Partial Replacement Research Articles

Effect of substituting soybean meal with sweet lupine on the performance of Sasso T44 dual purpose chicken

Approximately 70–75% of the costs of raising chickens are due to feeding expenses. Proteins, and energy account 95% of these costs. Soybean meal is primary protein source in chicken diets; however, it is expensive and not widely available in feed formulations. Therefore, exploring alternative protein sources like sweet lupines could be a promising option. This study aimed to evaluate the effect of substituting soybean meal with sweet lupine (lupinus angustifolius) on the performance of Sasso T44 dual purpose chicken. In the experimental treatments, soybean meal was replaced by sweet lupine at 0% (control), 15%, 25%, 30%, and 50% for T1, T2, T3, T4, and T5 respectively. A total of 180-day-old chickens with similar body weights (± 0.4 g SD) were used. A completely randomized design was employed, and the data were analyzed using one-way ANOVA with SAS software (version 9.1). Significant differences (p < 0.05) were observed in DM intake, body weight, body weight gain, and the characteristics of carcass and offal as the level of partial replacement increased from T1 to T5. Based on the findings of this study, broiler chickens can be fed sweet vitabor lupine as an alternative protein source in place of soybean meal.

Feasibility and efficacy of partial replacement of post transplantation cyclophosphamide with bendamustine on day +4 for graft versus host disease prophylaxis in patients undergoing allogeneic hematopoietic cell transplantation.

PT-CY use in T cell-replete haploidentical HCT has significantly improved outcomes. However, hyperhydration with MESNA in CY administration poses a challenge, in patients with cardiac/ renal problems. PT-CY also increases VOD risk with prior exposure to hepatotoxic drugs. Katsanis et al. in a phase Ia trial in patients undergoing HCT for hematological malignancies showed that partially replacing PT-CY with PT-BEN had comparable outcomes to conventional PT-CY. We conducted an ambispective study in 54 patients [haplo (39), MSD(14), and MUD(1)] with nonmalignant hematological disorders and hematological malignancies in pediatric and adult patients undergoing HCT (MAC/RIC) from February 2019 to May 2024. GvHD prophylaxis comprised of PT-CY/BEN (PT-CY 50 mg/kg Day +3; PT-BEN 90 mg/m2 Day +4) in a prospective arm (n = 21) and PT-CY/CY (50 mg/kg on Days +3, +4; comparator arm) in ambispective (prospective 12; retrospective 21) arm. In both groups, immunosuppression with CNI and MMF was also given. PT-CY/BEN was comparable to PT-CY/CY in terms of safety, efficacy, and GVHD prevention. In the PT-CY/BEN group, there was earlier neutrophil (0.008) and platelet (0.0057) engraftment with significantly lower BK viremia. Incidence of bacterial infection, TRM, EFS, and OS were comparable in both groups.

Abstract 1808: Engineering lipid-polymer nanoparticles for siRNA delivery to breast cancer cells

Abstract RNA interference (RNAi) is a powerful tool that can specifically target the expression of virtually any protein without the expensive and time-consuming drug development studies. Despite the initial excitement and extensive efforts, the potential impact of RNAi approaches is yet to be materialized fully in clinical settings. This is mainly due to the challenges in delivering RNA molecules. Lipid nanoparticles (LNPs) have been the leading delivery system for nucleic acids, an achievement established by introducing the first FDA-approved small interfering RNA (siRNA) drug and COVID-19 vaccine to clinics. However, targeted delivery to a solid tumor still eludes the developed LNPs. On the other hand, polymers are among the oldest delivery systems for nucleic acids, and polyethyleneimine (PEI) was once considered the gold standard in nucleic acid delivery. In this study, we introduce a novel lipid-polymer nanoparticle (LPNP) platform, meticulously engineered for targeted delivery of siRNA to cells implicated in breast cancer. We hypothesized that specially designed low molecular weight PEIs can partially or completely replace the ionizable lipids for a more accommodating structure for additional moieties, which could lead to a safer and more efficient nucleic acid delivery. We first optimized the LNP formulations as a point of reference for cellular uptake, cytotoxicity, and protein silencing efficiency, employing sophisticated designs facilitated by the Design-Expert software. Leveraging the optimal LNP formulation, we integrated specifically designed cationic polymers as partial or complete replacements for the ionizable lipid. This methodological approach, incorporating optimal combined designs and response surface methodologies, refined the LPNPs to an optimal efficiency. Our results indicate that these refined LPNPs enhance the delivery of siRNA, leading to efficient gene silencing in targeted cancer cells. The improved delivery efficiency not only underscores the potential for specific therapeutic applications, but also suggests a broader utility for this platform in various cancer treatments. Citation Format: Abdulelah Alhazza, Arthur Manda, Hamidreza Montazeri Aliabadi, Hasan Uludag. Engineering lipid-polymer nanoparticles for siRNA delivery to breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1808.

