Binder Components Research Articles

Heat transfer from a cylindrical heater to a medium with variable thermophysical characteristics and heat source power

The formulation and solution of the problem of non-stationary thermal conductivity in a composite material with variable thermophysical characteristics are considered. Density, heat capacity, thermal conductivity, as well as the power of the heat source due to the hydration reactions of the binder components change during the concrete hardening process. The heat transfer problem is formulated for the general case when there are no calculation formulas for thermophysical transfer coefficients. The “microprocess method” was used to calculate the dynamics of the temperature field. According to this method, the space from the outer surface of the heater is modeled by a system of successively located “rings”. When moving from the previous “ring” to the next one, the charge in the transfer coefficients and the power of the volumetric heat source were taken into account. At the same time, the initial and boundary conditions were corrected. The boundary value problems are formulated in the form of a differential equation of non-stationary heat transfer with an arbitrary initial distribution of transfer potentials, Dirichlet boundary conditions, and a heat source in the form Po=f(Fo).The obtained solutions are analyzed for some particular cases. Prospects for further theoretical and experimental research are determined.

Sustainable innovations and future prospects in construction material: a review on natural fiber-reinforced cement composites.

There is a growing trend in the construction industry to adopt environmentally friendly practices, and innovative materials are becoming increasingly popular. Within the scope of this paper, the potential of natural fiber-reinforced cement composites (NFRCs) as an environmentally friendly building material is examined. This work introduces plant fiber aspects such as micromorphology, primary components, physical and mechanical properties, chemical components, thermal properties, and degradation mechanisms in cement composites. It explores how plant fibers affect concrete's mechanical performance, durability, and thermal qualities. It is responsible for increasing permeability and decreasing durability in concrete material because plant fibers have porosity and a weak interface. The purpose of this in-depth investigation is to investigate the features, sustainability (social, environmental, and economical) performance, and applications of NFRCs, with a particular focus on environmentally responsible innovation and potential future applications. The exhaustive study also addresses the difficulties associated with attaining the highest possible level of compatibility between fibers and matrixes. The physical and chemical treatments of natural fibers in cement components give more resistance to aging by reducing water absorption and increasing roughness at the surface. It is also possible to reduce the effect of alkalinity of the cement mixture through optimization of the binder component and curing regimes, which retard the breakdown of natural fibers. The purpose of this study is to present a summary of existing research, with a particular emphasis on the benefits, drawbacks, and prospective ways in which NFRCs could potentially improve throughout the construction industry in the future.

The Effect of Fractional Composition on the Graphite Matrices' Porosity.

Synthetic graphite of complex fractional composition was mixed with phenolic resin as a binder and pore-forming component. The mixtures were pressed and subsequently heat-treated to obtain porous matrices. The structural transformations of phenolic resin by heating up to 900 °C in oxygen and inert gas media were studied and the patterns of amorphization of fixed carbon formed on the walls of the pore system during carbonization were investigated. We found regularities in the changes in matrix volume density in the function of the open porosity and the average pore diameter. It is shown that, in order to obtain graphitized carbon matrices with a density of 1 g/cm3 and an open porosity of at least 50%, it is necessary to introduce no more than 20% of phenolic resin into the molding powder with an equal content of 60, 100 and 250 μm graphite fractions. This allows for high intensity and completeness of bulk silicon infiltration.

Study on the Properties of All-Solid Waste Fluidized Filling Materials Applied to Mine Void Area Filling Engineering.

The extraction of mining resources, as well as processing processes such as ore beneficiation and smelting, generate large amounts of tailings that are difficult to directly utilize. Meanwhile, substantial filling materials are required for the voids formed after mining operations, and the environmental issues and safety hazards brought on by massive solid waste disposal cannot be ignored. By utilizing solid waste with alkaline and pozzolanic activity as the binder component and gold tailings as filler aggregate to prepare filler material to fill up the void areas, the purpose of waste treatment can be achieved. In this study, salt sludge, steel slag, ground granulated blast furnace slag, and gold tailings were used to prepare all-solid waste fluidized filling material for filling mine void areas, which not only solves the engineering safety problem of easy collapse of the mine airspace in the mining process but also ensures a backfill effect with high strength, which continuously guarantees the uninterrupted progress of the mining project. At the same time, the preparation of fluidized materials can consume a large amount of tailings and other solid waste, solving the problem of their stockpiling. The components of the solid wastes used are all general industrial solid wastes, so the preparation of the fluidized materials will not have an impact on the surrounding environment. The effects of binder ratios on the workability of the filling materials were investigated by means of the slump and slump flow tests. Combined with the unconfined compressive strength test, the change in backfill material strength with curing age and the water-binder ratio was studied. The experimental results showed that the slump and slump flow value of the filling material were positively correlated with the water-binder ratio. The water-binder ratio range satisfying a slump value of 180~260 mm and a slump flow value not less than 400 mm was 0.95~1.106. However, the strength decreased with the increase in the water-binder ratio, conforming to a hyperbolic relationship. The all-solid waste fluidized filling material had strengths not less than 0.22, 1.09, and 1.95 MPa at 3, 7, and 28 d, respectively, meeting the workability requirements. Finally, a method for determining the optimal range of water-binder ratio considering both workability performance and strength is proposed based on the relationship between slump value, slump flow value, unconfined compressive strength, and the water-binder ratio.

