Binder Components Research Articles

Effectiveness Evaluation Criteria of Using Fine Powders of Secondary Concrete as a Component of Composite Binder

The paper considers the possibility of using energy criteria (surface activity, free surface energy) to quantify the efficiency of a highly dispersed system consisting of fine particles of secondary concrete as a component of composite binder of the hydration type of hardening. Using the G.A. Zisman method, the value of the critical surface tension was determined for secondary concrete fractions with different degrees of dispersion, which gives an idea of the free surface energy of a surface area unit. Based on the experimental data for determining the specific surface area and critical surface tension, the free surface energy and surface activity of the studied concrete powder were calculated, which can serve as criteria for quantitative energy characteristics of raw materials for the production of composite binders. Calorimetric studies related to measurements of the thermal effects of the hydration reaction of highly dispersed samples of secondary concrete have shown that this process is exothermic, the enthalpy of hydration of which is comparable to a similar parameter for cement. It was experimentally shown that fine powders of secondary concrete are effective as components of a composite binder, but they need to be pre-activated to optimal parameters, one of which is surface activity. In addition, the symbasis of changes in surface activity, the specific heat of the hydration reaction of highly dispersed concrete fractions and the compressive strength of fine-grained concrete samples made by using a composite binder containing a highly dispersed fraction of secondary concrete was established.

Utilization of ground waste glass cullet in the industrial production of precast concrete elements

In the study, a field trial was carried out to evaluate the applicability of ground waste glass cullet as a binder component, in the industrial production of precast concrete elements. The influence of glass cullet addition on the properties of fresh and hardened concretes was compared to siliceous fly ash. Moreover, the effects of a partial substitution of the natural aggregate with recycled concrete and expanded clay aggregate were determined. The compressive strength of concretes, in which 25% of cement was substituted with ground waste glass cullet, was even 20% higher compared to elements with an analogous addition of siliceous fly ash. Over 56 days, no drops in strength related to the harmful effects of the alkali-silica reaction were observed. Replacing half of the natural aggregate with graded recycled concrete aggregate, allowed to lower the thermal conductivity of the walls by approx. 10%, with no negative impact on the compressive strength of precast elements. However, a decrease in the consistency of fresh mix was observed after 30 minutes. Replacing the 2÷8 mm gravel with the same fraction of expanded clay resulted in an approx. 18% decrease in thermal conductivity, while maintaining satisfactory mechanical properties. It was concluded that ground waste glass cullet can be successfully used as a fly ash replacement in the production of precast concrete elements.

Carbon fiber plastics for vehicles manufactured by resource-saving formation technology

The advantages of the technology of molding carbon plastics based on pre-pregs with separate application of components (SAC-technology) of epoxy binders cured by the mechanism of migration polymerization of epoxy cycles are presented. Using the methods of linear dilatometry and dynamic mechanical tests, the molecular mobility of the segmental and local types in polymer matrices of carbon fiber reinforced plastics based on traditional mixed pre-pregs and binary pre-pregs with separate application of components has been investigated. The question of the influence of the activation ability of an acid catalyst during the curing of an epoxy binder on the degree of decrease in internal stresses and the realization of an increased packing density of polymer chains in the polymer matrix of the composite is considered. The importance of choosing an acid catalyst for the curing of a polymer binder is shown, which for CFRP composites provides the necessary combination of elastic and dissipative properties. The use of the considered binders makes it possible to improve a number of important operational characteristics, especially in the case of the production of large-sized products: solidity, crack resistance, impact resistance, fracture toughness. These properties are very significant during the composite materials applying in transport engineering.

