Optimum Replacement Level Research Articles

Development of high strength light weight concrete for RC beams by using optimum replacement level of pumice aggregate

Development of high strength light weight concrete for RC beams by using optimum replacement level of pumice aggregate

Effect of Epoxy Resin on the Strength Propery of Portland Cement Concrete

In this study, the strength effect of partially substituting Portland Cement (PC) with epoxy-resin in making concrete was examined. A mix ratio of 1:1.87:2.67 (PC: sand: granite chippings) at water-cement ratio of 0.5 targeting a strength of 30N/mm2 was adopted. The epoxy resin was mixed with hardener at a proportion of 1:0.5 and this mixture was used to replace PC at 10% intervals starting from 0% to 40%. Six cubes were cast for each mix ratio and were cured in water at room temperature for 28 days. The first set of samples were treated by heating them in an oven to a temperature of 1000C for 1 hour before testing in compression while, the other set were not treated. Results showed that as the quantity of epoxy resin in the concrete enlarged the compressive strength values reduced. But a rise was observed at 30%. All concrete produced were structural in nature except for the heated 40% specimen. An optimal replacement strength of 32.10 N/mm2 at 30% inclusion (unheated) and lowest strength of 18.63 N/mm2 at 40% replacement (heated) were obtained. The heated samples experienced further reduction in their compressive strength values. An 8.94% drop in strength was observed between the maximum replacement values for the heated and unheated samples at 30%. In conclusion, epoxy resin concrete can be used for structural works at replacement levels up to 40%. However, if the concrete will be exposed to increased temperature of 1000C, then an optimal replacement level of 30% is recommended.

Investigating the synergistic effects of internal curing and pozzolanic activity in mortar utilizing clay-burnt brick fines

This study investigates the combined effect of internal curing and pozzolanic activity in mortar through the incorporation of clay-burnt brick fines (CBBF) as a partial substitute for sand. Simultaneously, the study explores the degree of pozzolanic reactivity by replacing a part of cement with finer clay-burnt brick fines (CBBP, particle size <75 μm). These materials are sourced from waste materials generated during brick-chip production. The 50 mm cubic mortar specimens were prepared by substituting a portion of fine aggregate with pre-wetted CBBF up to 20 % v/v and replacing cement with CBBP up to 27 % v/v. Two separate sand-to-cement ratios (S/C) of 1.2 and 1.6 were used in the mortar mixes. Samples underwent mechanical testing and were analyzed using ultrasonic pulse velocity (UPV) and accelerated carbonation tests. At a S/C of 1.6, increasing CBBF content in the mortar led to higher compressive strength. Conversely, for S/C = 1.2, the optimal replacement level was 4 % v/v of CBBF, beyond which compressive strength gradually decreased due to the porous nature of CBBF particles. Moreover, an 8 % CBBF replacement demonstrated maximum resistance to carbonation. SEM analysis revealed a denser matrix, indicating the effectiveness of CBBF in enhancing mechanical and durability properties.

Evaluation of Concrete Compressive Strength with Coral Stone as a Fine Aggregate Replacement

This study examines the effect of using coral stone as a substitute for fine aggregate on the compressive strength of concrete. Tests were conducted with varying coral stone replacement percentages ranging from 0% to 100%. The results showed that coral stone can enhance the compressive strength of concrete, with an optimal replacement level of 80%, resulting in a 21.16% increase compared to normal concrete. However, replacements above 80% led to a decline in compressive strength, particularly at the 100% replacement level, which showed a 9.37% reduction in strength compared to normal concrete. This decrease was caused by increased porosity, varying aggregate quality, and an imbalance in the water-cement ratio, which disrupted the hydration process and microstructure formation of the concrete. Based on these findings, coral stone can be an effective alternative to replace fine aggregate such as sand, but its use should be limited to 80% to maximize the strength improvement without reducing performance.