Evaluating the impact of waste marble on the compressive strength of traditional concrete using machine learning

Waste marble, an industrial byproduct generated from marble cutting and polishing processes, can be effectively utilized as a partial replacement in concrete mixtures. Incorporating waste marble in concrete not only addresses environmental concerns related to marble waste disposal but also contributes to the sustainability of construction materials. Using machine learning (ML) to predict the impact of waste marble on the compressive strength of traditional concrete offers several advantages over repeated laboratory experiments. ML offers a powerful alternative to costly and time-consuming laboratory experiments, enabling faster and more sustainable exploration of the potential of waste marble in improving concrete’s compressive strength. This research has focused on evaluating the impact of waste marble on the compressive strength of traditional concrete using machine learning (ML). Advanced ML techniques such as the Group Methods Data Handling Neural Network (GMDH-NN), Support Vector Regression (SVR), K-Nearest Neighbors (kNN) and Adaptive Boosting (AdaBoost) have been applied in this research work. The GMDH-NN model was created using GMDH Shell 3.0 software, while AdaBoost, SVR and kNN models were created using “Orange Data Mining” software version 3.36. Error indices such as the sum of squared error (SSE), mean absolute error (MAE), mean squared error (MSE), root mean squared error (RMSE), and Error (%), and performance metrics such as Accuracy % and the R2 between predicted and calculated compressive strength parameters were used to evaluate the overall behavior of the models. Finally, the Hoffman sensitivity analysis procedure was applied to determine the individual relative impact of the input variables on the output. At the end of the processes, a total of 1135 waste marble concrete entries were collected containing constituents such as the cement density (C), waste marble (WM), fine aggregate (FAg), coarse aggregate (CAg), water (W), superplasticizer (PL) and curing age (Age) used as input variables of the waste marble concrete model. The records were divided into training set (900 records = 80%) and validation set (235 records = 20%) following standard partitioning pattern reported in the literature. The kNN and AdaBoost, with SSE of 1408.5 MPa2 and 1397 MPa2 respectively and a tie Accuracy of 95.5% and R2 of 0.985 showed the best models suggesting excellent model performance while GMDH-NN showed the worst. Conversely, RF balances accuracy and model complexity, making it a practical alternative to kNN and AdaBoost. And lastly, Age, Coarse Aggregates, Water, and Plasticizer play the most significant roles in determining the compressive strength, while Cement, Waste Marble, and Fine Aggregates have comparatively smaller impacts. However, considering the standard proportion required for waste marble powder to replace cement, it showed a remarkable influence on the behavior of the concrete thus a recommended potential for its used as replacement for cement.

Effect of Carrot Pulp Incorporation and Partial Sodium Chloride Replacement on Hybrid Burger Characteristics.

Worldwide dietary sodium intake exceeds the recommended daily allowance, generating global interest in reducing sodium content in foods. This preliminary study aimed to evaluate the effects of decreasing sodium chloride (NaCl) levels on hybrid burger characteristics by partially replacing it with potassium chloride and carrot pulp. A total of 60 beef burger patties were divided into four treatments: A (control), 1.5% NaCl; B, 1.5% NaCl + 5% carrot pulp; C, 30% replacement of NaCl with potassium chloride (KCl) + 5% carrot pulp; D, 50% replacement of NaCl with KCl + 5% carrot pulp. Carrot pulp significantly influenced color indices and pH. The control (treatment A) exhibited the lowest lightness (L*) values (31.70 vs. 40.9, 38.67, and 38.44 for treatments B, C, and D, respectively; p < 0.05). Additionally, carrot pulp positively affected water-holding capacity, but it led to an increase in total aerobic bacterial count by approximately 2 logs and fungal count increased by about 4 logs (cfu/g). Sensory attributes were not impacted by the addition of carrot pulp; however, replacing 50% of NaCl with KCl significantly increased bitterness. In conclusion, replacing 30% of NaCl with KCl while incorporating carrot pulp was feasible without compromising sensory properties of the hybrid burger.

