This paper presents a new method for determining the effect of healthy personal protective material (HPPM) stripes, such as surgical masks, protective suits, and overhead and foot covers, on the durability and physicomechanical characteristics of concrete for use in architectural forms. Because of the current global epidemic caused by coronavirus (COVID-19), the use of HPPM, such as surgical masks, protective suits, and overhead and foot covers, has increased considerably. COVID-19’s second and third waves are currently affecting various countries, necessitating the use of facemasks (FM). Consequently, millions of single FM have been discharged into the wild, washing up on beaches, floating beneath the seas, and ending up in hazardous locations. The effect of stripe fibers on the physicomechanical characteristics of concrete, such as the workability, Uniaxial Compressive Strength UCS, flexural strength, impact strength, spalling resistance, abrasion resistance, sorptivity, Water absorption Sw, porosity (ηe), water penetration, permeability, and economic and eco-friendly aspects, need to be determined. With a focus on HPPM, especially single-use facemasks, this study investigated an innovative way to incorporate pandemic waste into concrete structures. Scanning electron microscope and X-ray diffraction patterns were employed to analyze the microstructures and interfacial transition zones and to identify the elemental composition. The HPPM had a pore-blocking effect, which reduced the permeability and capillary porosity. Additionally, the best concentrations of HPPM, particularly of masks, were applied by volume at 0, 1, 1.5, 2.0, and 2.5%. The use of mixed fibers from different HPPMs increased the strength and overall performance of concrete samples. The tendency of growing strength began to disappear at approximately 2%. The results of this investigation showed that the stripe content had no effect on the compressive strength. However, the stripe is critical for determining the flexural strength of concrete. The UCS increased steadily between 1 and 1.5% before falling marginally at 2.5%, which indicates that incorporating HPPM into concrete had a significant impact on the UCS of the mixture. The addition of HPPM to the mixtures considerably modified the failure mode of concrete from brittle to ductile. Water absorption in hardened concrete is reduced when HPPM stripes and fibers were added separately in low-volume fractions to the concrete mixture. The concrete containing 2% HPPM fibers had the lowest water absorption and porosity percentage. The HPPM fibers were found to act as bridges across cracks, enhancing the transfer capability of the matrices. From a technological and environmental standpoint, this study found that using HPPM fibers in the production of concrete is viable. The protection of steel bars from corrosion and sulfate attack, as well as from water and ion infiltration through pores and cracks, is linked to improving the longevity of reinforced concrete2. As a result, both the insertion of fibers and the replacement of traditional reinforcement with fibers are favourable in terms of long-term development1. Polypropylene fiber-reinforced concrete was experimentally investigated by3. The compressive strength decreased marginally over the testing period after the addition of a 3% polypropylene stripe by volume, with the most significant reduction at 10%. The splitting tensile strength improved by 39%, whereas compressive strength reduced with the inclusion of a 1% polypropylene stripe by volume.Concrete has a strong compressive strength but a tensile strength ten times that of steel. It also has a brittle property, which prevents stress transmission after cracking. It is feasible to add fibers to concrete mixes to prevent brittle failure and increase the mechanical qualities. Healthy Personal Protective Materials (HPPM) stripes are cementitious composite materials with scattered fibers, such as steel, polymer, polypropylene, carbon, and glass4, thin fibers may be a viable solution for reducing creep strain. The efficiency of fibers is determined not only by the metrics listed above but also by their concrete bonding strength5. In addition, fibers can be crimped, twisted, sinusoidal, or hooked to improve their contact surface with the matrix, and their indents can be fibrillated (the ends split during mixing). The mechanical properties of concrete mixtures are also affected by the fiber form6.In comparison to the fiber with the smallest size, scientists found that increasing the quantity of the fiber increased compressive, tensile, and flexural strengths by 10, 14, and 58%, respectively. Furthermore, based on the findings of7 conducted similar experiments on fiber-reinforced concrete and discovered that when cellulose fiber (CTF) was used at dosages of 1.5 kg/m3, the concrete's Uniaxial Compressive Strength (UCS) increased to 12%; however, when polyvinyl alcohol fiber (PF) was used at dosages of approximately 4.0 kg/m3, the concrete’s UCS was reduced by 35%. When the dosage was increased to 2.0 kg/m3, CTF's splitting tensile strength declined by 23%, while PF's decreased by 55%. The splitting tensile strength of the polyolefin fibers also degraded. Additionally, the use of fiber reinforcement in concrete imposes specific mix composition constraints; therefore, it may be necessary to make changes8. The number, form, and slenderness of fibers affect the workability of concrete11. It’s a promising field of use, particularly in metropolitan locations where there are adverse environmental conditions, damage caused by environmental conditions, abrasion of surfaces, and vandalism. However, HPPM fibers are more commonly used in architectural applications. Specifically, HPPM fibers are particularly successful in reducing plastic shrinkage fractures soon after concrete is made, and they considerably improve its post-cracking behavior.Xu et al.12 have presented an innovative method for integrating single-use face masks in the production of concrete. The method examined the impact of adding PPE on enhancing the mechanical characteristics of concrete by using cement and other aggregates that are frequently found in Australia, together with water reducer, and using rare lower amounts of PPE .Kilmartin-Lynch et al.13 used the recommended dosage of 1 mask per 1 L of concrete. According to their findings, adding processed masks improved compressive strength (by about 5%) and tensile strength (by about 3%).Koniorczyk et al.14 added