cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14321955.v1
title: Microscopic analysis of pigmented concrete with rubber waste applied to the interlocking block

description: ABSTRACT In this work the microstructure of pigmented concrete with and without rubber residue was analyzed by scanning electron microscope, aiming its application in the manufacture of interlocking block. It was verified that the reference concrete (without rubber) presented dense and compact paste and according to the increase of the rubber content in the concrete, the tendency was observed to increase the porosity and number of voids in the cement paste, appearance of cracks and zone of sharp transition between aggregates and paste, except for the trace containing 5% rubber. These analyzes allowed a better understanding of the mechanical behavior of these concretes. The binder employed was structural white Portland cement. In order to give the interlocking block another architectural and aesthetic advantage, an inorganic type pigment based on iron oxides and blue chrome was used. The rubber residue used as a partial replacement for fine aggregate (natural sand) came from the tire retreading process and was added to the concrete in the following proportions 2.5%, 5.0%, 10%, 20%, 30% while the pigment content was kept constant, being 6% in relation to the cement mass. Regarding the mechanical tests, the results indicated that, for the traces containing 2.5% and 5.0% of rubber residues, the ABNT NBR 9781:2013 standard is attended with respect to the characteristic compressive strength at 28 days (greater than or equal to 35 MPa), which did not happen for the traces with 10%, 20%, 30%. Considering the concrete compositions studied in this research, it can be stated that the use of rubber waste as a partial substitute for sand is an alternative for recycling the product which adds a lot to the environment and avoids the inappropriate disposal of this environmental liability.
DOI: 10.6084/m9.figshare.14321957
title: Analysis of concrete behavior with addition of vegetable biomass ash subjected to the attack of sulfate ions

description: ABSTRACT The negative impacts caused by civil construction to the environment are motivated mainly by the demand for natural resources. The cement industry stands out for being responsible for about 5% of global CO2 emissions. Strategies have been used to reduce these emissions, such as increasing the performance of the binder by reducing its content in the production of concrete, through dosing methods with the particle packing. In this sense, the objective of the study was to evaluate the behavior of low-cement concrete, and addition of Plant Biomass Ash (PBA), exposed to sodium sulfate. An experimental study was carried out characterizing the materials used, an evaluation of the dimensional changes of mortar specimens and analysis of the cracking of the pieces, physical and mechanical tests on concrete submitted to two curing processes (sodium sulfate solution or conventional curing). The mix was developed with the aid of the EMMA packaging software and spreadsheet available in the literature, in which the cement content was reduced by 10, 15 and 20% by weight, replacing with PBA. The reference material showed a significant reduction in expansion when exposed to sulfate solution compared to samples submitted to conventional curing. As for mixtures added with PBA, they showed a reduction in strength when exposed for conventional curing and better behavior when exposed to the aggressive sulfate medium, both in strength and in expansion for the mixes with 10 and 15% cement reduction, the latter being considered efficient for aggressive environments.
DOI: 10.6084/m9.figshare.14321957.v1
title: Analysis of concrete behavior with addition of vegetable biomass ash subjected to the attack of sulfate ions

description: ABSTRACT The negative impacts caused by civil construction to the environment are motivated mainly by the demand for natural resources. The cement industry stands out for being responsible for about 5% of global CO2 emissions. Strategies have been used to reduce these emissions, such as increasing the performance of the binder by reducing its content in the production of concrete, through dosing methods with the particle packing. In this sense, the objective of the study was to evaluate the behavior of low-cement concrete, and addition of Plant Biomass Ash (PBA), exposed to sodium sulfate. An experimental study was carried out characterizing the materials used, an evaluation of the dimensional changes of mortar specimens and analysis of the cracking of the pieces, physical and mechanical tests on concrete submitted to two curing processes (sodium sulfate solution or conventional curing). The mix was developed with the aid of the EMMA packaging software and spreadsheet available in the literature, in which the cement content was reduced by 10, 15 and 20% by weight, replacing with PBA. The reference material showed a significant reduction in expansion when exposed to sulfate solution compared to samples submitted to conventional curing. As for mixtures added with PBA, they showed a reduction in strength when exposed for conventional curing and better behavior when exposed to the aggressive sulfate medium, both in strength and in expansion for the mixes with 10 and 15% cement reduction, the latter being considered efficient for aggressive environments.
DOI: 10.6084/m9.figshare.14321960
title: Feasibility study of the use of ceramic polishing and grinding residues for mortar manufacturing

