Replacement Level Research Articles

Enhancement of mechanical and microstructural characteristics of magnesium oxychloride cement with metasteatite

Magnesium oxychloride cement (MOC) has recently garnered considerable research attention as an environmentally sustainable building material. Nevertheless, the mechanical characteristics of MOC have effectively hindered its extensive implementation in engineering structures owing to their inefficient water resistance. In this regard, this study investigates the novel application of steatite to MOC to augment the water resistance of paste. First, steatite was thermally processed to improve the reactivity of the particle and was introduced as a metasteatite with rich magnesium silicate. Furthermore, metasteatite is substituted for MgO in the MOC paste by varying the replacement level from 0 % to 25 % with an interval of 5 %. Thus, metasteatite's effect on MOC paste water resistance is investigated in terms of compressive strength, strength retention under water exposure, and microstructural characterization. Compressive strength results revealed that the influence of metasteatite deteriorated the strength of the matrix with an increased dosage of metasteatite. Moreover, the compressive strength of MOC paste susceptible to water enhanced the strength retention coefficient to 42.9 % for MS10 compared to control specimens. FE-SEM analysis exhibits the formation of M-S-H gel that leads to dense microstructure and contributes to water resistance. In addition, the porosity of the paste is decreased owing to the reaction of Phase 5 with SiO2. The EDS analysis and mapping showed the occurrence of hydration products and the binding affinity between Mg and Si, which improved the continuity of microstructure and water resistance of MOC paste. Therefore, the optimum enhancement is observed for the MOC paste with 10 % metasteatite, demonstrating its efficacy in bolstering water resistance. Finally, this investigation elucidates the feasibility of using metasteatite as a supplementary material for MgO in MOC for developing water resistant MOC.

Hydration and microstructure formation of magnesium oxysulfate (MOS) cement regulated by sepiolite with high adsorption ability

Magnesium oxysulfate (MOS) cement is a potential low-carbon cementitious material with its characteristic depending on the reaction between light-burned magnesia (LBM) and MgSO4 solution. This work aimed to elucidate the effect of sepiolite with high adsorption ability on regulating the reaction within MOS cement. Replacement levels of LBM by sepiolite at 2 and 5 wt% were adopted. Hydration kinetics, microstructure, phase composition and compressive strength of MOS cement without and with sepiolite were studied. Results showed that adding sepiolite into MOS cement adjusted the ion distribution at the early hydration stage and promoted the reaction with an early onset of heat flow peaks. The presence of sepiolite refined the morphology of formed needle-like 5 Mg(OH)2·MgSO4·7H2O (517 phase) and strengthened the bond water within its structure. The high adsorption ability of sepiolite enabled the nucleation of 517 phase and amorphous phase onto its surface. Sepiolite also densified the poorly hydrated regions by tightly combining with the incompletely hydrated MgO grains. Consequently, compressive strength of MOS cement under air curing was improved after adding sepiolite.

Experimental and thermodynamic investigating of carbonation behavior in Alkali-activated slag-calcined clay materials with different binder constituent

Alkali-activated materials (AAMs) have gained interest as sustainable alternatives to traditional Portland cement in recent years. However, concerns still exist regarding their durability against harsh environments such as carbonation. This study presents an experimental and thermodynamic investigation into the carbonation behavior of alkali-activated slag-calcined clay (AASCC) prepared with varying activator types (sodium hydroxide, sodium silicate, sodium carbonate), slag replacement levels with calcined clay (0 %, 10 %, 20 %), and alkali concentrations represented by the solid part of activator to base material ratio (SPA/B = 0.05, 0.075, 0.1). Furthermore, Portland cement mixtures were also prepared to compare the results with AASCC mixtures. Compressive strength, capillary water absorption, and accelerated carbonation testing were conducted on paste and concrete mixtures over 28–90 days. Thermodynamic modeling accurately predicted the experimental trends, demonstrating that this is a valuable tool for simulating complex processes in AAMs. Results illustrated that AASCC paste mixtures produced with sodium hydroxide demonstrated the best carbonation resistance due to higher pore solution pH (up to 13.74), sodium and alumino-substituted calcium silicate hydrate (CNASH) gels content, and layered double hydroxide phases (Mg-Al-LDH). Increasing alkali concentration further improved durability against the carbonation process by elevating pore solution pH and CNASH content. However, replacing slag with calcined clay reduced carbonation resistance regardless of activator type, attributed to lower pore solution pH, CNASH, and Mg-Al-LDH, although higher alkali concentrations alleviated this impact. In general, the study elucidates key chemical and physical factors regarding the carbonation of these novel materials by utilizing comparative experimental investigation and thermodynamic modeling.