Comparative Assessment of Effectiveness of Calcium Silicate Dispersions Produced Using Sucrose and Lactose as Components of Composite Cement Binder

Silicate micro- and nano-additives are multifunctional in relation to cement systems. Their application can solve a wide range of technological problems while maintaining the economic efficiency of technical solutions. The effect of silicate additives and fillers is determined by their level of dispersion, due to which the technologies for producing nano- and submicro-sized dispersed materials are being developed. The combination of mechanochemical synthesis of modified calcium hydrosilicates with subsequent thermolysis makes it possible to produce calcium silicate dispersions (SCD), which differ in polymodality of the fractional composition including submicro (10–7–10–6 m) and microdimensional (≥10–6 m) modes. The main element of the technology is the use of modifying carbohydrate, which acts as a stabilizer of hydrated phases of silicates. A comparative study of SCD produced using sucrose (sSCD) and lactose (lSCD) revealed the effect of these carbohydrates on the properties of sSCD and lSCD, as well as their effectiveness as a component of cementitious composite binder. It was found that the level of adsorption of modifying carbohydrate determines the physical properties of SCD (granulometry, specific surface area). The relatively high residual content of free sucrose (0.24%) in the composition of sSCD prevents the consolidation of silicates nanoparticles formed during the thermolysis, causes a high content of submicro sized fractions and a high specific surface area with sSCD (26.3 ± 0.7 m2/g). Lactose is absorbed by the silicate phase; the residual content of free lactose does not exceed 0.028% of lSCD. The low content of stabilizing carbohydrate contributes to the development of nanoparticle consolidation, a decrease in the specific surface area of lSCD to 13.0 ± 0.2 m2/g and content of submicrosized fractions. The residual content of free carbohydrates and particle size characteristics of sSCD and lSCD determine the nature of their influence on Cement-SCD-based concrete setting and hardening. The presence of residual sucrose in the composition of sSCD and fine fractions determines the competitive nature of the processes of retardation of hardening and acceleration of hardening of the cement system due to the nucleation effect, as a result of which the curve of the setting time is extreme. In addition, the inhibitory effect of sucrose reduces the strength of concrete on the 7th day. By the 28th day, the inhibitory effect of sucrose has been overcome, and concrete samples demonstrate an 18% increase in compressive strength with a sSCD content of 30%. The low content of residual free lactose in the composition of lSCD causes the nucleation effect. As a result, there is a monotonous reduction in the setting time of concrete mix with an increase in the content of lSCD in the composition of HF, as well as a significant increase in concrete strength (up to 127%) on the 7th day. At the same time, on the 28th day the strength of concrete increases slightly

Recipes and Properties of Multicomponent Systems "Aspiration Dust - Mineral Powder - Na<sub>2</sub>SiO<sub>3</sub>"

The paper presents the results of studies of the effect of the concentration of binder components on the properties of cement alkaline stone. Formulations of clinker-free binders of alkaline activation with the level of filling the system of 20 and 40% have been developed, the properties of the cement paste of the binding binder "aspiration dust - mineral powder - liquid glass" have been studied, the dynamics of a set of strength indicators has been studied, both for bending and compressive forces. The received results allow to estimate uniqueness of properties of a binding binder "a mineral powder - Na2SiO3" and to create new materials on resource saving and energy saving technology. The results presented in this article were obtained within the framework of studies on the implementation of scientific project No. 05. 607.21.0320. "Development of technology for new building composites based on clinkerless cement of alkaline activation using substandard natural and secondary raw materials" supported by the Federal Target Program "Research and Development in Priority Areas of Development of the Scientific and Technological Complex of Russia for 2014-2020". The unique identifier for the agreement is RFMTFI60719X0320.

MATERIALS AND TECHNOLOGIES FOR THE CONSOLIDATION OF HISTORIC PLASTERS BY THE WETTING AND SURFACE PENETRATION METHOD

The term of a historic plaster or surface coating, respectively, denotes a layer or a multilayer of materials firmly bonded to the substrate, whose structural and technical condition significantly affects not only the aesthetic effect, but mainly the service life of this surfacing. Due to the permanent exposure of plaster surfaces to the external environment (in the exterior as well as the interior), they belong to the group of the most exposed parts of historic and heritage buildings, often exhibiting a high degree of degradation and disintegration. The consolidation and rehabilitation of plasters with, among other things, a degraded binder component, damaged structure and insufficient adhesion of individual layers to each other and to the masonry substrate is a challenging task in the restoration of historic buildings. The paper presents the alternative of strengthening degraded surface layers by means of nanomaterials based on calcium hydroxide applied by the surface penetration method.

