Binary Binder Research Articles

Microstructure and mechanical properties of Cr doped WCoB based cermets by spark plasma sintering and first principle calculation

WCoB based cermet is a potential hard alloy to replace WC-Co cermets with high hardness and corrosion resistance. WCoB based cermets with different Cr doping contents were fabricated by spark plasma sintering in liquid phase sintering stage. The densification behavior, phase composition, microstructure and mechanical properties of Cr doped WCoB cermets were investigated by XRD, EDS and SEM. Due to the lower density of Cr, the density of WCoB cermets decreased with the increasing of Cr doping content. The phase composition consisted of Cr doped WCoB, unreacted W, Co–Cr binary binder phase. When the doping content exceeded 11.736 wt%, the Cr enrichment zones appeared, which was harmful to the TRS. The increasing of Cr doping content contributed to the increase of unreacted W phases content and the formation of pores. The maximum value of Vickers hardness was 1751 Hv0.5 at 9.356 wt% Cr doping content. The variation trend was explained by first principle calculation, which is consistent with Hv-Zhou hardness model.

Low-Carbon Concrete Based on Binary Biomass Ash-Silica Fume Binder to Produce Eco-Friendly Paving Blocks.

The civil construction industry consumes huge amounts of raw materials and energy, especially infrastructure. Thus, the use of eco-friendly materials is indispensable to promote sustainable development. In this context, the present work investigated low-carbon concrete to produce eco-friendly paving blocks. The binder was defined according to two approaches. In the first, a binary binder developed with eucalyptus biomass ash (EBA) and silica fume (SF) was used, in total replacement for Portland cement. In the second, the mixture of residues was used as a precursor in alkali-activation reactions, forming alkali-activated binder. The experimental approach was carried out using five different mixtures, obtained by varying the amount of water or sodium hydroxide solution. The characterization of this new material was carried out using compressive strength, expandability, water absorption, deep abrasion, microstructural investigation, and organic matter degradation potential. The results showed that the EBA-SF system has a performance compatible with Portland cement when used as an alternative binder, in addition to functioning as a precursor to alkali-activated concrete. The blocks produced degraded organic matter, and this degradation is more intense with the incidence of UV. In this way, the EBA-SF binder can be successfully used for the manufacture of ecological paving blocks with low carbon emissions.

Activation of Binary Binder Containing Fly Ash and Portland Cement Using Red Mud as Alkali Source and Its Application in Controlled Low-Strength Materials

AbstractThe feasibility of using red mud as an alkali source in alkali-activated fly ash and Portland cement (PC) based binary binder for controlled low-strength material (CLSM) is investigated. Th...

Life-cycle assessment of emerging CO2 mineral carbonation-cured concrete blocks: Comparative analysis of CO2 reduction potential and optimization of environmental impacts

Abstract CO2 mineral carbonation (MC) curing technology provides a promising solution for large-scale CO2 utilization and construction sectors towards low-carbon and environmentally friendly production of concrete, but studies on the total environmental impacts of this technology are scarce. Accordingly, this paper evaluated the life cycle environmental impacts of seven promising concrete blocks from CO2 MC curing manufacturing pathways (Ordinary-Portland cement block, MgO-Portland cement block, wollastonite-Portland cement block, limestone-Portland cement block, calcium silicate cement block, slag-Portland cement block and Waste Concrete Aggregate block), offering detailed results of cradle-to-gate life cycle assessment and inventory. Identification of the contributions of subdivided raw materials and manufacturing processes, as well as the energy consumption, transportation, and upstream processes for raw materials was performed. It was shown that 292–454 kg CO2-eq global warming potential (GWP) of 1 m3 CO2-cured non-hollow concrete blocks were obtained. By contrast, results indicated the 419 kg CO2-eq GWP from a base case of conventional (steam-cured, non MC) Ordinary-Portland cement block. Up to 30% of CO2 emission avoidance could be achieved when replacing steam curing by MC curing and adjusting the binder types. From the point of view of materials and manufacturing, the reduced use of Portland cement is a key step for environmental optimization, while reducing the energy consumption for maintaining high-pressure carbonation helps to cut down the cumulative energy demand. Increasing the blending ratio in binary binders and the lightweight redesign also proved to be beneficial solutions for mitigating environmental impacts of CO2-cured concrete blocks. Wollastonite-Portland cement block and slag-Portland cement block using natural wollastonite and blast furnace slag in binary binders obtained the most favorably scores in all impact assessment indicators, and thus, are arguably considered as the most sustainable types of concrete blocks.