Diverging destinies: How children are faring under demographic transition

India reached the replacement level of fertility in 2020. However, the journey of fertility transition is unconventional and heterogeneous within the country and across the different socio-economic groups. The fertility transition is considered to be faster than its socio-economic and health transition in several states. Thus, it has been presumed that the returns to fertility decline are heterogeneous across the states and population sub-groups. Our specific hypothesis is that although rich and poor, and educated and un-educated, everyone had significantly contributed to the fertility decline in response to family planning policies, only those socio-economically better-off have been investing relatively more in their children compared to the poor, and this has led to diverging destinies for children. We tested this supposition using a macro-level panel dataset (1992–2021), fixed and random effects, and IV regression models. The results confirm that child health care and outcomes have diverged while fertility declined from 1992 to 2021. These results are sustained in multiple robustness checks. While fertility is declining with highly state-sponsored family planning programmes, the persistent socio-economic inequalities are leading to unequal progress in health outcomes for children in India.

The effect of dietary full-fat Hermetia illucens larvae meal on growth performance and intestine physiology in largemouth bass (Micropterus salmoides)

The present study aimed to investigate the effects of different inclusion levels of full-fat Hermetia illucens larvae (HI) meal as a protein source on the growth performance, intestinal morphology, health, and microbiota of largemouth bass. Five isonitrogenous and isolipidic diets were formulated by adding HI to replace 0 % (HI0, control), 10 % (HI10), 20 % (HI20), 30 % (HI30) and 40 % (HI40) of fish meal (FM) in diets. Each diet was randomly assigned to triplicate groups of 30 fish per aquarium. Fish were fed two times daily to apparent satiation for 80 days. The results indicated that weight gain rate, specific growth rate and protein efficiency ratio were not appreciably reduced until more than 30 % of the FM protein was replaced with HI. Fish fed HI40 diet had the lowest fatty acid (C18:3, C20:5, C22:6) contents (P < 0.05). Moreover, the villi height was decreased, villi width and goblet cell number in hindgut was increased in the HI40 group compared with the other groups, respectively. Meanwhile, serum diamine oxidase activity, D-lactate and endotoxin contents increased markedly as the proportion of HI increased (P < 0.05). Notably, the increased dietary HI levels down-regulated the mRNA expression levels of cldnd1b and ocel1 in intestine. Higher malondialdehyde content and down-regulated expression of sod and gpx1a in the intestine were also observed in the HI40 group. Accordingly, the increased dietary HI levels upregulated the expression of intestinal pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-1β) and down-regulated anti-inflammatory cytokines (transcriptional growth factor-β1 and interleukin-10) (P < 0.05). In addition, the abundance of both intestinal Lactobacillus and Streptococcus increased significantly, while the abundance of Cetobacterium decreased in the HI20 group (P < 0.05). Broken-line model analysis based on weight gain rate against dietary HI replacement level indicated that the optimum replacement level was 26.79 %. However, including too high proportion of HI could induce intestinal dysbiosis, impair the intestine physical barrier, and finally reduced growth of Micropterus salmoides.

