Optimal Proportion Research Articles

Dynamic behavior of geopolymer stabilized kaolin clay under long-term cyclic loading

Geopolymer has emerged as an alternate cementitious material with a low carbon footprint, as they improve the engineering properties of soft soil without causing a detrimental effect on the environment. This study focuses on developing a combination of geopolymer materials that can fully replace the utilization of traditional binders to stabilize soft soil foundations in geotechnical engineering. Soft kaolin clay was stabilized using ground-granulated blast furnace slag (S) and dolomite (D) as a precursor (P) with combined content of 20% and NaOH: Na2SiO3 ratio of 25:75 as a liquid alkali activator (L) in the geopolymerization process. A series of Unconfined Compressive Strength (UCS) tests were conducted to analyze the influence of various parameters, such as the ratio of S and D, water content of kaolin clay, curing period, and L/P ratio, to select the optimum mix proportions based on strength improvement. This paper also discusses the behavior of geopolymer-stabilized kaolin clay under long-term cyclic loading in stress-controlled conditions. The effect of the S:D ratio, cyclic stress ratio (CSR), curing time, frequency, and confining pressure (CP) on the dynamic shear modulus (G), damping ratio (λ), and degradation index (G/Gmax) were analyzed. The results indicate that the S:D ratio of 16:4 with an L/P ratio of 1, NaOH: Na2SiO3 ratio of 25:75, and water content of liquid limit (LL) cured for 28 days gives the highest UCS value of 1.47 MPa. The initial dynamic shear modulus (Gmax) increases by 60% as the S:D ratio changes from 20:0 to 16:4. The cyclic performance of geopolymer-stabilized kaolin clay in terms of accumulative strain as a function of the number of loading cycles was also enhanced. The findings of the study provide guidance to a better understanding of the long-term dynamic behavior and application of geopolymer-stabilized kaolin clay as a greener approach to ground improvement.

Comparison of Thermophilic-Mesophilic and Mesophilic-Thermophilic Two-Phase High-Solid Sludge Anaerobic Digestion at Different Inoculation Proportions: Digestion Performance and Microbial Diversity.

This study investigated the performance of thermophilic-mesophilic (T-M) and mesophilic-thermophilic (M-T) two-phase sludge anaerobic digestion at different inoculation proportions after a change in digestion temperature. After temperature change, the pH, total ammonia nitrogen (TAN), free ammonia nitrogen (FAN), solubility chemical oxygen demand (SCOD), and total alkalinity (TA) levels of two-phase digesters were between thermophilic control digesters and mesophilic control digesters. However, the volatile fatty acid (VFA) levels of two-phase digesters were higher than those of thermophilic or mesophilic control digesters. The bacteria communities of M-T two-phase digesters were more diverse than those of T-M. After a change in digestion temperature, the bacterial community was dominated by Coprothermobacter. After a change of digestion temperature, the relative abundance (RA) of Methanobacterium, Methanosaeta, and Methanospirillum of M-T two-phase digesters was higher than that of T-M two-phase digesters. In comparison, the RA of Methanosarcina of T-M two-phase digesters was higher than that of M-T two-phase digesters. The ultimate methane yields of thermophilic control digesters were greater than those of mesophilic control digesters. Nevertheless, the ultimate methane yield levels of M-T two-phase digesters were greater than those of T-M two-phase digesters. The ultimate methane yields of all two-phase digesters presented an earlier increase and later decrease trend with the increasing inoculation proportion. Optimal methane production condition was achieved when 15% of sludge (T-M15) was inoculated under mesophilic-thermophilic conditions, which promoted 123.6% (based on mesophilic control) or 27.4% (based on thermophilic control). An optimal inoculation proportion (about 15%) balanced the number and activity of methanogens of high-solid sludge anaerobic digestion.