Development of scientifically-based recipe and technology for the production of natural honey-based muesli bar

The dynamic pace of life of a modern consumer necessitates nutritious, healthy and portable snacks. Based on the analysis of the component composition of muesli bars on the market, the authors propose the development of a science-based recipe of a muesli bar, in which natural honey is used as the determining structure and binder component. The developed food product is an alternative healthy snack, in the recipe of which there are no white sugar, “harmful” fats, synthetic additives. As part of the study, the optimal formulation was calculated and the technology for the production of a new product was developed; normative and technical documentation was developed; nutritional, energy value, warranty periods of storage of the product were calculated. The results of the study indicate that the developed product in terms of quality and safety meets the requirements of regulatory and technical documentation and can be recommended as dietary and sports nutrition.

Analysis of the behavior of epoxy composites with carbon nano additives under the influence of high temperatures on fires

The results of research on the thermal stability of epoxy resins modified with carbon nanomaterial as polymer composites matrices are presented. It is shown that modification of binder component of composite materials at deposition of carbon nanomaterials leads to improvement of thermal stability, including decrease of intensity of crystal lattice destruction, decrease of amplitude value of thermal effect, increase of duration of oxidation of material at high temperatures, promotes stable formation of heat-protective and insulating carbonized layer.

Experimental Studies On Strength and Durability Characteristics of 8M GeoPolymer Mortar Based On Fly Ash and GGBS

Ordinary Portland cement (OPC) is one of the most misfortune cover measurable in the structure business. It is evaluated that the production of OPC, discharges the enormous measure of Carbon-di-oxide (CO2) gas which makes the 65% of a global warming which leads to global weather imbalance. For the manufacture of one ton of OPC transmits roughly 0.8 ton of CO2 in the worldwide gases, along these lines the cement industry produces 7% of all (CO2 ) ecological contaminating gases. The properties of the mortar have been calculated according to Indian and ASTM standard requirements, specific gravity, compressive and split tensile strength. The ratio of “Na2SiO3 to NaoH” is 2.5, and the ratio of “alkaline solvent to binder” is equal to 0.4, 0.45, 0.5, 0.55 in the cases of binder components are calculated with each ratio like in this research we calculated with each fluid/binder ratio with different mix proportions 1:15, 1:2, 1:2.5, 1:3 in this research using only two materials fly ash then GGBS, using the different ratios of fly residue and GGBS with identical molarity and IS specified normal sand sieve sizes. Once prepared with the “alkaline liquid to binder” ratio, it creates higher strength to the geopolymer mortar. It can be inferred that the results in terms of intensity by ambient curing are strong relative to outdated mortar.

Abrasive Wear Resistance of Concrete in Connection with the Use of Crushed and Mined Aggregate, Active and Non-Active Mineral Additives, and the Use of Fibers in Concrete

Virtually every concrete structure comes into contact with abrasive effects of flowing media or solids, which have a direct impact on the durability of concrete. An abrasive effect is most pronounced in transport or water management structures, and these structures are often designed for a significantly longer service life (usually 100 years). This research evaluates the influence of the filler component in terms of the type of aggregate and its mineralogical composition on concrete abrasion resistance. As part of the impact of the binder component, several concrete mixtures were produced using the same aggregate and maintaining the same strength class with the addition of different types of active and inert mineral additives. In other parts of the research, the effect of adding fiber reinforcement on the abrasion resistance of concrete was verified. Mutual connections and correlations in different age groups (7, 28 and 90 days) were sought for all obtained results. The abrasion resistance of the composite was monitored by using standard procedures, especially using a Böhm device. It was found that for good abrasion resistance of concrete, it is not necessary to produce concretes with high strength classes using often expensive mineral additives (microsilica) and quality aggregates, but the maturation time of the composite and its microstructure plays an important role.