surgical wear masks (WM) to mortars in amounts up to 5% of the cement weight. The characterization of the mechanical and microstructural aspects has been done in their work. The findings show that adding MW to cement precludes a deterioration in the material's qualities, including strength and durability behavior.Castellote et al.Researchers have identified a number of benefits of employing HPPM in concrete mixtures, but few studies have been conducted on enhancing the durability and engineering qualities of concrete for use in buildings. Owing to the strong effect of HPPM on concrete behavior, multiple laboratory samples containing various percentages of HPPM were made in this study by utilizing the standard mix of concrete for architectural fabrication.The primary goal of this study was to explore whether single-use facemasks can be recycled and reused to reduce the amount of pandemic-related garbage that ends up in landfills or litters the streets during this crisis. We studied the influence of HPPM fibers on the physical and mechanical properties of concrete and how HPPM fibers might be employed in a potential sector of application, such as public spaces. This is an interdisciplinary study that involves both engineering and architecture. This revolutionary technique provides understanding of this topic by integrating various areas of knowledge and is noteworthy because no previous study has been published on the use of HPPM fibers in public settings.2/kg. The Bogue phases of the cement, according to the manufacturer, were 59% C3S, 12.1% C2S, 10.6% C3A, and 10.4% C4AF. The oxides found in the cement are listed in Table Type I ordinary Portland cement from Najran cement (OPC) was used in this study. The specific gravity of the cement was 3.15, and it had a Blaine fineness of 410 mTo cast the concrete samples that met ASTM C33/C33M-18, the fine aggregate was gathered from natural sand with a maximum size of 4.75 mm, and the coarse aggregate was natural crushed stone with a maximum size of 20 mm. The physical parameters of the aggregates are presented in Table Concrete mixtures and curing were performed using potable tap water. The ASTM C1602/C1602M criterion was satisfied for the properties of water.15. Since the polypropylene stripes have the same properties so the different proportions of these HPPMs will not affect the results. Polypropylene fibers were mixed into concrete at a rate of 2.5% of the total volume.The polypropylene stripes (HPPM) used in this study are commercially available, such as polypropylene stripes from surgical masks, protective suits, and overhead and foot covers, as indicated in Fig. 16. Najran cement with a specific gravity of 3.15 and a bulk density of 1250–1650 kg/m3 was utilized throughout the experiments, as well as coarse aggregates with a nominal size of 20 mm and fine aggregates with a specific gravity of 2.63, which were oven-dried for 48 h at 110 °C to remove excess moisture. Table The samples mixed with cut-up HPPM were analyzed using six concrete combinations in proportions of 0% (control mix), 0.5%, 1%, 1.5%, 2%, and 2.5% by volume of concrete (three samples for each mix). This choice is in line with prior studies byTable In a reference mixer, the concrete samples were prepared according to ASTM C192M with a water/cement ratio of 0.50. No additional materials or chemical admixtures were used in this study. HPPM fibers were employed in the proportions of 0.5, 1, 1.5, 2.0, and 2.5% as an extra percentage. The concrete was mixed and placed into various molds  for 24 h before being demolded and cured in clean drinkable tap water. The concrete samples were cured for 28 d at room temperature from 21 to 24 °C .All dry materials were weighed and then mixed in a concrete mixer for 3 min to mix. After 3 min of mixing with water, the dry materials were gently added and combined for another 3 min. After detachment from the mixer, concrete was poured into cylindrical molds. To avoid concrete adhesion, the inner surfaces of the assembled molds were thinly coated with mold oil. To allow the concrete to settle, cylindrical molds were filled with concrete and placed on a vibrating table for 20 s. The molds were filled with concrete after the first 20 s and then vibrated for another 20 s to ensure the absence of voids. The new concrete surface was finished by using a smooth steel trowel. The specimens were taken from the molds after 24 h and immediately submerged in clean fresh water for 28 d for the strength test. The procedure was performed for each concrete batch. Previous research 20 respectively. The compressive strength test was performed on 100 × 100 × 100 mm3 cube specimens (The results corrected to 15 * 15 cubes according to ASTM C39/C39M-2118), while the split test was performed on samples that were 100 mm in diameter and a height of 200 mm and had a flexural strength of 100 mm diameter, 200 mm height, prism specimens. The cube specimens were weighed in water immediately after they were removed from the water basin in the saturated surface dry state and in the dry state to determine the sample densities. The compression testing apparatus had a force of 2000 kg per square meter. Three samples from each mix configuration were inspected for defects before they were subjected to a force of 157 kN/min. To assess the homogeneity and structural integrity of the manufactured HPPM concrete, non-distractive pulse velocity (PV) testing was performed on compression samples in accordance with21. This test can be used to assess the consistency and uniformity of the concrete samples and to assess the cracks and voids that are not visible on the surface. To evaluate the effective porosity, two to three representative specimens  from a sample were immersed in water in a desiccator (e). A vacuum pressure of > 800 Pa (required by22) was maintained within the desiccator for at least 2 h to saturate the specimens. The dry (Mdry) and saturated (Msat) masses of a specimen and a saturated specimen suspended in water (Msus) were calculated. To calculate the effective porosity (e) and dry density (dry), the following equations were used:sat: saturated mass, Mdry: dry mass, MSSD: saturated surface dry mass.The compressive, split tensile, and flexural strength tests were conducted using18.After 28 d of curing, the concrete samples were removed from the curing tank and allowed to dry. The tops of the cylindrical samples were ground back after air-drying to produce a smooth contact surface with the compression and testing gear, as