Assessment of Cement Mortar Strength Mixed with Waste Copper Mine Tailings (CT) by Applying Gradient Boosting Regressor and Grid Search Optimization Machine Learning Approach

Growing environmental concerns and resource scarcity, the construction industry must investigate sustainable materials that reduce waste while improving building material properties. This study investigates the viability of using waste copper mine tailings (CT) as a partial replacement for river sand in cement mortar, assessing the impact on mechanical strength and developing a predictive model using a Gradient Boosting Regressor (GBR) and Grid Search Optimization (GSO). Copper tailings mix designs ranging from 0% to 50% replacement by volume (river sand) were developed, with a constant cement quantity while varying the proportions of sand and tailings. The experiments were carried out at Poornima University in Jaipur, using standard protocols to prepare specimens and measure their compressive strength for 0% CT to 50% CT as volume percent in the mixture. The results showed that the addition of copper tailings up to 20% (3CT2) had highly increased the mortar strength, while mix design 6CT3 showed the best strength at 30% CT. Beyond this threshold, strength declined, thus indicating an optimal replacement level. In the final step of the research, the GBR-GSO-based machine learning approach was employed for developing the predictive model for compressive strength in mortar with different contents of copper tailing for mix types 3CT and 6CT. The predictions obtained by the developed model were in very good agreement with empirical data, thus supporting the potential of machine learning to predict material performance for guiding the use of unconventional additives in construction. It could be said that this work not only represents the material properties of copper-tailing-infused mortar but also showcases state-of-the-art machine learning techniques in the building materials science domain while opening new paths for more innovative and sustainable building practices.

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.

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.

Response of Broiler Chicken Fed Graded Levels of Cassava Peel Leaf Meal (CPLM) Mix on Carcass Characteristics and Organ Weights

This experiment was conducted to evaluate the effects of replacing maize with different levels of Cassava Peel Leaf Meal mix on carcass traits and relative organ weights of broiler chickens. The study determined an optimum level of maize replacement by CPLM that would not compromise growth performance, carcass yield, and organ health. The broiler chicken were fed 0%, 10%, 20%, 30%, 40%, and 50% maize replaced by CPLM mix (9:1 ratio) diets for a certain duration of time. Variations in DW% and EW%; even the relative organ weights like heart, liver, and gizzard showed significant differences. The outcome indicated that up to 50% maize replacement with the CPLM mix seemed feasible without showing any negative impact on the performance of broiler chickens and eventually providing a possibly low-cost alternative feed resource. Keywords: Maize, Alternative Feed stuff, Poultry, Carcass, Organ Proceedings Citation Format Olowoyeye, Janet Chinwe (2024): Response of Broiler Chicken Fed Graded Levels of Cassava Peel Leaf Meal (CPLM) Mix on Carcass Characteristics and Organ Weights. Proceedings of the 38th iSTEAMS Multidisciplinary Bespoke Conference. 17th – 19th July, 2024. University of Ghana, Accra, Ghana. Pp 183-190. dx.doi.org/10.22624/AIMS/ACCRABESPOKE2024P19

Production of sustainable GGBFS-based Self-Compacting Geopolymer Concrete containing E-waste aggregates under ambient temperature curing

Geopolymer concrete (GPC) has gained global attention due to its environmentally friendly composition and a reduction in the carbon footprint compared to conventional concrete. Self-compacting geopolymer concrete (SCGC) combines the environmental benefits of geopolymers with the convenience of self-compacting concrete (SCC), offering a sustainable solution that minimizes manual labor, reduces noise pollution, and ensures a high-quality finish in diverse construction locations. The rapid proliferation of electronic devices in contemporary society has substantially enhanced electronic waste (e-waste), creating significant environmental challenges. This study explores a sustainable approach in managing the menace created by e-waste through its partial replacement against natural aggregates in producing ground granulated blast furnace slag (GGBFS)-based SCGC under ambient temperature curing. The research methodology involves the preparation of eleven mixes, including the control SCGC mix (with no e-waste aggregate), utilizing printed circuit boards (PCBs) as partial replacement in natural fine and coarse aggregates at varying percentages, i.e., 10 %, 20 %, 30 %, 40 %, and 50 %. It is revealed through a detailed fresh property, mechanical property, durability property, and microstructural analysis that the optimal replacement levels with e-waste are 30 % NFA or 10 % NCA in producing a sustainable and workable SCGC comprising 28.2 % and 19.2 % of waste materials (GGBFS, EWF, and EWC) moving towards a sustainable concrete yield.

