCMs) with electric arc furnace dust (EAFD) and other industrial by-products such as fly ash, conforming (FA) or not conforming (NcFA), from coal-fired power plants, or recovery filler (RF) from hot-mix asphalt plants. Three batches of SCMs, each with one industrial-by product (FA, NcFA, or RF), and three levels of EAFD ratio incorporation (0%, 10%, 20%), were tested. An extra batch with a greater amount of FA was manufactured. When the incorporation ratio of EAFD rose, the mechanical strength decreased, due to the presence of a calcium zinc hydroxide dihydrate phase; nevertheless, this decrease diminished over time. All SCM mixes, except the 40C 40FA 20 EAFD mix, were above 20 MPa at 28 days. All mixes named 70C and 40C reached 40 and 30 MPa, respectively, at 90 days. Mixes with EAFD showed less capillarity and no difference in water absorption by immersion with respect to mixes without EAFD after 91 days. The SCMs designed proved to be stable in terms of leaching of the heavy metals contained in EAFD, where all the hardened SCMs were classified as inert.
- Performance and durability properties of self-compacting mortars with electric arc furnace dust as fillerPublication . Lozano-Lunar, Angélica; Raposeiro Da Silva, Pedro; De Brito, Jorge; Álvarez, J. I.; Fernandez Rodriguez, Jose Maria; Jimenez, Jose RamonThis study analyses the feasibility of incorporating electric arc furnace dust (EAFD) in the production of self-compacting mortars from the point of view of durability. Two types of EAFD, previously characterized and classified as hazardous waste, were used. Siliceous filler (powder) was replaced at different ratios (25%, 50%, and 100%, by volume). The following self-compacting mortar properties were measured at different curing times: total heat of hydration, compressive strength, ultrasonic pulse velocity, pore size distribution through mercury intrusion porosimetry, shrinkage and mass loss, water absorption by capillary, water absorption capacity, bulk density, skeletal density, open porosity for water, wettability by contact angle measurement, electrical resistivity, and carbonation depth. Although some of properties linked to the durability of the mortars, such as water absorption by capillarity, wettability or carbonation, were negatively affected by the incorporation of the EAFD, the results show the feasibility of replacing siliceous filler at up to 25% and the valorisation of EAFD as a secondary raw material (SRM). This research demonstrated that EAFD can be used as SRM as an alternative to landfills, thereby contributing to the promotion of the new circular economic model pursued by the European Union.
- Performance and durability properties of self-compacting mortars with electric arc furnace dust as fillerPublication . Lozano-Lunar, A.; Raposeiro Da Silva, Pedro; De Brito, Jorge; Alvarez, Jose Ignacio; Fernandez Rodriguez, Jose Maria; Jimenez, Jose RamonThis study analyses the feasibility of incorporating electric arc furnace dust (EAFD) in the production of self-compacting mortars from the point of view of durability. Two types of EAFD, previously characterized and classified as hazardous waste, were used. Siliceous filler (powder) was replaced at different ratios (25%, 50%, and 100%, by volume). The following self-compacting mortar properties were measured at different curing times: total heat of hydration, compressive strength, ultrasonic pulse velocity, pore size distribution through mercury intrusion porosimetry, shrinkage and mass loss, water absorption by capillary, water absorption capacity, bulk density, skeletal density, open porosity for water, wettability by contact angle measurement, electrical resistivity, and carbonation depth. Although some of properties linked to the durability of the mortars, such as water absorption by capillarity, wettability or carbonation, were negatively affected by the incorporation of the EAFD, the results show the feasibility of replacing siliceous filler at up to 25% and the valorisation of EAFD as a secondary raw material (SRM). This research demonstrated that EAFD can be used as SRM as an alternative to landfills, thereby contributing to the promotion of the new circular economic model pursued by the European Union.
- Rheological behaviour of concrete made with fine recycled concrete aggregates - Influence of the superplasticizerPublication . Cartuxo, F.; De Brito, Jorge; Evangelista, Luis; Jimenez, Jose Ramon; Ledesma, E. F.This paper evaluates the influence of two superplasticizers (SP) on the rheological behaviour of concrete made with fine recycled concrete aggregates (FRCA). Three families of concrete were tested: family CO made without SP, family Cl made with a regular superplasticizer and family C2 made with a high-performance superplasticizer. Five replacement ratios of natural sand by FRCA were tested: 0%, 10%, 30%, 50% and 100%. The coarse aggregates were natural gravels. Three criteria were established to design the concrete mixes' composition: keep the same particle size distribution curves, adjust the water/cement ratio to obtain a similar slump and no pre-saturation of the FRCA. All mixes had the same cement and SP content. The results show that the incorporation of FRCA significantly increased the shrinkage and creep deformation. The FRCA's effect was influenced by the curing age. The reference concrete made with natural sand stabilizes the creep deformation faster than the mixes made with FRCA. The incorporation of superplasticizer increased the shrinkage at early ages and decreased the shrinkage at 91 days of age. The regular superplasticizer did not improve the creep deformation while the high-performance superplasticizer highly improved this property. The incorporation of FRCA jeopardized the SP's effectiveness. This study demonstrated that to use FRCA and superplasticizer for concrete production it is necessary to take into account the different rheological behaviour of these mixes. (C) 2015 Elsevier Ltd. All rights reserved.