DEVELOPMENT OF UNSATURATED POLYESTER RESIN MORTAR UTILIZING INDUSTRIAL WASTES

In recent years, polymer mortar (PM) has played a crucial role in the modern construction industry. It is gaining recognition as an effective and quick repair material in construction applications because it has several benefits over traditional Portland cement concrete. Various types of polymer binders, such as unsaturated polyester resin (UPR), have been used in these materials owing to their low cost, excellent strength, high workability, and rapid curing. This study investigates the feasibility of reutilizing locally available waste in the production of UPR-based polymer mortar, which facilitates the development of mortars with less environmental impact. In this study, the effects of various materials on the performance of an unsaturated polyester resin mortar (UPRM) made with dune sand (DS) as a fine aggregate were investigated. This study was initiated by investigating the impact of the DS content on the performance of the UPR-based polymer mortar. The DS content varied from 0% to 70 wt.%. To address the brittleness of UPR-based polymer mortars, crumb rubber (CR), which is derived from recycled tires, was introduced as a partial replacement for DS. The aim was to enhance the ductility of the developed mortar by incorporating crumb rubber. (CR) as a replacement for the DS (3, 5, 7, and 10 wt. % in 60/40 DS/UPR mortar formulation). Simultaneously, this study assessed the potential of date pits (DP), an agricultural waste product, as an alternative to DS (3, 5, 7, and 10 wt. % in 60/40 DS/UPR). DP exhibits promising potential as a viable substitute for mortar components, providing the advantage of improving their characteristics by exploiting their unique apparent and mechanical characteristics. Physical, mechanical, thermal, and durability tests were conducted to evaluate the suitability of the materials for desired applications. In addition, TGA, FTIR, XRD, DSC, and SEM analyses were conducted to confirm and explain the obtained results. The density of the developed UPRM decreased due to the incorporation of CR and DP replacements, resulting in a lightweight mortar (1475–1800 kg/m³)CR substitution resulted in a more substantial reduction in mechanical strength, while DP replacement exhibited a more positive effect, demonstrating a moderate improvement in compressive strength, splitting tensile strength and flexural strength. The incorporation of CR significantly improved the ductility index of the developed mortar by 28.6 %, whereas the replacement with DP increased the ductility index by 20.4 %. The use of CR and DP resulted in a decrease in thermal conductivity, thereby improving their insulation abilities. CR replacement resulted in higher resistance to abrasion and improved durability by resisting wear and tears. The findings of this study provide evidence supporting the utilization of crumb rubber (CR) and date pits (DP) in polymer mortars and highlight their potential value as aggregate alternatives for certain applications

Effect of Recycled Fibers on the Mechanical Properties and Durability of Sand Concrete

Recycling waste in construction materials is part of a sustainable development approach aimed at creating new materials with characteristics that have been shown to be competitive with traditional materials. In this context, this study aims to recover steel, copper and aluminum wastes from blacksmiths’ workshops together with the reuse thereof in the form of reinforcing fibers in sand concrete. However, in order to assess the impact of this waste on the concrete properties, we introduced such wastes in the form of fibers at different proportions (0.4 %, 0.8 % and 1.2 %). Further, a series of tests was then carried out to determine the evolution of the concrete characteristics in the fresh state (workability and density) and in the hardened state (compressive strength, flexural strength, compressive strength obtained using a sclerometer and the speed of ultrasonic waves), as well as the concrete’s durability (absorption coefficient by immersion, by capillarity and the porosity accessible to water). In closing, the behavior of the concrete was assessed in the face of a chemical attack by H2SO4 and HCl by measuring mass loss. In virtue of thus, the results obtained demonstrated a positive evolution of certain properties of sand concrete as a function of the type and percentage of fibers incorporated into the composition of the concrete

Sustainability of Concrete With Synthetic and Recycled Aggregates

Concrete is a material used widely in building and construction applications worldwide; hence, it plays a significant role in the global construction sector. Cement is a major component of concrete and is used in construction applications, either on its own or as a composite with other materials, to improve workability, durability, strength, weight, and shrinkage. However, cement and concrete production and use have adverse environmental effects. Thus, great efforts have been made to produce eco-friendly concrete. This book examines several aspects of sustainable concrete technologies, including new forms of concrete as well as different approaches for creating sustainable cement