Unlocking the Potential of Palm Kernel Shell and Quarry Dust: A Cost-Driven Approach to Replacing Sand and Gravel in Concrete

This research investigates the potential of palm kernel shells (PKS) and quarry dust (QD) as sustainable and cost-effective replacements for sand and gravel in concrete production. The study explores the impact of varying PKS and QD content on workability, density, water absorption, and mechanical properties. While increasing these alternative aggregates decreases workability and density, it improves water absorption and, in some cases, mechanical strength. Response Surface Methodology (RSM) identified a combination of 5% PKS and 20% QD (-1, -1) as the optimal replacement level for achieving a balance between cost and performance. This mix offers a significant cost reduction of 18.2% relative to concrete made with conventional aggregates. The study highlights the potential of PKS and QD as sustainable alternatives for conventional aggregates. Utilizing these readily available waste materials can reduce reliance on natural resources, promote waste management practices, and contribute to a more environmentally friendly construction industry. Additionally, the research suggests that quarry dust alone might be a more suitable replacement material than PKS due to its superior influence on concrete strength. This research provides valuable insights for optimizing concrete mix design with PKS and QD, promoting cost-effective and sustainable construction practices in regions with abundant palm oil production and quarrying activities.

Feasibility evaluation of cottonseed protein concentrate to replace soybean meal in the diet of juvenile grass carp (Ctenopharyngodon idellus): Growth performance, antioxidant capacity, intestinal health and microflora composition

An investigation into the replacement of soybean meal (SBM) with cottonseed protein concentrate (CPC) in the diet of grass carp feed (Ctenopharyngodon idellus) was carried out. During a 56-day feeding trial, 750 grass carp were fed five experimental diets (isonitrogenous and isolipidic) with different levels of CPC: SBM (control group), CPC25, CPC50, CPC75, and CPC100, corresponding to dietary SBM replacements levels of 0%, 25%, 50%, 75%, and 100%. The results showed that dietary CPC inclusion significantly increased FW, WGR, and PER (P < 0.05) except CPC100 groups, which did not differ with SBM group (P > 0.05). FCR was remarkably increased when SBM replacement levels reached up to 100% (P < 0.05). Based on broken-line regression analysis of WGR against the dietary replacement of SBM with CPC, the optimal replacement level of SBM with CPC was estimated to be 75.11% for juvenile grass carp. Muscle texture parameters hardness, gumminess and chewiness were apparently elevated (P < 0.05), demonstrated an improved flesh quality followed CPC added. The CPC inclusion groups showed significantly higher serum IgM, C3 amd C4 contents, as well as ACP and AKP activities than SBM group except CPC100 groups (P < 0.05). The hepatic antioxidant capacity was enhanced followed CPC inclusion verified at enzymatic and transcriptional levels (P < 0.05). The intestinal inflammation was relieved evidenced by the down-regulated il-β, il-6 and tnf-α expressive abundance mediated through NF-κB pathway (P < 0.05). Additionally, the intestinal mucosal barrier function was enhanced by the up-regulation of tight junction proteins (occludin, claudin12, zo-1, and zo-2). The intestinal lipase and trypsin activities in CPC50 and CPC75 and intestinal folds height in CPC25, CPC50 and CPC75 were advanced (P < 0.05). The gut microbiota revealed no significant differences in the alpha diversity indices across treatments (P > 0.05). While the key bacteria of Aeromonas in the CPC100 group was increased leading intestinal dysbacteriosis. Besides, the ME1 of the microbial network has a negative correlation with pro-inflammatory gens and a positive correlation with antioxidant gens and tight linking proteins (P < 0.05). Summarily, CPC could partially replace SBM with positive influences on growth, antioxidant capacity, immunity, and intestinal microbiota in grass carp.

Feasibility of incorporating coal mine overburden material as construction-grade fine aggregate

This study addresses the environmental challenge posed by coal mine overburden (CMOB) disposal by exploring its viability as a fine aggregate substitute for concrete production, particularly in response to the escalating demand for natural river sand (NS). Physical properties of CMOB, including particle size, specific gravity, density, water absorption, and the presence of deleterious materials, were rigorously evaluated. The results show that while some physical properties differ from NS, crucial parameters such as specific gravity, density, and soundness closely align with NS, all within specified code limits. Chemical-mineralogical analyses reveal the absence of sulfur and chloride in CMOB, mitigating the risk of sulfate and chloride attack on cement mortar/concrete. The study also highlights that CMOB-incorporated mortar exhibits enhanced compressive strength, with an optimum replacement level of 60%. Exceeding this level may elevate water demand in mortar, diminishing strength. This research not only establishes CMOB as a construction-grade fine aggregate but also presents it as a sustainable solution, conserving natural river sand and addressing environmental concerns associated with overburden disposal.

