DECIV - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/497
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Item Use of steel slag and LAS-based modifying admixture in obtaining highly eco-efficient precast concrete products.(2023) Martins, Ana Carolina Pereira; Carvalho, José Maria Franco de; Duarte, Matheus do Nascimento; Pedroti, Leonardo Gonçalves; Ribeiro, José Carlos Lopes; Peixoto, Ricardo André FiorottiThis paper presents a study on improving the eco-efficiency of no-slump concrete for precast elements using Basic Oxygen Furnace Slag (BOFS). Recycled BOFS powders and aggregates have been produced to obtain mixtures with better particle size distribution and improved packing density based on a particle packing method. A comprehensive experimental investigation was carried out on mixtures with different cement contents (5%, 10%, and 15% vol.) and compaction energy levels (6, 10, and 20 blows in a sand rammer). A modifying admixture based on Linear Alkyl Benzene Sodium Sulfonate (LAS) has also been evaluated as a workability and cohesiveness enhancer for steel slag concretes. In addition, concrete eco-efficiency was evaluated by measuring the binder intensity (bi) and waste consumption. The highest compaction energy provided packing densities ranging from 0.78 to 0.80, and BOFS aggregates led to better mechanical performances. The BOFS concrete containing 15% cement obtained the best strength (52.1 MPa) and bi value (7.0 kg/m3 /MPa), with a waste consumption of 2356.57 kg/m3 . The mixture with the lowest cement consumption (5% - 121.56 kg/m3 ) and the highest consumption of waste (2637.82 kg/m3 ) reached 16 MPa, delivering a bi of 7.6 kg/m3 /MPa.Item Quartzite tailings in civil construction materials : a systematic review.(2023) Martins, Letícia Matias; Peixoto, Ricardo André Fiorotti; Mendes, Júlia CastroThe inadequate management of waste from the mining industry can lead to several environmental problems. For instance, the extraction of quartzite, an ornamental stone, generates quartzite waste (or residues or tailings) (QTZ), which is commonly deposited in the environment, causing landscape degradation, contamination by dust, and silting of rivers. To mitigate this scenario and stimulate the circular economy, this literature review focuses on the use of quartzite tailings in construction materials. A systematic search was carried out in the Scopus, Web of Science, and Google Scholar databases, including articles in English and Portuguese published between 2007 and 2022. The results showed that the use of QTZ as aggregate in cement-based composites is viable, as this waste has physical, chemical, mineralogical, and microstructural characteristics similar to conventional natural aggregate. Quartzite waste has been successfully adopted in precast concrete, cladding, and laying mortars, soil–cement bricks, and interlocking pavements. Many works brought the physical and mechanical characterization of the proposed construction materials, with gaps being observed mainly in terms of durability and performance. In conclusion, the use of QTZ in construction materials is a promising alternative, especially in cement-based composites. An important advantage is that this material requires little or no prior processing. However, the reuse of quartzite tailings is still limited, showing that more academic studies, private initiatives, and public policies are required.Item Effects of glass wool residue recycled admixtures on the properties of portland cement-based composites.(2022) Silva, Keoma Defáveri do Carmo e; Cotta, Jéssica Fernandes; Elói, Fernanda Pereira da Fonseca; Carvalho, José Maria Franco de; Peixoto, Ricardo André Fiorotti; Silva, Guilherme Jorge BrigoliniIn this study, the effects of a recycled mineral admixture based on glass wool residue (GWR) in microstructural and mechanical properties of ordinary portland cement (OPC)-based composites are examined. The GWR was dried and milled into a fine powder, whereby it was physicochemically characterized. Physicomechanical tests, quantitative X-ray diffraction, and scanning electron microscope observation were performed in pastes and mortars at 28, 56, and 90 days of age. Moreover, the potential application of the GWR was evaluated by determining the pozzolanic activity and the fiber reinforcement effect. The results showed that the partial replacement of cement by 25% by weight of GWR presented no reductions in flexural strength at 28 and 56 days of curing, whereas the long-term flexural strength increased by 17%. This replacement also increased the long-term compressive strength of the composites—reaching a strength activity index of 1.06. The results also showed that GWR presented some fiber reinforcement effect—depending on the particle size. Promising properties were observed for samples blended with GWR, yielding technical, environmental, and economic benefits.Item Lignin-based admixtures : a scientometric analysis and qualitative discussion applied to cement-based composites.