Depopulation and deep aging: the former Yugoslav and Western Balkans space between the second demographic transition and emigration

The article introduces the tentative concept of deep aging – a label used for a situation when the overall ageing effects of the second demographic transition, due to fertility below replacement level, are topped by the excessive emigration of the fertile contingent (additional loss of active population). Deep ageing thus accelerates population decline. But the loss of fertile contingent may affect the total fertility rates and its apparent rise (TFR). Here, the tempo effect of fertility plays the decisive role. The article first assesses the demographic change in the European macroregions in the period after the fall of the Iron Curtain (1990–2020). It then analyses the changes in the area of former Yugoslavia to assess the extent of population change in the last intercensal period, 2011–2022. Building on the previous research of population loss and migration flows after the break-up of Yugoslavia, the overall population change in the region is being assessed. It is also shown that tempo distortion of fertility rates considerably affects the realistic level of fertility and that approximate completed fertility rates fell less dramatically. Since the migration data are less reliable, the analysis of intercensal change was applied to assess the migration losses across the ex-Yugoslav space. To assess the extent of deep ageing, the intercensal projection of fertile contingent was introduced. The stage of deep ageing is the most pronounced in Croatia and Serbia, especially at the younger fertile group, while the overall loss of fertile population is profound and will certainly affect the further future decrease in population. Similarly difficult demographic situation is in other post-Yugoslav countries, where only Slovenia has not yet slid into the stage of deep ageing.

Hydration characteristics and hydration products of calcium sulfoaluminate cement and fly ash blended pastes

This study investigated a binary blend of calcium sulfoaluminate cement and fly ash with a target compressive strength of more than 32.5 MPa based on the EN 197-1 standard, using as much fly ash as possible. In the binder system of calcium sulfoaluminate cement and fly ash, a decrease in the replacement level of fly ash results in an increase in compressive strength. Mortar with a 40% replacement level of fly ash for calcium sulfoaluminate cement and added gypsum shows 49.41 MPa strength at 28 d. Its hydrates are hydroxy-AFm, ettringite, crystalline aluminum hydroxide, amorphous aluminum hydroxide, strätlingite, and monosulfate. They are attributed to the hydration of ye’elimite, C2S, and C3A in calcium sulfoaluminate cement. The reactivity of fly ash is not observed until 28 d of hydration. The formation of ettringite is the main cause of the gains in compressive strength.

Optimization of Level of Incorporation of Different Dietary Fiber in the Development of Spent Hen Meat Snack Sticks

The study was conducted from October to December, 2021 in the Department of Livestock Products Technology, College of Veterinary Science, Jabalpur, Madhya Pradesh, India to prepare spent hen meat snack sticks (SHSS) by partially replacing rice flour (RF) from the product formulation with healthy, dietary fiber rich oat, finger millet and amaranth flours (OF, FMF and AF) at different levels. Four batches of SHSS were prepared by substituting RF with different levels of OF, FMF and AF each at 0%, 5%, 10% and 15%. The optimum level of incorporation of dietary fiber from each set of products was standardized based on sensory evaluation of SHSS for various attributes. A combination of steaming, drying and frying (170°C for 45 sec) was found to be the most suitable cooking method for SHSS. Substitution of RF with 15% OF resulted in a significant decrease in flavour, crispness, and overall acceptability of the snacks while lower levels did not affect the sensorial attributes. FMF at 5% level did not alter the sensory attributes while at higher levels of replacement a significant decrease in color, flavor, crispness, and overall acceptability scores were noted. Higher levels of AF (15%) significantly improved flavour and overall acceptability of SHSS. The study clearly revealed that OF (10%), FMF (5%) and AF (15%) can be used efficiently for substitution of RF in the formulation of healthier and sensorially acceptable products. Snacks crafted with spent hen meat and dietary fiber will enhance the nutritional value especially with respect to amino acids, flavour, taste and technological functionality.

