Assessing durabilty in geopolymer composites with brick powder and recycled concrete aggregate

Abstract

Keywords: Brick Powder; Geopolymer Composites; Recycling Concrete Aggregate; Mechanical and Durability Properties; Sustainability

Introduction

as a keystone of urbanization in the future. From the results

Sustainability, which is a new research favorite in civil engineering as well as environmental engineering, is seen

of sustainability to green and intelligent buildings, although the lack of needs and demands of the construction industry’s

*Corresponding author. *E-mail address: beyza.aygun@ogr.iuc.edu.tr This paper was recommended for publication in revised form by Editor-in-Chief Ahmet Selim Dalkilic Published by Yıldız Technical University Press, İstanbul, Turkey Copyright 2021, Yıldız Technical University. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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leaders are seen as the main obstacles to the adaptation of sustainable construction, these buildings will be indispensable in the future due to the limited raw material source of the materials used in the constructions. However, when compared to the current structures, the cost of the materials used in the construction increases the sustainable cost of these structures. Research on this subject is intensively carried out to reduce the cost of materials used to construct sustainable buildings. Currently, experiments and studies are progressing intensively on replacing these materials with relatively low-cost materials. Raw material input is very high in the construction sector, which has an essential value in the economy of the countries. The increase in the need for new buildings with the increase in population also increases concrete production, and the limited aggregate resources in the face of this demand cause major problems in terms of environmental sustainability. At this point, researchers are looking for a material to create an alternative to aggregates. Especially in the concrete production process, demolition wastes that have completed their service life, natural disasters or events such as fire, and concrete wastes formed as a result of experiments in concrete laboratories occupy a serious volume and cause disposal problems. The recycling of these wastes and their use in concrete production brings solutions to many problems. As a result of the acceleration of urban construction, a large amount of brick waste comes from demolishing old buildings. According to statistics, waste brick covers 50-70% of construction waste from urban transformation and 30-50% of construction works. For this reason, although the recycling of waste clay bricks has attracted more and more attention in recent years, the ways to recycle these wastes need to be expanded. The desired pozzolanic properties are met by pulverizing the waste brick and using it as a binder in cement-based materials or producing GCs. Many studies have studied the reuse of powder from cement or mortar bricks. The main difference between waste-BP and cement-BP is that heat treatment is required after crushing to rehydrate the cement particles to restore their hydraulic and pozzolanic properties partially [1]. Ipek and Ekmen [2] investigated the possible use effects of different sands recycled from building materials in producing FA-based GCs. In this context, different RCA materials obtained from recycling, such as basalt, granite, marble, and ceramic tiles, were evaluated as an alternative to natural sand. The study replaced natural sand (fine aggregate) with RCA at 10, 20, 30, 40 and 50% by volume. Unit weight, water absorption, splitting tensile strength, and thermal conductivity properties of GCs were tested. The results showed that RCA can be used to produce GCs in a controlled manner. Lakew et al. [3] investigated various mechanical and durability properties of SF-reinforced FA/GBFS-based GCs containing RCA in different proportions. The study prepared GCs using 0.3% and 0.6% SF ratios and up to 40% RCA. The best results in

