cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14321939.v1
title: Pozzolanic effect investigation of silica hydrosol (SH) nanoparticles with different granulometric distributions dispersed in cement paste

description: ABSTRACT The addition of nanomaterials to concrete allows structural modifications, improving their properties like mechanical strength and durability. Within these possible nanoscale materials is silica hydrosol (SH). There are many studies highlighting the influence of the surface area of SH particles on the pozzolanic reaction with cement, however little has been studied on the influence of percentage and particle size on the reaction. In this context, the objective of this work was to investigate the influence of the particle size distribution of silica nanoparticles on the pozzolanic reaction in cement pastes, from the comparison of 4 colloidal suspensions. The addition content of these particles, with different sizes, was defined as 3.00% (SH-A), 0.89% (SH-B), 0.77% (SH-C) and 0.32% (SH-D), to equalize the surface areas of all of them, so that the only variables were the percentage and particle size distribution of the silicas. The pozzolanic effect was evaluated by the direct method named Modified Chapelle test, and by indirect methods like Fourier transform infrared spectroscopy (FT IR), and mechanical strength tests. It was concluded that for the same surface area resulting from the addition of SH, the sample that presented the best performance was the CP SH-A, which presented the largest particle size and volume of addition. However, when analysing the relative performance, regarding the concentration of SH added to the paste, the CP SH-D sample obtained the highest mechanical resistance and the highest pozzolanic index. It showed that concentration and particle size, not just surface area, influenced the performance of the nanosilica pozzolanic reaction. The conclusions obtained in the present work allow a better understanding about the addition of SH in cementitious composites and how the content and particle size of such products impact their performance.
DOI: 10.6084/m9.figshare.14321941.v1
title: Electrocatalytic activity of a hybrid ormosil film containing phosphomolybdic acid toward prometon herbicide

description: ABSTRACT Organically modified silicate (whose abbreviation is ormosil) can be used to immobilize chemical species of interest for applications such as sensors and optical devices. Polyoxometalates (POMs) can be immobilized to the pores of the ormosil network to investigate their electroactive properties since they are widely used as electrocatalysts. However, few studies have explored the electrocatalytic properties of immobilized POMs in ormosil networks toward triazinic herbicides, which are extensively used in agriculture in the cultivation of grains and sugar cane. The work reported here describes the electrocatalytic activity of a hybrid film formed by an organically modified silica (ormosil) with 3-cyanopropyltriethoxysilane containing a POM, phosphomolybdic acid, toward prometon, a triazinic herbicide. Cyclic voltammetry and differential pulse voltammetry experiments were performed using as supporting electrolyte an aqueous solution of sulfuric acid at pH 1,0 and showed that this hybrid ormosil film deposited on gold electrode electroreduced prometon in a concentration range of 3,6 x 10-6 to 18 x 10-6 mol L-1. The potential value where the herbicide reduction ocurred was around 0,0 V vs. Ag / AgCl, lower than those found in the literature as for example + 0,75 V or -1,0 V vs. Ag/AgCl. With these features, the resulting film can be used for novel applications of environmental interest.
DOI: 10.6084/m9.figshare.14321941
title: Electrocatalytic activity of a hybrid ormosil film containing phosphomolybdic acid toward prometon herbicide

description: ABSTRACT Organically modified silicate (whose abbreviation is ormosil) can be used to immobilize chemical species of interest for applications such as sensors and optical devices. Polyoxometalates (POMs) can be immobilized to the pores of the ormosil network to investigate their electroactive properties since they are widely used as electrocatalysts. However, few studies have explored the electrocatalytic properties of immobilized POMs in ormosil networks toward triazinic herbicides, which are extensively used in agriculture in the cultivation of grains and sugar cane. The work reported here describes the electrocatalytic activity of a hybrid film formed by an organically modified silica (ormosil) with 3-cyanopropyltriethoxysilane containing a POM, phosphomolybdic acid, toward prometon, a triazinic herbicide. Cyclic voltammetry and differential pulse voltammetry experiments were performed using as supporting electrolyte an aqueous solution of sulfuric acid at pH 1,0 and showed that this hybrid ormosil film deposited on gold electrode electroreduced prometon in a concentration range of 3,6 x 10-6 to 18 x 10-6 mol L-1. The potential value where the herbicide reduction ocurred was around 0,0 V vs. Ag / AgCl, lower than those found in the literature as for example + 0,75 V or -1,0 V vs. Ag/AgCl. With these features, the resulting film can be used for novel applications of environmental interest.
DOI: 10.6084/m9.figshare.14321942
title: Effect of Portland cement replacement by BSSF steel slag in the physical and mechanical properties of concrete