per ASTM C31/C31M-21. The loading rate was 0.34 MPa/s23. A 150-mm cube specimen was used for the permeability test. Before we measured the permeability, the specimen was cured for 28 d. Figure A Hitachi U8040 scanning electron microscope was used for the scanning electron microscopy (SEM) study. The liquid permeabilities of the hardened specimens were determined according toHPPM stripes (polypropylene) have been utilized in concrete as crack-resistant improvement materials. The HPPM was constructed from plastic polypropylene fibers according to the manufacturer’s instructions. It also exhibits high chemical stability and strength. By volume, the fiber content ranged from 0.5 to 2.5%. HPPMs were chopped into small pieces that were 1 cm in length and 1 cm in width. The physical parameters of single-use HPPM are listed in Table Figure 2, calcite Ca(CO)3, and silicon dioxide (SiO2) are the primary peaks. The Ca(CO)3 and Ca(OH)2 levels did not change appreciably when HPPM fibers were added. Similarly, when the fibers were added, they were observed at 650 intensity. This phenomenon demonstrates that the fibers are incapable of participating in chemical processes. Furthermore, the presence of amorphous materials is indicated by the convex form between 2 theta between 16° and 36°.The specimens were studied using XRD to determine the influence of adding HPPM fibers to the concrete mixtures on the phase changes. Figure 29, increasing the amount of HPPM resulted in lower slump values. The volume, form, and slenderness of the fibers, as well as the mix composition, influence the workability of concrete11. When the fiber dose exceeds this critical amount, the likelihood of fiber clamping or balling increases, resulting in an uneven fiber distribution and a greater reduction in flowability27.Figure 2, but the 2% addition of shredded HPPM by volume produced the best results. For the control mix study, UCS increased steadily between 1 and 1.5 % before falling marginally at 2.5 %. In comparison to the control sample, volume increments of 0.5, 1, 1.5, and 2% resulted in sample increases of 8.82, 11.05, 13.68, and 9.40 %, respectively .The UCS values of the samples are shown in Figure 32. The addition of HPPM to the mixtures considerably modified the failure mode of concrete from brittle to ductile, as shown in Fig. When the fiber dosage was increased from 0 to 3%, the UCS increased by 6%21. The test was performed by crossing the two faces of the specimen with two probes of the instrument. The PV test is a nondestructive method for determining the consistency and efficiency of concrete. Concrete cracks and pores are also referred to as PV33. Non-destructive testing is a good way to assess the quality of concrete. The effects of the PV test are shown in Fig. 35, concrete with a PV result of more than 4500 m/s is considered outstanding with a high-quality rating. The quality of the concrete decreased once again at the 2.5% volume mark compared to the control specimen in the experiment; regardless, the quality of the concrete improved in all mix designs, signifying beneficial features. According to36, good-quality concrete has no substantial voids or cracks in the ranges mentioned; consequently, as shown by the research of37, the usage of shredded facemasks reduced the number of microcracks in the concrete, thereby enhancing the overall quality of the concrete. The absence of voids or cracks can jeopardize the structural integrity of concrete within the above-mentioned limits. Owing to an increase in void content and thus porosity with increased fiber, PV values tend to drop beyond a fiber composition of 2.5%. According to BIS, the ultrasonic pulse velocity (UPV) values ranged between 3.8 and 4.04 km/s, indicating that the concrete quality is good38. The HPPM was added to the equation, which increased the UPV values up to a particular volume fraction. However, as expected, the increased HPPM stripe content resulted in lower UPV values. This decrease in the change in velocity is thought to be due to the existence of voids and microcracks in the concrete specimens, which reduce the homogeneity at higher fiber volume fractions. For specimens containing HPPM at any %, UPV values ranging from 4200 to 4600 m/s were discovered, and they were regarded as good quality concrete.At 28 d, an ultrasonic test was performed on water-saturated cubic concrete specimens of 150 mm to assess the number of internal pores in the specimens. This non-destructive test uses reflected waves that radiate between probes to assess the permeability of a specimen, according to2 value of 0.872 for all samples, indicating a high level of confidence in the association.The UPV values are related to their matching cube compressive strength. The relationship between the UCS and UPV values of concrete mixtures that include HPPM fibers is strong, as shown in Fig. 39. The minimum S for 2% HPPM is 2.55(106) m/s, whereas the maximum value for 2.5% HPPM is 3.46 m/s. Furthermore, all HPPM concretes had a lower S than the control mix, despite the fact that the high value for 2.5% HPPM was similar to a mix with considerable porosity. This result demonstrates the considerable reduction in the capillary n and inner conductivity of the pores when HPPM fibers are used, and it confirms all of the other durability findings in this study.The sorptivity (S) results are shown in Fig. The FS of UCS and PV follows a similar pattern, with an increase up to 2% of HPPM fiber content and then a reduction as the number of fibers increases. The results shown in this graph Fig.  indicateThe fibers intersecting the cracks in the tension zone of the specimens caused an increase in the FS. The HPPM fibers flex to hold the crack face separation, offering a larger energy absorption capacity and stress relaxing the micro-cracked area adjacent to the crack tip Fig. a,b. This40. The addition of just 1% micro PPF increased the number of blows till failure by nearly thrice41. The number of blows at first crack was assessed to be 76, 35, 546, 654, 987, and 698 percent for 0 percent, 0.5%, 1%, 1.5%, 2%, and 2.5% of HPPM, respectively, when HPPM was added to concrete mixtures. Furthermore, with 0%, 0.5%, 1%, 1.5%, 2%, and 2.5% of HPPM, the number of strikes required to destroy the sample increased 3.0, 3.3, and 4.8 times, respectively  for ordinary concrete to 355 (367.105%), 546 (618.421%), 654 (760.526%) 987(1198.68%), and 689 (818.421%) for concrete with HPPM fibers equal to 0%, 0.5%, 1%, 1.5%, 2%, and 2.5%, respectively, for