REUSE OF SEWAGE SLUDGE ASH IN PRODUCING SELF COMPACTING CONCRETE

Rapid growth of self-compacting concrete (SCC) marks a significant milestone in enhancing the product quality and effectiveness of the construction industry. This special type of concrete is known for its high flowability characteristics and surface finish without the tendency for segregation. To achieve the desired properties, the production of SCC requires high powder content, i.e. higher cement content. Cement production is considered to be an extreme energy intensive process; which is responsible for the emissions of a greenhouse gas such as carbon dioxide (CO2). Recently, due to the current innovations and development worldwide, the rate of producing solid waste has increased considerably. Therefore, examining the potential applications for recycling and reusing such waste is a significant step towards sustainable development. Incorporation of solid by-products materials, produced by thermal power plants and metallurgical industries, as partial replacement of Portland cement, played a major role in enhancing the properties of SCC, besides it reduces the cost and heat of hydration. The main aim of this study is to investigate the viability of utilizing sewage sludge ash (SSA) produced from wastewater treatment plants (WWTP) in the mixture composition of SCC. These ashes can lead to serious economic and environmental issues, hence their utilization in the construction sector will be of great benefit in mitigating their negative impact, and will help in reducing the cement content in the SCC, thereby reducing its environmental footprint. This research includes a series of experimental procedures divided into two phases; in the first phase it is essential to burn the organic compounds that comprise a large fraction of the raw sewage sludge. Therefore, the raw sludge was incinerated at different temperatures and for different burning periods, resulting in a powder material what is known as SSA. The morphology, chemical and mineral composition of the produced material of the produced ash were evaluated using scanning electron microscopy (SEM), X-ray fluorescence (XRF), and X-ray diffraction (XRD). Moreover, strength activity index and Frattini tests were conducted to assess the pozzolanic activities of the produced ash. In addition to the effect of SSA as replacement of OPC in terms of workability, workability retention, pore size distribution, and heat of hydration were assessed. In the second phase, SSA was used as a partial replacement of ordinary Portland cement (OPC) at different ratios (0%, 20%, and 40%) to produce SCC mixtures. Fresh concrete properties, hardened concrete properties, and durability characteristics of the produced SCC were examined. It was concluded that SSA can be used to successfully produce SCC mixtures with minor modification in the mix design to achieve satisfactory fresh properties. SCC mixtures obtained by reusing SSA as OPC replacement exhibited considerable strength gain with age and represented a comparable durability characteristic to control mix. SSA is a promising addition considering its feasibility in producing SCC with acceptable fresh and hardened properties and potential environmental benefits

Porous aggregate developed with the use of coal-containing clays of the Angren field

Relevance. One of the ways to solve the issues of resource and energy conservation is the production and use of porous aggregates. Porous aggregates allow obtaining effective lightweight concrete for thermal insulation, wall panels, monolithic walls and other load-bearing structures, contribute to the increase of energy efficiency, improvement of thermal insulation, reliability, increase of fire resistance, frost resistance and seismic resistance of buildings, reduction of their weight. Therefore, in the production of porous aggregates, the primary task is the use of industrial waste and products of their processing. Solving these problems leads not only to saving valuable natural resources, but also to solution of environmental problems. Aim. Development of compositions and study of properties of porous aggregate based on bentonite clay of Navbakhar deposit and coal-containing clay of Angren brown coal deposit. Object. Coal-containing clay of Angren brown coal deposit, bentonite clay of Navbakhar deposit and artificial porous aggregate based on them. Methods. Chemical, energy-dispersive X-ray, X-ray phase and infrared spectroscopic analysis, scanning electron microscopy, mathematical modeling, etc. Results. The authors have determined chemical and mineralogical compositions of the clays used. Using the mathematical modeling method they developed the regression equations describing the effects of the amount of bentonite clay in the batch, firing temperature and isothermal holding time on the bulk density and water absorption of the porous aggregates. The resulting porous aggregates with a bulk density of 395 to 690 kg/m3 have a compressive strength in a cylinder of 2.74 to 6.46 MPa, respectively. It was found that the aggregates obtained meet the requirements of regulatory documents

Seagrass as a Sustainable Alternative for Building Materials: Assessing its Feasibility, Processing Methods, and Performance in Construction