Behaviour of calcined gypsum-based materials during setting

The behaviour at early age of several composed gypsum-based materials was investigated. The binary binder, composed of calcium sulphate hemihydrate and slaked lime, several ternary binders with different types of pozzolans were prepared, and their behaviour during setting was studied. Unrestrained volume changes of calcium sulphate-based pasts were measured by displacement of liquid, in which the specimens were submerged. The hydration heat of composed binders was measured by isothermal calorimetry. The behaviour of composed materials with different types of pozzolans was compared with the behaviour of calcined gypsum.

Utilization of high volume cement kiln dust and rice husk ash in the production of sustainable geopolymer

This study investigates the feasibility of using combination of Cement Kiln Dust (CKD) which is classified as a hazardous solid waste material and Silica Fume (SF), as a sustainable precursor to make binary binder based geopolymer paste. Furthermore, Rice Husk Ash (RHA) an agricultural waste is used as the main source for preparing amorphous silica in order to produce sustainable sodium silicate solution and also to replace it with the standard commercial sodium silicate. In this study alkaline activator solution was prepared through the combination of RHA powder with 10-M sodium hydroxide solution (NaOH) to adjust the Na2O/SiO2 and H2O/Na2O molar ratio. Geopolymer paste was produced by mixing different SF/CKD proportion (15/85%, 30/70%, 45/55%, 50/50%, 55/45%, 70/30% and 85/15% by weight) with the RHA-NaOH alkaline activator solution. The compressive strength test, Fourier transform infrared spectroscopy (FTIR), mini-slump test, setting time and X-ray diffraction (XRD) were carried out to characterize the geopolymer. The results show that it was feasible to make sustainable geopolymer with combination of SF/CKD binder and sodium silicate solution from RHA. By increasing CKD up to the optimum amount (45%) the compressive strength increased linearly and then the compressive strength decreased when it exceeds the optimum amount. The results also showed that the setting time of the geopolymer can be modified by changing the SF/CKD proportion. Moreover, the XRD presented that the geopolymer paste has an amorphous to semi-crystalline phase. Also, FTIR analysis illustrated that by increasing silica content, Si-O-Si (Al) bonds which are considered as the geopolymeric fingerprint area, will shift to the higher wavenumber.

Hydration of Binary Portland Cement Blends Containing Silica Fume: A Decoupling Method to Estimate Degrees of Hydration and Pozzolanic Reaction

Determination of degrees of hydration/reaction of components of blended cementitious systems (i.e., cement and SCMs: supplementary cementitious materials) is essential to estimate the systems’ properties. Although the best methods for determining degrees of reaction of different SCMs have been recommended by RILEM TC238, they rely on either expensive equipment (e.g., nuclear magnetic resonance) or time-consuming sample preparation and data processing (e.g., backscattered electron image analysis). Furthermore, these methods cannot simultaneously characterize degree of hydration of cement and degree of reaction of SCMs. A novel decoupling method, which can simultaneously estimate the degree of hydration of cement and the degree of reaction of silica fume in binary cementitious materials, is proposed in this study. Based on experimentally determined and theoretically validated stoichiometric parameters of cement hydration and pozzolanic reaction, the contents of calcium hydroxide and hydrate water in pastes are expressed as functions of degree of hydration of cement and degree of reaction of silica fume. With the two contents determined by thermogravimetric analysis, the two degrees can be solved mathematically. It is found that in binary binders the incorporation of silica fume affects hydration kinetics of cement, leading to lower ultimate degree of hydration, shorter dormant stage, and faster hydration in the acceleration stage. As a result, the degree of hydration of cement in blended paste is higher at early ages (e.g., 3 days) but lower at later ages (e.g., 120 days) than that in plain cement paste. In a given blended paste, the degree of reaction of silica fume can be tied to the degree of hydration of cement. The decoupling method is promising for rapid estimations of degrees of hydration/reaction of cementitious materials in a blended system, since it does not require expensive characterization tools or complex data processing methods.