concrete with HPPM fibers equal to mix control  could be attributed to an increase in “n” as the HPPM fiber content increased. In fact, the 2% decrease in water depth is most likely attributable to pore blockage and decreased capillary porosity. This result supports the results of other durability tests presented in this study. Figure 3 found that adding PPF to concrete increased both water and gas permeability. Hager et al.56 reported a similar finding. Many studies, on the other hand, have discovered that fibers have a favorable effect on permeability. According to57, the addition of PPF to concrete reduces the duration of water permeability. Similarly, samples with fibers demonstrated poorer permeability than samples without fibers58. Studies have also shown that permeability declines as the volume of fibers increases up to a certain point, then increases, and sometimes exceeds that of plain concrete59. This is usually due to a lack of workability and an excessive amount of fibers in the mixture.In addition, the effect of HPPM fibers on permeability is not well understood. The presence of HPPM fibers in concrete reduces the likelihood of the concrete breaking by limiting crack formation. Fibers also cause the pore structures in hardened concrete to become more separated, resulting in a lower capillary porosity and concrete water penetration.The microstructure of the HPPM fibers with 0.5, 1, 1.5, 2, and 2.5% volume fractions were examined using SEM to evaluate the bond characteristics of the mixture. Figure 60. Traditional reinforcement and, to a lesser extent, the use of a suitable amount of particular fibers will assist in overcoming tension weakness61. The microstructure of HPPM concrete with a 2% volume fraction of HPPM was investigated using SEM to assess the bond characteristics of HPPM in the mixture. The microstructures at 0.5, 1, and 1.5% of the HPPM surface and hydrated cement matrix after the fracture of the concrete specimen are shown in Fig. Another disadvantage of concrete is that it breaks almost immediately after it is poured and before it is fully set. These fissures are a key source of concrete weakness, especially in large-scale worksite applications, causing fracture and failure, as well as a general lack of resilience30, who discovered that adding polypropylene to concrete substantially increased its flexural strength.The HPPM and cement matrix had a strong interfacial connection, as shown in Fig. At 2% HPPM fiber, the highest compressive strength values were attained. The highest UCS increases measured at 1.5% and 2% HPPM were 13.6% and 9.40%, respectively. Therefore, it is reasonable to conclude that stripes have a significant effect on the compressive strength. According to these findings, the HPPM stripes have a considerable effect on the UCS values compared to those of the control concrete. The high fineness and variable length of fibers in staple HPPM stripes form a network that works as a bridge, preventing the microfracture from spreading further. When the HPPM stripe level was higher (2.5%), however, the fiber stripes were dispersed unevenly in the concrete owing to poor workability and mixing. As a result, these fiber masses collected to generate weaker locations Fig. f.After the flexure test, the fibers operated as a bridging element, effectively transferring the load from the matrix to the HPPM fibers, allowing them to take on the additional load, and resulting in an increase in the UCS and FS compared to those of the control concrete. The size and shape of the polypropylene fibers affected the increase in the flexural strength of the concrete. Additionally, as a result of the lower effective w/c ratio, the splitting tensile and FS values were relatively high, with 17.8, 24, 27.5, 33.4, and 1.6% increases in FS at 0.5, 1, 1.5, 2, and 2.5% HPPM, respectively, compared to those of control samples. In a scattered striped cement matrix, the stress concentrations are not uniform along the length of the fiber.62. Importantly, cracks are not detrimental to construction or serviceability if they do not exceed a particular size. When concrete transitions from a plastic to a solid state and the Young’s modulus of the concrete exceeds the Young’s modulus of the fibers, micro HPPMs are no longer considered to play a significant role. Furthermore, in a prior study63, the cracking area in concrete with 0.5% PPF was reduced by 99%. PPF prevents cracks from forming not only against plastic shrinkage but also against drying shrinkage63.The combination of HPPM stripes and fibers is a factor that improves the FS. The HPPM stripes flexed to keep the fracture face apart, offering a larger energy absorption capacity while relaxing the microcracked area adjacent to the crack tip. However, a higher fiber content (2.5% HPPM) resulted in a reduction in FS Fig. f. This cHowever, as shown in Fig. 64 investigated the effect of the fracture width on concrete permeability in an experimental setting. Shin et al.65 studied the influence of concrete permeability on fracture type, crack width, and water head. Yang et al.66 used X-ray CT to monitor the water transport parameters of cracked concrete and indicated that fracture morphology and tortuosity should be studied in future research.Some researchers have recently emphasized the effect of fissures on concrete permeability5. Of note, cracks are not detrimental to construction or serviceability if they do not exceed a particular size. When concrete transitions from a plastic to a solid state and the Young’s modulus of the concrete exceeds the Young's modulus of the fibers, micro HPPMs no longer play a significant role. In this study, concrete samples with no fibers had a breaking area of 1743 mm2 in the study67, whereas those containing 0.5 and 1.0% PPF had cracking areas of 992 and 99 mm2, respectively. According to this study, the presence of HPPM increases the drying shrinkage resistance of concrete.The main role of HPPM in concrete construction is shown in Fig. The addition of macro HPPM fibers can change the fracture shape based on the aforementioned physical and mechanical data. This behavior can be attributed to the macro polypropylene fibers, which are scattered stochastically in the matrix, preventing the matrix fracture from propagating without stretching and debonding the fibers, resulting in a deviated crack-extension route. When comparing HPPM fiber specimens to control concrete samples, specimens with a fiber dosage of 2.5% showed the most significant increase in crack