Optimal Mixture Ratio Research Articles

Experimental research on the flexural properties and pore structure characteristics of engineered geopolymer composites prepared by calcined natural clay

The synthesis of high ductility geopolymer composites using excavated natural clay is an economical and environmentally friendly method to realize the utilization of excavated natural clay. This paper presents an experimental research on the flexural properties and pore structure characteristics of engineered geopolymer composites (EGC) prepared by calcined natural clay. The EGC with different slag and fiber contents were prepared and the four-point bending tests were conducted on the EGC. The effect of slag and fiber content on the flexural strength, flexural deflection and flexural toughness were discussed. The microscopic pore structure characteristics of EGC were further analyzed. The optimal mixture ratio of calcined clay-based EGC with the highest flexural toughness was proposed. The results show that fiber can significantly enhance the flexural properties and cracking control ability of EGC. The ultimate flexural strength, flexural deflection, flexural strengthening index and flexural toughness of EGC all increase with increasing fiber content. The results also show the addition of 10.0% slag can increase the flexural strength and flexural toughness, while excessive slag content reduces the flexural properties. The EGC with 10.0% slag content and 2.5% fiber content exhibits excellent flexural properties and cracking control ability. The ultimate flexural strength and flexural toughness index reach 9.75 MPa and 486.11, showing the highest flexural toughness.

Investigating the interfacial vertical shear behavior of BFPMPC mortar and cement concrete with pothole repair

Magnesium phosphate cement (MPC) has both traditional cement properties and ceramic properties with fast setting and hardening characteristics. To rapidly reopen traffic and extend its service life, MPC has been widely used in the rapid repair of highway and airport cement concrete pavement. This study utilizes basalt fiber-reinforced polymer-modified magnesium phosphate cement (BFPMPC) developed in previous research to rapid repair the typical potholes on cement concrete pavement, aims to reveal the interface properties between BFPMPC mortar and cement concrete and further investigate the underlying mechanisms for such properties. Firstly, the optimal mixture ratio was determined by orthogonal test design. Then, the shear strength of the repair interface was measured by composite BFPMPC mortar and cement concrete specimens. The mechanical characteristics of the repair interface and the microscopic mechanism were characterized by nano-indentation technology and SEM/EDS. Finally, the interface constitutive model was established by DIGIMAT and finite element model was developed to simulate the interface failure. Results showed that the no new hydration products were produced by the addition of polymer in BFPMPC. BFPMPC matrix became denser with the increase of age, resulting in the better bonding between fiber and paste. The interface vertical shear strength at 6 h and 3 d were 3.1 MPa and 3.9 MPa, respectively. SEM/EDS results showed that polymer has a certain self-healing ability to decrease the crack width with increase of curing age, and a variety of inclusions in the repair interface were observed. The elastic modulus of each inclusion phase can be effectively analyzed by nanoindentation. The simulation results showed that the pressure on upper surface of BFPMPC mortar transfers to the bottom through the repair interface. As the tensile stress on the bottom over the maximum interface tensile stress, the cracks were extend from the bottom to upper, then the structure was failed. Interface vertical shear strength of numerical simulation was, respectively, 3.149 MPa and 3.957 MPa. It is close to the plain shear strength experimental value, validating the proposed interface constitutive relationship.

An Experimental Investigation on Nano-Enhanced Tertiary Blended Concrete Incorporating Industrial Wastes

Concrete is a crucial material in the construction industry; however, its production process releases carbon dioxide into the atmosphere. Undoubtedly, the building sector's increasing global interest unveils a challenge to its ability to withstand cement alternatives and manage the resulting outflows. Fly ash, GGBS (ground granulated blast furnace slag), Zeolite, rice husk, silica fume, metakaolin, and various industry by-products can typically replace cement. This research study aims to replace cement with multiple cementitious materials, individually and in combination, to evaluate the strength characteristics of blended concrete. The replacement percentages ranged from 0 to 30% for each substitute material, such as fly ash, GGBS, and Zeolite, and strength tests were done to assess the performance of the modified concrete after 7 and 28 days of water curing. Ordinary Portland Cement (OPC) is used to create M30 and M50 grades of concrete. Similarly, cement was replaced with fly ash, GGBS, and Zeolite in amounts ranging from 10 to 30% for M30 and M50 grades, and their strength was evaluated after 7 and 28 days of curing. The most efficient percentage of substitution for both the concrete grades is determined, and the corresponding replacement ratio is used to produce the blended concrete, which incorporates cement, fly ash, GGBS, and Zeolite. The overall findings reveal that the composite concrete, comprising four binding materials, demonstrated superior strength for the concrete grade compared to alternative substitutes. The optimal mixture ratios for M30 concrete after 28 days consist of 20% fly ash, 20% GGBS, and 10% zeolite. Moreover, different ratios of Zeolite-10%, Fly-Ash-30%, and GGBS-20% were used to produce M50 concrete.