Effects of slag and alkaline solution contents on bonding strength of geopolymer-concrete composites

Geopolymer has received widespread attention due to their excellent mechanical properties and more environmentally friendly characteristics. Studying the bonding performance between geopolymer and concrete is of great significance for the development of a building material for repairing damaged concrete. The paper studied the effects of slag and alkaline solution contents on bonding strength of geopolymer-concrete composites (GCC). Firstly, 15 groups of geopolymer concrete mix proportions with 5 groups slag contents and 3 groups alkaline solution contents were designed. GCC specimens were prepared by casting geopolymer concrete on cement concrete substrates. Secondly, the splitting tensile test was conducted on GCC specimens. The strain field during the testing process of GCC specimens was analyzed based on the digital image correlation (DIC) technique. Thirdly, the effects of slag and alkaline solution contents on the splitting tensile strength of GCC specimens were discussed. Finally, the optimal mix proportion of geopolymer concrete which has the highest bonding strength with cement concrete was proposed. The results show that the splitting tensile strength of GCC specimens increases first and then decreases as the slag content increases. The splitting tensile strength of GCC specimens decreases linearly as the alkaline solution content increases. In addition, the crack growth rate of GCC specimens increases with the increase of slag content during the splitting processing. The geopolymer concrete with 50.0 % slag content and 0.7 alkaline solution-binder ratio shows the highest bonding strength with cement concrete, which is recommended for the potential application in the pavement repair works.

A novel approach to increase calcium and fiber content in pasta using kadamb fruit (Neolamarckia cadamba) powder and study of functional and structural characteristics.

Kadamb is a unique and underutilized fruit having rich nutritional profile. The utilization of kadamb fruit in value addition is very limited. In this study, pasta was made using kadamb fruit powder (KFP). The effect of fortification of KFP on the quality parameters (color, solid loss, percent expansion, hardness, bulk density, and overall acceptability) of pasta was studied. Pasta was prepared using semolina as the base ingredient, and various proportions of KFP (ranging from 0 to 20%) were added for fortification. Dietary fiber and calcium contents of dry pasta were increased from 5.21 ± 0.02 to 15.36 ± 0.02 and 17.57 ± 0.15 to 37.97 ± 0.03, respectively. As the proportion of KFP increased, the cooking time, hardness, and percent solid loss of the cooked pasta also increased. The highest values for overall acceptability, hardness, cooking solid loss, and bulk density were achieved with 10% KFP and 90% semolina were 7.93 ± 0.41, 19.92 ± 0.21 N, 6.30 ± 0.46%, and 331.67 ± 9.60kg/m3 respectively. Percent expansion of the pasta was noted to be around 98.33 ± 6.5%. The optimal proportion of KFP was found to be 10% for achieving the best overall quality attributes. FTIR (Fourier-transform infrared spectroscopy) and SEM (scanning electron microscopy) analyses were conducted on the pasta, confirming the presence of functional groups and revealing structural changes due to fiber content of KFP. KFP can be used to create functional and nutritious food products, and further research could explore its application in other food formulations as well.

Application of hybrid intelligent algorithm for multi-objective optimization of high performance concrete in complex alpine environment highway

Concrete mix proportion affects concrete performance and cost. Therefore, it arouses an increase of interest in the research on performance improvements in concrete through the optimization of the raw material mix proportion, especially in the high cold, high-salinity and other complex environment. In this paper, an intelligent multi-objective optimization framework is constructed based on Bayesian optimization Random Forest (BO-RF) algorithm and fast non-dominated sorting genetic algorithm (NSGA-III). The key factors affecting concrete performance are taken as the input indexes, the freezing resistance, impermeability, carbonization depth and cost are taken as the evaluation indexes of concrete. Based on 400 groups of freeze–thaw cycle of salt invasion experiments in cold environment, the orthogonal experiment method is used to obtain the index system of the original data sets, then, the RF prediction algorithm is adopted to establish the key factors and performance index of a nonlinear mapping relationship and the Bayesian optimization random forest is used to establish a high-precision fitness function. Ultimately, the BO-RF-NSGA-III model is applied for multiobjective optimization. The results show that (1) Based on the proposed framework, the rapid prediction and optimization of concrete performance can be realized, which can well meet the needs of the complex alpine environment (2) Accurate model prediction can be made through BO-RF. The R2 values obtained at the time of prediction range from 0.944 to 0.998, the mean absolute error (MAE) range from 0.001 to 0.09. (3) Based on BO-RF-NSGA-III and grey correlation method, the comprehensive optimal mix proportion of concrete is obtained.