Ground granulated blast furnace slag-modified magnesium phosphate cement used as grouting material: Workability, mechanical property and corrosion resistance optimization

Calcium oxide and alumina, which are significant components of ground granulated blast furnace slag (GGBS), can participate in the hydration reaction with phosphate. This study examines the effect of incorporating GGBS as a mineral admixture on the fresh, mechanical, and durability properties of two-component magnesium phosphate cement (MPC)-based grouting materials. The findings reveal that GGBS replacement not only reduces the setting time and the heat released during hydration but also optimizes the fluidity of the fresh slurry at the appropriate replacement level. The optimal content of 20 % GGBS replacement significantly improves the mechanical properties of MPC grouts, achieving up to 28.4 MPa at 28 days, and enhances their resistance against the corrosion of water, chloride, and sulfate ions. XRD results show that the incorporation of GGBS leads to the formation of amorphous phases and secondary hydration products. These findings are corroborated by SEM analysis, which reveals gel-like new hydration products in matrices containing GGBS. Additionally, the incorporation of GGBS reduces the appearance of microcracks and gaps, resulting in a denser microstructure of the MPC matrix.

Effects of dietary replacement of fishmeal by defatted Tenebrio molitor meal, Clostridium autoethanogenum protein meal and Chlorella vulgaris meal on the freshness of turbot (Scophthalmus maximus) during chilled storage

The present work evaluated the effects of dietary fishmeal replacement with three non-food protein sources, including defatted Tenebrio molitor meal (TM), Clostridium autoethanogenum protein meal (CAP) and Chlorella vulgaris meal (CV), on the freshness traits of turbot Scophthalmus maximus. TM, CAP, or CV were used to respectively replace 0 %, 15 %, 30 %. 45 %, 60 % and 75 % of dietary fishmeal protein. Turbot (180.5 ± 2.5 g) were fed with eighteen experimental diets for 70 days, and were stored at 4 ℃ for 3 days. TM and CAP linearly increased QIM scores, but no obvious trend between QIM scores and CV dietary level. The TM15 diet decreased the QIM score, indicating better overall freshness compared to the other TM-groups. Chromameter indicated that consumers could not distinguish the color differences among groups (ΔE < 3). The muscle hardness of all groups was significantly reduced after storage (P<0.05), except the fish fed TM15 diet. Moreover, the TM15 group showed lower pH, TVB-N, and TBA levels after storage, whereas higher TM replacement levels (>30 %) resulted in increased pH, TVB-N, and TBA levels compared with the fish fed TM0 diet. But cathepsin B and L activities showed no significant differences across all TM-groups. Among the CAP-groups, no significant differences were noted in pH and TBA levels; however, CAP linearly increased TVB-N levels after storage. CV did not significantly influence the post-storage pH, TVB-N, and TBA levels. The muscle glycogen content showed no significant variance among the groups. In conclusion, a 15 % dietary replacement of fishmeal with TM optimized the freshness of turbot by decelerating muscle softening, lipid oxidation, and the production of volatile nitrogen compounds, whereas higher levels of TM accelerated these processes. CAP replacement level exceeding 15 % enhanced the production of volatile nitrogen compounds. Dietary inclusion of CV did not impact the freshness of turbot during storage.

Effect of waste travertine powder on properties of rhyolitic tuff-based geopolymer

This investigation explores the potential of geopolymer technology as an eco-friendly substitute for conventional construction materials by emphasizing the innovative use of naturally occurring green rhyolitic tuff and repurposed travertine powder in geopolymer paste formulations. Replacement levels of tuff with travertine at 40 %, 45 %, and 50 %, along with an alkaline solution with a NaOH molarity range of 8.2 M–22.1 M, have been analyzed for their impact on flowability, water absorption, porosity, compressive strength, and unit weight of the geopolymers over curing periods of 2, 28, and 90 days. The flowability measurements show that adding 40 %, 45 %, and 50 % travertine leads to approximately 7 %, 31 %, and 31 % reductions in the flowability of the geopolymer, respectively. It is demonstrated that adding 40 % travertine significantly improves the geopolymers’ compressive strength with an 11.5 M NaOH concentration, showing substantial increases of approximately 15.5, 9.0, and 2.4 times at the curing duration of 2, 28, and 90 days, respectively, relative to the geopolymer without travertine. As an optimum points, an 18.5 M NaOH and an 0.7 solution-to-powder ratio decrease the long-term apparent porosity and water absorption of the geopolymer without travertine by about 14 % and 19 % compared to those at the same solution-to-powder ratio with 11.5 M NaOH, respectively. Microscopic examinations were employed to validate the development of sodium aluminosilicate hydrate, calcium aluminosilicate hydrate, and calcium silicate hydrate gels, underscoring the advantageous contribution of the elevated CaO content in the travertine to the geopolymer matrix. This research not only highlights the environmental benefits of repurposing waste materials but also contributes to the development of more sustainable and durable geopolymer pastes, offering a promising approach to enhancing environmental stewardship in material science practices.