Improving the processability and cycling stability of nano-LiFePO4 cathode by using PVDF/TX binary binder

ABSTRACTIn lithium-ion battery industry, the nanoscale electrode materials usually have difficulty to be dispersed well in the electrode slurry. The inferior processability thus results in deteriorated electrochemical performances of the cell. In this work, poly(vinylidene fluoride) (PVDF) and terpene resin (TX) as a binary binder are used to improve the dispersibility and cycling stability of nanoscale LiFePO4 (nano-LFP) cathode. The wettability, dispersibility, adhesion strength and electrochemical performance of nano-LFP cathode using PVDF/TX are measured and compared with that using only PVDF binder. Nano-LFP cathode using PVDF/TX binder (the optimal ratio of PVDF to TX is 97:3) exhibits better dispersibility and stronger adhesion strength than that of PVDF. In addition, nano-LFP cathode with PVDF/TX binder shows better cycling stability, rate capability, and electrochemical kinetics than that with PVDF, retaining 97.4% capacity after 100 cycles test at C/5 in room temperature and 93.4% capacity after 60 cycles test at C/2 in 55℃, respectively.

A long-cycling anode based on a coral-like Sn nanostructure with a binary binder.

A coral-like metallic Sn nanostructure was synthesized towards an advanced Li-ion battery anode via a facile one-pot displacement reaction. In the presence of 5 wt% sodium carboxymethyl cellulose and 5 wt% graphene oxide as a binary binder, the electrode demonstrates extraordinary Li storage behaviors in terms of high initial coulombic efficiency (68.7%), long-cycling life (800 cycles with a retention capacity of 422 mA h g-1 at 500 mA g-1), and superb rate capability. The fascinating electrochemical performance could be attributed to the 3D interconnected nanostructure together with the binary binder to ease the volume expansion of Sn.

Feasibility of Eco-Friendly Binary and Ternary Blended Binders Made of Fly-Ash and Oil-Refinery Spent Catalyst in Ready-Mixed Concrete Production

Large-scale recycling of new industrial wastes or by-products in concrete has become a crucial issue for construction materials sustainability, with impact in the three pillars (environmental, social and economic), while still maintaining satisfactory, or improved, concrete performance. The main goal of the paper is to evaluate the technological feasibility of the partial, or total, replacement of fly-ashes (FA), widely used in ready-mixed concrete production, with spent equilibrium catalyst (ECat) from the oil-refinery industry. Three different concrete mixtures with binary binder blends of FA (33.3% by mass, used as reference) and of ECat (16.7% and 33.3%), as well as a concrete mixture with a ternary binder blend with FA and ECat (16.7%, of each) were tested regarding their mechanical properties and durability. Generically, in comparison with commercial concrete (i) 16.7% ECat binary blended concrete revealed improved mechanical strength and durability; (ii): ternary FA-ECat blended binder concrete presented similar properties; and (iii) 33% ECat binary blended concrete has a lower performance. The engineering performance of all ECat concretes meet both the international standards and the reference durability indicators available in the scientific literature. Thus, ECat can be a constant supply for ready-mixed eco-concretes production, promoting synergetic waste recycling across industries.

Low-carbon and low-alkalinity stabilization/solidification of high-Pb contaminated soil

Stabilization/solidification (S/S) is a low-cost and time-efficient method for soil remediation, however, delayed hydration reactions and high carbon footprint are major limitations for the treatment of high-Pb contaminated soil. This study develops a novel and low-carbon approach that combines ground granulated blast furnace slag (GGBS) and ordinary Portland cement (PC) with phosphate-/sulphate-rich byproducts to produce low-alkalinity, high-compatibility, high-strength binary cement (BC) for S/S process. Results show that contaminated soil with a large fraction of exchangeable and soluble Pb (e.g., shooting range sites) severely disturbed the formation of hydration products in conventional S/S treatment, whereas BC system could mitigate the Pb interference via precipitation and sorption evenly distributed on the BC hydrates as shown by elemental mapping. Thus, BC presented superior environmental performance in terms of toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching tests, which were substantiated by quantitative X-ray diffraction and thermogravimetric analyses. The addition of potassium dihydrogen phosphate reduced TCLP leachability of Pb by 86.9% and Pb diffusion coefficients by 69.4% due to the formation of insoluble Pb3(PO4)2. Similarly, incinerated sewage sludge ash enhanced Pb stabilization, whereas waste phosphogypsum increased early strength via precipitation of PbSO4, although the effectiveness of physical encapsulation was compromised due to reduction in hydration products. Therefore, the proposed binary binders with selected additives present a new and low-carbon S/S treatment for high-Pb shooting range soil remediation.