The Material Mix Proportion of Roadside Backfill Body (RBB) Based on Spatiotemporal Law of Ground Pressure: A Case Study

The law of ground pressure behavior can accurately guide the material proportion and performance of the roadside backfill body (RBB) in gob-side entry retaining (GER), thereby reducing the waste of materials and the cost of retaining roadway. In this study, a similar material modeling is used to verify the spatiotemporal law of the ground pressure in the engineering case of solid dense backfilling mining in Xingtai Mine, China. Based on that law, the theoretical requirements for the bearing performance of the RBB are proposed. Finally, a material mix proportion that meets the theoretical requirements is obtained by compression test, and the deformation and failure characteristics of the backfill body with that mix proportion are analyzed. The results show that the maximum pressure of the backfill body measured in Xingtai Mine is 5.5 MPa, which is about 40 m away from the coal face; after 40 m, the force on the backfill body will not increase anymore. The physical simulation experiment also proved that the ground pressure behind the coal face increases gradually and tends to be during the backfilling process, which shows certain spatiotemporal characteristics. Through the proportioning experiment, it is determined that the optimal material mix proportion of the RBB is gangue:fly ash:cement = 10:3:1, which meets the theoretical requirement that the strength of the RBB at any position is not less than the ground pressure at that position. The research results provide theoretical support for the field practice of GER in solid dense backfilling mining.

Study on properties and application of chloroprene rubber/polyurethane modified asphalt sealant

Under the long-term effect of loads and climate conditions, various diseases can appear on the surface of asphalt pavement, causing deterioration in its performance. To address the pavement surface cracks during service, the present study developed a crumb rubber/polyurethane (CR/PU) compound as the modified asphalt sealant with excellent properties. The optimal material proportion, ensuring the best asphalt compatibility was selected to meet the requirements of standard hot-poured sealants for pavement. Additionally, the fineness and content of CR were determined. The research investigated rheological properties, aging performance, microstructure, and modification mechanism of the CR/PU sealant was then applied in an engineering project to evaluate its effectiveness in treating pavement cracks, and suitable construction techniques were summarized. The results revealed that the in-situ polymerization method is an appropriate approach for preparing the CR/PU sealant, demonstrating good high-temperature deformation resistance and low-temperature crack resistance, indicating synergistic interactions between CR and PU. Among various compositions, the sealant with 30 %PU and 15 %CR content exhibited the best thermal oxygen and UV aging properties. Microscopic tests indicated that CR was physically blended with asphalt, while PU underwent chemical modification and formed a cross-linked network structure with asphalt, resulting in CR dispersion around it, enhancing the thermal stability of the system. Furthermore, the test section displayed an ideal crack treatment effect, demonstrating the sealant’s excellent sealing, durability, and watertight capacity.

Optimal capacity configuration of the hydro-wind-photovoltaic complementary system considering cascade reservoir connection

To address the critical issues on environmental pollution and energy consumption, humans began vigorously developing and employing renewable energy sources (RESs). Hydro-wind-photovoltaic(PV) complementary system plays an indispensable part in the sphere of renewable energy research, while the optimal capacity proportion serves as a foundation and premise for building hybrid energy systems. Taking the lower portion of the Jinsha River in Sichuan Province as an example, this research presents a novel capacity configuration model of hydro-wind-PV complementary systems. Based on the consideration of cascade hydropower station connection, the model aims to minimize discarded energy and maximize delivery channel utilization. A new DE based on chaotic local search is then employed to solve the model. The result shows that the optimal proportions for the complementary system with 35 GW, 40 GW and 45 GW of delivery channel capacity are (0.93,0.93), (1.18,1.18) and (1.35,0.35), respectively. Meanwhile, as the affordability of complementary systems increases, the total installed capacity of wind power and photovoltaic power that may be accessible will also rise. Consequently, this paper not only offers a novel strategy for tackling similar issues on optimal capacity configuration, but also makes a contribution to maximizing the accessed installed capacity of RESs.