Advances in using seawater in slag-containing cement systems

The use of seawater as mixing water in concrete is motivated by an increasing danger of freshwater shortages. The factors restricting its use in concrete include a high risk of concrete structure degradation as well as steel reinforcement corrosion initiated by the chlorides and sulphates in seawater. The objective of this study is to evaluate the potential of ternary cementitious systems containing the substitution of a clinker constituent in cements with ground granulated blast furnace slag (GGBFS) at rate of 45 wt% and 85 wt% and zeolite (10 wt%) mixed with seawater. Moreover, the effects of alkaline activators were evaluated as a potential method to compensate the low strength of high volume slag-zeolite-cement systems containing seawater. The hydration process was evaluated by means of calorimetry, X-ray diffraction (XRD) and scanning electron microscopy (SEM), and was supplemented by the compressive strength development (2, 7, 28 days) evaluation. It was found that presence of GGBFS in seawater-mixed systems, promotes an increase in the volume of low-calcium silicate hydrate gel-like phases, which (in addition to the layered double hydroxide phases) bind the Cl-- and SO42--ions of seawater. However, at high volume replacement level (85 wt%) the accelerating effect of seawater is limited resulting in slow rate of concrete strength gain. The proposed alkaline activation, allowed the strength enhancement, but also satisfied the conditions for the complete binding of Cl-- and SO42− -ions, due to the formation of zeolite-like alkaline aluminosilicate hydrates in the resultant cement matrix. It was found that the addition of natural zeolite accelerates hydration reactions and crystallization processes in cement systems. As an outcome, due to synergistic effect of seawater and alkali-activation, the proposed ternary blend containing 5 wt% of Portland cement exhibited only 24 % lower 28 days compressive strength when compared to freshwater-mixed Portland cement (90 wt%) – zeolite (10 wt%) reference mix.

Mechanical properties, microstructure and GEP-based modeling of basalt fiber reinforced lightweight high-strength concrete containing SCMs

The pressing need to address recent global climate changes calls for replacing high-carbon-emitting cement with environmentally friendly materials that retain the strength and properties of conventional concrete. This study explored the mechanical properties of lightweight concrete (LWC) incorporating shale aggregate and basalt fibers alongside a partial replacement of environmentally detrimental cement with pozzolanic materials like fly ash (FA), blast furnace slag (BS), and silica fume (SF) up to 30 %. Twenty mix designs were developed to examine their mechanical properties and microstructural characterization. It was also observed that SF outperformed other industrial byproducts and gave better strength with the optimum replacement of 20 % cement, achieving 102.6 %, 105.6 % and 109.5 % of the control mix compressive, flexural, and split-tensile strength, respectively. However, a further increase of up to 30 % decreased strength. FA and BS resulted in lower strength than the control sample and other byproducts-based mixes, with compressive strength decreasing by 4 %–20.5 % at replacement levels of 10 %–30 %, respectively. BS resulted in an initial increase in strength at 10 % replacement but decreased by 10.8 %–21.6 % at higher levels. This trend was similar for flexural and tensile strengths. However, adding basalt fibers resulted in higher strength compared to non-fiber mixes and increased the strength of LWC by up to 25.2 %. The micromorphology and pore structure study indicated that the high-performance paste and fibers bridging effect were crucial for high strength. Gene expression programming (GEP) based modeling, validated against our own experimental results, was employed to predict the outcomes, demonstrating strong correlation coefficients for compressive, flexural and tensile strength (0.9430, 0.9609 and 0.9353, respectively). Additionally, SHapely Additive exPlanations (SHAP) analysis was used to assess the impact of each input parameter, highlighting the positive effects of the water-to-binder ratio and lightweight aggregate on the LWC's mechanical properties. This study is novel in its comprehensive examination of the combined impact of SCMs, shale aggregate and basalt fibers on the performance of LWC, a synergy not extensively explored in prior research. Furthermore, a novel generalized constitutive model was developed, and a SHAP analysis was performed to help design an efficient mix design to enhance the mechanical performance of LWC.