morphology.37. Because they restricted the motions of the micro-level in concrete by bridging and stitching fine fractures, the PPF in concrete decreases the drying shrinkage and early cracking5. The effect of HPPM on matrix fracture behavior can be divided into two categories. First, the addition of HPPM fibers reduces the maximum stress as well as the elastic modulus of the mixtures. Second, after the grain-bridging crack face breaks, the stress can be transferred via cracks through the intersection of the fibers and cracks. Crack-bridging activity results in increased ductility in HPPM-fiber-reinforced concrete . As previously stated, the primary application of fiber-reinforced concrete is in the construction of structural elements. The prospect of employing such concrete to build architectural shapes is rarely considered. Public spaces are one of the fields of application in architecture. Public open spaces are one of the most important aspects of city life74, and their attractiveness affects how people view the city. Furthermore, as a result, cities are viewed as pleasant and inviting to people. HPPM stripes can be used to produce architectural shapes in public spaces, such as decorative pavements in scientific centers, shopping centers, restrooms, promenades, zoos and gardens, bus stations, parking areas, ferry terminals, feck rocks, beach areas, landscapes, door surrounds, and skate parks. Finally, characteristics of the materials utilized in these spaces should be considered.In today's construction business, the issues of susceptibility and environmentally friendly materials are hotly debated2O2) for high-throughput decontamination of PPE, either alone or in combination with ozone.To help with supply constraints caused by the COVID-19 pandemic, the FDA in the United States has approved hydrogen peroxide in vapour 2 was altered appreciably. This demonstrates that the fibers are incapable of participating in chemical reactions. The presence of fibers causes a considerable change in the cracking pattern of the concrete. While unreinforced concrete forms wide and long cracks, the inclusion of fibers reduces the crack width opening, cracked area, and crack propagation through the bridging activity of the fibers. Crack networks become less connected as a result of adding the fibers.XRD showed that after introducing PP fibers, neither Ca(CO)Water absorption in hardened concrete is reduced when HPPM stripes and fibers were added separately in low-volume fractions to the concrete mixture. Furthermore, the use of HPPM fibers in small volume fractions reduced the porosity of the concrete specimens. Among all the concrete specimens, the concrete containing 2% HPPM fibers had the lowest water absorption and porosity percentage. Regardless of the volume concentration of HPPM, all concrete mixes were subject to the same high standard of excellent quality and structural strength.Microfractures propagate along concrete with HPPM, according to a concrete microstructure study. As demonstrated in SEM images, HPPM fibers (2%) play a significant role in fracture bridging. However, when the volume percentage of the fibers is higher (2.5% of HPPM), voids form and grow between the cement paste and the fiber, reducing the concrete's strength qualities. As a result, HPPM can be utilized to make sustainable concrete and produce a clean, environmentally friendly building material. In addition, the HPPM fibers employed in this study were classified as short or discontinuous, which could lead to increased UCS, FS, and abrasion resistance.In sustainable concrete, various percentages of iron waste  were employed. The slump, compressive strength, flexural strength, abrasion resistance, impact resistance, sorptivity, spalling test, water absorption, porosity, water penetration, permeability, and UPV were investigated. The following conclusions were drawn based on the results of these experiments.


Extrusion at 70 °C prevented thermal degradation. A stabilizing molecular interaction between enalapril maleate and Eudragit® E PO was identified via FT-IR spectroscopy. Dissolution studies were carried out to study the influence of the formulation on the dissolution behavior of enalapril maleate. These promising results can be transferred to other thermo-sensitive and peptidomimetic drugs to produce extrudates which can be used, for instance, as feedstock material for the production of patient-specific dosage forms via Fused Deposition Modeling (FDM) 3D printing.The aim of this research was the production of extrudates for the treatment of hypertension and heart failure and the investigation of the degradation of the peptidomimetic drug enalapril maleate (EM) during hot-melt extrusion (HME). A fast HPLC method was developed to quantify enalapril maleate and possible degradation products. Screening experiments revealed that the diketopiperazine derivative (Impurity D) was the main degradation product. Hot-melt extrusion of enalapril maleate with the polymer Soluplus The peptidomimetic drug enalapril maleate is an angiotensin-converting enzyme inhibitor (ACEI), which is one of the active ingredients on the World Health Organization (WHO) model list of essential medicines and is used, in particular, for heart failure and hypertension in both adults and children ,2. EnalaDue to the instability of peptidomimetic drugs in an aqueous solution, hot-melt extrusion (HME) can be a preferred method for the preparation of solid dispersions because of the lack of solvents ,8,9,10.® VA 64 , Soluplus®  and Eudragit E® PO  as carriers to improve the drug-polymer miscibility and decrease the process temperature 28]. The Consequently, extrusion must take place below the melting temperature of enalapril maleate, since melting was accompanied by decomposition.Obtained extrudates from screening experiments differed in their properties. Formulation F1 with the polymer K 12 PF could be extruded between 120 °C and 130 °C. While extrudates at 120 °C exhibited a rough surface, likely due to the glass transition temperature (Tg) of K 12 PF at 90 °C being close to the extrusion temperature ,30, extrFormulation F2 with the polymers HPMC and bPMMA were extruded at 130 °C because the polymer HPMC has a higher Tg of 115 °C compared to the polymer bPMMA with a lower Tg of 57 °C ,32,33. EFormulation F3 with the polymers K 12 PF and K VA 64 could be extruded at a temperature of 140 °C as the lowest extrusion temperature. The reason for this is the higher glass transition temperature of the polymer