Predictive modeling of concrete properties with waste glass powder as a partial cement replacement

AbstractThe accurate analysis and design of structural concrete elements containing waste glass powder (GP) require a comprehensive understanding of their mechanical behavior and associated equations. Fortunately, extensive research has been conducted over several decades on various properties of concrete that incorporates GP, contributing to an improved understanding of this concrete type. In this study, experimental data from 22 peer‐reviewed journals on GP‐containing concrete were collected, statistically analyzed, and then used to develop equations for predicting various concrete properties, including compressive strength, splitting tensile strength, concrete compressive strain at peak compressive strength, concrete tensile strain at peak tensile strength, and the compressive stress–strain behavior up to peak compressive stress. The prediction accuracy of the developed models was evaluated using various statistical performance metrics. Interestingly, the analytical results revealed a minimal impact of GP particle size on predicting various mechanical properties of GP‐modified concrete, rendering it a negligible factor. Conversely, both the compressive strength of GP and the GP percentage of cement replacement used exhibited strong correlations with the key concrete properties investigated in this study, highlighting their significant influence as independent variables. The proposed equations provide accurate predictions of the experimental data reported in the literature. They can be used to analyze and design structural elements made of GP‐modified concrete.

Correction: Comprehensive experimental investigation on using single size glass granular as partial replacement of sand on the fresh and mechanical, durability, thermal conductivity properties of mortar

Correction: Comprehensive experimental investigation on using single size glass granular as partial replacement of sand on the fresh and mechanical, durability, thermal conductivity properties of mortar

OPTIMAL CEMENT REPLACEMENT LEVELS IN CONCRETE USING GROUND GRANULATED BLAST FURNACE-SLAG FOR WORKABILITY AND STRENGTH DEVELOPMENT.

Workability and strength development of concrete incorporating Ground Granulated Blast-furnace Slag (GGBS) as partial replacements (10%, 20%, and 30%) for Portland cement (PC) has been investigated. The nature of the components of GGBS has shown a glassy sphere with a composite shell. The form, size, and physical nature of the particles are shown to be the main influences affecting the workability of fresh GGBS concretes and the strength development of the hardened GGBS concrete. The relationship between progressive GGBS particle reaction and strength gain with time has been observed for standard cured concretes up to 28 days. The workability of the concrete was measured by the slump tests. Reductions in the workability were obtained when the mixtures contained 10% GGBS, with greater reductions being experienced as the GGBS replacement level increased up to 30%. Similarly, a relationship between progressive GGBS particle reaction and strength gain with prolonged days of curing time has been observed for standard cured concretes. The early strength development due to the addition of GBBS is largely a beneficial interaction between the normal hydration of cement and the latently hydraulic reaction of GBBS. The study concluded that replacing up to 30% of the optimal replacement of cement in concrete with GGBS could reduce concrete production costs on a project while retaining the acceptable levels of concrete workability and required strength developed.

Impact of recycled plastic waste on the corrosion behaviour of steel rebar in concrete