Sustainable Pervious Concrete with Silica Fume as Cement Replacement: A Review

Pervious concrete is a unique type of concrete with high porosity that allows water to pass through. This characteristic makes it beneficial for various applications, such as stormwater management, groundwater recharge, and reduced heat island effect. However, pervious concrete typically requires more cement than conventional concrete because of its mix design. This increased cement content can be partially replaced with supplementary cementitious materials, such as silica fume. This review article investigates the influence of silica fume on the properties of pervious concrete, including the mechanical properties (compressive strength, splitting tensile strength, and flexural strength), durability (resistance to freeze–thaw cycles and abrasion), and environmental aspects. The article highlights that silica fume can improve the mechanical properties and durability of pervious concrete up to an optimal replacement level. The optimum replacement level of cement with silica fume was found to be 10%–15%. Beyond this level, the performance of pervious concrete decreases. The pervious concrete containing silica fume showed superior abrasion resistance and improved freeze–thaw resistance compared to conventional pervious concrete. In addition, incorporating silica fume in pervious concrete reduces cement usage, leading to a lower environmental impact and more sustainable construction practices. The article also analyzes the limitations of using silica fume, such as the potential for reduced workability because of its fine particle size. Overall, the review suggests that silica fume is a promising supplementary cementitious material for enhancing the performance and sustainability of pervious concrete.

Utilizing Marble Wastewater in Cement Pastes and Mortars for Enhanced Physico-Mechanical and Microstructural Properties

This research explored the potential of marble wastewater (MWW) in cement paste and mortar production, addressing water scarcity, sustainable growth, and resource management. It investigated the physico-mechanical properties and microstructure of cement materials incorporated with varying amounts of MWW. In this study, we utilized tap water and MWW for mortar quality testing, focusing on parameters including setting times, water absorption, and mechanical strength. The viability of MWW in concrete formulations was confirmed by its acceptable total dissolved solids and alkalinity levels. A comprehensive experimental program determined that using marble wastewater in place of tap water reduced the quantity of water required for cement consistency and generated slightly higher compressive strengths (2, 3, 4, and 6%) after 28 days of curing. Analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis, and X-ray diffraction (XRD), were employed for molecular and microstructural analyses, which revealed that MWW had a significant influence on portlandite development and CSH formation at higher replacement levels. In short, this research highlights the feasibility of using MWW in cement products, contributing to sustainable water resources, and industrial waste management and utilization.

Replacing soybean meal with fermented rapeseed meal in diets: potential effects on growth performance, antioxidant capacity, and liver and intestinal health of juvenile tilapia (Oreochromis niloticus).