Effect of calcined Czech claystone on the properties of high performance concrete: Microstructure, strength and durability

Most supplementary cementitious materials (SCM) have been only rarely used in high performance concrete (HPC) design to date, silica fume being one of the very few exceptions in that respect. The content of many SCMs in blended cements was also often low because at higher dosage they were not capable to replace Portland cement effectively. Their environmental and economical advantages could thus be utilized in a limited extent only. In this paper, the effect of calcined Czech claystone (CCC) on the properties of HPC based on a binary binder containing Portland cement and silica fume was analyzed over a 10–60% range of Portland cement replacement in the mix. The material characterization experiments carried out using mercury intrusion porosimetry and scanning electron microscopy showed that an up to 30% presence of CCC in the blend resulted in a formation of closer packed HPC microstructures than if only silica fume was used as SCM. The highest compressive and bending strengths were achieved for the 30% Portland cement replacement level over the whole one year testing period. The best durability properties expressed in terms of water and water vapor transport parameters were observed for the same mix with 30% of CCC used instead of Portland cement.

Response of concrete with blended binders and nanoparticles to sulfuric acid attack

Concrete has long been the most popular material for the construction of key infrastructural elements such as sewerage pipes, water treatment facilities, industrial floors and foundations, which can be chemically vulnerable to damage by sulfuric acid attack. Since high alkalinity is required for stability of the cementitious matrix, concrete is susceptible to attack by acidic media, which may disintegrate the hydrated cement paste to various levels based on the prevailing exposure conditions and key mixture design parameters of concrete. This study investigated the response, in terms of physico-mechanical and microstructural features, of concrete comprising different types of cement (general-use or Portland limestone cement (PLC)) with various combinations of supplementary cementitious materials (fly ash, silica fume and nanosilica) to severe sulfuric acid exposure (immersion of test specimens in 5% sulfuric acid solution with a maximum pH threshold of 2·0 for 90 d). The results revealed that the surface degradation (mass loss) of concrete under severe sulfuric acid attack was independent of its penetrability (physical resistance), since very dense cementitious matrices (low penetrability) suffered severe deterioration. PLC may slightly improve the resistance of concrete to sulfuric acid attack whereas, among the blended binders tested, binary binders comprising 30% fly ash particularly improved the resistance of concrete to sulfuric acid attack due to an inert filler effect of fly ash particles at the exposed surface.

The role of synthesis parameters on the workability, setting and strength properties of binary binder based geopolymer paste

In this paper the effect of different binder to solution ratio (B/S) and different Si/Al molar ratio in the synthesis of binary binder based geopolymer paste on their workability, setting and compressive strength is investigated. Geopolymer paste was prepared by combination of metakaolin (MK) and silica fume (SF) as aluminosilicate source with a mixture of sodium hydroxide with concentration of 14M and sodium silicate as alkaline activator solution having constant H2O/Na2O and Na2O/SiO2 molar ratio. For having different Si/Al ratio, metakaolin has been replaced partially by silica fume in precursor. Workability of fresh paste was measured by mini-slump test. Compressive test at the ages of 1, 3 and 7days, setting time, FTIR and XRD analysis were used to characterize the geopolymer paste. Results show that the combination of MK and SF can be used as the aluminosilicate source materials for making geopolymer. Also, results concluded both B/S and Si/Al ratios had a significant effect on workability, setting time and strength. By increasing B/S and decreasing Na2O/binder ratio in the system the compressive strength increased, also, in constant B/S=1.2, 1.4 ratio, by increasing Si/Al ratio in binder growth compressive strength was obtained, but in B/S=1.6, 1.8 with high Si/Al ratio increases, the strength will be reduced. XRD analysis showed that geopolymer has an amorphous to semi-crystalline phase which, by increasing Si/Al ratio, will decrease the intensity of crystalline phases. FTIR spectra results illustrate that when both B/S and Si/Al ratio increase in the system, SiOT bonds will shift to higher wave number.