Control of Thermochemical Transformations of Components of Coal-Based Binders

The possibility of considering coal pitch as a material suitable for research modeling the processes of thermochemical transformations of the plastic mass of coal carbonization and their interaction with the solid carbon phase is analyzed. The possibilities of controlling the properties of coal pitch and blast furnace coke during its production with the help of aprotic acid additives in the presence of a co-catalyst are shown.

Multimodal Hard X‐Ray Nanotomography Probes Pore Accessibility of Technical Catalysts after Coking

AbstractCoking is a common catalyst deactivation route in industrial processes involving carbonaceous species. While coking is easy to diagnose, this is often performed by bulk analysis. Understanding specific symptoms such as pore blockage and obstruction of active sites is especially challenging for technical catalysts and requires a spatially‐resolved approach. Here a combination of ptychographic X‐ray computed tomography (PXCT) and X‐ray fluorescence nanotomography (XRF‐CT) could identify and allocate regions of coke deposition within a technical zeolite‐based propane dehydrogenation catalyst. PXCT is sensitive to the quantitative electron density of the sample, therefore indirectly visualising coke deposition in meso‐ and macropores with 56–61 nm 3D spatial resolution. For more direct visualisation the catalysts were treated with Cu solution as fluorescent marker, whereby complementary XRF‐CT analysis could distinguish accessible and blocked pores based on the presence or absence of adsorbed Cu. This strategy was used to assess coking as a function of time on stream, to evaluate coke removal by oxidative regeneration, and to distinguish the presence of coke deposits separately within the zeolite and binder components. This strategy is applicable to virtually any porous solid catalyst and can deliver previously unknown insights into the common phenomenon of coke deposition particularly in technical catalysts.

Physicochemical processes during solidification and the peculiarities of structure formation in aerated concretes using metallic silicon as a gas generator

The results of research on the structure and phase composition of non-autoclaved aerated concrete with a density of 550–750 kg/m3 using metallic silicon as a gas generator are presented. The peculiarities of the structure formation of aerated concrete products and the mineralogical composition of their hydration products were investigated. It was established that increasing the content of metallic silicon in aerated concrete leads to an increase in the pore space of the compositions. The results of diffractometric and thermal analysis methods for establishing the phase composition of aerated concrete compositions with metallic silicon as a gas generator are also presented. Analysis of XRD patterns and derivatograms showed that the aerated concrete samples under investigation contain a binder component, obermorite (5CaO6SiO25.5H2O); xonotlite (6CaO6SiO2H2O); -dicalcium silicate hydrate (2CaOSiO2H2O); and hillebrandite (2CaOSiO21.17H2O). It was established that increasing the amount of metallic silicon as a gas generator stimulates an increase in the content of hydrated phases in aerated concrete compositions.

Physicochemical processes during solidification and the peculiarities of structure formation in aerated concretes using metallic silicon as a gas generator

The results of research on the structure and phase composition of non-autoclaved aerated concrete with a density of 550–750 kg/m3 using metallic silicon as a gas generator are presented. The peculiarities of the structure formation of aerated concrete products and the mineralogical composition of their hydration products were investigated. It was established that increasing the content of metallic silicon in aerated concrete leads to an increase in the pore space of the compositions. The results of diffractometric and thermal analysis methods for establishing the phase composition of aerated concrete compositions with metallic silicon as a gas generator are also presented. Analysis of XRD patterns and derivatograms showed that the aerated concrete samples under investigation contain a binder component, obermorite (5CaO6SiO25.5H2O); xonotlite (6CaO6SiO2H2O); -dicalcium silicate hydrate (2CaOSiO2H2O); and hillebrandite (2CaOSiO21.17H2O). It was established that increasing the amount of metallic silicon as a gas generator stimulates an increase in the content of hydrated phases in aerated concrete compositions.