K VA 64 with a Tg of 101 °C ,30. ExtrExtrudates from formulations F1 and F3, which contained either K 12 PF alone or a combination of K 12 PF and K VA 64 appeared milky-white and sticky. The extrudates of both formulations were smooth, but brittle despite a high plasticizer content.Formulation F4 with the polymer HPMC could be extruded at a temperature of 140 °C, which is considered a suitable process temperature for HPMC in literature and can be explained by the higher proportion of this polymer in the formulation ,37,38,39Formulation F5 and F6, unlike the previous formulations, were extruded at a feed rate of 100 g/h.Compared to 50 g/h, 100g/h was used to investigate the influence of the feed rate on the degradation of enalapril maleate. Formulation F5 was extruded at a temperature above the melting point of enalapril maleate at 150 °C , whereasDue to their low glass transition temperatures, bPMMA Tg = 57 °C) and SOL (Tg = 70 °C) in formulations F5 and F6 were identified as suitable formulations for extrusion at lower temperatures ,41. The  °C and SThe results of the content uniformity showed that in all formulations, besides the active ingredient enalapril maleate, the diketopiperazine derivative  occurred as the main thermal degradation product in the extrudates . FormulaFrom the extrusion of these four formulations, which were all fed at a feed rate of 50 g/h, it could be observed that not only the temperature but also the used polymers have an influence on enalapril maleate degradation. The formulations F2 and F4, which both contained the polymer HPMC showed, due to a higher melt viscosity, a higher pressure at the die during extrusion ,42. ThisThe process temperature and also the applied shear forces had a great impact on enalapril maleate degradation. A higher feed rate could shorten the residence time, and thus, reduce the amount of degradation. Process conditions and formulations were optimized since degradation of enalapril maleate already takes place below the melting temperature contrary to DSC and TG measurements. The optimized formulations F5 and F6 containing the polymers bPMMA and SOL were extruded again at reduced temperatures and with a higher feed rate of 100 g/h into the extruder.For formulation F5 with bPMMA extruded at 100 °C, it was observed that the content of enalapril remained constant over the extrusion and was 98.44 ± 0.30% versus 2.83 ± 0.09% Imp-D in the middle of the run a. For foThe lowest possible extrusion temperature for F6 was 100 °C, whereas F5 could be extruded at 70 °C. The content of enalapril was 101.72 ± 1.65% and no degradation products were found . The difFT-IR spectroscopy was used to investigate interactions between enalapril maleate and the polymers. The structures of the basic polymer bPMMA and the neutral polymer SOL are shown in −1 (C=O of the carboxylic group), 1645 cm−1 (C=O of the tertiary amide), 1578 cm−1  and 1225 cm−1 (C-C-O of acetate and ester) [−1 and 2770 cm−1. FT-IR spectrum of bPMMA showed further characteristic peaks for the ester groups at 1144 cm−1, 1238 cm−1 and 1267 cm−1 and the C = O ester vibration at 1724 cm−1 [−1 (C-H), 2857 cm−1 (C-H), 1740 cm−1 (C=O of the carboxylic group) and 1633 cm−1 (C=O of the amide group) [−1 (C-H), 1240 cm−1 (O-H), 1093 cm−1 (C-O) and 1059 cm−1 (C-O) [The FT-IR spectrum of enalapril maleate showed characteristic bands at 1749 cmd ester) ,44. Char724 cm−1 ,45. FT-Ie group) ,47. FT-I−1 (C-O) .For the filament of F6 containing the polymer SOL no interaction could be observed as peak shifts or loss of disappearance of peaks. b, wherea−1 and 1578 cm−1, and also, for dimethylamino groups of the bPMMA at 2822 cm−1 and 2770 cm−1 indicates a cation-anion interaction between the carboxylic groups of enalapril maleate and the dimethylamino groups of bPMMA  monograph for enalapril maleate tablets specifies that at least 80% enalapril has to be released after 30 min in the paddle apparatus (USP II method) in phosphate buffer pH 6.8 at a rotational speed of 50 rpm . HoweverIn the basket apparatus formulation F6 with SOL released 25.81 ± 0.53% enalapril after 30 min and 91.74 ± 4.72% after 150 min a. After Formulation F5 with bPMMA extruded at 70 °C released 17.39 ± 0.57% after 30 min and 100% after 180 min in phosphate buffer pH 6.8 (100.19 ± 2.47%). However, when released in 0.1 N hydrochloric acid, 99.87 ± 1.56% enalapril was released after 30 min b.As expected, the formulation composition has a decisive influence on the release of the active ingredient. Since bPMMA is a pH-dependent polymer that dissolves at a pH below 5.5, the release of enalapril from the bPMMA extrudates is prolonged at higher pH compared to the extrudates with the polymer SOL. However, a fast drug release from the extrudates with bPMMA in 0.1 N hydrochloric acid could be observed. Thus, the criterion of Q = 80% after 30 min could be fulfilled. Depending on the intended target profile, a suitable formulation has to be identified.The obtained results showed that the peptidomimetic drug enalapril maleate could degrade during the hot-melt extrusion process at temperatures above 120 °C, more than 30 °C below the degradation temperature identified via thermo analysis. The main thermal degradation product formed during this process was the cyclization product enalapril diketopiperazine (Imp-D). Extrusion with bPMMA and SOL at 100 °C revealed a higher drug content in the formulation containing bPMMA. FT-IR data hints towards a cation-anion interaction with the basic bPMMA and enalapril maleate, which might have a stabilizing effect. Further formulation development and optimization of the process conditions during hot-melt extrusion could completely avoid the degradation of the drug enalapril maleate.Our study demonstrates that by selecting suitable polymers and extrusion conditions, thermo-sensitive drugs can be hot-melt extruded and the formation of degradation products can be avoided. The question to what extent other even more thermo-sensitive compounds, such as proteins and peptides, can also be stabilized by melt extrusion remains to be clarified in the future. Furthermore, it should be noted that the formulation, in particular the polymers used, can have a decisive influence on the properties of the extrudate, such as the physical properties, the content as well as the release of the active ingredient. This work highlights the importance for formulation scientists to first know the properties of the active ingredient in order to select suitable polymers for melt extrusion.