This study examines the corrosion behaviour of steel rebar in concrete with recycled plastic waste (RPW) from single-use plastics as a partial replacement for conventional fine aggregate. The use of RPW in concrete helps reduce environmental impact and reliance on natural sand. To improve bonding between RPW and the cement matrix, RPW was chemically treated. Five RPW content levels (0, 5, 10, 15 and 20%) and two RPW types (treated and untreated) were considered. Concrete permeability was evaluated through water absorption, sorptivity and chloride ion penetration tests. Corrosion behaviour of embedded steel rebars was assessed using electrochemical impedance spectroscopy and potentiodynamic polarisation techniques under accelerated conditions with 3.5% NaCl solution in alternating wet-dry cycles. Open circuit potential was monitored throughout. The study revealed that using T-RPW fine aggregate reduced water absorption by 16.1% and increased resistance to chloride ion penetration by 17.3% compared to UT-RPW at a 20% replacement level. Additionally, the corrosion rate for T-RPW (0.0144 mm/year) was 50% lower than that of UT-RPW (0.0288 mm/year), highlighting its effectiveness in enhancing concrete durability. This study highlights both the benefits and limitations of using treated RPW as a sustainable alternative in concrete.

Sustainable Utilization of Waste Ceramic as Partial Aggregate Replacement In M-40 Concrete: A Comprehensive Review on Strength and Durability Enhancements

The increasing demand for sustainable construction materials has led to extensive research on the utilization of waste materials as partial replacements in conventional concrete. Among these, waste ceramic materials have gained attention due to their pozzolanic properties and potential to improve concrete performance. This review explores the effectiveness of waste ceramic as a partial aggregate replacement in M-40 concrete, emphasizing strength and durability enhancements. Various studies indicate that ceramic waste improves compressive, tensile, and flexural strengths while enhancing durability characteristics such as water absorption, chloride resistance, and sulfate attack resistance. The integration of waste ceramics in concrete aligns with the principles of sustainability by reducing environmental burdens associated with ceramic waste disposal and decreasing the reliance on natural aggregates. This review consolidates recent findings on the mechanical and durability aspects of ceramic-based concrete and identifies potential research gaps for further studies. Keywords: Sustainable construction materials, waste ceramic, Partial replacements

Partial Replacement of Cement with Bagasse Ash in Concrete

The construction industry is one of the largest contributors to environmental degradation, with cement production being a major source of CO2 emissions. In response to this environmental challenge, the partial replacement of cement with alternative materials, such as agricultural byproducts, has gained significant attention. This project explores the use of Bagasse Ash (BA), a byproduct of sugarcane processing, as a partial substitute for cement in concrete. Bagasse ash, rich in pozzolanic properties, has the potential to improve the mechanical and durability characteristics of concrete while reducing its environmental impact. The study investigates the effects of varying percentages of bagasse ash (ranging from 5% to 30%) as a partial replacement for cement on the workability, compressive strength, and durability of concrete. The research includes experimental tests on fresh and hardened concrete, assessing properties such as slump, setting time, compressive strength, and water absorption. Results indicate that bagasse ash can be used effectively in concrete mixes, with the optimal percentage of cement replacement being 15%, achieving best balance of workability, strength, and durability. Beyond the environmental benefits, this substitution also leads to a reduction in the overall cost of concrete production. The findings of this study contribute to the growing body of knowledge on sustainable construction materials and provide valuable insights into the practical application of bagasse ash as a cement replacement. The results suggest that bagasse ash not only serves as an environmentally friendly alternative to cement but also enhances the long-term performance of concrete, making it a promising material for sustainable construction practices. The project advocates for further research to refine the mix design and explore other applications of bagasse ash in the construction industry, ultimately supporting the development of greener and more cost-effective building materials.

Evaluation of Cement Brick with Cocopeat as Partial Replacement of Sand

The rising population has fueled construction growth, increasing the demand for bricks and raising concerns about the depletion of raw materials, especially sand. To address this, research was carried out to investigate the utilization of cocopeat (CCP) as a partial sand replacement in the construction industry. In this study, a total of 72 specimens were manufactured with varying proportions of cocopeat to replace sand, ranging from 0% to 25%. A 1:2.5 of cement-to-sand ratio and 0.5 of water-to-cement ratio were used. Performance of the cement brick was evaluated based on dimension, compressive strength, density, water absorption, crack development, and effective strength-to-weight ratio ( ratio). Results showed that all bricks met industrial requirements. Satisfactory compressive strength was achieved with 5% to 15% of cocopeat, meeting the minimum requirements in British Standard BS 3921:1985. Bricks with 5% to 10% of cocopeat have no crack on the sample. These bricks resulted in a lower density than solid bricks, while still fulfilled the percentage of water absorption requirements of British Standard, 1985. Cement bricks with 5% and 10% cocopeat had an effective strength-to-weight ratio ( ratio) above 1.0. Notably, brick with 10% cocopeat fulfilled all the industry requirements. Therefore, the cocopeat can be recommended as a partial replacement in brick production.