Electrochemical Performance of Co3O4 Anode Material with Conductive Binder

A water-soluble conductive binder consisting of poly-3,4-ethylenedioxythiophene:polysterne sulfonate and carboxymethyl cellulose was proposed for conversion Co3O4 anode material. This type of electrode shows ultrahigh specific capacity value and brilliant C-rate capability in comparison with Co3O4 electrode with poly(acrylic acid) and carboxymethyl cellulose was used. It also demonstrates better stability during continuous cycling at 0.2 C. Long-term cycling voltammetry measurements show that using of conducting polymer as binder component lead to superior stability of the Co3O4 electrodes.

Effect of Binder Components on the pH of Concrete Mixture with Low pH Intended for Deep Geological Repository for Radioactive Waste in the Czech Republic

This paper deals with the development and research of low pH concrete mixtures intended for the deep geological repository for radioactive waste. Mixtures, in particular those made from materials originating in the Middle Europe, specifically Czech Republic, were designed due to the diversity of the raw materials’ properties. In this first part, a large number of cement mortars were designed, on which the effect of active ingredients (microsilica, slag) on the pH value over time were tested. From the results of the cement mortars’ pH measured after 90 days, a concrete formula was designed. A mixture with a lower proportion of cement and a higher proportion of microsilica seems to be the best. The slag serves only as a supplement in the place value of several weight percent of the total binder volume. Also, the control measurements of basic material characteristics, such as volumetric mass density and compressive strength were performed on these mixtures.

Experimental Development Process of a New Cement and Gypsum-Cemented Similar Material considering the Effect of Moisture

A new type of similar material considering water characteristics is developed through orthogonal experiments. The similar material is composed of river sand, barite powder, cement, gypsum, and water. We determine the best test development process. First, the proportion test scheme is designed based on the orthogonal test. Then, the effects of the moisture content, mass ratio of aggregate to binder and other components on the density, uniaxial compressive strength, elastic model, and Poisson’s ratio of similar materials are analyzed by range analysis. Finally, the multiple linear regression equation between the parameters and the composition of similar materials is obtained, and the optimal composition ratio is determined according to the relationship between the test’s influencing factors and the mechanical properties of similar materials. The results show that the selected raw materials and their proportioning method are feasible. The content of barite powder plays a major role in controlling the density and Poisson’s ratio of similar materials. The mass ratio of aggregate to binder is the main factor that affects the uniaxial compressive strength and elastic modulus of similar materials, while the moisture content has the second largest effect on the density, uniaxial compressive strength, elastic modulus, and Poisson’s ratio of similar materials. When the residual moisture content increased from 0 to 4%, the uniaxial compressive strength and elastic modulus of similar materials decrease by 49.5% and 53.3%, respectively, and Poisson’s ratio increases by 54.8%. Determining the residual moisture content that matches the design of similar material model tests is critical to improving the test accuracy and provides a reference to prepare similar materials with different requirements.

Recycling of concrete construction and demolition waste in alternative binders: Part 2 – Environmental footprint

The concrete demolition and construction waste (CDW) is usually recycled as aggregate. The fine fraction (crushed sand and powder) obtained from the recycling process remains less recovered – for downcycling purposes such as backfilling, if recovered at all. The feasibility study on the recycling of concrete waste as a component of a blended binder is presented in Part 1 of the study. Part 2 is dedicated to a preliminary assessment of the environmental impacts of the partial replacement of Portland cement binder by a waste concrete powder (WCP). The assessment is focused on the binder production stage as per BDS EN 15804 and does not consider any further scenarios. The environmental impacts of alternative binders with a different amount of WCP is compared to the impacts of conventional cement types CEM I, CEM II/A and CEM II/B. The results confirm that there is a significant reduction of the environmental impacts when WCP is used for cement replacement, because of the more efficient use of material resources and energy. The effect is more pronounced with the higher replacement rate. Therefore, the use of WCP in cements leads to more eco-friendly binders and can contribute to closing the concrete loop.