This study aims to evaluate the effects of substituting soybean meal with fermented rapeseed meal (FRM) on growth, antioxidant capacity, and liver and intestinal health of the genetically improved farmed tilapia (GIFT, Oreochromis niloticus). A total of 450 tilapia (7.22 ± 0.15g) were fed with five experimental diets, including a basal diet containing 40% soybean meal (CP0), which was subsequently replaced by 25% (CP25), 50% (CP50), 75% (CP75), and 100% (CP100) FRM in a recirculated aquiculture system for 9weeks (30 fish per tank in triplicates). The results showed that the weight gain, specific growth rate, feed intake, feed efficiency, hepatosomatic index, and viscerosomatic index of fish in both CP75 and CP100 groups were significantly lower than those in CP0 group (P < 0.05). The fish in CP100 group had the lower content of muscle crude protein while the higher level of muscle crude lipid (P < 0.05). Activities of serum aspartate aminotransferase, alanine aminotransferase along with total triglyceride in CP100 group were significantly higher than those in CP0 group (P < 0.05). There were no significant differences in the contents of liver protease, amylase, and lipase among five groups (P > 0.05). The activities of liver total antioxidant capacity and superoxide dismutase exhibited the increased tendency with the increase of FRM replacement levels from 25 to 50% (P < 0.05), while then significantly decreased from 75 to 100% (P < 0.05). Histological morphology indicated that the fish in between CP75 and CP100 groups had poor liver and intestine health. Intestinal microbial diversity analysis showed that the relative abundance of Cetobacterium and Alcaligenaceae in both CP75 and CP100 groups were lower than that in other three groups. In conclusion, the maximum replacement level of soybean meal with FRM in the diet was determined to be 50% without compromising the growth performance, antioxidant status, and liver and intestinal health of tilapia under the current experimental conditions. The observed decrease in food intake and subsequent retarded growth performance in the CP75 and CP100 groups can be attributed directly to a reduction in feed palatability caused by FRM.

Exploring the potential of sugarcane bagasse ash as a sustainable supplementary cementitious material: Experimental investigation and statistical analysis

Exploring nonconventional cementitious materials is vital for enhancing material performance, reducing construction industry's environmental footprint, and promoting sustainable resource management. This study investigated the potential of minimally processed sugarcane bagasse ash (SCBA) as a supplementary cementitious material in mortar mixes, examining its effects on compressive strength, ultrasonic pulse velocity, density, water absorption, and microstructure. Notably, the SCBA used in this study was processed with minimal energy input, involving only sun drying, coarse sieving through a 150-μm mesh, and gentle oven drying to remove residual moisture. In this view, seven cementitious mixes were prepared, comprising a control mix and six mixes with SCBA replacement levels ranging from 5 % to 30 % by weight of binder (Cement + SCBA). Initially, the 7-day compressive strength decreased with increasing SCBA replacement, whereas 28-day strength increased for mixes containing 5–15 wt% SCBA, with a maximum 12.67 % increase at 5 wt% replacement, and all mixes up to 15 wt% SCBA met ASTM C270 specifications. Up to 5 wt% SCBA substitution enhanced both ultrasonic pulse velocity (UPV) and density, but further additions led to decreased UPV and density values due to the formation of a porous microstructure resulting from increased SCBA content. However, despite this decrease, mortars containing up to 15 wt% SCBA achieved UPV values surpassing the literature-defined thresholds for good (3500 m/s) and excellent (3800 m/s) quality cement mortar at 28 days, indicating yet a well-packed microstructure. The incorporation of upto 15 wt% SCBA resulted in reduced water absorption at 28 days, meeting the requirements of ASTM C62. A quadratic regression model was employed to investigate the relationship between SCBA content and mortar properties, including compressive strength, ultrasonic pulse velocity, density, and water absorption. The analysis revealed a statistically significant fit (p < 0.05) with a high coefficient of determination (R2 > 0.90), indicating a strong relationship between SCBA content and mortar properties. Microstructural evaluation confirmed beneficial effects of SCBA incorporation on mortar morphology, within moderate dosage ranges (up to 15–20 wt% SCBA). The study highlights the potential of using energy-efficient SCBA as a sustainable supplementary cementitious material to improve mortar mix performance and contribute to the development of environmentally friendly cementitious materials.

Increasing levels of fishmeal replacement by defatted black soldier fly larvae meal reduced growth performance without affecting fillet quality in largemouth bass (Micropterus salmoides).