Elevated temperature effects on the compressive strength and radiation shielding capability of waste granite and marble concrete

In an effort to promote the development of sustainable construction practices, this study explores the utilization of construction waste powders as partial cement replacements in concrete. Specifically, granite and marble waste powders were incorporated at varying replacement ratios up to 9% by cement weight. The influence of these waste materials on the compressive strength and radiation shielding effectiveness of ordinary concrete was evaluated under both ambient and elevated temperature conditions (up to 800 °C). The findings revealed significant enhancements in the mechanical properties. Notably, 9% cement replacement ratio with waste granite powder (WGP, 9G) yielded the optimal performance for compressive strength, exhibiting increasements of 25.6% and 33.2% at room temperature and 800 °C, respectively. Similarly, a 5% replacement ratio with waste marble powder (WMP, 5M) demonstrated moderate improvements, achieving gains of 10.3% and 18.7% in compressive strength at room temperature and 800 °C, respectively. The samples at optimal replacement ratios of 9% and 5% for granite and marble, respectively, were tested alongside the control sample (CO) to study their effectiveness in attenuating the various types of radiation. The radiation shielding assessment was evaluated against gamma and neutron using the MC Monte Carlo simulation-5 algorithm and Phy-X software. The gamma ray linear attenuation for concrete mixes (CMLAC) order for the CO group was found to be CO < 400CO < 600CO < 800CO. The CMLAC order for the G9 group is G9 < 400G9 < 600G9 < 800G9. The CMLAC order for the M5 group is M5 < 400M5 < 600M5 < 800M5. The neutron performance (FC) of the CM-concrete samples has values 0.079, 0.075, 0.071, and 0.067 cm−1 for CO, 400CO, 600CO, 800CO samples, 0.094, 0.090, 0.085, and 0.080 cm−1, for G9, 400G9, 600G9, 800G9 samples, and 0.089, 0.083, 0.079, and 0.074 cm−1, for M5, 400M5, 600M5, 800M5 samples, respectively. Thus, the studied CM-concrete samples at room temperature provide the best protection against gamma and fast neutrons. Exposure to high temperatures significantly reduced the gamma and neutron attenuation of concrete samples. However, mixes with optimal granite and marble waste replacements showed enhanced resistance to this effect compared to the control mix.

Simulating the Thermal Behavior of Compressed Earth Brick Walls

The production of conventional bricks has negative impact on the environment due to CO2 emissions. Therefore, the use of alkali-activated by-product materials as partial or full replacement of cement has been promising in producing eco-friendly compressed earth bricks for sustainable construction. This research aims to simulate the thermal behavior of an office building prototype composed of eco-friendly compressed earth brick (CEB) walls using Design Builder software to investigate the impact of CEB walls on the indoor thermal comfort, total energy consumption and CO2 emissions. In addition to investigate the influence of the type and thicknesses of walls, and thickness of expanded polystyrene (EPS) insulating layer on the total energy consumption and (CO2) emissions. The results indicated that using walls of compressed earth bricks (CEB) made by alkali-activated ground granulated blast furnace slag (GGBS) as soil stabilizer with full replacement of cement is promising for reducing the total energy consumption and CO2 emissions with competitive compressive strength to those stabilized by cement. The results also revealed the noticeable effect of the type and thicknesses of walls in addition to the thickness of EPS insulating layer in reducing the total energy consumption and CO2 emissions. This reduction reached about 21–25% for different wall types of thickness 120 mm when EPS thicknesses increased up to 50 mm compared to the same walls without EPS.