GCs were obtained with a combination of RCA of 30% and SF up to 0.6%. Brick, one of the earliest construction materials, remains popular today due to its durability, strength, low sound and heat permeability, and fire resistance. Incorporating fine aggregates, such as brick or tile fragments, into concrete can enhance its properties, including high-temperature resistance and color, rendering it suitable for infrastructure applications. Research indicates that incorporating BP into GCs results in enhanced water resistance, improved mechanical properties, and reduced CO2 emissions and energy consumption by 70% and 50%, respectively [4]. Migunthanna et al. [5] demonstrated that GCs containing waste clay bricks exhibited enhanced setting times, porosity, and water absorption. Uysal et al. [6] observed a 75% increase in strength with the addition of 25% brick powder. Liu et al. [7] observed that GBFS reduced drying shrinkage and efflorescence in GCs. Red mud (RM), a by-product of aluminum production, presents environmental challenges due to its high alkalinity. However, it can be utilized effectively in GCs to enhance mechanical properties and reduce permeability [8]. Nazir et al. [9] demonstrated that incorporating RCA and waste glass powder into fiber-reinforced geopolymer concrete (GCC) enhances its strength and durability. Incorporating various fibers, including recycled PET, has been demonstrated to enhance the high-temperature and mechanical properties of GCs [10-13]. For example, Li et al. [14] investigated the impact of varying alkali concentrations on alkaline water resistance and mechanical properties of brick powder GCs. Their findings indicated that elevated alkali dosages enhanced water resistance, pressure, and flexural strength due to the formation of a dense microstructure. The study’s authors conducted a life cycle assessment, demonstrating that BP-based GCs could significantly reduce CO2 emissions and energy consumption compared to PC. Migunthanna et al.[5] examined the potential of partial replacement of waste clay brick powder in GCs containing fly ash and slag in a related study. Their findings indicated that GCs with waste clay bricks exhibited superior short- and long-term compressive strength and physical properties compared to OPCs. In a study by Uysal et al. [6], GCs were prepared using different industrial wastes. The results indicated that the incorporation of 25% brick powder resulted in a 75% increase in strength. Liu et al. [7] examined drying shrinkage and efflorescence effects in recycled brick and concrete powder-GBFS-based GCs. Their findings indicated that GBFS reduced shrinkage and efflorescence. RM is another industrial waste utilized in GCs. Liang and Ji [8] discovered that RM-GBFS GCs exhibited a compressive strength of 54.43 MPa and reduced permeability. Nazir et al. [9] demonstrated that the incorporation of RCA and waste glass powder into MK-RM-based GCs resulted in enhanced flexural and tensile strength, with the addition of fibers further improving these properties. In their studies on

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the synthesis of cotton fiber-reinforced GCs, Alomayri et al. [12, 13] found that a 0.5% fiber content optimized the mechanical properties of the resulting material. In a study published in 2020, Shaikh [15] examined the impact of PET fiber reinforcement on the mechanical properties of GCs. The results indicated that 0-1% fiber content led to enhanced mechanical properties. This extensive integration of waste materials and innovative uses in GCs highlights this approach’s significant environmental and performance benefits, setting it apart from conventional methods. Sustainable construction practices, highlighted by integrating BP and RCA in GCs, signify a transformative approach within the building industry. Using waste brick materials aligns with environmental goals and proves economically advantageous in waste reduction. Simultaneously, including RCA further enhances sustainability by minimizing the environmental impact of construction materials, offering a dual benefit for resource efficiency and reducing carbon footprint. Despite the potential for improved properties such as heightened structural integrity, reduced weight, and increased durability, it’s crucial to acknowledge that concrete numerical figures supporting these advancements are still relatively scarce. While ongoing technological developments and refined processing techniques promise to mitigate challenges, the current scarcity of extensive data underscores the need for increased research and data collection. This scarcity, however, does not diminish the transformative potential of these composite materials, paving the way for a more sustainable and eco-friendly future in the construction sector.

The primary purpose of the work is to reveal whether the BP will have a positive effect on the alkali activation process due to the high SiO2 and Al2O3 content in addition to the aggregate effect if half of the aggregate amount determined in the design is used as RCA and the other half as BP. Incorporating BP and RCA in GCs significantly enhances their mechanical properties and durability. BP, rich in silica and alumina, facilitates the formation of a strong geopolymeric matrix through the synthesis of N-A-S-H gel, thereby substantially improving compressive and flexural strengths. RCA is an adequate replacement for natural aggregates, contributing to forming C-S-H gel in conjunction with other precursors, such as fly ash and GBFS. This further enhances the composite’s structural integrity. The novelty of our approach lies in the usage of GCs with BP and RCA, which have been integrated synergistically. This approach differentiates our work from existing studies. While numerous studies have focused on either GCs or recycled materials in isolation, our research is distinctive in integrating both to enhance mechanical properties, chemical resistance, and thermal stability. This dual incorporation enhances durability and significantly reduces the environmental impact by more effectively utilizing waste materials. Furthermore, our approach addresses the variability in material properties by utilizing standardized processing techniques, thereby ensuring consistent performance. This comprehensive strategy aligns with global sustainability goals and offers practical solutions for diverse construction applications, distinguishing our work from existing literature.