Beam–column joints are extremely vulnerable to lateral and vertical loads in reinforced concrete (RC) structures. This insufficiency in joint performance can lead to the failure of the whole structure in the event of unforeseen seismic and wind loads. This experimental work was conducted to study the behaviour of ternary blend geopolymer concrete (TGPC) beam-column joints with the addition of hybrid fibres, viz., steel and polypropylene fibres, under reverse cyclic loads. Nine RC beam-column joints were prepared and tested under reverse cyclic loading to recreate the conditions during an earthquake. M55 grade TGPC was designed and used in this present study. The primary parameters studied in this experimental investigation were the volume fractions of steel fibres (0.5% and 1.0%) and polypropylene fibres, viz., 0.1 to 0.25%, with an increment of 0.05%. In this study, the properties of hybrid fibre-reinforced ternary blend geopolymer concrete (HTGPC) beam-column joints, such as their ductility, energy absorption capacity, initial crack load and peak load carrying capacity, were investigated. The test results imply that the hybridisation of fibres effectively enhances the joint performance of TGPC. Also, an effort was made to compare the shear strength of HTGPC beam-column connections with existing equations from the literature. As the available models did not match the actual test results, a method was performed to obtain the shear strength of HTGPC beam-column connections. The developed equation was found to compare convincingly with the experimental test results. Reinforced concrete (RC) constructions are becoming more popular as a result of recent earthquakes in different parts of the world. In RC multi-storey frames subjected to unstable wind and seismic loads, beam-column joints are the most critical sites in the structure. During earthquakes, shear failure is the most typical kind of brittle failure and is undesirable. These joints need to be constructed to handle shear pressures accompanied by substantial deformations in order to avoid the rapid collapse of the entire structure. The joint shear strength of the structure can be improved by using transverse reinforcement. As a result of transverse shear reinforcement in the connections, placing and compacting the concrete becomes difficult . Hence, To minimise transverse reinforcement congestion at beam-column connections, FRC (fibre-reinforced concrete) is an excellent and practical solution ,3,4,5. TIn order to achieve a level of performance that is superior to that of FRC, hybrid fibre, a relatively new innovation, involves the mixing two or more kinds of fibres in concrete ,20,21,22Numerous researchers have examined the consequences of fibre hybridisation on the structural behaviour of different concretes such as conventional cement concrete (CC), high-performance concrete (HPC), lightweight concrete (LWC), high strength concrete (HSC), self-compacting concrete (SCC) and geopolymer concrete (GPC) ,32,33,34Inorganic geopolymer is one of the more promising materials in the context of efforts to replace conventional cement in concrete in order to minimise the carbon footprint associated with its production . StudiesRaj and Ramachandran  studied GPC produced with blended source materials exhibits increased and high early strength. Vijayasarathy et al.  presenteThe source materials used in this experiment included low calcium class F fly ash, GGBS and metakaolin (MK). Fly ash from Mettur Thermal Power Station in Tamil Nadu (India), which met IS 3812:2003 , was useFly ash was substituted with GGBS compliant with BS 6699:1992  collecteFor the ternary blend binder material, metakaolin (MK) was employed as the third precursor to the source material. MK has an average particle size of 2–3 microns and a cream-coloured appearance. It mostly contains silica and alumina at the percentages of 56.64 and 42.38, respectively, and has a specific gravity of 2.56. The complete morphological and chemical composition data of the source materials were presented in the previous studies conducted by the authors ,57. The Fine aggregate (M-Sand) with a maximum particle size of 4.75 mm according to Zone II of IS 383:1970 (reaffirmed 2002)  was util2SiO3) containing 28 percent SiO2, 8 percent Na2O and 64 percent H2O was used to activate the alumino-silicate binder. Sodium hydroxide (NaOH) pellets of 99 percent purity were added along with Na2SiO3 to prepare the alkaline activator.Sodium silicate solution  30 mm long crimped steel fibres (SF) with a diameter of 0.45 mm and (ii) 12 mm long polypropylene fibres (PF) with a diameter of 40 microns. The polypropylene and steel fibres had a tensile strength of 600 MPa and 800 MPa, respectively. For the M55 grade TGPC, Rangan’s standards  were folAs part of this experiment, nine external beam-column joints with cross-sectional dimensions of 150 × 200 mm were cast and examined. The beam was 800 mm long, and the height of the column was 1000 m. The column and beam were reinforced with four 10-mm HYSD bars each. The column and beam stirrups, which were both 6 mm in diameter, were also made of HYSD bars. The reinforcing bars utilised in the project have the following mechanical characteristics, which are shown in The beam-column joints were cast using a horizontal tilting drum concrete mixer, whereby the powder components were initially mixed with M-sand and coarse aggregates. To make the alkaine liquid, the sodium silicate solution was combined with 14 M sodium hydroxide solution 24 h before casting . After 2The experimental test was performed in a steel loading frame with a capacity of 300 kN. The frame consists of a pair of channel sections placed face-to-face as a horizontal member and two pairs of channel sections placed back-to-back as vertical members. The lateral stability of the loading frame is provided by two additional channel sections on either side of the vertical members for support. The column portion of the specimen was placed between the horizontal member of the loading frame and a steel I-beam that was firmly fixed to the test floor by proper bolt connections. The top of the column was a hinge supported by a steel ball that was inserted into the semi-circular grooves of two steel plates, and the lower end of the column was simply supported. A hydraulic jack was placed in the centre of the steel plates. Using the hydraulic jack, the column was loaded with an initial compressive axial force of 20% of the load-carrying capacity in order to keep the joint stable . Figure To apply a reverse cyclic load to the joint, a 50 kN hydraulic jack connected to a load cell was used, as shown in The specimens were whitewashed, making it possible to observe the crack patterns more clearly, and loaded in the positive direction up to a particular level. They were then unloaded to the same level of magnitude in the opposite direction and finally reloaded to the initial position to achieve one complete cycle of reverse cycling loading . The magThe load-deflection curves for the specimens investigated are shown in The procedure adopted for calculating the moment-curvature relationship was previously explained by the authors elsewhere . The momA structure’s load-deflection envelope curve illustrates how much energy it can withstand. The capacity of a material to deform past its initial yield deformation while still carrying a load is known as its ductility . If the The hysteresis loop obtained from the load-displacement characteristics was used to obtain the energy dissipation capacity. The area enclosed by this hysteresis loop is expressed as the energy dissipation capacity. The difference between the energy received and released during loading and unloading determines the energy dissipation capability in each loading cycle . A strucRepetitive or cyclic stress on an RCC beam-column junction reduces the rigidity of the joint. The secant stiffness is used to calculate the stiffness deterioration at the joints, and this may be used to compute the stiffness degradation . The secThe HTGPC beam-column joints’ shear strength was predicted using the available models in the literature. The specifications of the various models are shown below:The following equation for the nominal joint shear strength of beam-column joints was certified by ACI-ASCE committee 352 .