Advancing Sustainability and Performance with Crushed Bottom Ash as Filler in Polymer-Modified Asphalt Concrete Mixtures.

Amid the growing demand for sustainable pavement solutions and the need to incorporate recycled materials into construction practices, this study explored the viability of using crushed thermal power plant bottom ash as a filler in polymer-modified asphalt concrete mixtures. Conventional lime filler was replaced with bottom ash at varying levels (0%, 25%, 50%, and 75%), and the resulting mixtures were evaluated using several performance tests. The optimal replacement level was determined to be 25%, based on the results of the indirect tensile strength (ITS) test. Comparisons between the control mixture and the 25% bottom ash-modified mixture were conducted using the dynamic modulus test, Cantabro test, Hamburg wheel tracking (HWT) test, and tensile strength ratio (TSR) test. The findings indicate that the 25% bottom ash-modified mixture demonstrated improved performance across multiple parameters. The HWT test showed enhanced rut durability, with a recorded depth of 7.56 mm compared to 8.9 mm for the control mixture. The Cantabro test results revealed lower weight loss percentages for the modified mixture, indicating better abrasion resistance. The dynamic modulus test indicated higher resilience and stiffness in both high- and low-frequency stages. The TSR test highlighted improved moisture resistance, with higher TSR values after 10 wet-drying cycles. These improvements are attributed to the fine particle size and beneficial chemical composition of bottom ash, which enhance the asphalt mixture's density, binder-aggregate adhesion, and overall durability. The results suggest that incorporating 25% crushed bottom ash as a filler in polymer-modified asphalt concrete mixtures is a viable and sustainable approach to improving pavement performance and longevity.

Improvement in organization of Cu–O coordination and super-electrons in Bi-2212 ceramic matrix with Ag/Sr partial substitution

This study rationalizes the reason for an increase in the electrical conductivity, crystal quality, surface morphology, and superconductive transition temperatures for Bi-2212 superconductors via scientific facts and discussions depending on replacing the optimum Ag/Sr sites in the system for the first time. Every experimental result and related calculations indicate the successful replacement of monovalent Ag+ ions for the divalent Sr2+ ions in the polycrystalline Bi-2212 structure. Moreover, it is observed that the bulk Bi-2212 ceramic prepared with a partial substitution level of x = 0.01 is observed to possess the highest electrical conductivity and superconductive transition temperatures of 84.68 K and 86.26 K for the Tcoffset\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T_{c}^{offset}$$\\end{document} and Tconset\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T_{c}^{onset}$$\\end{document}, respectively. Besides, in the case of the optimum replacement level, the Bi-2212 ceramic exhibits the most uniform and smoothest surface appearance, highest interactions between the grains, best microcrystal distributions/orientations, and largest average crystalline distribution along the crystal structure. In this regard, this study becomes a leader in broadening the application spectra including the heavy-industrial technologies, innovative, advanced engineering-related sectors, and large-scale application fields for Bi-2212 superconducting ceramics.

Towards improved flexural behavior of plastic-based mortars: An experimental and modeling study on waste material incorporation

A considerable fraction of solid waste, which is harmful, chemically reactive, and infectious, is generated globally. The frequent deposition of these wastes in landfills has significant environmental and health consequences. This study aims to develop an environmentally conscious approach by incorporating finely ground waste materials, namely marble powder (MP), glass powder (GP), and silica fume (SF), into plastic waste (PW) based mortar to assess their efficacy in improving flexural strength (FS). Plastic waste mortar samples were cast using shredded PW, replacing sand in amounts ranging from 5 % to 25 %. The FS of these samples was measured after 28 days and used as a reference. MP, GP, and SF were individually incorporated into PW-based mortar formulations in varying quantities of 5–25 %, with increments of 5 %, by replacing cement. In PW-based mortar formulations, waste materials were also utilized in various combinations, including GP+SF, MP+SF, MP+GP, and MP+GP+SF. In addition, prediction models, including decision tree (DT) and artificial neural network (ANN), were constructed utilizing experimental data for the FS of PW-based mortar. The substitution of PW with sand reduces the FS of mortar samples. The research findings emphasize that optimal replacement levels for MP, GP, and SF in PW-based mortar mixtures, based on their ability to enhance FS, were 15 %, 10 %, and 15 % by cement mass, respectively. However, the cumulative incorporation of MP, GP, and SF in PW-based mortar suggests cement should not be replaced beyond 15 %, as it reduces the FS. Both prediction models exhibited a high degree of correlation with the coefficient of determination (R2) value of 0.925 for ANN and 0.959 for the DT model. The findings showed that MP, GP, and SF may be used in PW-based mortar to improve the FS while producing eco-friendly building material.