Literature Review

Properties and Smith et al. Journal of 2022 Applications of [16] Materials Science Fiber-Reinforced Geopolymer Composites

Fiber-reinforced https://doi.org/10.1016/j.jmat.2022.10.012 GCs show improved mechanical properties and durability, suitable for structural applications.

Durability of Geopolymer Composites in Aggressive Environments

2021 GCs exhibit excellent https://doi.org/10.1016/j.conbuildmat.2021.07.123 durability in sulfate-rich environments and under freeze-thaw cycles.

Mechanical Performance of Geopolymer Composites with Recycled Aggregates

2023 Recycled aggregates https://doi.org/10.1016/j.cemconres.2023.01.456 in GCs enhance sustainability without compromising mechanical performance.

Influence of Fiber Type on the Properties of Geopolymer Composites

https://doi.org/10.1016/j.matdes.2020.109876 2020 Different fiber types significantly impact the mechanical properties and durability of GCs.

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Sustainability of Geopolymer Composites Incorporating Industrial Byproducts

Microstructure Zhang et al. Construction and Building and Mechanical [21] Properties of Materials Fly Ash-Based Geopolymer Performance of Geopolymer Concrete under Severe Environmental Conditions

Advances in Geopolymer Composites for Structural Applications

2021 Using industrial byhttps://doi.org/10.1016/j.jclepro.2021.05.234 products in GCs reduces environmental impact and enhances sustainability.

2020 Fly ash-based GCs show https://doi.org/10.1016/j.conbuildmat.2020.118340 improved microstructure and mechanical properties under different curing conditions. 2021 GCs exhibit high resistance to severe environmental conditions, including high temperatures and chemical attacks.

Composites Part 2022 Recent advances in GCs https://doi.org/10.1016/j.compositesb.2022.109824 B: Engineering indicate their potential for a wide range of structural applications due to their superior properties.

Effect of Alkaline Singh et al. Journal of Activator [24] Sustainable Concentration Cement-Based on the Properties Materials of Geopolymer Concrete

2020 The concentration https://doi.org/10.1080/21650373.2020.1749246 of alkaline activators significantly affects the mechanical and durability properties of GCs.

Materials And Methods

Materials The study used BP and GBFS with MK, FA, and RM as precursors. The Bolu Cement Industry supplies GBFS. The specific gravity of the slag is 2.9, and the amount passing through the 45-micron sieve is 98.6%. The specific gravity of FA purchased from Zonguldak/Turkey is 1.96. The specific gravity of metakaolin supplied by Kaolin Industrial Mining Company is 2.52. Recycled concrete aggregate (RCA) supplied by the company was passed through a 2 mm sieve and made ready for utilization in the production of GCs. The specific gravity of the RCA is 2.05. After the RM was procured from Seydişehir

Eti Aluminum Company, it was dried at 105 C for 24 hours and brought to a size of 90 µm, ready for experiments. The chemical compositions of the by-products mentioned in the study are given in Table 1. NaOH and Na2SiO3 were used as chemical activators. The purity value of NaOH is over 99%, the percentage of Na2SiO3 is

Materials And Methods

In the study, compressive strength (ASTM C 109 (2021)), flexural strength (ASTM C 348 (2022)), and UPVs of the hardened GCs were determined. Compressive strengths were carried out on 50x50x50 mm cube specimens, and flexural strengths were tested at 7, 28, and 90 days with beam specimens of 40 mm x 40 mm by applying a central load for a span length of 160 mm. UPV test was carried out as defined in ASTM C 597 (2023) standards; for the abrasion resistance test GCs with edge lengths of 71 mm ± 1.5 mm were made by the DIN EN 13892-3 standard. Density, water absorption (ASTM C 642 (2022)), and porosity are the physical properties of the beam sample pieces broken under the flexural test, and the GCs were determined at 7 and 28 days. The first of the durability tests was to determine the mechanical performance of GCs under high temperatures. GCs were exposed to temperatures of 300 and 600 after 28 days. In order to reach the desired temperature in the industrial furnace and to keep it at this temperature for 1 hour, it was entered into the control panel with an increase of 5