description: ABSTRACT The civil construction sector is responsible for consuming a large part of the existing natural resources. In this context, the need for studies regarding the feasibility of using alternative materials in the production of cementitious composite additions becomes relevant. The growing and intense rate of waste generation of elements and processes linked to civil construction over the years justifies this research. The use of these fines in addition and / or substitution to cement in the preparation of mortars and concretes, has been considered a viable alternative, with regard to environmental, economic benefits, gain of mechanical properties and increased durability. Therefore, this study seeks the valorization of the residues of the ceramic industry, through the production of mortars with partial substitutions of 10 and 20% of cement by Polishing Residue (RP) and Polishing and Grinder Residue (RPR) for two types of cement, CP II F 32 and CPV ARI, respectively. The effect of substituting for each type of cement with RP and RPR, the influence of the type of residue and the percentage of substitution were analyzed for the fresh and hardened properties of mortars. Mortars produced with RP and RPR showed less fluidity, requiring the use of additives when compared to those prepared only with cement. The compressive strength of mortars, respectively, obtained with residues of RP and RPR, presented a behavior superior and / or equal to the reference mortar. The superior results obtained in the mechanical properties of mortars produced with RP and RPR are related to the pozzolanic nature of the residue, the interface of the paste and sand in the mixture.
DOI: 10.6084/m9.figshare.14321960.v1
title: Feasibility study of the use of ceramic polishing and grinding residues for mortar manufacturing

description: ABSTRACT The civil construction sector is responsible for consuming a large part of the existing natural resources. In this context, the need for studies regarding the feasibility of using alternative materials in the production of cementitious composite additions becomes relevant. The growing and intense rate of waste generation of elements and processes linked to civil construction over the years justifies this research. The use of these fines in addition and / or substitution to cement in the preparation of mortars and concretes, has been considered a viable alternative, with regard to environmental, economic benefits, gain of mechanical properties and increased durability. Therefore, this study seeks the valorization of the residues of the ceramic industry, through the production of mortars with partial substitutions of 10 and 20% of cement by Polishing Residue (RP) and Polishing and Grinder Residue (RPR) for two types of cement, CP II F 32 and CPV ARI, respectively. The effect of substituting for each type of cement with RP and RPR, the influence of the type of residue and the percentage of substitution were analyzed for the fresh and hardened properties of mortars. Mortars produced with RP and RPR showed less fluidity, requiring the use of additives when compared to those prepared only with cement. The compressive strength of mortars, respectively, obtained with residues of RP and RPR, presented a behavior superior and / or equal to the reference mortar. The superior results obtained in the mechanical properties of mortars produced with RP and RPR are related to the pozzolanic nature of the residue, the interface of the paste and sand in the mixture.
DOI: 10.6084/m9.figshare.14321961
title: Static bending of Eucalyptus grandis wood: plant spacing and radial variation effect

description: ABSTRACT Studies that approach the technological parameters of wood with wide use, such as Eucalyptus grandis, are fundamental, since their suitable use and exploitation are dependent on these characteristics. Currently, this species implantation has been expanded and the spacing is a determining factor. Therefore, the aim of present study was to evaluate the plant spacing and radial variation in static bending of Eucalyptus grandis wood. For the experiment conduction, six trees were sampled for each spacing: 2.0 x 1.0 m, 3.0 x 1.0 m and 3.0 x 1.5 m, totalizing 18 specimen at seven years old. Subsequently, the first log of each sample was sectioned into radial boards and then made into test specimens, which were identified at regular intervals in the pith-bark direction, with dimensions of 2.5 x 2.5 x 41.0 cm, to perform the mechanical static bending test, following the ASTM recommendations. The mechanical resistance results showed a variation in the pith-bark direction, where the highest MOE, MOR and TPL values were near to the bark. However, the spacing did not change the modulus of elasticity, modulus of rupture and tension on proportional limit of the material subjected to static bending. Thus, only the radial position influences in the wood quality. The values of the studied mechanical properties had an increase in the pith-bark direction, being more accentuated in the region near the bark.
DOI: 10.6084/m9.figshare.14321961.v1
title: Static bending of Eucalyptus grandis wood: plant spacing and radial variation effect

description: ABSTRACT Studies that approach the technological parameters of wood with wide use, such as Eucalyptus grandis, are fundamental, since their suitable use and exploitation are dependent on these characteristics. Currently, this species implantation has been expanded and the spacing is a determining factor. Therefore, the aim of present study was to evaluate the plant spacing and radial variation in static bending of Eucalyptus grandis wood. For the experiment conduction, six trees were sampled for each spacing: 2.0 x 1.0 m, 3.0 x 1.0 m and 3.0 x 1.5 m, totalizing 18 specimen at seven years old. Subsequently, the first log of each sample was sectioned into radial boards and then made into test specimens, which were identified at regular intervals in the pith-bark direction, with dimensions of 2.5 x 2.5 x 41.0 cm, to perform the mechanical static bending test, following the ASTM recommendations. The mechanical resistance results showed a variation in the pith-bark direction, where the highest MOE, MOR and TPL values were near to the bark. However, the spacing did not change the modulus of elasticity, modulus of rupture and tension on proportional limit of the material subjected to static bending. Thus, only the radial position influences in the wood quality. The values of the studied mechanical properties had an increase in the pith-bark direction, being more accentuated in the region near the bark.
DOI: 10.6084/m9.figshare.14321963
title: Influence of carbon source in the properties of Ni/Carbon prepared by hydrothermal carbonization and thermal treatment and used as supports for PtRu/C electrocatalysts