Study on Solidification Characteristics of Granular Coal Gangue: Fine Sand Paste-Cemented Filling Materials

Three groups of filling materials with different mix proportions were prepared. PO42.5 grade cement was selected as the binding material, mechanized granular coal gangue and fine sand were used as the filling aggregate, and then the specimens were curing at room temperature and 95% moisture. Through the uniaxial compression test, the influence of gangue–sand ratio, the mass fraction, and curing age on the mechanical properties of filling materials was analyzed. The microstructure analysis of SEM was conducted to explore the internal mechanism of the strength difference of filling materials. The results show that the gangue–sand ratio dramatically influences the uniaxial compressive strength. The strength increases first and then decreases with the gangue–sand ratio increase. The mass fraction of filling paste is positively correlated with specimen strength. When the sand–cement ratio, gangue–sand ratio, and the mass fraction remain unchanged, the longer the curing age, the greater the uniaxial compressive strength of specimens. The specimens with a sand–cement ratio of 3.5 : 1, a gangue–sand ratio of 5 : 5, and a mass fraction of 86% reach the maximum value of 11.03 MPa at a curing age of 10 days. It can be seen that when the gangue–sand ratio is 5 : 5, the filling material has the best mechanical properties, so it can be recommended as the optimal mix proportion for goaf filling. Thus, it provides a solid technical guarantee for the treatment of mine surface collapse disasters and the utilization of bulk coal gangue resources.

Design and performance evaluation of the epoxy-based self-luminous pavement marking

This study aims to prepare the self-luminous pavement marking (SLPM) to enhance driving safety and reduce the risk of traffic accident. Firstly, the composition of the SLPM was determined by the mechanical properties and luminous performance tests. The optimal mass proportions of epoxy resin, toughening agent, curing agent, curing accelerator, luminous powder, reflective powder, glass bead and glass powder was 1.0:0.1:0.3:0.006:0.4:0.3:0.25:0.55. In addition, test results showed that the SLPM has satisfactory mechanical properties, durability and luminous performance, which met the engineering requirements for practical application. The afterglow time was more than 11 h at night in laboratory test. Moreover, it is feasible to prepare different colors of the SLPM according to the RGP principle. The afterglow color and luminous intensity of SLPM strongly depend on the luminous material and its proportions. Overall, this paper provides a reference for designing and applying SLPM materials in road engineering.

The application of Anaerobic Digestion Model No. 1 for the optimization of biogas production from maize silage, pig manure, cattle manure, and digestate in a full-scale biogas plant

The main aim of this study was to evaluate the applicability of a mathematical model based on Anaerobic Digestion Model No. 1 (ADM1) for optimizing biogas production during a two-stage anaerobic digestion process in a full-scale biogas plant. Biogas production was analyzed in two variants. Variant I involved two decision variables: the proportion of the gaseous phase in the total volume of each digester within a preset limit of 0.05 to 0.95. Four decision variables were adopted in variant II: total digester volume during the first and second stage of anaerobic digestion, and the proportion of the gaseous phase in each digester. Digester volume was set at 10–1000 m3 for the primary digester, and at 300–5000 m3 for the secondary digester. The proportion of the gaseous phase was also set within the range of 0.05–0.95. Optimal digester volume (131 m3 for the primary digester and 5000 m3 for the secondary digester) and the optimal proportions of the gaseous phase in total digester volume (0.35 and 0.05, respectively) were generated by the modified ADM1xp model. The modeled parameters predicted a 67% increase in methane yields in a two-stage anaerobic digestion process (acidogenesis and methanogenesis).