description: ABSTRACT The present study aimed to investigate the physical and mechanical properties of concrete with use of BSSF steel slag fines in partial replacement to Portland cement. The experimental work consisted of physical-chemical characterization tests of BSSF steel slag, as well as characterization of the properties in the fresh and hardened concrete state produced by the replacement of cement by BSSF steel slag fines at 3%, 6% and 12%. The properties analyzed were: specific mass, incorporated air content, consistency, compressive strength at the ages of 7, 28 and 63 days, modulus of elasticity, tensile strength, voids index and water absorption. All data collected were statistically analyzed using Analysis of Variance (ANOVA) and Tukey test. With the obtained results, it can be seen that in the fresh state, the concretes presented higher additive demand for same consistency and higher values of specific mass. In the hardened state, concretes showed significant improvements in compressive strength and modulus of elasticity. Regarding durability, concretes with higher replacement contents presented the lowest values of water absorption by immersion and voids index
DOI: 10.6084/m9.figshare.14321942.v1
title: Effect of Portland cement replacement by BSSF steel slag in the physical and mechanical properties of concrete

description: ABSTRACT The present study aimed to investigate the physical and mechanical properties of concrete with use of BSSF steel slag fines in partial replacement to Portland cement. The experimental work consisted of physical-chemical characterization tests of BSSF steel slag, as well as characterization of the properties in the fresh and hardened concrete state produced by the replacement of cement by BSSF steel slag fines at 3%, 6% and 12%. The properties analyzed were: specific mass, incorporated air content, consistency, compressive strength at the ages of 7, 28 and 63 days, modulus of elasticity, tensile strength, voids index and water absorption. All data collected were statistically analyzed using Analysis of Variance (ANOVA) and Tukey test. With the obtained results, it can be seen that in the fresh state, the concretes presented higher additive demand for same consistency and higher values of specific mass. In the hardened state, concretes showed significant improvements in compressive strength and modulus of elasticity. Regarding durability, concretes with higher replacement contents presented the lowest values of water absorption by immersion and voids index
DOI: 10.6084/m9.figshare.14321946
title: Activated carbon quality produced by Tectona grandis wastes: activation methods and adsorption capacity

description: ABSTRACT Activated carbons (AC) are high porosity and adsorptive carbonaceous materials. These adsorbents can be produced using different organic materials. Precursor material properties may impact their quality. This study aimed to produce activated carbon from Tectona grandis wood wastes, besides determining efficiency in adsorption of different pollutants. Chemical activation, with ZnCl2 (AC_ZnCl2) and CuSO4 (AC_CuSO4), and physical activation, with CO2 (AC_CO2) were performed. Activated carbons were characterized by FTIR, surface functional groups (Boehm) and surface area analysis. Moreover, ACs were tested regarding adsorption capacity of methylene blue (MB), phenol and Cr+6 ions in aqueous medium. Higher total pore volume (0.62 cm³ g-¹), micropore volume (0.31 cm³ g-¹) and surface area (524.50 m² g-¹) were obtained in AC_ZnCl2, which was also the most effective in MB and phenol adsorption. AC_CuSO4 obtained high adsorption capacity for phenol and presented functional groups different from the other AC. AC_CO2 was the second with better adsorption performance for all pollutants.
DOI: 10.6084/m9.figshare.14321946.v1
title: Activated carbon quality produced by Tectona grandis wastes: activation methods and adsorption capacity

description: ABSTRACT Activated carbons (AC) are high porosity and adsorptive carbonaceous materials. These adsorbents can be produced using different organic materials. Precursor material properties may impact their quality. This study aimed to produce activated carbon from Tectona grandis wood wastes, besides determining efficiency in adsorption of different pollutants. Chemical activation, with ZnCl2 (AC_ZnCl2) and CuSO4 (AC_CuSO4), and physical activation, with CO2 (AC_CO2) were performed. Activated carbons were characterized by FTIR, surface functional groups (Boehm) and surface area analysis. Moreover, ACs were tested regarding adsorption capacity of methylene blue (MB), phenol and Cr+6 ions in aqueous medium. Higher total pore volume (0.62 cm³ g-¹), micropore volume (0.31 cm³ g-¹) and surface area (524.50 m² g-¹) were obtained in AC_ZnCl2, which was also the most effective in MB and phenol adsorption. AC_CuSO4 obtained high adsorption capacity for phenol and presented functional groups different from the other AC. AC_CO2 was the second with better adsorption performance for all pollutants.
DOI: 10.6084/m9.figshare.14321948
title: Utilização de um modelo de empacotamento de partículas considerando o cimento como parte do "arranjo seco