Universal measuring cell and installation for determining dielectric parameters during the transition from a liquid oligomer to a solid polymer

This paper presents the design of a new installation and a universal measuring cell that allows determining the dielectric properties of materials in various states of aggregation.The data of dielectric permittivity studies for the initial components of the oligomeric binder, ED-20 epoxy oligomer and aminetype hardener triethylenetetramine (TETA), as well as the kinetics of its curing process, established by the change in dielectric permittivity, were obtained for the first time. It is also shown that the maximum temperature of the curing reaction of the ED20+TETA system can be determined from dielectric permittivity data.

Effects of binder component and curing regime on compressive strength, capillary water absorption, shrinkage and pore structure of geopolymer mortars

Effects of binder component and curing regime on compressive strength, capillary water absorption, shrinkage and pore structure of geopolymer mortars

Combustion synthesis of TiC- high entropy alloy CoCrFeNiMn composites from granular mixtures

The advantage of combustion synthesis is the ability to produce composites from powders in a single technological step, using the heat of an exothermic reaction, in a fast and energy-efficient manner. Ceramic-metal composites TiC–High-Entropy Alloy (HEA) CoCrFeNiMn were fabricated by combustion synthesis from granular mixtures. The content of the metal binder components varied from 10 to 30 wt% and the combustion velocity and temperature gradually decreased as the binder content increased. Scaling up synthesis requires clarification of the parametric range for implementing a safe combustion mode. The impurity gas content and the range of safe conductive combustion were determined from known theoretical models and experimental combustion velocities of samples of granules of 0.6 and 1.1 mm size. The main phases of the product were titanium carbide with up to 3 at. % Cr and HEA CrCoFeNiMn with a reduced Mn content compared to the equimolar composition. The content of secondary phases Cr7C3 and carbon did not exceed 5 wt%. The use of granular mixtures solved the problem of significant sintering of exothermic powder mixtures containing metal binder during combustion. After synthesis, the granules retain their size and do not sinter together, making it easy to grind the sample and obtain a TiC-HEA composite powder.

Towards 3D Pore Structure of Porous Gypsum Cement Pozzolan Ternary Binder by Micro-Computed Tomography

A sophisticated characterisation of a porous material structure has been challenging in material science. Three-dimensional (3D) structure analysis allows the evaluation of a material’s homogeneity, pore size distribution and pore wall properties. Micro-computed tomography (micro-CT) offers a non-destructive test method for material evaluation. This paper characterises a novel ternary binder’s porous structure using micro-CT. Gypsum–cement–pozzolan (GCP) ternary binders are low-carbon footprint binders. Both natural and industrial gypsum were evaluated as a major components of GCP binders. Porous GCP binder was obtained by a foaming admixture, and the bulk density of the material characterised ranged from 387 to 700 kg/m3. Micro-CT results indicate that pores in the range from 0.017 to 3.0 mm can be effectively detected and described for porous GCP binders. The GCP binder structure proved to be dominant by 0.1 to 0.2 mm micropores. For GCP binders produced with natural gypsum, macropores from 2.2 to 2.9 mm are formed, while GCP binders with phosphogypsum possess pores from 0.2 to 0.6 mm. Micro-CT proved to be an effective instrument for characterising the homogeneity and hierarchical pore structure of porous ternary binders.

Interfacial adhesion between recycled asphalt binder and aggregates considering aggregate surface anisotropy: A molecular dynamics simulation

In this study, the interfacial adhesion properties between reclaimed asphalt binder and aggregates were investigated using the molecular dynamics (MD) simulation method. Surface free energy theory (SFE) was applied to analyze the changes in adhesion properties before and after asphalt binder reclamation. The asphalt binder model was constructed from the four components of asphalt binder and validation of the model was carried out. The five common crystalline surfaces of two types of aggregates were sliced. The asphalt binder-aggregate interface was modelled to investigate the effect of the anisotropic surface of the aggregates on the adhesion of the asphalt binder. The adhesion properties of the recycled asphalt binder-aggregate interface were characterized from micro and multiscale simulations using the work of adhesion and relative concentration. Results showed that the rejuvenators enhanced the adhesive properties of the asphalt binder by rebalancing the components and adding the light components lost from aging. Surface anisotropy had significant effect on the bonding at the asphalt binder-aggregate interface because α-SiO2 bonded to acid surfaces less strongly than CaCO3 linked to alkali surfaces. Van der Waals forces dominated the adhesion energy in the α-SiO2-asphalt binder interfacial model system. In the CaCO3-asphalt-binder interface model system, the combined effect of van der Waals forces and the CaCO3 surface void reduced the adhesion energy of the aggregate surface to the asphalt binder.