Properties of saline soil stabilized with fly ash and modified aeolian sand

Against the backdrop of saline soil solidification and the resource utilization of solid waste and aeolian sand in cold and arid regions, this study employs locally accessible fly ash and aeolian sand to solidify saline soil. By combining unconfined compressive strength tests, X-ray diffraction analysis, scanning electron microscopy, orthogonal experiments, and single-factor analysis, the strength characteristics, mineral composition, and interfacial structure changes of saline soil solidified with different freeze-thaw cycles and varying amounts of fly ash, aeolian sand, and alkali activators were investigated. The effects of each factor were analyzed to determine the optimal mixture ratio and to explore the solidification mechanism.The results indicate that the unconfined compressive strength of saline soil is most significantly enhanced when solidified with a combination of fly ash, aeolian sand, and alkali activators. The optimal mixture ratio was found to be 24 % fly ash, 7 % aeolian sand, and 4.5 mol/L alkali activator. With the incorporation of these solidifying materials, the failure mode of saline soil transitions from plastic to brittle, and the stress-strain curve exhibited a strain-softening behavior. The combined solidification method demonstrated the most pronounced effect in mitigating freeze-thaw damage, with the unconfined compressive strength of the solidified soil reaching 7.01 MPa after seven freeze-thaw cycles, compared to 0.03 MPa for the untreated soil, an increase by a factor of 234.This significant enhancement is attributed to the formation of substantial gel substances, which mitigate the strength loss caused by freeze-thaw cycles. The gel locking mechanism between particles in the solidified soil far exceeds the detrimental effects of freeze-thaw cycles, effectively inhibiting freeze-thaw deterioration. Additionally, the reaction pathways involving AFt and AFm phases reduce the content of SO42- and Cl- in the solidified soil, effectively suppressing salt expansion and significantly improving the soil's strength.

Elucidating Synergetic Effects of Anaerobic Co-Digestion of Slaughterhouse Waste with Livestock Manures

This study quantitatively analyzed the synergistic effects of co-digestion of slaughterhouse waste (SHW) with cattle manure (CM) and pig manure (PM) on methane production by applying statistical methods. The biochemical methane potential of volatile solid concentration-based mixtures showed that the biodegradability (BD) of the co-substrates was improved as the mixing proportion of the highly biodegradable SHW increased. Furthermore, mathematical analysis using the modified Gompertz model showed that an increase in the SHW mixture ratio shortened the lag phase at the initial period by more than 58%. The synergy index (SI) analysis revealed that co-digestion of CM and SHW mixed at an equal ratio of 1:1 in sample S4 resulted in a higher SI of 1.18 compared to 1.10 for PM and SHW in sample S5. An overlay plot based on BD and SI identified the optimal mixture ratio as 26.9:31.0:42.1 (CM/PM/SHW), where both BD and SI reached their maximum values. The study successfully demonstrated that co-digestion of SHW with livestock manure enhances BD through a synergistic effect.

Liquid Phase Parameter Analysis of Methanogenesis in Anaerobic Digestion of Coal Promoted by Kitchen Waste

In order to study the effect of food and kitchen waste on promoting methane production by collaborative fermentation of coal, this paper selected lignite and food and kitchen waste as the research objects, and carried out the gas production experiment of mixed fermentation of coal and food and kitchen waste with different ratios at 35 ℃ with mine water as the bacteria source. The results showed that the cumulative CH4 production was the highest in the mixed fermentation with the ratio of 1:4 (coal: kitchen waste). Therefore, exploring the optimal mixture ratio of coal and food waste fermentation can not only effectively improve the gas production effect, but also broaden the diversified utilization ways of coal and food waste, which has a good development potential.