Partial Gini Coefficient for Uncertain Random Variables with Application to Portfolio Selection

The partial Gini coefficient measures the strength of dispersion for uncertain random variables, while controlling for the effects of all random variables. Similarly to variance, the partial Gini coefficient plays an important role in uncertain random portfolio selection problems, as a risk measure to find the optimal proportions for securities. We first define the partial Gini coefficient as a risk measure in uncertain random environments. Then, we obtain a computational formula for computing the partial Gini coefficient of uncertain random variables. Moreover, we apply the partial Gini coefficient to characterize risk of investment and investigate a mean-partial Gini model with uncertain random returns. To display the performance of the mean-partial Gini portfolio selection model, some computational examples are provided. To compare the mean-partial Gini model with the traditional mean-variance model using performance ratio and diversification indices, we apply Wilcoxon non-parametric tests for related samples.

Enhancing the mechanical and environmental performance of engineered cementitious composite with metakaolin, silica fume, and graphene nanoplatelets

Engineering cementitious composites are designed to offer high ductility, enhanced strength, and enhanced impact resistance as rehabilitation materials for various support structures and equipment. ECC is an inventive material for construction with tensile strain hardened properties and multiple fracture behaviors, which is highly encouraged in the construction industry. The objective of this study was to create an eco-efficient engineered cementitious composite (ECC) with binary systems of cement with metakaolin (MK) and silica fume (SF) and an optimized dosage of graphene nanoplatelets (GNPs). To optimize mixture proportion, an experimental design was developed using the response surface method. We analyzed the compressive strength, split tensile strength, flexural strength, dried density, embodied carbon, and eco-strength efficiency of the optimal mixture proportion to determine its mechanical properties and low-carbon footprint. Results analysis showed a total of 10% content of SF and MK is optimum for an eco-friendly (low carbon profile) and mechanically strong ECC mixture. If it exceeds 10%, the mechanical strength of the composite decreases. Furthermore, 0.02%to 0.03% GNP concentration improved mechanical characteristics even further. According to the results of the multi-objective optimization, the optimal values for the variables Mk, SF, and GNPs are 9.19%, 4.83%, and 0.03%, respectively.

Effect of polyanionic cellulose modification on hydraulic and consolidation performance of sand-calcium bentonite slurry trench cutoff walls

Sand-bentonite slurry trench cutoff wall is one of the most common vertical barriers to retard the migration of contaminants. This study aimed to explore the hydraulic and consolidation performance of cutoff-wall materials containing polyanionic cellulose (PAC)-modified calcium bentonite (CaB) through a comprehensive laboratory investigation. First, physicochemical properties tests were conducted to demonstrate the superiority of PAC-CaB over CaB. Subsequently, modified fluid loss tests were conducted to investigate the effects of PAC modification and CaCl2 solution concentration on the chemical compatibility of CaB cake formed during slurry trench protection. Finally, slump, Atterberg limit, oedometer, and rigid/flexible-wall hydraulic conductivity tests were performed to evaluate the effect of PAC modification on the hydraulic conductivity (k) and compressibility of sand-CaB backfill. The results indicate that PAC can significantly enhance the impermeability of CaB cake when permeated with salt solutions. The 4 %PAC-CaB cake in 40 mM CaCl2 solution had the lowest k value (9.3 × 10−10 m/s), and was therefore recommended as the optimum proportion for trench protection. The addition of PAC considerably reduced the consolidation coefficient of CaB backfill and increased its compression index and swell index. Moreover, with the increase of PAC dosage from 0% to 0.2%, 0.4%, and 0.8%, the k values of CaB backfill decreased by 0.75, 0.96, and 1.29 orders of magnitude, respectively. The k values of PAC-CaB materials were lower than those of sodium bentonite materials, indicating that PAC is a promising modifier to achieve a low k value of CaB cake and sand-CaB backfill for slurry cutoff walls.