description: ABSTRACT The “dry arrangement” of a cementitious compound can be defined as the mass or volumetric relationship between the dry materials that constitute it. By fixing the kind of material that makes up this arrangement and the cement compound production process, it is possible to more clearly analyze the dosage process of any cement compound. To analyze the behavior of these compounds in regard to the changes in volumetric quantities of their components, it is known the basic particle packing models, such as Funk and Dinger Particle Packing Model. The present article aims to analyze the properties in fresh (consistency index) and hardened state (water absorption, specific mass and axial compressive strength) of mortars produced with the Funk and Dinger Particle Packing Model. In this model, the cement particles were considered as part of the “dry arrangement” (aggregates), assuming only the water volume as the “matrix” (or separation agent), thus simplifying the definition of cement consumption. Results demonstrated that it is possible to achieve, by changing the volumetric quantity of the components, a reduction in cement consumption of approximately 32% and at the same time achieve an increase in axial compressive strength of approximately 59%, a reduction in absorption and an increase in the specific mass of the specimens. However, a significant decrease in the workability of the produced mortars was verified.
DOI: 10.6084/m9.figshare.14321948.v1
title: Utilização de um modelo de empacotamento de partículas considerando o cimento como parte do "arranjo seco

description: ABSTRACT The “dry arrangement” of a cementitious compound can be defined as the mass or volumetric relationship between the dry materials that constitute it. By fixing the kind of material that makes up this arrangement and the cement compound production process, it is possible to more clearly analyze the dosage process of any cement compound. To analyze the behavior of these compounds in regard to the changes in volumetric quantities of their components, it is known the basic particle packing models, such as Funk and Dinger Particle Packing Model. The present article aims to analyze the properties in fresh (consistency index) and hardened state (water absorption, specific mass and axial compressive strength) of mortars produced with the Funk and Dinger Particle Packing Model. In this model, the cement particles were considered as part of the “dry arrangement” (aggregates), assuming only the water volume as the “matrix” (or separation agent), thus simplifying the definition of cement consumption. Results demonstrated that it is possible to achieve, by changing the volumetric quantity of the components, a reduction in cement consumption of approximately 32% and at the same time achieve an increase in axial compressive strength of approximately 59%, a reduction in absorption and an increase in the specific mass of the specimens. However, a significant decrease in the workability of the produced mortars was verified.
DOI: 10.6084/m9.figshare.14321949
title: Comparative analysis of hemosorbents obtained at different modes

description: ABSTRACT When using hemosorbent laminar flow, a large active area of sorbents is used, the trauma of the blood corpuscles decreases dramatically, the ash content of the saline solution is absent. One of the methods of solving environmental problems is to develop various materials based on industrial waste. In the article, the method of obtaining carbonized rice husks is described, the adsorption capacity for methylene blue was measured for the obtained sample, the morphological structure was examined, comparative analysis with analogs was carried out. The authors carried out research work, such as collecting information, selecting methods, conducting analysis, processing the results. Granular hemosorbents that have been used until recently penetrate the blood-forming elements, creating a mechanism for thrombosis that violates the integrity of the erythrocyte membrane.
DOI: 10.6084/m9.figshare.14321949.v1
title: Comparative analysis of hemosorbents obtained at different modes

description: ABSTRACT When using hemosorbent laminar flow, a large active area of sorbents is used, the trauma of the blood corpuscles decreases dramatically, the ash content of the saline solution is absent. One of the methods of solving environmental problems is to develop various materials based on industrial waste. In the article, the method of obtaining carbonized rice husks is described, the adsorption capacity for methylene blue was measured for the obtained sample, the morphological structure was examined, comparative analysis with analogs was carried out. The authors carried out research work, such as collecting information, selecting methods, conducting analysis, processing the results. Granular hemosorbents that have been used until recently penetrate the blood-forming elements, creating a mechanism for thrombosis that violates the integrity of the erythrocyte membrane.
DOI: 10.6084/m9.figshare.14321951.v1
title: Study of the use of expanded vermiculite in the mechanical properties of light mortars