Selection of an alternate cementitious mortar using ceramic tile dust waste: a hybrid MCDM approach.

Selection of a suitable alternative material from a pool of alternatives with many conflicting criteria becomes a Multi-Criteria Decision Making (MCDM) problem. In the present study, ternary blended mortars were prepared using ceramic tile dust waste (CTD), fly ash (FA), and ground granulated blast furnace slag (GGBFS) as binder components. Crusher dust (CD) was used as a fine aggregate component. Binder to aggregate ratios of 1:3 and 1:1 were prepared considering suitable flow. A total of 16 mortar mixes were cast. These mortars were tested for various conflicting criteria compressive strength, flexural strength, porosity, water absorption, bulk density, thermal conductivity, specific heat, thermal diffusivity, and thermal effusivity whose weightages obtained were 29.09%, 20.08%, 12.77%, 10.60%, 8.74%, 6.74%, 5.54%, 4.47%, and 1.97%, respectively, as per AHP analysis. Later, considering these different criteria and alternate mortars, it was observed that a 1:1 mortar with 20% CTD, 30% FA, and 50% GGBFS (RC20F30G50) is found to be the suitable mortar with the highest relative closeness coefficient of 0.861 and the highest net outranking flow of 0.316 with respect to MCDM techniques: technique for order of preference by similarity to ideal solution (TOPSIS) and preference ranking organization method for enrichment of evaluations (PROMETHEE-II), respectively. The ranking of the mortar in both methods complies with the relative weightages of the criteria and the performance of the mortars with respect to the above criteria.

Eco-friendly lactose/tannin-based binder in MgO–C refractories produced from MgO–C recyclate

This study deals with the design and development of a new generation of MgO–C refractory material implementing spent MgO–C recyclate as a partial replacement of fresh raw materials, and a non-hazardous environment-friendly lactose- and tannin-based binder system. Throughout the experimental campaign the used MgO–C recyclate, which was received in three size fractions, was analysed, and building on the obtained results, multiple batches of various compositions of next-generation MgO–C bulks were prepared. These bulks varied in the ratio between the individual size fractions of the MgO–C recyclate, the ratio between the individual binder components and the amount of water used during the preparation of the raw material batches. The bulk samples were prepared in the form of cylinders through uniaxial pressing, cured and coked, and studied in terms of their cold crushing strength, microstructural parameters, thermal behaviour, residual carbon content, and microstructure. The proposed next generation of MgO–C composites represents a potential eco-friendly alternative to MgO–C refractories prepared from traditional raw materials while utilizing waste material which would otherwise end up landfilled.

Performance and microstructural development of 3D printable MgO-SiO2 mixes containing magnesium silicate monohydrate

This study investigated the inclusion of magnesium silicate monohydrate (MSMH) crystal in MgO–SiO2 mixes designed for extrusion-based 3D printing. Considering the adjustment and optimization of rheological properties are fundamental for the printability of cement pastes, the dynamic rheology, thixotropy and strength development of the prepared mixes were analyzed to characterize their fresh properties, workability, buildability, and mechanical performance. Furthermore, isothermal calorimetry, X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), and scanning electron microscopy (SEM) were employed to investigate the phase composition and microstructural evolution of the pastes, with and without the presence of MSMH. Addition of MSMH at 2 % of the binder component significantly enhanced the plastic viscosity, dynamic yield stress and thixotropy. Pastes incorporating 2 % MSMH exhibited excellent structural build-up without affecting extrudability, with a minimal strain deformation in the printed structure. The compressive strength of all pastes exceeded 20 MPa after 3 days, reaching ∼50 MPa at 28 days with 2 % MSMH inclusion. The introduction of MSMH improved the peak heat flow measured by isothermal calorimetry and enhanced the formation and growth of hydration products after 7 days of curing, resulting in a more compact microstructure.