DAAD (Deutscher Akademischer Austauschdienst)Seegräser leisten einen wichtigen Beitrag zum Ökosystem, indem sie CO2 aus der Atmosphäre absorbieren und Sauerstoff für das Meeresleben erzeugen. Wenn sie sich jedoch zersetzen, kann die angesammelte Biomasse an den Ufern zu Problemen wie CO2- und CH4-Emissionen und Eutrophierung führen. Obwohl Seegrasreste für lokale Lebensräume wichtig sind, beeinträchtigen sie die landschaftliche Schönheit von Touristenstränden. Anstatt diese Biomasse zu deponieren, kann sie in Baumaterialien umgewandelt werden. Ziel dieser Studie ist es, die wichtigsten Eigenschaften von Seegras, geeignete Verarbeitungsmethoden und Kombinationen mit verschiedenen Bindemitteln zur Herstellung von Bauprodukten zu untersuchen. Leichte Gipsverbundwerkstoffe, die Seegrasfasern (Posidonia oceanica) enthalten, wurden durch Gießen hergestellt. Seegrasfasern wurden in den Gipsbrei bis zu einem Anteil von 6 Gewichtsprozent zugegeben. Die seegrasbasierten Verbundwerkstoffe wurden mit reinen Gipsverbundwerkstoffen und solchen auf Holzfasernbasis verglichen. Die Ergebnisse zeigten, dass Seegras bei einem geringen Anteil an Fasern keinen signifikanten Einfluss auf die Biege- und Druckeigenschaften der Verbundwerkstoffe hatte, im Gegensatz zu den Holzfaserverbundwerkstoffen, die sogar im Vergleich zu reinen Gipswerkstoffen eine höhere Festigkeit aufwiesen. Dennoch führte die Beimischung von Seegrasfasern zu einer signifikanten Erhöhung der Rauheit der Verbundwerkstoffe. Weitere Untersuchungen konzentrierten sich auf die Herstellung von Faserplatten unter Verwendung von Seegrasfasern (Posidonia oceanica) als Rohmaterial, sowohl mit Portlandzement. Es wurde ein Vergleich zwischen den seegrasbasierten Zementplatten und solchen aus Holzpartikeln angestellt. Vor der Herstellung der Platten erfolgte eine chemische Analyse der Rohmaterialien und deren Auswirkung auf die Zementhydratation. Zementpulver wurde mit einem großen Anteil lignozellulosischem Material (bis zu 52 Gewichtsprozent) gemischt. Die Mischung wurde heißgepresst, 28 Tage lang konditioniert und anschließend in Testproben geschnitten. Mechanische und physikalische Tests wurden durchgeführt, um die Eigenschaften der Platten zu bewerten. Zusätzlich wurde eine strukturelle Analyse mit einem 3D-Digitalmikroskop und einer micro-CT durchgeführt, um die Bindungs- und Versagensmechanismen sowohl intakter als auch gebrochener Proben zu untersuchen. Die seegrasgebundenen Zementplatten zeigten im Vergleich zu mit Zement gebundenen Holzspanplatten eine wesentlich höhere mechanische und physikalische Leistung. Die hohe Festigkeit und Beständigkeit gegenüber Wasser und Hitze kann auf die Morphologie der Seegrasfasern zurückgeführt werden, die durch ihre lange und flexible Natur (hoher Aspektverhältnis) sowie ihre chemische Zusammensetzung gekennzeichnet sind. Auslaugungen aus Seegrasfasern schienen die Zementhydratation nicht signifikant zu beeinflussen, was sie zu einem kompatiblen Material für die Verwendung in der Herstellung von Zementfaserplatten macht. Geopolymer-gebundene, seegrasbasierte Platten wurden ähnlich wie zementgebundene Platten mit dem Trockenmisch-Sprühverfahren hergestellt und mit Platten aus Holzfasern verglichen. Diese Technik ermöglichte das Mischen und Pressen großer Mengen lignozellulosischer Materialien, um starke Platten zu erhalten. Ziel dieses Teils der Studie war es, geopolymergebundene Platten mit einem hohen lignozellulosischen Gehalt von bis zu 50 Gewichtsprozent herzustellen. Mechanische Tests, einschließlich Biegefestigkeit, Schraubenrückzugstest und Innenausreißfestigkeit, wurden durchgeführt, sowie physikalische Tests wie Kegelkalorimetrie, Wasseraufnahme und Dickenquellung. Die Verteilung des Bindemittels und die Effektivität des Trockenmischverfahrens wurden mit Hilfe von Mikroskopieverfahren wie SEM, 3D-Mikroskop und micro-CT bewertet. Die Ergebnisse zeigten, dass seegrasbasierte Faserplatten im Vergleich zu Holzfaserplatten deutlich bessere Leistung aufwiesen. Es wurde festgestellt, dass die Eignung des Mischens von der Größe und Morphologie der gemischten Aggregate beeinflusst wurde. Sandwichplatten, die mit geopolymerem Bindemittel hergestellt wurden, wurden ebenfalls mit dem Trockenmisch-Sprühverfahren produziert. Wenn Seegrasfasern in den äußeren Teilen der geopolymergebundenen Holzspanplatten eingesetzt wurden, wirkten sie als