A 90-day feeding trial was conducted to evaluate the effects of replacing dietary fishmeal (FM) with defatted black soldier fly larvae meal (BSFL) on the growth performance and fillet quality of largemouth bass (Micropterus salmoides). The largemouth bass was divided into six groups (BSFL0, BSFL15, BSFL30, BSFL45, BSFL75, and BSFL100) and fed six isonitrogenous(CP 50%, 508 g/kg) and isolipid (CL 9%, 124 g/kg) diets, in which 0, 15%, 30%, 45%, 75%, and 100% of the fishmeal was replaced with BSFL, respectively. The results showed that the final body weight (FBW) and specific growth rate (SGR) of the largemouth bass decreased with increasing BSFL content, and they were significantly lower in BSFL75 than in BSFL0. The weight gain rate (WGR) decreased with increasing BSFL content and the feed conversion ratio (FCR) of largemouth bass increased with increasing BSFL content. The saturated fatty acids (SFAs) and n-3 polyunsaturated fatty acids (PUFA) contents of the largemouth bass fillet significantly decreased, and the n-6 PUFA content of the largemouth bass fillets significantly increased with increasing dietary BSFL. The fillet b* significantly decreased with increasing BSFL content. The biological parameters, fillet proximate nutrient composition, fillet amino acid composition, skin color, and fillet texture of the largemouth bass were not affected by the replacement of BSFL. Transcriptomic analysis revealed that BSFL replacement of FM affects the immune system and metabolic processes of largemouth bass through signaling pathways such as complement and coagulation cascades, the PPAR signaling pathway, cholesterol metabolism, and fat digestion and absorption. In conclusion, a replacement level lower than 45% BSFL was suggested for the overall growth and fillet quality of largemouth bass.

Investigation properties of ultra-high performance concrete incorporating pond ash

Abstract The study aims to substitute river sand used in ultra-high performance concrete (UHPC) with pond ash (PA), a waste by-product from the Sikka thermal power station in Gujarat, India, at replacement levels ranging from 0 to 20%. Also, 20% of the cement was replaced with ground granulated blast-furnace slag, which is a sustainable, eco-friendly material. As a result, this concrete is both environmentally and economically feasible. Experimental analysis evaluated the workability, compressive strength, split tensile strength, flexural strength, and microstructure of the UHPC mixtures. Incorporating 10% PA as a sand replacement enhanced the compressive strength, reaching 117 MPa at 90 days, as well as the flexural strength of 23 MPa and the split tensile strength of 14 MPa. The strength is positively impacted when 10% of the river sand is replaced with PA, while the strength of UHPC appears to be diminished if PA content is increased beyond 10% replacement of sand. Petrographic microscopy and X-ray diffraction were used to study the microstructure of UHPC made with PA. When PA was used instead of sand, the mortar mass solidified and became denser, resulting in an improved microstructure of the UHPC with fewer surface cracks. With the inclusion of PA, the calcium silica hydrate gel content of the concrete increases, and enhanced performance of UHPC up to a certain amount of replacement has been observed.

Development of Ultra-High-Performance Concrete Using GGBS and Alccofine

Abstract: Ultra-high-performance concrete, or UHPC, is a cementitious mixture that is distinguished by its exceptionally high compressive strength—more than 120 MPa as well as its remarkable toughness, tensile ductility, and longevity. Ground Granulated Blast Furnace Slag (GGBS) and Alccofine (AF) are commonly used in the matrix composition to increase the particle system's packing density and subsequently enhance the matrix's strength in order to guarantee that UHPC has the proper strength. To investigate the engineering properties of ternary blended UHPC with GGBS, AF, a comparative study was conducted. In comparison to the control UHPC mix, the ternary blended UHPC mix's mechanical and durability qualities were improved by the percentage variation of AF within specific bounds. In this study, the experimental work included mix proportioning and preparation of ternary blended UHPC specimens and various tests like Compressive Strength, Split Tensile Strength, Flexure Strength and RCPT (Rapid Chloride Penetration Test) were performed in the laboratory. The results show that under normal water curing conditions, the strength qualities of UHPC based on GGBS are considerable, up to a cement replacement level of 40%. In addition, compared to the binary counterpart, the mixture of 20 Percent AF and 40 Percent GGBS showed better mechanical and durability properties.