Enhancing sustainability in self-compacting concrete by optimizing blended supplementary cementitious materials

Within concrete engineering, the uptake of self-compacting concrete (SCC) represents a notable trend, delivering improved workability and placement efficiency. However, challenges persist, notably in achieving optimal performance while mitigating environmental impacts, particularly in cement consumption. However, simply reducing the cement content in the mix design can directly compromise the structural-concrete requirements. Towards these challenges, global trends emphasize the utilization of appropriate waste materials in blended concrete. This study explored a promising strategy by integrating supplementary cementitious materials (SCMs) to contribute to the United Nations' Sustainable Development Goals (SDGs) in addition to the engineering contributions. It suggests an optimal combination of Metakaolin (MK) and Limestone Powder (LP) to partially substitute cement. The research methodology employs the response surface method (RSM) to systematically explore the ideal ingredient ratios. Through a comprehensive analysis of orthogonal array of 16 mixes, encompassing both mixture and process variables, this study aims to explain the effects of MK and LP addition on the rheological and mechanical properties of SCC with varying cement replacement levels. In terms of mixture constituents, the total composition of cement, MK, and LP was fixed at 100%, while coarse aggregate (CA), fine aggregate (FA), and the water-to-binder ratio were held as process variables. In order to assess the rheological properties of the mix-design, various tests including slump flow, L-box, and sieve segregation were conducted. Additionally, to evaluate mechanical strength, samples were tested for compressive strength at both 7 and 28 days. Findings from the experiments reveal higher concentrations of MK result in reduced workability and hardened properties. Through RSM-based designed experimentation covering both rheological and mechanical aspects, it is observed that the optimal cement replacement level lies between 40 and 55%. The findings of this study contribute to the advancement of sustainable and structurally robust concrete practices, offering insights into the optimal utilization of SCMs to meet both engineering requirements and environmental sustainability goals.

Influence of Rice Straw Ash on Workability and Strength of Concrete

Cement manufacturing is a major contributor to the waste of energy as about 3.4GJ of thermal energy is needed to produce 1 tonne of Portland cement, not to mention the emissions of greenhouse gases like carbon di oxide due to the calcination of limestone during Portland cement production. These emissions have caused a dramatic rise in global warming. There is a pressing need for innovative recycling technology that can reduce the negative effects of waste on ecosystems and people. Rice straws are the waste produced after the threshing of rice. The goal of this study is to investigate the influence of rice straw ash on workability and strength of concrete. The rice straw used was the straw of a specific rice variety locally called mass I gotten from Akpugo, Enugu, Nigeria. The rice straw was calcined by open burning to produce the rice straw ash (RSA). The materials used were preliminary tested to determine their physical properties and chemical composition. The rice straw ash was used to replace Ordinary Portland Cement (OPC) at 0, 5, 10, 15, 20 and 30% respectively. The workability and compressive strength test were done for all replacement levels. Using slump test, the concrete workability was evaluated. For this study, 72 cubes were cast, cured in water for 7, 14, 21, and 28days before been tested under compression. From the investigation, percentage increase in RSA replacement decreased the concrete workability. The sample containing 0%, 5%, and 10% RSA attained 9%, 6.1% and 2.2% more strength compared to the design strength at 28th day of curing. While the 15%, 20% and 30% attained 17.3%, 28.9% and 67.6% lower strength compared to the design strength at 28th day of curing. The experimental result was analysed using statistical product and service solution (SPSS) and excel spreadsheet regression (ESR). This study suggests that the optimum replacement level of rice straw ash from structural reinforced grade 25 concrete point of view is 10%. The predictive models were tested and found to be adequate.