Multi-response optimization of charcoal briquettes process for green economy using a novel TOPSIS linear programming and genetic algorithms based on response surface methodology

The production of charcoal briquettes was based on the concept of utilizing waste for sustainable and eco-friendly solutions within the green economy. This study introduces a new approach for optimizing important properties of charcoal briquettes. The approach aims to determine the appropriate operating conditions using a hybrid method. It integrates a novel TOPSIS linear programming with genetic algorithms based on response surface methodology. The experiment used an optimal mixture ratio of 25:10:6, including coconut shell, bagasse ash, and corncob. The results of the responses showed increased heating value and burning time by 5.13 % and 5.71 %, respectively, and moisture content decreased by 15.12 %. Furthermore, confirmation experiments within a 95 % confidence interval verified that the three responses obtained at the optimal operating conditions of process factors. The total cost of charcoal briquettes is 0.903 USD/kg and a payback period of 4.85 years. This illustrates that process improvement also aligns with the broader goals of promoting green and a circular economy.

Enhanced anaerobic co-digestion of cattle manure with food waste and pig manure: Statistical optimization of pretreatment condition and substrate mixture ratio

This study investigated the optimal pretreatment condition and mixture ratio of cattle manure (CM) for its efficient anaerobic co-digestion (AcoD) with food waste (FW) and pig manure (PM). The pretreatment performances of thermal (TM), microwave (MW), and ultrasound (US) technologies and the AcoD performance were statistically and experimentally evaluated at various mixture ratios of CM, FW, and PM. The results revealed that the most effective pretreatment condition with the TM, MW, and US pretreatments was 129.3 °C for 49.6 min, 824.2 W for 7.3 min, and 418.0 W for 36.3 min, respectively. The best AcoD performance of optimally pretreated CM (PCM) was achieved when 30.5 % PCM was mixed with 42.5 % FW and 27.0 % PM. A long-term evaluation showed that the start-up rate for the anaerobic mono-digestion of PCM was 2.3 times faster than that of CM and the amount of methane produced was 4.7 times higher; process stability was thus preferentially maintained under a higher organic loading rate (OLR) (2.0 kg-VS/m3∙d). The start-up rate for the AcoD of PCM with FW and PM was 1.2 times higher than that of the AcoD of CM with FW and PM. Although the performance gap between the AcoD reactors after steady state was not significantly different, the PCM AcoD reactor provided a more stable operation under a higher OLR (5.0 kg-VS/m3∙d). This study demonstrates that the pretreatment and co-digestion of CM could significantly enhance the production of biogas and improve process stability.

Rapid, graded sand preparation method using grain size distribution results for cement mortar testing

Adhering to ASTM C109/C109M-20 standards ensures quality in cement mortar specimens. However, achieving the required sand gradation per ASTM C778-21 can be challenging. This paper presents a faster method for adjusting sand gradation without compromising ASTM quality standards. The proposed method involves analyzing six silica sand samples of different gradations, pre-screening sands, using Excel Solver for optimal mixture ratios, making automated gradation tweaks with precise calculations, and validating the gradation to ensure ASTM compliance. After making the adjustments, compressive strength tests were conducted on mortars with the modified sands, and the results were compared with those of standard-graded sand. Based on statistical analysis, the new method yielded reliable outcomes with compressive strengths similar to standard sands. This innovation offers a more efficient alternative, paving the way for streamlined practices in civil engineering.

Formulasi campuran olein minyak sawit untuk memproduksi shortening bebas lemak trans [Formulation of palm oil olein mixture to produce trans-fat-free shortening

Shortening is a solid fat with the functional properties needed to produce a better texture and appearance for bakery or confectionery products, as well as frying and cooking media. Shortening is made by mixing two or more vegetable oils and then modifying them through a chemical or enzymatic interesterification process. In this research, the raw material for shortening was prepared from a mixture of 2 types of palm oil olein: refined olein (ROL) and mid olein (MOL). This research aimed to determine the optimal ROL and MOL mixture ratio in the chemical interesterification process, which produces shortening with the best quality and specifications. Five levels of ROL/MOL comparison consisting of (100/0), (95/5), (90/10), (85/15), and (80/20) were chemically inter-esterified using a sodium methoxide catalyst under a vacuum of 0.8 bar at a temperature of 110 oC and speed of 500 rpm. The results showed that the increase of MOL in the ROL/MOL formulation tends to increase the shortening melting point. However, increasing MOL did not change the iodine value, and all the ROL/MOL ratios produced shortening with specifications that met the SNI 3718:2018 requirement, and the best ROL/MOL ratio was 80/20.