Synthesizing fine-grained powders of complex compositions B4C–TiB2–WC–Co

Fine-grained boron carbide and metal boride composites are known for their superhardness, which is used in many industrial technologies. The introduction of binder components in free metallic (alloy) state and/or additional ceramic components can further improve the material mechanical properties by making it more dispersive. A new chemical method is proposed for the synthesis of the fine-grained powder complex composites boron carbide–titanium diboride–tungsten boride–cobalt (B4C–TiB2–WC–Co).

Cathode material for sodium-ion batteries based on manganese hexacyanoferrate: the role of the binder component

Sodium manganese hexacyanoferrate (NaMnHCF) was synthesized by a hydrothermal method and investigated as a cathode material for sodium-ion batteries. The morphology and the structure of NaMnHCF were investigated by X-ray diffraction, scanning electron microscopy, and EDX analysis. New composition of NaMnHCF cathode material for sodium-ion batteries with eco-friendly water-based binder consisting of conducting polymer poly-3,4-ethylenedioxythiopene/polystyrene sulfonate (PEDOT:PSS) dispersion and carboxymethyl cellulose (СМС) was proposed. The electrochemical properties of NaMnHCF cathode material with conductive polymer binder were investigated by cyclic voltammetry and galvanostatic charge-discharge, and the results were compared with the performance of a conventional PVDF-bound material. It was shown that the initial discharge capacity of electrodes with conductive binder is 130 mAh g−1, whereas the initial discharge capacity of PVDF-bound electrodes was 109 mAh g−1 (both at current density 120 mA g−1, values normalized by NaMnHCF mass). The material with conductive binder also has better rate capability; however, it is losing in cycling capability to the electrode composition with conventional PVDF binder.

Predictive model of modified asphalt mixtures with nano hydrated lime to increase resistance to moisture and fatigue damages by the use of deicing agents

Deicing agents are used to dissolving the frost on road surfaces in winter and cold areas. Researchers have evaluated the impact of different deicing agents on the moisture susceptibility performance of asphalt mixtures, but they have not investigated the effect of these agents on fatigue failure and thermodynamic parameters of asphalt mixtures. Therefore, in this research, by investigating the effect of two new deicing agents of calcium magnesium acetate (CMA) and potassium acetate (PA) as well as sodium chloride (NaCl) traditional agent on moisture and fatigue performances of asphalt mixtures, predictive model of the tensile strength ratio (TSR) and the fatigue life ratio (NFR) using genetic programming (GP) based on the surface free energy (SFE) components and other properties of asphalt mixtures were presented. Nano hydrated lime (NHL) was applied as an asphalt binder modifier and an anti-stripping agent to improve the strength of asphalt mixtures. The results indicated that the saturated mixtures in CMA had the highest indirect tensile strength (ITS) and fatigue life in lower freeze-thaw cycles, while the NaCl-saturated samples had more ITS and fatigue life in higher cycles. The CMA-saturated samples had the greatest TSR and NFR. Using NHL in all saturated samples resulted in increasing TSR and NFR values. Results of SFE method showed that using NHL increased the polar, non-polar and basic components of asphalt binders and decreased their acidic components. Also, using NHL increased the total SFE amount of asphalt binder, enhancing the adhesion of aggregate and asphalt binder and cohesion in asphalt binder membrane, and as a result, improving the moisture resistance in asphalt mixtures. Using 1.5% NHL had the greatest effect on improving adhesion free energy (AFE), cohesion free energy (CFE) and detachment energy (DE). Among deicing solutions, CMA had the highest CFE, in general, and NaCl had the best DE values. PA-saturated samples had the greatest permeability of asphalt mixture (PAM) values. GP model had a high R2 96.4% and 98.3% for TSR and NFR, respectively. Using GP model to achieve the maximum TSR and NFR, the Pareto curve showed that 1.32% NHL was the optimum value for simultaneously increasing moisture resistance and fatigue life.