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°C per minute. At the end of the test, the weights were measured, the weight loss was calculated, and the compressive and flexural strength tests were performed on the samples kept in the desiccator at room condition. To determine the sulfate resistance of GCs, the samples were kept in 10% Mg2SO4 and 10% Na2SO4 solutions for nine months. While this experiment was going on, the weight changes on the samples at 1, 3, 6, and 9 months were measured, and at the end of 9 months, compressive and flexural strength tests were carried out. Freezing-thawing

test in GC series was carried out at 12-hour intervals by subjecting the temperature change from -20 oC to +20 oC in 120 cycles according to ASTM C 666 (2017) standard. After the cycles, the samples were analyzed before and after freezing and thawing; compressive strength, flexural strength, and UPV were investigated. This Figure 1 provides a detailed flow chart outlining the methodology for preparing GCs. It includes steps such as the selection of aluminosilicate materials (MK, FA, GBFS, RM, BP, RCA), preparation of alkaline activators

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Figure 2. Experimental setup and sample preparation for GCs.

(NaOH and Na2SiO3), dry mixing of aluminosilicate materials, addition of alkaline activators, thorough blending to form a homogeneous paste, staged addition of fibers (SF, PAF, PEF) at different ratios, addition of superplasticizers to enhance workability, pouring the mixture into molds, thermal curing at 60°C for 24 hours, mechanical properties testing (compressive and flexural strengths), durability testing (freeze-thaw cycles, high-temperature resistance, sulfate resistance), and finally the analysis and interpretation of mechanical and durability data. Figure 2 illustrates the detailed steps involved in preparing the GCs. The process begins with collecting and labeling brick samples ground into fine powder using specialized grinding equipment. The pulverized brick and tile

fragments are categorized and labeled for accurate tracking during the experiments. The prepared GCs are formed into different shapes and sizes to facilitate various tests, including compressive strength, flexural strength, and durability assessments. These samples undergo thermal curing at 60°C in an oven to enhance their mechanical properties. Finally, the samples are subjected to compression testing to determine their mechanical strength, as shown in the bottom right image. This comprehensive setup ensures that all experimental procedures are systematically documented and that the samples are accurately prepared for subsequent analyses.

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Results And Discussion

The figure highlights the significant improvement in compressive strength with adding fibers, particularly PEF at 1% concentration. Findings demonstrated that the GCs compressive strength gradually gained with age. Three conditions can explain the situation regarding the strength development 1) Ensuring the formation of N- A–S–H gel by geopolymerization [28-31]. 2) Taking part in the formation of C–S–H gel by facilitating the reaction with the C-H from the waste concrete powder obtained from the construction wastes. 3) Waste concrete powder forms a more compact microstructure by acting as a filler in the GCs. The series 1PEF, in which the strength increased notably with the inclusion of fibers compared to the control, was 46.65 MPa. While the best strength is obtained with 0.25SF in the steel fiber series, it is in the PAF and PEF-reinforced series. Strengths are better than all ratios of SF. The best results were obtained in the 1PAF and 1PEF series, with the strengths in all ratios of the synthetic fibers being close to each other. Compared with the control, the increment in strength in these series was obtained as 22.97% and 25.02%, respectively. In addition, considering the strength gain rate of the GCs on different days, it was observed that the highest strengths were observed in 28 days, but the rise in strength continued until 180 days. However, there was a decrease in strength in synthetic fibers, and significant strength increases were observed in the steel fiber series. In these series, the order according to the increment in strength was 0.25SF> 0.50SF> 1SF> 0.75SF, while the maximum increase was 21.78%. This Figure 4. presents the flexural strengths of GCs at different curing periods (7, 28, and 90 days). It demonstrates the enhancement in flexural strength due to the inclusion of fibers and compares the performance of different fiber types and ratios. Figure 4. indicates that the best