Quantum dots luminescent compounds with multimodal luminescence for fuel labeling

The article considers the possibility of labelling oil products using luminescent ‘fingerprints’ based on several types of quantum dots to protect fuel from falsification. For the synthesis of quantum dots, a scalable universal method was proposed using an available large-producible solvent and a stabilizer, oleic acid. Using the developed technique, quantum dots were obtained that luminescence in the entire visible range of the electromagnetic radiation spectrum. The formation of nanoparticles was confirmed by a set of instrumental research methods. The determination of the presence of quantum dots in the composition of an oil product was proposed using spectrofluorometry with no additional separation or dialization of nanoparticles from the sample. Using normal regular gasoline as an example, the effect of fuel on the luminescence of quantum dots and their aggregation was studied. The interaction of different types of quantum dots in the composition of the indicator and their influence on each other’s luminescence in solvent and gasoline were analyzed. The minimum detectable by the spectrofluorometric method concentrations of quantum dots in normal gasoline and the optimal proportions of quantum dots of various types in mixtures were determined.

Laboratory proportion design and performance evaluation of Fiber-Reinforced rubber asphalt chip seal based on multiple properties enhancement

Chip seal is an effective preventive maintenance technology for the pavement distress repair and pavement service life extension. Adding fiber or rubber powder alone has been shown to improve chip seal performance. However, the full potential of chip seal could not be attained by utilizing only fiber or rubber powder singularly. In this study, a fiber-reinforced rubber asphalt chip seal was prepared and evaluated based on multiple properties enhancement. Analysis of Variance (ANOVA) was conducted to assess the level of significant influence of rubber powder content and shearing time on the results of the penetration, softening point, ductility, and elastic recovery tests. The optimal process parameters for rubber asphalt were further analyzed and determined based on the ANOVA results. Bending beam rheometer (BBR) and rotational viscosity tests were executed to evaluate the low-temperature crack resistance and workability of the rubber asphalt. Cover, sweep, 45-degree skew shear and texture depth tests were performed to identify the optimum proportion of fiber-reinforced rubber asphalt chip seal. Tensile, temperature stability, water stability and three-point bending tests were conducted to evaluate chip seal performance. Cost analysis for mature preventive maintenance technology was carried out to evaluate equivalent annual costs. The results show that essential parameters for preparing rubber asphalt were the rubber powder content of 22.5% and the shearing time of 60 min. Moreover, the optimum proportion of fiber-reinforced rubber asphalt chip seal was determined to be 9.55 kg/m2 of aggregates, 2.3 kg/m2 of rubber asphalt, and 80 g/m2 of fiber. This study also confirmed that the fiber-reinforced rubber asphalt chip seal outperformed the rubber asphalt chip seal in terms of crack resistance, skid resistance, bonding performance, temperature stability, water stability and fatigue resistance. Combined with cost analysis, it was found that the fiber-reinforced rubber asphalt chip seal was a type of cost-effective preventive maintenance technology.

Reactivation and utilization study of melting furnace slag generated from co-processing MSW incineration fly ash

Melting furnace slag (MFS) is a potentially active by-product of the synergistic treatment of iron and steel dust sludge and Municipal Solid Waste (MSW) incineration fly ash in the flue gas magnetization fusion separator furnace of the “fire method + wet method”. This paper focuses on the MFS reactivated by mechanical grinding, and the reactivity of MFS is synergistically enhanced by alkaline, sulfate-based solid wastes. The particle size distribution, specific surface area, morphology, and physical phase composition of MFS with different grinding times resulted in the best performance of MFS when mechanically ground for 80 min and the specific surface area reached 450 m2/kg, and the reactivity indexes reached 100.94% and 103.7% for 7 and 28 d, respectively. The synergistic activation of steel slag and flue-gas desulfurization gypsum can play an effective role in stimulating the MFS, and the optimal proportion is m (MFS): m (SS): m (FGDG) = 42%: 42%: 16%. The reactivity enhancement mechanism of the ternary slag-based system on MFS: SS provides high alkalinity hydration reaction conditions for MFS and FGDG provides SO42−, which continuously promotes the hydrolysis of MFS under the synergistic reactivity stimulation to generate AFt and C–S–H gels.