Behavior of Self-Compacting Concrete Cylinders Internally Confined with Various Types of Composite Grids

Composite grids serve as reinforcement in concrete structures, offering alternatives to conventional steel reinforcement. These grids can be fabricated from various materials, including synthetic polymers, metals, and natural fibers. This study explores the use of composite grids as lateral confinement of self-compacting concrete (SCC) cylinders and examines their impact on the failure mode under axial compression. In the experiment, the types of grids and mesh shapes used were plastic grids of diamond mesh (PGD) and regular mesh (PGT), metallic grids of diamond mesh (MGD) and square mesh (MGS), vegetable grids of Alfa fiber mesh, 10 × 10 mm (VGAF-1) and 20 × 20 mm (VGAF-2), and vegetable grids of date palm fibers (VGDF). The binder of SCC mixtures incorporated 10% marble powder as a partial replacement for ordinary Portland cement (OPC). SCC mixtures were tested in the fresh state by measuring the slump flow diameter, V-funnel flow time, L-box blocking ratio, and segregation index. Cylinders with a diameter of 160 mm and a height of 320 mm were made to assess the mechanical properties of hardened SCC mixtures under axial compression. The results indicate that most of the confined cylinders exhibited an increase in ductility compared to unconfined cylinders. Grid types MGD and PGD provided the best performance, with ductility increases of 100.33% and 96.45%, respectively. VGAF-2 cylinders had greater compressive strength than cylinders with other grid types. The findings revealed that the type and mesh shape of the grids affects the failure mode of confined cylinders, but has minimal influence on their modulus of elasticity. This study highlights the potential of lateral grid confinement as a technique for rehabilitating, strengthening, and reinforcing weaker structural concrete elements, thereby improving their mechanical properties and extending the service life of building structures.

Impact of dietary supplementation with Antarctic krill meal on growth performance, biochemical parameters, and antioxidant status in Coho Salmon (Oncorhynchus kisutch) post-smolts

Due to the increasing trend in aquaculture and fisheries production, conventional feed resources, especially protein ingredients, are overburdened, and sometimes their price fluctuations limit quality feed formulations for farmers, thus leading to the exploration of alternative protein feed resources. Antarctic krill meal (AKM) has emerged as a potential candidate ingredient for sustainable and suitable partial replacement of conventional fish meal. A 10-week feeding trial was designed to investigate the effects of different concentrations of AKM on the growth performance, antioxidant capacity, and serum biochemical indices of coho salmon (Oncorhynchus kisutch) post-smolts. In total, 150 post-smolt fish with an average initial weight of 178.17 ± 0.73 g were divided into five groups with three replicates in each group and 10 fish in each replicate. Five experimental diets were formulated by substituting 0%, 3%, 6%, 9%, and 12% fish meal (protein source) with AKM (protein source), which were designated AKM0 (the control), AKM3, AKM6, AKM9, and AKM12, respectively. The results showed that the addition of AKM to the salmon diet increased (P &amp;lt; 0.05) the weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER). There was no effect (P &amp;gt; 0.05) on body composition and essential amino acid profile of the meat except for methionine, isoleucine, lysine, and threonine. The liver concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and malondialdehyde (MDA) significantly decreased while the concentration of catalase and superoxide dismutase (SOD) increased in the AKM supplemented groups compared to the control group. The serum concentrations of ALT and AST decreased (P &amp;lt; 0.05) while total cholesterol, triglyceride, and total protein content increased (P &amp;lt; 0.05) in the AKM treatment groups compared to the control. Based on the results of this study, supported by polynomial quadratic regression analyses of WG, SGR, FCR, and PER, we conclude that 6.73%–7.08% AKM is the best possible suitable inclusion level range to partially replace conventional fish meal in the diet of coho salmon post-smolt.

Impact of Pumice Substitution on Mortar Properties: A Case Study on Mechanical Performance and XRD Analysis

The incorporation of sustainable construction is essential for minimizing the environmental footprint of cementitious composites. This research examines the mechanical behavior and microstructural features of alternative mortars in which pumice acts as a partial cement replacement. By applying the Taguchi methodology, nine mortar mix variations were assessed at different pumice replacement rates (15%, 25%, and 50%), and their mechanical strength was compared against a control mixture without substitution. Additionally, an X-ray diffraction (XRD) analysis identified the mineral components in the pumice to evaluate their performance and durability. Based on a statistical variance analysis (ANOVA), mortars with up to 25% substitution are suggested as they attain mechanical strength values comparable to those of a control mixture. This study contributes to the advancement of environmentally sustainable construction materials and provides valuable insights into the viability of using pumice in sustainable infrastructure developments.