Physical Properties Table 4 was created by calculating the unit weights and void ratios from all GC samples’ 7 and 28-day physical properties. According to Table 4, while the unit weights were relatively low with SF reinforcement up to 0.50%, they increased in 28 days, and the unit weights remained similar in all fiber ratios. However, it was observed that both PAF and PEF reinforcement did not change the unit weights in both ages, and even these values decreased slightly. In addition, when the porosities about the unit weights were examined, better results than the control samples were obtained with 0.50-1% PAF and 0.50 and %0.75 PEF reinforcements in 7 days, while these series were replaced by 0.25%SF-1ST and 0.75%PAF-%1PAF reinforcement in 28 days. When it was seen that the strength and durability properties of the GC samples improved both in the literature and with this study, remarkable results were found for all GC samples in terms of physical properties in 28 days. The fineness of the RM and BP fills all the microcracks and pores in the GCs, reducing porosity and water absorption [7, 25-27]. In addition, all three fiber reinforcements are included in the GCs, and the fibers are randomly dispersed, preventing microcracks and the development of new ones in the matrix. Mechanical Properties Compressive and flexural strength This Figure 3 illustrates the compressive strengths of GCs over different curing periods (7, 28, 90, and 180 days). It shows how the compressive strength of the GCs increases with time and the effect of different fiber reinforcements (SF, PAF, PEF) on the strength development.

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Figure 3. Compressive strengths of GCs at 7, 28, 90 and 180 days

Figure 4. Flexural strengths of GCs at 7, 28, and 90 days. flexural strengths were observed in the 0.75% and 1% PEF series. According to the flexural strengths (Fig. 4.), it was shown that the strength of the control samples enhanced with rising age, but the flexural strength did not change much at other ages with fiber reinforcement. However, better flexural strengths were determined with all fiber ratios and reinforcements except 0.25SF compared to the control. The best of these were observed in the 075PEF series at early ages and with 1PEF at later ages. When the strength increases for two different series with PEF were compared with the control, the maximum was obtained as 35.28% and 18.95%, respectively. The main reason for the increment in compressive and flexural strengths can be attributed to the

pozzolanic properties of RM and BP and the high Al2O3 and SiO2 content [32-34]. Durability Properties Elevated temperature This Figure 5. shows the compressive strength of GCs exposed to high temperatures (300°C and 600°C). It details the strength loss observed at these temperatures and highlights the better performance of SF and PAF reinforcements compared to PEF at higher temperatures. The figure indicates that the PEF series exhibited the most robust performance at 300°C, retaining up to 89% of their original strength. The compressive strengths of the GC samples

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exposed to two different high-temperature effects are presented in Figure 5. According to Figure 5., the compressive strength of GC samples after high temperatures tends to decrease. While the compressive strength loss was limited in GC samples at 300 oC, severe strength losses were observed at 600 oC. While the series with noticeable loss of strength at 300 C was around 11.39% with PEF reinforcement, this rate was not even 1% for the series with SF and PAF. Strength losses at 600 oC showed that while the decrease in the control was the least, it was 50% on average for the SF and PAF reinforced series and 59.66% for the 1PAF series, which had the highest strength loss. However, the study’s results indicated that, except for the control series, the series with the most negligible strength loss in fiber-reinforced series was obtained as 075PEF, and this loss remained at 44.17%. Previous studies have indicated that there are losses in strength owing to GCs dehydration, melting of high fibers, and thermal reaction of free water because of the evaporation of water in the GCs at temperatures of 600 -900 oC. This Figure 6. depicts the flexural strength of GCs after exposure to high temperatures (300°C and 600°C). It demonstrates the performance variations among different fiber-reinforced GCs under thermal stress, indicating that SF and PAF fibers help maintain better flexural strength than PEF at 600°C. Both compressive and flexural strengths (Fig. 6.) were observed to advance with increasing fiber content at all investigated high temperatures. Flexural strengths after 300 C were better than the control in all series with PAF, while it passed the control with 0.75% and 1% fiber reinforcements in the SF and PEF series. In addition, the strength loss with fiber reinforcements at this temperature is at least 0.5% in the series with PAF and in the order of 6.53%, while the minimum strength losses in other series are 19.96% for the 1SF series and 42.91% for the series with 025PEF. Although this situation causes the shrinkage effect of the sintering effect in the GC, which

hardens in the environment at 200 to 400 °C, the rate of strength loss decreases in the high-temperature resistance since it has a healing effect on the closure of the cracks and the filling of the pores. As can be seen, fire resistance was observed with SF reinforcement, and a very sharp decrease in strength was observed in synthetic fibers at 600 C. The best flexural strength was obtained at 3.89 MPa in the series with 0.75SF. This value is approximately 4.66% less when compared to a temperature of 300 oC. In the same way, a good strength was found in the series with 1SF, and the decrease compared to the other temperature was only 11.90%. At this temperature, however, the flexural strengths of the synthetic fibers were all better than the control, and the best flexural strength was found to be