description: ABSTRACT In this work, Ni/Carbon hybrids were prepared in two steps (hydrothermal carbonization and thermal treatment at 900 °C under argon atmosphere) using different carbon souces: glucose, starch and cellulose. PtRu/C electrocatalysts were prepared by an alcohol-reduction process using the hybrids as support. The materials were characterized by energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), B.E.T isotherms, X-ray diffraction (XRD), transmission electron microscope (TEM) and cyclic voltammetry (CV) in acidic medium. The electro-oxidation of methanol was studied by chronoamperometry. The PtRu/C electrocatalyst prepared using the hybrid synthesized from cellulose showed an electroactivity slightly superior compared to other obtained materials.
DOI: 10.6084/m9.figshare.14321963.v1
title: Influence of carbon source in the properties of Ni/Carbon prepared by hydrothermal carbonization and thermal treatment and used as supports for PtRu/C electrocatalysts

description: ABSTRACT In this work, Ni/Carbon hybrids were prepared in two steps (hydrothermal carbonization and thermal treatment at 900 °C under argon atmosphere) using different carbon souces: glucose, starch and cellulose. PtRu/C electrocatalysts were prepared by an alcohol-reduction process using the hybrids as support. The materials were characterized by energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), B.E.T isotherms, X-ray diffraction (XRD), transmission electron microscope (TEM) and cyclic voltammetry (CV) in acidic medium. The electro-oxidation of methanol was studied by chronoamperometry. The PtRu/C electrocatalyst prepared using the hybrid synthesized from cellulose showed an electroactivity slightly superior compared to other obtained materials.
DOI: 10.6084/m9.figshare.14321969
title: Development of TiO2 layer produced by electrochemical treatment on Ti6Al4V alloy: its physicochemical and mechanical characterization

description: ABSTRACT The biomaterials based on titanium and their respective alloys are still widely applied as implants in dentistry and medicine fields. Among the many factors propitious to its wide use in regenerative medicine, its mechanical and, above all, its physicochemical properties are highlighted. The latter, besides being inherent to surface of this material, confer biocompatibility to it in physiological environment. According to the literature, the compound responsible for these properties is the naturally passivated titanium dioxide (TiO2) layer on its surface. In order to improve the bio-functionality of this surface, the scientific community has been studying ways to activate the passivated TiO2 layer through anodic electrochemical treatment. In this work, Ti6Al4V alloy had the characteristics of its TiO2 film modified through this processing in order to verify aspects such as the thickness of the formed layer, its porosity, its micro-hardness and its roughness. In the anodic electrochemical process, parameters of processing time, electrolyte concentration and voltage were controlled. The physicochemical characterization involved Scanning Electron Microscopy (SEM) analyzes with Energy Dispersive Spectroscopy (EDS), X Ray Diffraction (XRD) and X Ray Fluorescence (FRX). The mechanical characterization involved evaluation of Vickers Micro-hardness, roughness, thickness and porosity measurement of the formed layer. These evaluations showed that thicker and porous films were obtained under higher electrolyte concentrations and longer processing time. Roughness was also influenced by increasing electrolyte concentration and the voltage increase. Vickers Micro-hardness, on the other hand, was influenced inversely proportional to these parameters.
DOI: 10.6084/m9.figshare.14321969.v1
title: Development of TiO2 layer produced by electrochemical treatment on Ti6Al4V alloy: its physicochemical and mechanical characterization

description: ABSTRACT The biomaterials based on titanium and their respective alloys are still widely applied as implants in dentistry and medicine fields. Among the many factors propitious to its wide use in regenerative medicine, its mechanical and, above all, its physicochemical properties are highlighted. The latter, besides being inherent to surface of this material, confer biocompatibility to it in physiological environment. According to the literature, the compound responsible for these properties is the naturally passivated titanium dioxide (TiO2) layer on its surface. In order to improve the bio-functionality of this surface, the scientific community has been studying ways to activate the passivated TiO2 layer through anodic electrochemical treatment. In this work, Ti6Al4V alloy had the characteristics of its TiO2 film modified through this processing in order to verify aspects such as the thickness of the formed layer, its porosity, its micro-hardness and its roughness. In the anodic electrochemical process, parameters of processing time, electrolyte concentration and voltage were controlled. The physicochemical characterization involved Scanning Electron Microscopy (SEM) analyzes with Energy Dispersive Spectroscopy (EDS), X Ray Diffraction (XRD) and X Ray Fluorescence (FRX). The mechanical characterization involved evaluation of Vickers Micro-hardness, roughness, thickness and porosity measurement of the formed layer. These evaluations showed that thicker and porous films were obtained under higher electrolyte concentrations and longer processing time. Roughness was also influenced by increasing electrolyte concentration and the voltage increase. Vickers Micro-hardness, on the other hand, was influenced inversely proportional to these parameters.
DOI: 10.6084/m9.figshare.14321970
title: Performance evaluation of commercial superplasticizing additives based on polycarboxylate on the mechanical and microstructural properties of Portland cement pastes