Evaluation of Concrete Incorporated with Waste Plastic and Tyre Rubber as Partial Replacements for Fine Aggregate

The improper disposal of waste plastic and tyre rubber significantly contributes to environmental pollution; however, these materials can be repurposed for use in construction. This study investigates the impact of partially replacing fine aggregates with recycled plastic and tyre rubber waste on the strength properties of concrete. Concrete samples were prepared with 0, 5, 10, and 15% replacement of fine aggregates using plastic waste, tyre rubber waste, and a combination of both, while maintaining a constant water-cement ratio of 0.5. The samples, cast using 100 mm x 100 mm x 100 mm size cubic moulds were tested for compressive strength at 7, 14, and 28 days. Results revealed that increasing the percentage of waste replacement improved workability and compacting factor but reduced compressive strength. At 28 days, compressive strength ranged from 10.83 N/mm² to 8.28 N/mm² for plastic waste, 12.83 N/mm² to 5.67 N/mm² for rubber waste, and 12.02 N/mm² to 9.10 N/mm² for the combined waste, compared to 15.80 N/mm² for the control mix. The findings indicate that 5 to 15% of all waste-based mixtures exhibited lower strength than the control, rubber waste contributed to higher strength than plastic, while the combined waste mixtures displayed intermediate strength. At 5% of plastic and rubber (12.02 N/mm2) is higher than 10% and 15% (11.74 N/mm2 and 9.10 N/mm2) respectively. It also clearly showed that as the percentage of the plastic and rubber fibres increased from 10% upward the compressive strength of the concrete decreased. This study highlights the potential of using recycled waste materials in concrete, particularly for low-bearing structural applications, promoting sustainable construction practices and environmental conservation.

An evaluation of the effects of Corncob Ash on the Properties of Concrete

Cement is the most energy-intensive and expensive material in concrete production. However, energy efficient and cost-effective concrete could be achieved using Supplementary Cementitious Materials (SCMs), which require less heating and emit less CO2. The research evaluated the effects of corncob ash (CCA) as a partial replacement of cement on the properties of concrete. A grade 20 N/mm2 concrete was produced using the Department of Environment (DoE) method of concrete mix design which served as control and another concrete was produced by partially replacing the cement content in the concrete with 5, 10 and 15% corncob ash. The concrete properties were evaluated for workability at the fresh stage while the compressive strength was assessed at 3-, 7-, 14- and 28-days curing periods. The specimens were characterized using scanning electron microscopy (SEM-EDX) and Fourier Transform Infrared Spectroscopy (FTIR). Result shows decrease in slump value and increase in compressive strength with increase in the percentage of corncob ash. Samples with 5% corncob exhibited similar compressive strength (20.57 N/mm2) compare to the control (20.87 N/mm2) at 28 days of curing, as confirmed by SEM-EDX images and FTIR result. The addition of CCA leads to increase in water absorption. Therefore, corncob ash can be used to replace up to 15% cement in concrete production, and where higher compressive strength is required, 5 % replacement is recommended.

Durability of Mortars with Partial Cement Replacement by Recycled Brick Powder

Over the past decade, global cement production has exceeded 4 billion tonnes annually. This process has a considerable environmental impact and is estimated to account for approximately 5% to 7% of the total annual CO2 emissions released into the atmosphere. To mitigate the environmental consequences of cement production, extensive research has been conducted on alternative materials that can partially replace cement in concrete manufacturing, thereby reducing its carbon footprint. This study explores the utilisation of recycled brick powder as a supplementary cementitious material in mortar production, with replacement levels ranging from 5% to 45%. In addition to evaluating their mechanical properties, such as flexural and compressive strength, this research investigates the durability of the newly developed mortars. The results indicate a reduction in porosity of up to 50% and an enhancement in chloride penetration resistance by up to fourfold when the substitution rate is between 35% and 40% compared with mortar without replacement. Although no improvements were observed in carbonation resistance, the new mixtures exhibited an increase in resistivity of up to ninefold.