Verstärkungselemente und führten zu einer Erhöhung der Biegefestigkeit der Platten. Die Leistung dieser Platten wurde mit der von kommerziellen Zementplatten verglichen. Neben mechanischen und physikalischen Tests wurden zusätzliche Untersuchungen durchgeführt, um die Mischeffizienz von Metakaolin und dem alkalischen Aktivator zu bewerten. Diese Bewertung umfasste die Zugabe eines Farbstoffs zum alkalischen Aktivator und anschließende mikroskopische Untersuchungen der Geopolymerpaste. Die Einbindung von Seegrasfasern schien die Biegefestigkeit der Geopolymer-Sandwichplatten zu verbessern und eine leichte Verbesserung des Brandschutzes zu bieten. Isolationsplatten wurden unter Verwendung von Seegrasblättern und pMDI als Bindemittel hergestellt. In dieser Studie wurden Seegrasblätter von zwei Seegrasarten verwendet (Posidonia oceanica und Zostera marina). Die mechanischen und physikalischen Eigenschaften der Platten mit geringer Dichte (Dichten im Bereich von 80 bis 200 kg m-3) wurden gemäß den Standards für Isolationsplatten bewertet. Die Wärmeleitfähigkeitsmessungen wurden mit einem Wärmeflussmessgerät durchgeführt, und der Brandschutz wurde durch Kegelkalorimetrie- und Einflammtests bewertet. Es wurde eine Wirtschaftsanalyse durchgeführt, um die Herstellungskosten und Rentabilität von Seegrasisolationsplatten im Vergleich zu solchen aus Holzfasern zu bewerten. Die Platten aus Seegrasblättern hatten eine niedrige Wärmeleitfähigkeit, ähnlich wie Holzfaserplatten, sowie eine hohe Feuerbeständigkeit. Die Kostenanalyse ergab, dass Seegrasblätter aufgrund geringer Rohstoffkosten, geringem Energiebedarf für die Produktion und dem Potenzial für eine reduzierte Verwendung von flammhemmenden Mitteln eine kostengünstige Alternative zu Holzfaserplatten darstellen. Zusätzlich wurden flexible Matten unter Verwendung von Zostera marina und Bicomponent-Fasern als Bindemittel hergestellt. Die Korrelation zwischen Kompression, interner Haftfestigkeit, Flexibilität und Dichte wurde durch eine vertikale Dichteprofilanalyse und eine Mikroskopieanalyse bewertet. Diese Matten wiesen eine hohe Elastizität und eine Wärmeleitfähigkeit von 0,039 bis 0,051 W m-1K-1 auf. Insgesamt scheint die Verwendung von Seegrasfasern und -blättern zur Herstellung von Baumaterialien ein vielversprechender Ansatz für deren effektive Nutzung zu sein. Nach dem Ende der Lebensdauer kann die Seegras-Biomasse weiterverwendet werden, was ihren Lebenszyklus verlängert und nachhaltige Praktiken in der Bauindustrie fördert.Seagrasses are vital contributors to the ecosystem, absorbing atmospheric CO2 and generating oxygen for marine life. However, when they decompose, the accumulated biomass along the shores can lead to concerns like CO2 and CH4 emissions and eutrophication. Although seagrass remains are essential for local habitats, they hinder the scenic beauty of tourist beaches. Instead of landfilling this biomass, it can be transformed into building materials. This study aims to investigate the main characteristics of seagrass, suitable processing methods and combinations with several binders to produce building products. Lightweight gypsum composite materials containing seagrass fibers (Posidonia oceanica) were prepared by casting. Seagrass fibers were added to the gypsum paste at a proportion of up to 6 wt%. The seagrass-based composites were compared with pure gypsum composites and those based on wood fibers. The results revealed that at a low proportion of fibers, seagrass had no significant effect on the bending and compression properties of the composites, unlike the wood fiber composites which exhibited increased strength even compared to pure gypsum ones. Still, the inclusion of seagrass fibers led to a significant increase in the roughness of the composites. Further investigations focused on the production of fiberboards using seagrass fibers (Posidonia oceanica) as the raw material, both with Portland cement. A comparison was made between the seagrass-based cement boards and those made from wood particles. The chemical analysis of the raw materials and their effect on cement hydration was conducted prior to the production of boards. Cement powder was mixed with a large proportion of lignocellulosic material (up to 52 wt%). The blend was hot-pressed, conditioned for 28 days, and then cut into testing samples. Mechanical and physical tests were performed