Properties of foam concrete based on highly concentrated aluminosilicate binder suspension

Cementless binders and building materials are promising. The article presents results of production of foam concrete compositions using high-concentration aluminosilicate binder suspension based on granodiorite. Their basic physical and mechanical characteristics and microstructural features are described. The method of multifactor experiment was used, which allows to vary the parameters: water-solid ratio, amount of binder component and stabilizing additive. Thus, during steps of mathematical planning, optimal parameters were recommended, the observance of which is necessary to obtain cementless cellular composites with the best properties.

Study on Binder of Cold-Bonded Pellets Containing Basic Oxygen Furnace Dust Based on Hydration Mechanism of Magnesium Potassium Phosphate Cementitious Material

Basic Oxygen Furnace (BOF) dust can be mixed with binders to prepare cold-bonded pellets and return to BOF for recycling, because of its high total iron and alkaline oxide content. Nevertheless, the lengthy digestion reaction of dead-burned MgO and CaO contained in BOF dust causes expansion and cracking of the pellets, which seriously affect the pellet strength. In this study, it was first proposed to use a hydration reaction between dead-burned MgO and KH2PO4 to form bonding phases based on the hydration mechanism of magnesium potassium phosphate (MKP) cementitious material, to solidify MgO contained in BOF dust and improve the pellet strength. The key issue of using MKP cementitious material as a binder to improve the pellet strength is to choose appropriate magnesium-to-phosphate molar ratio M/P and water-to-binder mass ratio w/b. Based on this, cold-bonded pellets were prepared by using different ratios of MKP binder. The compressive strength, hydration products, microstructure and thermal properties of the pellets were analyzed, and the bonding mechanism of MKP binder in the pellets was proposed. The results show that the pellets have the highest mechanical strength and the most K-Struvite crystals under M/P molar ratio of 4 and w/b mass ratio of 0.5. At high temperatures, K-Struvite crystals will not evaporate harmful phosphorus-containing substances due to the decomposition of the binder components. MKP binder is unevenly distributed in the pellets: in the binder concentrated areas, the massive and dense K-Struvite crystals wrap BOF dust particles; in the binder decentralized areas, the fine K-Struvite crystals are filled between the dust particles or adhere to the surface of dust matrix, connecting the dust particles into a whole.

Couscous manufacture in fluidized bed by wet agglomeration of wheat semolina

Agglomeration is a key unitary operation in a number of industries (pharmaceutical, chemical, food, civil engineering). The agglomeration process controls the structural characteristics and final properties of agglomerates. One of the activities involving food agglomeration is the production of couscous by agglomeration of durum wheat semolina. Couscous is considered the most important traditional dish among the Maghreb people. The industrial process of couscous production includes various stages, the most important of which is wet granulation of semolina, which contributes to the quality of the final product. The agglomeration of cereal powders from different origins (durum wheat, maize and barley) has been performed in a variety of equipment such as high shear mixers, drum mills and fluidized beds. However, the agglomeration of semolina in fluidized beds has had very limited study. The purpose of this research is, therefore, to study couscous production using durum wheat semolina in a fluidized bed equipped with a spray nozzle. The fluidized bed has the advantage of generating strong particle movement and intense mixing to increase the size of the granules evenly throughout the mass used.The efficiency of this process is determined by the couscous yield defined as the mass ratio of couscous to raw material. The results showed that couscous can be produced from semolina by wet fluidized bed agglomeration with a specific effect of fluidification air flow, liquid flow, bed temperature and spray liquid properties on the couscous quality (size, brittleness and morphology) as well as on yield. The latter rose by 60% when the water containing flour was sprayed. Furthermore, the results of this study showed that granules size changes directly with the liquid flow rate, while temperature and air flow have an opposite effect. It was also found that changing binder components have an effect on the quality of the agglomeration of the product. Key words: Couscous, agglomeration, fluidization, semolina, friability, granulation, atomization, size enlargement, drying