Role of Fly Ash in the Repair Interface between Magnesium Phosphate Cement and Cement Concrete

This paper examines a rapid repair material for cement concrete pavement based on magnesium phosphate cement (MPC) blended with fly ash (FA). Three kinds of stress forms for rapid repair of Portland cement concrete pavement (PCCP) were evaluated and the role of FA in the repair interface was studied. The optimal mixture ratio of FA-MPC mortar was determined, and the compressive and flexural strength tested. The composite specimens were then designed to test the interfacial bonding, tensile, and plain shear strength. Finally, the multi-scale mechanism of FA in the interface was analyzed by a pull-off adhesion test, nanoindentation test, scanning electron microscope (SEM)/energy dispersive spectrometer (EDS), Raman spectrum, and molecular dynamics simulation. The optimal content of FA in MPC mortar was 20%. The laminated beam structure had the maximum strength, and the interface load bearing capacity was the lowest. For further multi-scale analysis, the results of the pull-off adhesion test showed the adhesion strength of interface was increased by the curing age and loading rate. Adhesion capacity of basalt aggregate and FA-MPC was stronger than that of Portland cement mortar and FA-MPC. The elastic modulus of MPC-aggregate interface was more than that of MPC-OPC mortar. SEM/EDS and Raman spectrum results showed that the MPC blended with FA had cracks and defects at the interface formed with cement mortar. Less FA formed near the interface. The good adhesion ability of FA and basalt aggregate was verified by molecular dynamics simulation. By contrast, poor adhesion strength with cement mortar was confirmed.

Numerical study on throttling characteristics of RBCC engines in ejector mode

Investigating the throttling characteristics of Rocket-Based Combined Cycle (RBCC) engines in ejector mode is crucial for adapting to varied flight mission demands. This study employs validated RANS numerical methods to investigate throttling effects on an experimental kerosene-fueled RBCC engine under two representative flight conditions: ground take-off (Mach 0) and supersonic flight (Mach 2.0). Results indicate that, at Mach 0, throttling reduces the entrained secondary stream and increases mixing efficiency, but exacerbates mixing losses, which cannot be offset by the thrust produced by the secondary stream due to its weak working capacity. Therefore, specific impulse performance deteriorates during throttling. Moreover, the optimum mixture ratio remains at 2.4, consistent with conventional rockets. Conversely, at Mach 2.0, throttling mitigates the primary stream’s squeezing effect to augment the entrained secondary stream. Simultaneously, throttling enhances mixing efficiency to improve the utilization of residual fuel. Consequently, the optimum mixture ratio shifts from 2.4 to below 1.4, which contributes to harnessing the work capacity of the secondary stream generated by ram effects, and significantly improves specific impulse performance. This study emphasizes the distinct throttling characteristics at different Mach numbers and provides pivotal insights for developing more efficient RBCC engines in ejector mode.

Experimental Study and Application of Controlled Low-Strength Materials in Trench Backfilling in Suqian City, China.

When backfilling narrow spaces, controlled low-strength materials (CLSM) can be used to achieve an effective backfilling effect. The pipeline engineering in Yahnghe Avenue of Suqian, China, provides a favorable on-site condition for the use of CLSM. However, no guidance exists for the determination of the material mixture ratio of CLSM for this geological condition. Laboratory tests were performed to investigate the basic physical parameters of excavated soil and the optimal mixture ratio of CLSM. Results indicate that the sand and silt account for 29.76% and 57.23% of the weight of excavated soil, respectively. As the water content increases (from 40% to 50%), the flowability of the CLSM approximately shows a linear increase (slumps values from 154.3 mm to 269.75 mm for 9% cement content), while its compressive strength shows a linear decreasing trend (from 875.3 KPa to 468.3 KPa after curing for 28 days); as the cement content increases (from 6% to 12%), the flowability approximately shows a linear decreasing trend (from 238.8 mm to 178.5 mm for 45% water content), while the compressive strength shows a linear increasing trend (from 391.6 KPa to 987.6 KPa after curing for 28 days). By establishing the relationship between compressive strength/flowability and the water-cement ratio, the optimal material ratio is determined to be 9% cement content and 40-43% water content. The engineering application results indicate that the use of CLSM can achieve efficient and high-quality backfilling effects for pipeline trenches. The findings of this research may provide a reference for the application of CLSM in fields with similar geological conditions.