Utilization of fused deposition modeling in the fabrication of lattice structural Al2O3 ceramics

This study focuses on fabricating lattice structural Al2O3 ceramics with lattice infill densities ranging from 25 % to 70 % using filament-based fused deposition modeling (FDM) technology. A specialized filament for FDM printing was developed, comprising 53 vol% Al2O3 powder and ethylene vinyl acetate (EVA) as the primary binder component. The filament demonstrated excellent flexibility as assessed by a self-designed three-point bending test. The impact of lattice infill density and sintering temperature on dimensional changes, microstructure evolution, compressive strength, and strength-to-density ratio was explored. It was found that with increasing sintering temperature, the samples became more compact, resulting in higher levels of shrinkage, bulk density, and compressive strength. At a sintering temperature of 1600 °C, the sintered parts reached their maximum density through the solid-state sintering process. The sample sintered at 1600 °C with 70 % infill density exhibited the maximum compressive strength of 31.47 MPa, with a corresponding strength-to-density ratio of 20.84 MPa/g·cm−3. These findings highlight the successful fabrication of lattice structural Al2O3 with low density and high compressive strength by FDM technology.

Aging behaviors of asphalt binders rejuvenated by different chemical fractions from waste cooking oil

Waste cooking oil (WCO) can be recycled cleanly as the rejuvenating agent for aged asphalt, boosting the utilization of reclaimed asphalt pavement materials in road engineering. However, the sensitivity of asphalt rejuvenated by WCO to secondary aging is unknown, which has an impact on its durability in practical engineering. The objective of this work is to explore the aging behaviors of asphalt binders rejuvenated by different chemical fractions of WCO. The performance of different fractions of WCO before and after aging treatment was evaluated. The sensitivity to aging was discussed for rejuvenated binders with WCO’s fractions as rejuvenating agents including the differences in aging resistance between them and the virgin binder. The experimental results indicate that the aging resistance of WCO’s fractions depends mainly on their carbon chain length. The sensitivity of rejuvenated asphalt to aging depends strongly on the aging resistance of WCO’s fractions. Additionally, it is found that the resistance of rejuvenated binders to aging is better than that of the virgin binder because the WCO's fractions are less volatile than the original light components of the virgin binder. Therefore, substances with strong fluidity and weak volatility in WCO are the optimal candidates for rejuvenating agents of aged asphalt considering both the rejuvenation effect and the resistance to aging. The findings of the research contribute to the sustainability of road engineering.

Comparative profiling of microbial communities and volatile organic compounds in fermented wrapper, binder, and filler cigar tobaccos

BackgroundEconomic benefits for tobacco growers are closely linked to the quality of fermented cigar tobacco leaves (CTLs). This research focused on an in-depth examination of the microbial community and flavor compounds within CTLs, specifically analyzing the wrapper, binder, and filler components of a cigar. The primary objective was to unravel the complex relationship between the microbial composition and the resultant flavor profiles, thereby providing insights that could enhance the economic value of CTLs.ResultsThe study revealed distinct variations in flavor chemicals and microbiota across different sections of CTLs. Prominent species identified in the fermented CTLs included Corynebacterium, Pseudomonas, Staphylococcus, Aspergillus, and Cladosporium. Bidirectional orthogonal partial least squares (O2PLS) analysis pinpointed five bacterial and four fungal species as key contributors to flavor compound formation. Additionally, an analysis considering Within-module and Among-module connectivity highlighted two bacterial and thirteen fungal genera as keystone species. The insights from Partial Least Squares Structural Equation Modeling (PLS-SEM) further underscored the influential role of fungal microorganisms in defining CTLs' flavor profile.ConclusionsThe research findings illuminate the intricate interplay between flavor chemicals and microbes in the traditional fermentation process of CTLs.Graphical

Recycling of mineral wool waste as supplementary cementitious material through thermochemical treatment.

Mineral wool is commonly used in construction as thermal insulation material. After the product's lifetime, it is classified as hazardous waste if no trademark of the European Certification Board for Mineral Wool Products (EUCEB) or the German Institute for Quality Assurance and Labelling (RAL) exists. Mineral Wool Waste (MWW) is typically landfilled in Europe, which is challenging due to its low bulk density and dimensional stability. This circumstance highlights the need for alternative recycling methods that increase the recycling rate of construction and demolition (C&D) waste. This article outlines the recycling opportunities of MWW and focuses on the use of thermochemical treatment of different mixtures of input materials to produce a supplementary cementitious material (SCM). The material characterisation results and investigations on the binder suitability demonstrate that the slag fractions after the thermochemical treatment are well-qualified to be used as reactive binder components. Additionally, a material flow analysis was conducted to estimate the substitution potential of MWW as SCM in the Austrian cement industry.