(2023) Carvalho, Victor Rezende; Costa, Laís Cristina Barbosa; Baeta, Bruno Eduardo Lobo; Peixoto, Ricardo André FiorottiThe development of lignin-based admixtures (LBAs) for cement-based composites is an alternative to valorizing residual lignins generated in biorefineries and pulp and paper mills. Consequently, LBAs have become an emerging research domain in the past decade. This study examined the bibliographic data on LBAs through a scientometric analysis and in-depth qualitative discussion. For this purpose, 161 articles were selected for the scientometric approach. After analyzing the articles’ abstracts, 37 papers on developing new LBAs were selected and critically reviewed. Significant publication sources, frequent keywords, influential scholars, and contributing countries in LBAs research were identified during the science mapping. The LBAs developed so far were classified as plasticizers, superplasticizers, set retarders, grinding aids, and air-entraining admixtures. The qualitative discussion revealed that most studies have focused on developing LBAs using Kraft lignins from pulp and paper mills. Thus, residual lignins from biorefineries need more attention since their valorization is a relevant strategy for emerging economies with high biomass availability. Most studies focused on production processes, chemical characterizations, and primary fresh-state analyses of LBA-containing cement-based composites. However, to better assess the feasibility of using different LBAs and encompass the multidisciplinarity of this subject, it is mandatory that future studies also evaluate hardened-sate properties. This holistic review offers a helpful reference point to early-stage researchers, industry professionals, and funding authorities on the research progress in LBAs. It also contributes to understanding the role of lignin in sustainable construction.Item Mechanical and durability performance of concretes produced with steel slag aggregate and mineral admixtures.(2022) Costa, Laís Cristina Barbosa; Nogueira, Marcela Aguiar; Andrade, Humberto Dias; Carvalho, José Maria Franco de; Elói, Fernanda Pereira da Fonseca; Brigolini, Guilherme Jorge; Peixoto, Ricardo André FiorottiThe steel slag is a residue for the steel industry that is already applied in many cement-based composites, although there is a lack of studies on the durability of this material in aggressive environments. This work evaluated the durability against chloride attack of concrete produced using steel slag as aggregate and mineral admixture, called steel slag powder. For comparison purposes, reference concretes using conventional aggregates and commercial mineral admixtures (silica fume and metakaolin) were produced. The concretes produced with steel slag aggregates and steel slag powder had lower chloride penetration depths compared to conventional ones. The steel slag powder presented an ability similar to silica fume of forming Friedel salt. The concrete produced with steel slag aggregates also presented a smaller water absorption and a higher compressive/tensile strength compared to the reference one. In general, this research observed that steel slag concretes are techni- cally feasible options for the construction sector.Item Eco-efficient steel slag concretes : an alternative to achieve circular economy.(2022) Costa, Laís Cristina Barbosa; Nogueira, Marcela Aguiar; Ferreira, Larissa Caroline; Elói, Fernanda Pereira da Fonseca; Carvalho, José Maria Franco de; Peixoto, Ricardo André FiorottiAnnually billions of tonnes of aggregates are extracted to apply in civil construction generating environmental impacts and energy consumption. So, based on circular economy principles applying residues as aggregates is a good solution to reduce the mining activity and to generate a more efficient destination for the residues. Thus, this research aims to evaluate the technical, economic, and environmental performance of concretes produced entirely with steel slag aggregates. The concretes were characterized through physical properties, as specific gravity, water absorption, compressive and tensile strength. Durability tests (expansibility) were also conducted. The authors analyzed the cost assessment and environmental impact of steel slag concrete production as well. The incorporation of steel slag increases the compressive and tensile strength of concrete, analyzed in different ages. Additionally, the steel slag does not present expansibility when confined in the concrete matrix. The entire replacement of natural aggregates for steel slag allowed to reduce in 31% the cement consumption, a decrease of 140 kg/m3 , for the same strength class. The environmental analysis showed that the incorporation of steel slag aggregates reduced the cement intensity of concrete and its impact. Regarding the cost assessment, the mixtures with steel slag presented a lower cost compared to the conventional one. These results indicate that steel slag aggregates could be used in a cleaner production of concrete, replacing natural aggregates with no injury. This research provides the feasibility of using steel slag aggregates in a cleaner and cheaper concrete production and contribute to the promotion of sustainable solutions for the construction sector through the circular economy principles.Item Steel slags in cement-based composites : an ultimate review on characterization, applications and performance.