Analysis of compressive strength, durability properties, and micromechanisms of solidified loess using industrial solid waste: Slag–white mud–calcium carbide residue

Traditional lime-solidified loess presents the issue of high carbon dioxide emissions. This paper presents the development of a kind of cementitious material using industrial solid waste: slag–white mud–CCR (calcium carbide residue). The slag mainly contains CaO, SiO2, and Al2O3, with a 10.6 pH value. The white mud and CCR mainly contain CaCO3 and Ca(OH)2, respectively. We further assessed the efficacy of slag–white mud–CCR in solidified loess and employed SEM and TG/DTG to explore their micromechanisms. The pH value of the CB4 sample (slag–white mud–CCR with the lowest CCR content) was 42.3 % higher than that of pure loess. Considering the 3-day and 28-day compressive strength and the material costs, the optimal mortar mixture ratio was found to be slag–white mud–CCR = 60:32:8, and this mixture was used to solidify loess. The unconfined compressive strength of 15 % slag–white mud–CCR-solidified loess is almost 5.0 times and 6.0 times higher than that of lime-solidified loess at 7 and 28 days of curing age, respectively. The durability of the solidified loess after freeze–thaw and wet–dry cycles was significantly improved compared with that of lime- or slag-solidified loess. Specifically, 10 % and 15 % slag–white mud–CCR-solidified loess maintained a high compressive strength after eight freeze–thaw and wet–dry cycles. SEM and TG/DTG analyses of the mortar and solidified loess confirmed the formation of hydration products of C–S–H- and C-A-(S)–H-type gels. The compressive strength results were obtained using a dual mechanism: the cementation of loess particles through the formation of hydration products and their subsequent filling action.

Curing Behavior of Sucrose with p-Toluenesulfonic Acid.

With respect to the fossil resources shortage, the development of bio-based wood adhesives is an important research topic in wood science. There has been research on using sucrose for bio-based adhesives. However, a high acid catalyst content and a high hot-pressing temperature are required when manufacturing particleboards. In this study, to explore the possibility of p-toluenesulfonic acid (PTSA) as a promising acid catalyst for sucrose-based adhesives, the curing behavior of sucrose with PTSA (Suc-PTSA) was clarified. The thermal analysis results showed that the thermal properties of sucrose decreased significantly with the addition of PTSA. Based on the results of the insoluble matter rate, the optimal mixture ratio and heating conditions were determined to be 95:5 and 180 °C for 10 min, respectively. According to the results of FT-IR, the heat-treated Suc-PTSA contained furan compounds. In the context of the dynamic viscoelasticity, the onset temperature at which the storage modulus (E') begins to rise was significantly lower than those of the other sucrose-based adhesives. PTSA has the potential to cure sucrose more efficiently and at lower temperatures than previous sucrose-based adhesives, making it a promising acid catalyst for sucrose.

Effects of combustion and emission performance of ammonia/natural gas engines ignited by diesel

Ammonia fuel engines face problems such as low combustion efficiency, ammonia escape, and high N2O emissions. However, natural gas reserves are abundant, and the combustion speed is fast. In order to explore whether the mixing of natural gas can promote the combustion of ammonia fuel, this article discusses the combustion and emission performance of ammonia/natural gas hybrid fuel engines through simulation research. The results indicate that mixing ammonia fuel with natural gas can greatly improve the combustion efficiency of ammonia in the cylinder. Appropriate natural gas can greatly improve the power and economic efficiency of engines. Although the N2O emissions of the engine have significantly decreased, the CO2 and NOx emissions of the engine have significantly increased, and the engine's overall emission performance has become worse. Considering the engine's overall performance, this article selects A50/N50 as the optimal mixture ratio for ammonia/natural gas. The article's research results have effectively improved the problems existing in ammonia engines, providing research direction and data support for the development of ammonia fuels.

Development of a novel ultra-high performance concrete (UHPC) suitable for underwater operation: Design and performance evaluation

This study has developed a new type of ultra-high performance concrete (UHPC) with excellent performance that can be used for underwater operations. Firstly, the sulfur aluminate cement(C S‾ A)-gypsum(CS‾)-silicate cement(OPC) ternary system is used as the cementitious material, and the optimal mixture ratio of underwater non-dispersive ultra-high performance concrete (UN-UHPC) is designed by the D-optimal design method. Then, the macroscopic properties, hydration process, and microscopic structure of the developed UHPC are evaluated. The experimental results show that UN-UHPC has excellent performance and good anti-dispersion properties, with a cement loss rate of 4.8% and a total porosity of 3.39%. Besides, due to the incremental effect of water, UN-UHPC has better mechanical properties and lower porosity than the one formed on land. In general, the developed UN-UHPC in this study further demonstrates the excellence and feasibility of D-optimal design in advanced building materials area and provides technical support for rapid underwater repair projects and the development of ocean resources.