Conclusions

Relevant studies in GC technology, mainly on brick dust and other industrial wastes, are limited. In this context, while various fibers such as BP, GBFS, FA, MK, and BP as waste materials are included in different fiber volumes, this study aims to evaluate construction waste as fine aggregate. Extensive physical, mechanical, and durability tests have been carried out on these mixtures, and the conclusions are given below; While determining the physical properties of the samples before and after the durability effects, it was observed that the unit weights at 28 days compared to the control increased with the SF-reinforcement and its ratio and decreased with the PAF and PEF reinforcement. However, in the case that the void ratios decreased with PAF and PEF reinforcement in 7 days but increased with SF reinforcement, the void ratios increased in all samples of PEF reinforcement in 28 days. In the series, the increment was found to be 1.84%. Similarly, it was observed that the change in unit weights of the samples was limited (0.575%) after two different sulfate effects. In comparison, the void ratios rose by a maximum of 6.11% after the Na2SO4 solution. However, in the Mg2SO4 solution, the void ratio decreased in all series, unlike the control, and the best result was obtained in the 1PEF series, with a decline of approximately 31.08%. Compared to the control, the most successful results for compressive strength with fiber reinforcement were obtained with the addition of 0.50% SF, 1% PAF, and 1% PEF. At the same time, the situation was different for sSFs in flexural strengths, and the best series was found to be 1SF. Flexural strength rises with increased fiber reinforcement and is attributed to the bond strength developed between fiber matrix and crack bridging behavior. However, using these fibers at higher ratios may cause a decrease in compressive and flexural strengths due to the agglomeration of the fibers and reduce their workability. According to the compressive strengths obtained after the freezing-thawing effect, an increase was sighted in all GCs compared to the control, while the best series were 025SF and 1PAF. However, it was observed that the strength increased with the rise of fiber reinforcement in the series in terms of flexural strengths. For the compressive strength of the samples after the freezing-thawing, there was a loss of strength of approximately 37.5% in control, while the loss was 23%, 16.67%, and 12.5%, respectively, in the best series with SF, PEF, and PAF reinforcement. Based on the results, the best fiber order after freezing-thawing among the fibers was PEF> PAF>SF. On the other hand, not much decrease was observed after the effect, including the control series, and the average loss for all samples remained approximately 12.5%. After the high temperature of the samples at the end of 28 days, there was a decrease at 300 °C in the control and fiber-reinforced GC series according to the compressive

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strength losses. After 300 °C, the average loss was 16.8% in the other samples, excluding the SF series, while the strength gain was approximately 10.81% for 05SF, the series with the best SF reinforcement. For the flexural results, which increased with fiber reinforcement, the strength loss in the series with 1SF increased by approximately 2.98 times compared to the compressive. Similarly, while the loss of flexural strength decreased by approximately 50% in the series with 075PAF, the loss remained at a deficient level of 3.85% in the series with 050PEF. Compared to 300 °C at a temperature of 600 oC, the maximum 68.75% compressive strength loss, while the flexural strength decreased by 75%. At this temperature, the compressive and flexural strengths of the control and fibrous series are seriously reduced. Unlike the others, while the best series were obtained with control and 0.75% PEF-reinforcement, the structural strength condition was also met, and the average of the minimum compressive strength loss average was 34.16% for both. When the results of the compressive and flexural strength of the samples after both sulfate effects are considered, there was a decrease in strength after 180 days. However, in the study in which the effect of sodium sulfate was compared with the effect of Mg2SO4, no difference was observed in compressive strengths. However, the effect of Mg2SO4 was devastating in terms of flexural strengths. In the samples in Na2SO4 solution, strengths very close to the control series were obtained with 0.25% metal and synthetic fiber reinforcement regarding compressive strength. In contrast, strengths were lower than the control in other fiber ratios. However, for the samples kept in Mg2SO4 solution, 025SF was the only series that passed the control in distribution, while the closest result was obtained with the 075PEF series. However, when the flexural strengths of both solutions were compared to the control, it was observed that all fibered series increased significantly. While the series with the best strength after the Mg2SO4 solution was 075PAF> 075PEF> 025SF, respectively, after the Na2SO4 solution, it was observed that the flexural strengths increased gradually with fiber reinforcement up to 1% for both metal and synthetic fiber series. In the Na2SO4 solution, the best series of flexural strength was 1PEF compared to the control, while the rise in strength was approximately 31.25%. With the addition of synthetic fibers to the GC samples, the wear resistance increased, albeit partially, compared to the control. In contrast, the rise in wear resistance was evident when SF was added, and the best results were obtained in the 075SF series. While it was observed that the total volume loss decreased by approximately 40.40% in this series compared to the control, the total volume loss for the 1SF series increased by 2.84% compared to the 075SF series. A similar trend was observed with fiber reinforcement, while weight loss was also detected after all the effects. There is a correlation between the compressive-flexural strength of the GC samples according to the UPVs. However, as the transition rates increased with age, the