(2021) Martins, Ana Carolina Pereira; Carvalho, José Maria Franco de; Costa, Laís Cristina Barbosa; Andrade, Humberto Dias; Melo, Tainá Varela de; Ribeiro, José Carlos Lopes; Pedroti, Leonardo Gonçalves; Peixoto, Ricardo André FiorottiSteel slags are by-products generated in high volumes in the steel industry. Their main constituents are calcium, silicon, ferric, aluminum, and magnesium oxides. Larnite, alite, brownmillerite, and ferrite are also found. The presence of expansive compounds cause concern when used in cement-based compos- ites; however, mitigating routes have been proposed. Activation techniques improve the binding proper- ties of steel slag powder, potentiating its use as a supplementary cementitious material (SCM). As an aggregate, steel slag presents good morphological and mechanical properties. Promising mechanical and durability performances in cement-based composites encourage further research to promote the use of steel slag.Item A review on the evolution of Portland cement and chemical admixtures in Brazil.(2021) Natalli, Juliana Fadini; Thomaz, Eduardo Christo Silveira; Mendes, Júlia Castro; Peixoto, Ricardo André FiorottiOver the years, Portland cement concretes have undergone increasing demands for constructability, cost, quality, and environmental impact. These demands were met, mainly, through changes in the cement composition and the introduction of chemical admixtures. In this sense, through a literature review, the authors sought to create a collection of information on the evolution of these materials and their standards from 1937 to 2020 in Brazil . This work is part of a research project that aims to elaborate a dating protocol for Brazilian concretes. From the review conducted, the authors observed that the absence of systematic records in the Brazilian civil construction sector hinders the attempt to create a chronology of the development of concrete in the country. In addition, we concluded that the knowledge of the evolution of Portland cement and chemical admixtures is relevant information that can assist in concrete dating processes. The reliable comparison data, posteriorly combined with microstructural characterisation techniques, may lay the basis for an effective dating methodology.Item Application of construction and demolition waste in civil construction in the Brazilian Amazon : case study of the city of Rio Branco.(2021) Souza, Fernando da Silva; Carvalho, José Maria Franco de; Silveira, Gabriela Grotti; Araújo, Vitória Cordeiro; Peixoto, Ricardo André FiorottiThe lack of usable aggregates for civil construction in Rio Branco (capital of Acre, a Federal State in the Amazon region) makes the production and use of recycled aggregates from construction and demolition waste (CDW) an alternative of great interest. In this study, a comprehensive char- acterization of CDW collected from 24 construction sites of six building types and three different construction phases (structures, masonry, and finishing) was carried out. The fine and coarse recycled aggregates were produced and evaluated in 10 different compositions. The aggregates’ performance was evaluated in four mixtures designed for laying and coating mortars with a total replacement of conventional aggregates and a mixture designed for a C25 concrete with 50% and 100% replacement of conventional aggregates. CDW mortars showed lower densities and greater water retention, initial adhesion, and mechanical strength than conventional mortars. CDW concretes presented lower densities and greater resistance to chloride penetration than conventional concrete, with a small mechanical strength reduction. The recycled CDW aggregates proved to be technologically feasible for safe application in mortars and concrete; for this reason, it is believed that the alternative and proposed methodology is of great interest to the Amazonian construction industry, considering the high costs of raw materials and the need for defining and consolidating a sustainable development model for the Amazon region.Item Mechanical performance and resistance to carbonation of steel slag reinforced concrete.(2021) Andrade, Humberto Dias; Carvalho, José Maria Franco de; Costa, Laís Cristina Barbosa; Elói, Fernanda Pereira da Fonseca; Silva, Keoma Defáveri do Carmo e; Peixoto, Ricardo André FiorottiThe use of residues as alternative materials in the production of cement-based composites is significantly growing since it embraces the circular economy concepts. This alternative reduces the demand for nat- ural resources by the construction sector and provides a proper destination for a range of industrial resi- dues. However, the alternative materials must perform properly for safe applications. In this way, the steel slag, a residue of the steel industry, stands out. The steel slag is already applied in some cement- based composites showing enhancement in the mechanical performance, although its durability is barely evaluated. So, this research produced eco-friendly structural concretes of three compressive strength classes and for similar application parameters. The evaluations were performed in concretes with total replacement of conventional aggregates by steel slag aggregates, containing no chemical admixtures and in the presence of a PCE-based superplasticizer. The mechanical performance and resistance to car- bonation of these products were evaluated. An accelerated carbonation test was proposed and adopted to better understand the carbonation phenomenon within the research timeframe. The steel slag concretes presented higher compressive strengths and reductions in carbonation depths up to 60% compared to conventional ones. These results corroborate the technical feasibility of applying steel slag as aggregates in cement-based composites.