A novel TOPSIS linear programming model based on response surface methodology for determining optimal mixture proportions of lightweight concrete blocks containing sugarcane bagasse ash

The idea of utilizing waste from the agro-industrial sector to produce lightweight concrete is one of the good ideas for recycling and reusing waste materials. In a lightweight concrete production process, determining a material's optimal parameters is crucial, since it can help optimize the important properties of lightweight concrete blocks. This study introduces a novel TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) linear programming model, based on the Response Surface Methodology (RSM), to optimize the parameters of lightweight concrete blocks. The compressive strength, dry density, and water absorption are considered important responses, while black bagasse ash, cement with white bagasse ash, and aluminum powder are the factors considered. The proposed method successfully optimized the parameters, as confirmed by experimental results, showing a 7.22% increase in compressive strength, a 9.19% increase in dry density, and a 16.83% decrease in water absorption compared to the original condition. These improvements were achieved by using the optimal mixture ratio of 6:1:0.05 by weight, which consists of sugarcane bagasse ash, cement, and aluminum powder. The advantages of the proposed method are as follows: This paper presents a novel method called the TOPSIS linear programming model, which is a modified version of the original TOPSIS method, to calculate the closeness efficiency for each run. The proposed method is simpler and more practical, making it useful for solving multi-response optimization problems with large inputs. In addition, this research contributes to the advancement of sustainable materials and offers a practical solution for optimizing lightweight concrete block properties.

Effect of Nanographite Conductive Concrete Mixed with Magnetite Sand Excited by Different Alkali Activators and Their Combinations on the Properties of Conductive Concrete

In order to obtain conductive concrete with good electrical conductivity and good mechanical properties, nanographite and magnetite sand excited by different activators and their combinations are added to ordinary concrete to obtain high quality and efficient conductive concrete. The optimal mixture ratio of alkali-excited conductive concrete and the effects of different activators and their combinations on the mechanics and electrical conductivity of concrete were studied. The microstructure of alkali-excited conductive concrete was analyzed by scanning electron microscope (SEM) to study its conductive mechanism. Results show that the conductive concrete obtained by compounding sodium hydroxide, sodium sulfate and calcium hydroxide has optimal mechanical and electrical properties when the graphite is 6% cement, and magnetite sand is 40% fine aggregate. The conductive concrete sample prepared by this method has a flexural strength of 6.84 MPa, a compressive strength of 47.79 MPa and a resistivity of 4805 Ω·cm (28 days). Compared with ordinary concrete (no nanographite and no magnetite sand), the compressive strength of conductive concrete is increased by 122.3%, the bending strength is increased by 116.5%, and the resistivity is reduced by 99.1%. SEM shows that the distribution of conductive materials in concrete is more uniform due to alkali excitation and calcium silicate hydrate (CSH) gel can be formed, which leads to better performance. The research in this paper is only a preliminary exploration of the characteristics of green conductive concrete, and the conductive heating characteristics and electromagnetic wave absorption properties of concrete, along with strength characteristics after adding conductive fillers, need to be further studied. It is suggested that further research should be carried out on the deicing characteristics of conductive concrete and the electromagnetic wave absorption properties used in stealth military engineering.

LGBM-based modeling scenarios to compressive strength of recycled aggregate concrete with SHAP analysis

Concrete production contributes significantly to global greenhouse gas emissions, and its manufacture requires substantial natural resources. These concerns can be partly mitigated by recycling construction demolition waste as aggregates to produce Recycled Aggregate Concrete (RAC). RAC has gained momentum due to its lower environmental impact, production costs, and increased sustainability. The aim of this study was to advance the reasonable use of recycled aggregate in concrete and achieve optimal mixture ratio design. Four advanced machine learning algorithms, Support Vector Machine (SVR), Light Gradient Boosting Machine (LGBM), Random Forest (RF), and Multi-Layer Perceptron (MLP), were employed, and the novel optimization algorithms, biogeography-based optimization (BBO), Multi-Verse Optimizer (MVO) and Gravitational Search Algorithm (GSA), were integrated to to predict the compressive strength of RAC. Six potential influential factors for RAC strength were considered in the models. The study employed four evaluation metrics, Taylor diagrams and Regression Error Characteristic plots to compare model performance. The result shows LGBM-based hybrid model outperformed other methods, demonstrating high accuracy in predicting compressive strength. The Shapley Additive Explanation (SHAP) results emphasize the importance of understanding the interactions between the various factors and their effects on the mechanical properties of the RAC. The findings can inform the development of more sustainable and environmentally friendly building materials.