3D-printing of hierarchical porous ZSM-5: The importance of the binder system

Intelligent catalyst design can help to further improve the stability, selectivity and activity of existing adsorbents and catalysts. The use of 3D-printing for manufacturing of structured supports is a useful tool for the rapid prototyping of different compositions and different architectures of structured adsorbents and catalysts. Despite their proven advantages in use as adsorbents and catalytic supports with respect to heat and mass transfer and pressure drop, coated structured supports still encompass some such as loading of catalyst. To overcome these drawbacks, in this work, 3D-printed monoliths were manufactured directly using ZSM-5 as active material to build up the structured adsorbent or catalyst. As sufficient mechanical strength of such structures is crucial for the use in industry, this was one of the main focus points in this work. A combined binary binder system is shown to be advantageous for the adjustment of the mechanical properties of the self-supporting structured material. Furthermore, the chemical properties can be adjusted according to the binder used.

Performance of concrete with blended binders in ammonium-sulphate solution

Concrete elements in agricultural, wastewater treatment, mining, and industrial applications can be vulnerable to chemical attack by ammonium-based solutions. In particular, ammonium sulfate (commonly used as a fertilizer) is extremely deleterious to concrete. This is due to its dual acid–sulfate action, which may disintegrate the hydrated cement paste to various levels based on the prevailing exposure conditions and key mixture design parameters of concrete. The aim of this study was to investigate the response, in terms of physico-mechanical and microstructural features, of concrete comprising different types of cement (general use [GU] or Portland limestone cement [PLC]) with various combinations of supplementary cementitious materials (SCMs: fly ash, silica fume, and nanosilica) to a severe ammonium sulfate exposure. The study comprised 12 months of immersing test specimens in 5% ammonium sulfate solutions with a pH level of 6.0–8.0. The results revealed that the type of binder along with the dosage and nature of SCMs dictated different modes and levels of deterioration, and consequently the physico-mechanical trends of concrete were characterized by softening with (single binders) or without (blended binders) significant expansion. PLC may slightly improve the resistance of concrete to ammonium sulfate attack, whereas among the blended binders tested, binary binders comprising 5% silica fume, 5% nanosilica, or 30% fly ash improved the resistance of concrete to this type of chemical attack.

Strength and workability of magnesium silicate hydrate binder systems

This paper discusses the optimization of magnesium silicate hydrate (M-S-H) binder systems for cement paste and mortar. The compressive strength and workability (water demand, flow) of M-S-H binder systems were studied. The binary systems contain magnesia and silica fume in which each constituent accounts for 40–60% by mass of the binder. The ternary systems include 10–40% very fine crushed quartz which is used as a fine filler for the partial replacement for the cementitious materials. It was found that the pure M-S-H binder system has a much higher water demand compared to Portland cement due to the very high silica fume content. The use of polymer-based superplasticizer effectively reduced water to cementitious materials ratio (w/c) for M-S-H binder system. The optimal binary binder composition for strength and workability was found to contain 60% magnesium and 40% silica fume (Mg/Si molar ratio=2.25). The addition of very fine crushed quartz filler from 10 to 40%, as a partial replacement for the magnesia and silica fume, further improved the rheology of the mixture allowing for a workable mix with a w/c=0.30. The highest compressive strength of mortar samples achieved with ternary M-S-H system is up to 87MPa.