Thermal insulation performance of green concrete using bio and industrial wastes: An experimental approach

The research concentrates on improving the thermal conductivity of green concrete. Cement is a high thermal conductivity material, so the aim of the research is to reduce the amount of cement for the concrete production. The aluminum dust is having low thermal conductivity based on earlier studies as well as it was proved in this research. The Portland cement has been replaced by fine aluminum dust with 5 % interval and is to be determined the optimum mix proportion. Another problem is that structural strength is lost due to improper water curing, so Calotropis gigantea milk was added to concrete to improve the curing properties. Calatropis gigantea acts as bio self-curing agent of concrete which can treat on its own without external curing without compromising its strength and durability. The dosage of Calatropis gigantea milk is taken in different percentage of cement weights, like 0.1%, 0.2%, 0.3%, 0.4% and 0.5%. The tests found in the research are workability, compressive strength, and thermal conductivity for green concrete and conventional concrete then which are compared between them. The green self-curing concrete technology can be recommended for tall structures, remote constructions, and energy saving buildings.

Numerical Modelling of Impact Loads on RC Beams Utilizing Spent Garnet as a Replacement for Fine Aggregate

Spent Garnet (SG) is one of the waste materials that attracts the interest of researchers to use it as a replacement for fine aggregate in concrete materials. As experimental investigation was carried out to assess the performance of a reinforced concrete (RC) beam incorporating SG as a substitute for fine aggregate. The study involved subjecting the beam to low-velocity impact loads within a controlled testing configuration. The primary objective of this study was to determine the optimal proportion of spent garnet (SG) to replace fine aggregates in reinforced concrete (RC) beams subjected to impact loads with a 100 kg impact weight dropped from a height of 1.5m, equivalent to a velocity of 5.4 m/s. To evaluate the effectiveness of SG as a replacement for fine aggregates, RC beams with varying percentages of SG (0%, 10%, 20%, 30%, and 40%) were numerically modelled using the Finite Element Method (FEM) incorporating the Concrete Damage Plasticity (CDP) constitutive model to simulate their behaviour under low-velocity impact loads. The study aimed to comprehensively examine the failure mode of the RC beams. The findings through FEM showed that the inclusion of SG in the concrete mix enhanced the material's behaviour and decreased the failure and damage of the beams as the percentage of SG in the mix increased, indicating its effectiveness as a replacement for fine aggregates, which is consistent with the experimental results.

Preparation, characterization and application of BaZr0.1Ce0.7Y0.2O3-δ for a high-performance and stable proton ceramic electrochemical cell

The high sintering temperature (＞1500 °C) of the electrolyte is the main challenge for the application of proton ceramic electrochemical cells (PCECs). In this work, we prepare BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte materials by various synthetic routes, compare their physicochemical properties and optimize their applications in PCEC. The BZCYs powder prepared by the solid state reaction method shows a large grain size of 2–3 μm and is used in the support layer. The optimal proportion of the support is determined according to the thermal expansion characterization. The BZCYp powder from the ultrasonic-assisted co-precipitation method presents well dispersed particles of 30∼50 nm and is used as the electrolyte layer and in the fuel electrode layer. The electrolyte becomes very dense after co-sintering with the support at 1400 °C without any sintering aids, giving a low conducting activation energy of 0.26 eV. The single cell demonstrates excellent performance and good stability. Under steam electrolysis mode, the cell gives 840 and 260 mAcm−2 @1.3V at 600 °C and 500 °C. Under cell mode, the cell displays 0.46 and 0.21Wcm−2@0.7V at 600 °C and 500 °C, respectively.