Microscopic analyses and performance characteristics of granite powder blended cement

This research investigates the characteristics of Granite Powder (GrP) and its potential use as a partial replacement for cement in mortar production. The GrP samples were analyzed via microscopic techniques. The effects of GrP Blended Cement (GrPBC) were examined on the workability and mechanical characteristics by partially replacing Ordinary Portland Cement (OPC) with 0–40 wt% GrP in 4 wt% increments. Life cycled assessment in terms of Embodied Energy (EE) and Global Warming Potential (GWP) of GrPBC-based mortar were assessed based on cradle-to-gate boundaries and the sustainability and economic indexes were determined at 28 days compressive strength. The study proposed new models to predict the compressive strength of GrPBC with respect to Water to Binder (W/B) ratio. The presence of active minerals depicts GrP as pozzolanic materials. The optimum replacement level of GrP in the blended mix, based on the fresh and hardened properties of GrPBC, is 20 wt% to achieve 75% of the strength activity index. GWP and EE declined as the GrP in the mixtures rose. The best sustainable and economic prospects were attained at the 25 wt% GrP replacement level. The compressive strength and the W/B ratio are highly correlated. Thus, GrP has proven to be a sustainable construction material in the construction sector.

Disposal of solid waste as building materials: A study on the mechanical and durability performance of concrete composed of gold tailings

The purpose of this study is to explore the possibility of gold tailings as an alternative to natural river sand for preparing concrete, to solve the problems of rapid increase in gold tailings and insufficient natural river sand stock. Additionally, gold tailings upgraded by centrifugal separation are compared with untreated gold tailings. The performances and modification mechanisms of gold tailings on the mechanical strength and durability performance of concrete were investigated. The results demonstrate that concrete composed of gold tailings exhibits commendable mechanical and durability properties, with the optimal replacement level of natural river sand being 30%. Replacing river sand with gold tailings enhances the compressive and split tensile strengths of concrete, reduces water absorption, and improves its resistance to freeze-thaw cycles and chloride ion permeability, primarily owing to the pozzolanic activity and filling effect of the gold tailings. The upgrading of gold tailings not only changed altered the particle size but also changed the active SiO2 and Al2O3 content, thus, further enhancing the mechanical and durability of concrete. The study establishes that utilizing gold tailings in construction can serve as a viable substitute for river sand, thereby mitigating potential environmental repercussions associated with gold tailings. The findings hold promise for diminishing the reliance on river sand, thereby markedly enhancing resource sustainability.

Enzymolytic soybean meal-impact on growth performance, nutrient digestibility, antioxidative capacity, and intestinal health of weaned piglets.

Enzymolytic soybean meal (ESBM) enriches free amino acids and small peptides, while mitigating anti-nutritional factors. Substituting soybean meal with ESBM enhances animal performance, though optimal piglet dietary supplementation levels vary. The present study aimed to assess the impact of ESBM on the growth performance, nutrient digestibility, antioxidative capacity and intestinal health of weaned piglets. A total of 120 piglets (initial body weight, 7.0 ± 0.4 kg) were randomly allocated into 4 dietary groups, each comprising 5 replicates with 6 piglets per replicate. The control group received the basal diet, while the experimental groups were fed diets containing 2, 4% or 8% ESBM as a replacement for soybean meal over 28 days. Compared with the control group, piglets supplemented with 4% ESBM exhibited a significant increase (p < 0.05) in average daily gain and the apparent total tract digestibility of dry matter, ether extract and gross energy (p < 0.05), alongside a notable decrease (p < 0.05) in diarrhea incidence. Fed ESBM linearly increased (p < 0.05) the villus height in the ileum of piglets. The levels of superoxide dismutase and total antioxidant capacity in serum of piglets increased (p < 0.05) in the 2 and 4% ESBM groups, while diamine oxidase content decreased (p < 0.05) in the 4 and 8% ESBM group. ESBM inclusion also upregulated (p < 0.05) the expression of superoxide dismutase 1 (SOD-1), Catalase (CAT) and claudin-1 mRNA. In terms of cecal fermentation characteristics, ESBM supplementation resulted in a increase (p < 0.05) in valerate content and a linear rise (p < 0.05) in propionate, butyrate, and total short-chain fatty acids levels, accompanied by a decrease (p < 0.05) in the concentrations of tryptamine and NH3 in cecal digesta. ESBM had no discernible effect on cecal microbial composition. In summary, substitution of soybean meal with ESBM effectively improved the growth performance of piglets by enhancing nutrient digestibility, antioxidant capacity, intestinal barrier and cecal microbial fermentation characteristics, with the optimal replacement level identified at 4%.