Novel Binary Binder PAA-SBR Towards Silicon Anodes in Li-Ion Batteries

Silicon remains a promising anode material for next generation lithium-ion batteries, despite the well-documented issues associated with it, due to its abundance and high capacity (3579mAh/g: almost 10 times higher than the capacity of graphite). The problems still facing Si-based battery commercialization are volume expansion, which results in rapid capacity fade, and continued Li loss through SEI formation from electrolyte decomposition. To address this problem, effective binders are considered to be one solution, and could help to maintain good contact between the active material and current collector but also to generate effective, stable networks between silicon particles and conductive carbon additives. This work will introduce a new binder system: Polyacrylic Acid-Styrene Butadiene Rubber (PAA-SBR). PAA is an aqueous-based polymer and possesses a high concentration of carboxyl group, which effectively bonds with the surface of silicon but also can H-bond with other polar species contributing to a good cohesive composite. SBR (Styrene Butadiene Rubber) is well known for its good flexibility, which can improve the tensile property of the electrode towards volume expansion. Therefore, it is hypothesized that the binary binder PAA-SBR can help Si anode achieve an improved, more stable performance because it can preserve good adhesion and flexibility simultaneously under the stress of the Si expansion. A preliminary study was conducted on Si vs.Li/Li+ half cells with different binder systems: PAA, PAA-SBR (2:1 mass ratio) and PAA-SBR (5:1 mass ratio), where PAA-only is used as the control binder. Cells are tested under the maximum lithiation capacity of 1200mAh/g at a C rate of C/5. Electrochemical cycling data indicates that for first 100 charge-discharge cycles, the PAA-SBR (2:1) showed a similar level of performance compared with PAA in terms of specific capacity (~1194mAh/g) and columbic efficiency (~99.5%), while the PAA-SBR (5:1) displayed capacity fade after 80 cycles, as shown in Fig.1. We anticipate that an optimized PAA-SBR ratio will generate superior composite durability during longer-term electrochemical testing. To further approve the hypothesis, a comprehensive study based on PAA-SBR (2:1) will be followed including polymer stability in electrolyte solvents, tensile properties, adhesion and impedance testing. Figure 1

Effect of glass powder on sulfuric acid resistance of cementitious materials

In an attempt to enhance the durability of cementitious materials subjected to acid environments, this paper outlines an investigation into the effect of incorporating glass powder (GP) as a cement replacement on mortar resistance against sulfuric acid attack. The study examined mass, compressive strength, ultrasonic pulse velocity (UPV) and electrical resistivity changes of mortars based on 15, 30 and 45% GP replacement rates and 12weeks immersion in fresh water and 5% acid solutions. The effects of binary binders based on GP and limestone powder (LP), GP and slag (SG) and GP and fly ash (FA) were also investigated. Experimental results showed improved sulfuric acid resistance with increased GP content, and binary binder results confirmed the beneficial effect of incorporating limestone powder with GP. Mortars with 45% GP and binary binder based on 20% GP and 20% LP showed a loss that was significantly lower in terms of physical and mechanical characteristics. Microstructural analysis showed that Si/Al-rich residue, which was surface generated from pozzolanic reaction of GP, has the potential to inhibit further corrosion by acting as a barrier to acid ions. Therefore, incorporating glass powder up to 45% replacement of cement can enhance mortar resistance to aggressive sulfuric acid attack.

Rice husk ash and spent diatomaceous earth as a source of silica to fabricate a geopolymeric binary binder

The goal of this research is to propose the use of industrial by-products as solid sources of silica in replacement of commercial sodium silicate (SS) for the manufacture of geopolymeric binary binders. The result of this approach is a binder with good mechanical properties and environmental benefits, which can be used in civil engineering applications such as the manufacturing of masonry elements.A Colombian fly ash (FA) and a commercial metakaolin (MK) were used as geopolymer precursors. Rice husk ash (RHA), spent diatomaceous earth (SDE) and commercial sodium silicate were used as sources of silica to adjust the SiO2/Al2O3 molar ratio. These silica sources were mixed with a sodium hydroxide (NaOH) solution. Three alkaline solutions were used to activate the binary system FA/MK; SN (sodium silicate and sodium hydroxide), RN (rice husk ash and sodium hydroxide) and DN (spent diatomaceous earth and sodium hydroxide). A FA/MK proportion of 70/30 by weight, and the respective SiO2/Al2O3 and Na2O/SiO2 molar ratios of 4.4 and 0.2 were kept constant for all experiments. Mechanical and microstructural analyses were conducted on the three systems, and compressive strength was measured at 28, 180 and 360 days. The reaction products were characterized by using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).Results show that it was feasible to utilize RHA and SDE as a source of silica for geopolymerization. The use of these alternative silica sources delayed the initial and final setting time at 60 °C of a FA/MK-based binary alkali activated geopolymer system. Regardless of the source of silica used, the mechanical strength of the resulting geopolymer binders did not show a significant change over time. The FA/MK-SN system exhibited a final compressive strength of 75 MPa at 360 days, and at the same age FA/MK-DN and FA/MK-RN both reached final compressive strength values of 38 MPa.