description: ABSTRACT The performance of dispersing admixtures is directly related to the characteristics of the utilized molecule and it can vary according from the original. In this context, the objective of this study is to evaluate the performance of four commercial polycarboxylate-based in Portland cement pastes with low w/c ratio. The admixtures were characterized through tests of solids content and Fourier Transform Infrared Spectroscopy. The performance of the admixtures in the pastes was evaluated by the mini-slump test, as well as by the air void content, compressive strength at 28 days and thermogravimetry. For both a / c ratios evaluated, the four additives showed different spreadings for the same solids content used. It was also found that different types of additives caused different changes in the induction periods, as well as different air incorporations, which resulted in different compressive strengths of the pastes, so that the greatest compressive strength can be attributed to the lowest content of incorporated air. These results can be explained because the performance of the additive is associated with the size of its molecule, side chains, molecular weight and the adsorption of the molecule in the chemical compounds of cement. Noting that the same chemical bases of additives (polycarboxylates) result in different behaviors of cement mixtures, it is emphasized that the prior compatibility test between Portland cement and the chemical additive that will be used in the production of the cement matrix is of paramount importance.
DOI: 10.6084/m9.figshare.14321970.v1
title: Performance evaluation of commercial superplasticizing additives based on polycarboxylate on the mechanical and microstructural properties of Portland cement pastes

description: ABSTRACT The performance of dispersing admixtures is directly related to the characteristics of the utilized molecule and it can vary according from the original. In this context, the objective of this study is to evaluate the performance of four commercial polycarboxylate-based in Portland cement pastes with low w/c ratio. The admixtures were characterized through tests of solids content and Fourier Transform Infrared Spectroscopy. The performance of the admixtures in the pastes was evaluated by the mini-slump test, as well as by the air void content, compressive strength at 28 days and thermogravimetry. For both a / c ratios evaluated, the four additives showed different spreadings for the same solids content used. It was also found that different types of additives caused different changes in the induction periods, as well as different air incorporations, which resulted in different compressive strengths of the pastes, so that the greatest compressive strength can be attributed to the lowest content of incorporated air. These results can be explained because the performance of the additive is associated with the size of its molecule, side chains, molecular weight and the adsorption of the molecule in the chemical compounds of cement. Noting that the same chemical bases of additives (polycarboxylates) result in different behaviors of cement mixtures, it is emphasized that the prior compatibility test between Portland cement and the chemical additive that will be used in the production of the cement matrix is of paramount importance.
DOI: 10.6084/m9.figshare.14321972
title: Analysis of the physical-mechanical properties of coating mortars with the incorporation of polypropylene and nylon fibers

description: ABSTRACT The search for new mixtures and materials that will improve the properties of coating mortars and consequently their performance in service is becoming more and more frequent, thus synthetic fibres appear as a possibility for a new material to be used in the composition of mixtures. The study aims at analyzing the behavior of coating mortars with the incorporation of different contents of polypropylene and nylon fibers. The experimental program was based on the incorporation of 500, 900 and 1300 g/m³ of polypropylene and nylon fibers in a reference mortar with a trace of 1:0.5:5 (cement:lime:sand). As a parameter, the amount of water used in all mortars produced was fixed and a plasticizer additive was added when necessary. Thus, this work aimed to analyze the influence of the incorporation of different contents of polypropylene and nylon fibers on the physical characteristics and mechanical properties of mortars in their hardened state. For this purpose, analyses of tensile strength in bending, compression strength, modulus of elasticity, dynamic and static, capillary water absorption and analysis of characteristics by scanning electron microscopy were performed. The results indicate that the mortars with incorporation of nylon fibers presented higher values of tensile strength in bending, axial compression and lower values of water absorption by capillarity. The analysis of the images obtained by the microscopy of the mortars showed that the mortars with polypropylene insertion showed greater porosity than the mortars with nylon addition. The mortars incorporating polypropylene fibers showed lower values of dynamic and static modulus of elasticity, which indicates that these mortars have a good capacity to suffer deformation.