to evaluate the properties of the boards. Additionally, a structural analysis was carried out using a 3D digital microscope and micro-CT to examine the bonding and failure mechanisms of both intact and broken samples. The seagrass cement bonded boards exhibited much higher mechanical and physical performance compared to wood particleboards bonded with cement. The high strength and resistance to water and heat can be attributed to the morphology of the seagrass fibers, characterized by their long and flexible nature (high aspect ratio), as well as their chemical composition. Leachates released from seagrass fibers did not seem to significantly affect cement hydration, making them a compatible material for use in cement fiberboard production. Geopolymer-bonded seagrass-based boards, similar to cement bonded boards, were produced using the dry mixing-spraying process and they were compared to boards made from wood fibers. This technique allowed for the mixing and pressing of large amounts of lignocellulosic materials to obtain strong boards. The objective of this part of the study was to produce geopolymer bonded boards with high lignocellulosic content, with proportions of up to 50 wt%. Mechanical tests, including bending strength, screw withdrawal test, and internal bond tests, were conducted, along with physical tests such as cone calorimetry, water absorption, and thickness swelling. The distribution of the binder and the effectiveness of the dry mixing process were assessed through microscopy techniques such as SEM, 3D microscope, and micro-CT. The results demonstrated that seagrass-based fiberboards exhibited significantly better performance compared to wood fiberboards. It was concluded that the adequacy of mixing was influenced by the size and morphology of the mixed aggregates. Sandwich boards bonded with geopolymer binder were also produced using the dry mixing spraying process. When seagrass fibers were allocated in the outer parts of geopolymer bonded wood-based particleboards, they acted as reinforcements, resulting in an increase in the bending strength of the boards. The performance of these boards was compared to that of commercial cement boards. Besides performing mechanical and physical tests, additional investigations were conducted to assess the mixing efficiency of metakaolin and the alkaline activator. This evaluation involved adding a colorant to the alkaline activator and subsequently using microscopy investigations to analyze the geopolymer paste. The incorporation of seagrass fibers appeared to enhance the bending strength of the geopolymer sandwich boards and provided a slight improvement in fire protection. Insulation boards were manufactured using seagrass leaves and pMDI as a binder. Seagrass leaves from two species of seagrass were used in this study (Posidonia oceanica and Zostera marina). The mechanical and physical properties of the low-density boards (densities ranging from 80 to 200 kg m-3) were evaluated according to the standard requirements for insulation boards. Thermal conductivity measurements were conducted using a heat flow meter, and fire resistance was assessed through cone calorimetry and single flame tests. An economic analysis was performed to assess the production cost and profitability of seagrass insulation boards compared to those made from wood fibers. The seagrass leaves boards exhibited low thermal conductivity similar to wood fiber boards, as well as high fire resistance. Cost analysis indicated that seagrass leaves are a cost-effective alternative to wood fibers due to low raw material costs, minimal energy requirements for production, and the potential for reduced fire-retardant usage. Additionally, flexible mats were produced using Zostera marina and bicomponent fibers as a binding agent. The correlation between compression, internal bond strength, flexibility, and density was assessed through a vertical density profile analysis and microscopy analysis. These mats displayed high elasticity and a thermal conductivity ranging from 0.039 to 0.051 W m-1K-1. Overall, the use of seagrass fibers and leaves to produce building materials appears to be a promising approach for its effective utilization. After the end of life, seagrass biomass can be further utilized, extending its life cycle and promoting sustainable practices in the construction industry.2023-12-1