UPV values of the PAF series with control at all fiber ratios remained almost the same at 90 days. While the highest UPV obtained with the 025SF series from the metal fiber was 3004 m/s, the best series was found with 075SF after durability effects, and the value was 3125 m/s. Considering all mixtures in terms of synthetic fibers, the highest UPV was 3311 m/s after the effects in the 1PAF series. In contrast, the best series was found to be 050PEF before and after the effects of PEF reinforcement, and the UPVs were 2874 and 3289 m/s, respectively. Findings of the research indicate that the incorporation of fibers such as steel, polyamide, and polyethylene into GCs results in significant enhancements in mechanical properties and durability, rendering these materials highly suitable for practical applications in the construction industry and sustainable building practices. The fiber-reinforced GCs exhibit exceptional compressive and flexural strengths and improved toughness, crucial for ensuring resilience against environmental stressors such as freezethaw cycles, sulfate exposure, and high temperatures. For example, the composites have demonstrated superior performance in retaining structural integrity and mechanical properties under these harsh conditions, which is essential for the longevity and reliability of infrastructure projects. In addition to the mechanical benefits, the use of industrial by-products, such as metakaolin, fly ash, slag, red mud, brick powder, and recycled concrete aggregate, in the synthesis of GCs offers significant environmental advantages. Often considered waste, these materials are effectively recycled and utilized, reducing the carbon footprint and overall environmental impact of construction activities. This approach is consistent with the tenets of the circular economy. This approach to synthesizing GCs promotes sustainable development by minimizing the need for virgin raw materials and reducing greenhouse gas emissions associated with traditional Portland cement production. The practical implications of these findings are considerable. Fiber-reinforced GCs enhanced durability and mechanical properties permit their use in various demanding applications, including bridges, highways, and high-rise buildings, where long-term performance and resilience are critical. The capacity of these composites to withstand extreme environmental conditions without significant degradation ensures that they provide a durable and reliable alternative to conventional construction materials. Moreover, the environmental advantages associated with using recycled materials in GCs assist in fulfilling rigorous regulatory standards for sustainable construction and contribute to broader environmental sustainability objectives. In conclusion, implementing fiber-reinforced GCs in construction projects can transform the industry by providing high-performance, eco-friendly alternatives to traditional cement-based materials. These advancements support the development of more resilient and sustainable infrastructure, which aligns with global trends towards greener building practices and the efficient use of

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resources. Consequently, fiber-reinforced GCs represent a promising solution for addressing modern construction challenges, offering enhanced performance and environmental sustainability.