description: ABSTRACT The search for alternative materials with the potential to benefit the properties of the mortar is growing. The use of lightweight aggregates is a possibility that generates reduction in the weight of the coating itself and tend to provide great advantages as regards the thermal and acoustic insulation. Therefore, the objective of this study is to analyze the use of expanded vermiculite in the mechanical properties of light mortars. The experimental procedure started with the characterization of the materials and the production of mortars with proportions in volume of 1: 1: 6 (cement: lime: sand) with substitutions in volume of 25, 35 and 45% of the sand for the expanded vermiculite, and in then testing the fresh state (consistency, density and water retention) and in the hardened state (density, compressive strength, modulus of elasticity and adhesive strength). The results showed that the incorporation of expanded vermiculite decreases the water / binders factor, reducing the mass density in the fresh and hardened state. Water retention decreases for substitution levels of 25 and 35% and increases to 45% substitution. The bond strength is increased, while the compressive strength and the modulus of elasticity is reduced. Therefore, the use of expanded vermiculite in coating mortars has great potential for partial replacement to the natural aggregate, for the preparation of light mortars.
DOI: 10.6084/m9.figshare.14321951
title: Study of the use of expanded vermiculite in the mechanical properties of light mortars

description: ABSTRACT The search for alternative materials with the potential to benefit the properties of the mortar is growing. The use of lightweight aggregates is a possibility that generates reduction in the weight of the coating itself and tend to provide great advantages as regards the thermal and acoustic insulation. Therefore, the objective of this study is to analyze the use of expanded vermiculite in the mechanical properties of light mortars. The experimental procedure started with the characterization of the materials and the production of mortars with proportions in volume of 1: 1: 6 (cement: lime: sand) with substitutions in volume of 25, 35 and 45% of the sand for the expanded vermiculite, and in then testing the fresh state (consistency, density and water retention) and in the hardened state (density, compressive strength, modulus of elasticity and adhesive strength). The results showed that the incorporation of expanded vermiculite decreases the water / binders factor, reducing the mass density in the fresh and hardened state. Water retention decreases for substitution levels of 25 and 35% and increases to 45% substitution. The bond strength is increased, while the compressive strength and the modulus of elasticity is reduced. Therefore, the use of expanded vermiculite in coating mortars has great potential for partial replacement to the natural aggregate, for the preparation of light mortars.
DOI: 10.6084/m9.figshare.14321952
title: Evaluation of crystalline rock mining waste for use as a concrete aggregate according to its petrography, physical indexes and mechanical strength

description: ABSTRACT Currently, mining waste has been take an important role as a raw material in environmental sustainability programs, with the objective of minimizing the impacts resulting from mining activity. Given this, this research proposes to analyze pegmatite mining waste for use in aggregate for concrete. The samples were petrographically characterized according to their reactive potential to the Alkali-Aggregate Reaction under standard ABNT 15577-3 and tests were performed to evaluating the physical indexes and mechanical strength. It was found among the dimensions of pegmatites that two of them shows innocuous for alkali-aggregate reaction, because it contains levels of deleterious phases for RAA below the limit acceptable by the norm. Though, the other samples showed potential reactivity to RAA, because either contains deformed quartz, or both deleterious phases identified according to the standard used: deformed quartz and microgranular. The mechanical resistance assumed values below the average values presented by the consulted literature. This fact is justified by the degree of alteration observed in the studied samples. Mining residues were found to have been subjected to weathering, resulting in a drop in expected mechanical strength values. Considering the physical indexes, the samples showed good results regarding the moisture absorption capacity.
DOI: 10.6084/m9.figshare.14321952.v1
title: Evaluation of crystalline rock mining waste for use as a concrete aggregate according to its petrography, physical indexes and mechanical strength

description: ABSTRACT Currently, mining waste has been take an important role as a raw material in environmental sustainability programs, with the objective of minimizing the impacts resulting from mining activity. Given this, this research proposes to analyze pegmatite mining waste for use in aggregate for concrete. The samples were petrographically characterized according to their reactive potential to the Alkali-Aggregate Reaction under standard ABNT 15577-3 and tests were performed to evaluating the physical indexes and mechanical strength. It was found among the dimensions of pegmatites that two of them shows innocuous for alkali-aggregate reaction, because it contains levels of deleterious phases for RAA below the limit acceptable by the norm. Though, the other samples showed potential reactivity to RAA, because either contains deformed quartz, or both deleterious phases identified according to the standard used: deformed quartz and microgranular. The mechanical resistance assumed values below the average values presented by the consulted literature. This fact is justified by the degree of alteration observed in the studied samples. Mining residues were found to have been subjected to weathering, resulting in a drop in expected mechanical strength values. Considering the physical indexes, the samples showed good results regarding the moisture absorption capacity.
DOI: 10.6084/m9.figshare.14321955
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.