PERFORMANCE OF CEMENT-FREE GEOPOLYMER COMPOSITES MADE WITH LOCALLY AVAILABLE INDUSTRIAL SOLID WASTE MATERIALS

This dissertation is concerned with developing sustainable cement-free mortars made with local industrial by-product materials. Ladle slag is generated in mass quantities from secondary steel treatment in the United Arab Emirates (UAE). It is typically disposed of in stockpiles and landfills. Ladle slag is an excellent candidate for geopolymer composites because of its aluminosilicate composition. Such composites are developed by activating industrial by-products in alkaline solutions. This project aims to utilize locally produced ladle slag from the secondary steel treatment in the UAE to produce geopolymer mortars. The effect of various mixture proportions on the developed composites was assessed using the Taguchi design of experiments. Further, other industrial by-products, including fly ash and ground granulated blast furnace slag, were utilized in combination with the ladle slag to produce binary/ternary mortars. The performance of the geopolymers was evaluated through workability, setting time, and compressive strength testing. The TOPSIS method was employed to optimize the mixture proportions for superior performance, i.e., fresh and hardened properties. The optimum mixes for each blend of geopolymer mortar (i.e., ladle slag, ladle slag/fly ash, ladle slag/blast furnace slag, and ladle slag/fly ash/blast furnace slag) were obtained for maximum signal-to-noise ratio responses and validated through experimental testing. Their reaction kinetics and microstructure characteristics were analyzed using an X-Ray Diffractometer (XRD), Fourier-Transform Infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) with electron-dispersive X-ray (EDX). Additionally, the economic and environmental footprint of the optimum mixes was assessed by carrying out cost and environmental impact analyses. Experimental findings showed that the optimum mix was made with a binder content of 650 kg/m3, ladle slag-to-fly ash ratio of 9:1, sodium hydroxide molarity of 8 M, alkaline activator solution-to-binder ratio of 0.50, sodium silicate-to-sodium hydroxide ratio of 2.0, and crushed sand replacement by dune sand of 75%. It is characterized by compressive strength of 20.3 MPa, a flow of 160 mm, and initial and final setting times of 98 and 230 minutes, respectively. Meanwhile, its equivalent carbon dioxide emissions and cost are 343 kg and 442 AED (120 USD) per 1 m3 of mortar produced. This work provides a sustainable solution to valorize locally abundant industrial waste in a cement-free geopolymer mortar while also conserving natural resources and alleviating greenhouse gas emissions. Implementing the TOPSISTaguchi method on single, binary, and ternary mixes offered a better understanding of the effect of various design parameters on the performance of alkali-activated composites with minimum experimental runs

PERFORMANCE EVALUATION OF CEMENT-FREE GEOPOLYMER CONCRETE MADE WITH RECYCLED CONCRETE AGGREGATES AND STEEL FIBERS

Sustainable and innovative alternatives have been investigated to replace concrete’s main components, natural aggregates, and cement. Previous studies have been carried out to replace NA and cement with recycled concrete aggregates (RCA) and inorganic alkali-activated geopolymer binders, respectively. Yet, such sustainable concrete has only been proposed for non-structural purposes, owing to the inferior properties of RCA. This research work aims to assess the feasibility of reutilizing RCA from construction and demolition waste and locally available industrial solid by-products in the production of sustainable geopolymer concrete for structural applications. The binding materials were either in the form of a single precursor, ground granulated blast furnace slag (simply slag), or a blend of slag and class F fly ash. Steel fibre reinforcement was added at different volume fractions to promote the use of structural geopolymer concrete made with 100% RCA. The mechanical behaviour of such steel fibre-reinforced RCA geopolymer concrete was studied through extensive testing of compressive strength, splitting tensile strength, and modulus of elasticity. The flexural strength, toughness, deflection, and residual strength were used to describe the flexural performance. In turn, the durability properties were assessed by measuring the bulk electric resistivity, water absorption, sorptivity, and abrasion resistance. Experimental findings revealed the ability to produce 100% RCA slag-based and slag-fly ash blended geopolymer concrete incorporating a 2% steel fibre volume fraction having superior mechanical performance and comparable durability properties relative to those of the plain NA-based control mix. The steel fibre-reinforced RCA geopolymer concrete developed in the current study is considered a feasible and sustainable alternative to conventional concrete that promises to recycle industrial wastes, alleviate carbon dioxide emissions, and conserve natural resources without compromising performance