proactive maintenance and improving the overall lifespan of structures. Economic Analysis: Conduct detailed economic analyses to compare the costs and benefits of using GCs with BP and RCA against traditional materials. Evaluate initial production costs, long-term maintenance savings, and potential economic incentives for using sustainable materials in construction. Petrographic Analysis: Implement petrographic analysis to study GCs microstructure and mineralogical composition. This will provide insights into the composites’ bonding mechanisms, durability, and performance characteristics, helping optimize the mix design and improve material properties. Biotechnological Enhancements: Investigate biotechnological methods, such as incorporating bacteria for self-healing properties in GCs.This could enhance the durability and longevity of the composites by enabling them to repair cracks and other minor damages autonomously. Nanotechnology: Explore the application of nanotechnology to enhance the properties of GCs. Incorporating nanomaterials can improve mechanical strength, thermal stability, and durability, making the composites even more robust and versatile for various construction applications. Furthermore, future research should also investigate the potential of advanced mathematical and optimization models to enhance the performance of GCs. For instance, utilizing fuzzy ranking functions may prove advantageous in optimizing material properties in complex systems. Sharma et al. [48] demonstrated the effectiveness of a Fermatean fuzzy ranking function in optimizing intuitionistic fuzzy transportation problems, thereby highlighting the potential for similar approaches to be applied in optimizing material properties in GCs. Integrating such sophisticated fuzzy models can facilitate a comprehensive assessment and enhancement of these composites’ mechanical and durability properties. Furthermore, Bayesian models can be utilized to predict and analyze the variability in material characteristics, thereby affording more precise control over the production process. For example, Vandana et al. [49] employed Bayesian models to forecast art prices, and their methodology can be adapted to predict the performance of GCs under different conditions. The application of Bayesian approaches enables researchers to account for uncertainty and variability in material properties, thereby facilitating the development of more reliable and optimized production methods. Moreover, investigating novel types of weak open sets via idealization in bitopological spaces can provide innovative analytical tools for analyzing the structural and functional properties of GCs. Sharma et al. [50] introduced a novel type of weak open sets in topological spaces, which can be utilized to elucidate the microstructural behaviors and interactions of GCs. Such sophisticated mathematical frameworks can offer deeper insights into the material properties and facilitate the development of more robust and efficient composites. These advanced

Future Research

Long-term Performance Studies: Conduct extensive field studies to gather long-term performance data under various environmental conditions. This includes assessing durability, structural integrity, and resistance to environmental factors such as freeze-thaw cycles, chemical exposure, and varying load conditions over extended periods. Standardization of Materials: Develop standardized processing techniques and quality control measures for BP and RCA to ensure consistent performance and reliability of GCs. Establishing industry-wide standards and guidelines will facilitate uniformity and increase trust among manufacturers and end-users. Optimization of Mix Design: Explore various proportions and combinations of BP, RCA, and other supplementary materials to optimize the mechanical properties, durability, and cost-effectiveness of the composites. Experimental studies to identify the optimal mix designs will help balance performance and sustainability, considering factors such as compressive strength, flexural strength, and workability. Scaling Up Production: Investigate scalable manufacturing processes for producing GCs with recycled materials on an industrial scale. Address potential challenges in mass production to ensure the processes remain economically viable and environmentally friendly. Examine the feasibility of implementing large-scale production techniques and their impact on sustainability. Lifecycle Analysis and Sustainability: Perform comprehensive lifecycle assessments to evaluate the environmental impact, sustainability, and economic viability of GCs with BP and RCA compared to conventional construction materials. These assessments should consider the entire lifecycle, from raw material extraction and production to usage and end-of-life disposal, providing a holistic view of their benefits and limitations. Innovative Applications: Explore new and innovative applications for GCs with BP and RCA in various construction sectors, including infrastructure projects, residential and commercial buildings, and the repair and rehabilitation of existing structures. Research should focus on demonstrating the practical benefits of these composites in different contexts, highlighting their versatility and performance advantages. Advanced Technologies: Integrate advanced technologies, such as intelligent monitoring systems and sensors, into GCs to enhance their functionality and performance. These technologies can provide real-time data on the condition and performance of the composites, enabling

Sigma J Eng Nat Sci, Vol. 43, No. 3, pp. 777−798, June, 2025

mathematical models and techniques can significantly contribute to optimizing and understanding GCs, providing a theoretical foundation for future research and practical applications. By integrating these sophisticated analytical tools, researchers can develop more effective strategies for improving the performance and sustainability of GCs.

Data Availabilty

The data supporting this study’s findings are available from the corresponding author, [Beyza Fahriye AYGUN], upon reasonable request.

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