(1)Vn=γThe following equation was developed by the Architectural Institute of Japan  to deterλ = a capacity reduction factor of 0.78;2.Based on the studies carried out by Bakir , an equaN = the axial compressive load of the column, in N;D = the effective depth of the beam, in mm;d′ = the effective cover to compressive reinforcement, in mm.Based on the concept that even after cracking, the composite still retains considerable tension until fibres are pulled from the matrix, a model was constructed to predict ultimate shear strength . The equAfter a series of investigations, Tsonos  came up This Equation was developed based on the basis of the hypothesis that the strength of the core concrete is directly proportional to the strength of the strut and truss mechanisms, respectively.Comparison of analytical models with the experimental results:The shear strength of the joints was calculated for the TGPC and HTGPC specimens using the above equations, and a comparison of the experimental results is provided in Regression analysis was used in the model developed by Jiuru et al.  to accouThe values of As the experimental shear strength should be equal to the corrected shear strength, It is shown in The first crack load, ultimate strength, ductility, stiffness degradation and energy dissipation capacity were improved with the incorporation of hybrid fibres in TGPC. This shows that the fibres in a hybrid form can be effectively used in TGPC.The first crack loads of HTGPC joints with a constant volume of steel fibres of 1% and a varied volume fraction of fibres of 0.10%, 0.15%, 0.20% and 0.25% are 33%, 68%, 53% and 36%, respectively, making them higher than that of TGPC joints without fibres.The energy absorption capacity and the ductility of the HTGPC6 were improved by 3.3 times and 2.73 times, respectively, compared to TGPC without fibres.The cumulative energy dissipation and the stiffness degradation of the HTGPC6 were improved by a maximum of 3.7 and 1.6 times, respectively, when compared to the TGPC specimen.HTGPC with 1.0% steel and 0.15% polypropylene fibres demonstrated the maximum deflection at the ultimate load and performed better than the other combinations considered in this study. The deterioration in the performance with the further addition of fibres resulted from poor workability and a balling effect at higher volume fractions.Hybrid fibres can reduce steel reinforcement congestion in HTGPC beam-column junctions and ease construction difficulties, resulting in cost-effective construction.HTGPC beam-column joints with a maximum content of 1% steel and 0.25% polypropylene fibres may be predicted using the proposed equation. HTGPC structures will benefit from the findings of this investigation’s tests.HTGPC can be used as the superior alternative for conventional cement concrete structures which are required to withstand unforeseen situations such as seismic and wind loads.This experimental investigation leads to the following conclusions:


Ternary Portland cement usage with a high amount of cement constituents different from clinker can afford great climate change advantages by lowering the Portland cement clinker content in the final product. This will contribute to cutting greenhouse gas emissions to close to zero by 2050. Such ternary Portland cements can be composed of different amounts of ground granulated blast-furnace slag (GBFS), coal fly ash (CFA), and clinker (K). Cements made with GGBFS, or CFA boast pozzolanic characteristics. Therefore, they would improve both the concrete compressive strength at later ages and durability. The 28- and 90-days mechanical strength test, non-steady state chloride migration test, described in NT BUILD 492, and natural chloride diffusion test (NT BUILD 443) were performed in concrete. Ternary cements made with GBFS and/or CFA presented better chloride diffusion resistance than concrete made with plain Portland cements. Furthermore, the development of compressive strength was delayed. The service life study was developed for concretes made with ternary cements with regard to the chloride penetration case. The rapid growth of populations and cities has led to significantly increasing demand for Portland cement. This phenomenon is particularly harmful as it can increase the risk of more severe climate change impacts. Currently, Portland cement production accounts for approximately 7.4% of the anthropogenic emissions of carbon dioxide across the world (2016: 2.9 Gtons of carbon dioxide emissions) [Accordingly, a reduction in carbon dioxide emissions within the cement manufacturing sector can be achieved by lowering the amount of clinker in blended cements . Some inIn addition, mechanical strength improvement was found in some ternary systems made with FA and GGBFS ,5.Compressive strength development is particularly enhanced with very fine granulated blast-furnace slag and coal fly ash . In contGlobal production of ground granulated blast-furnace slag is expected to reach 280 million tons in 2025, with China’s production to total around 153 million tons ,10. The The widespread application of coal fly ash (FA) and ground granulated blast-furnace slag (GGBFS) ternary Portland cements in building and civil engineering would have significant positive impacts on the environment, as the cement sector is a major emitter of greenhouse gases . AccordiThe methods commonly used to determine the chloride diffusion coefficient are defined by the standards ASTM C 1556 ,14, AASHBlast-furnace slag (ground granulated) and coal fly ash have been widely employed as constituents in common Portland cements since they enhance some properties of concrete by chemical and physical  effects, principally as a function of the effectiveness of the amount and particle size distribution (PSD) . FurtherSome studies have reported the influence of coal fly ash addition on the chloride-resistance of Portland cement-based materials. In general, concrete made with Portland-fly ash cement or pozzolanic cement made with coal fly ash offer a higher resistance to chloride ingress than concretes made with CEM I .The coal fly ash pozzolanic reaction directly affects the content of hydration products, which positively influences and determines the chloride resistance characteristics. Therefore, parameters influencing the pozzolanic reaction, such as water/cement ratio, replacement level of coal fly ash and type of coal fly ash, will play a key role ,22. NeveGround granulated blast-furnace slag has been utilized for many years as a Portland cement constituent to improve the mechanical and durability characteristics of concrete . ConcretThis paper carried out non-steady state chloride migration test, described in NT BUILD 492, and a natural chloride diffusion test (NT BUILD 443) on the concrete samples with ternary cements, whose measurements were used to estimate the service life, which contributes in a major way to promoting the usage of industrial wastes as Portland cement constituents. One of the milestones of the novelty and relevance of this study is the determination, for the first time, of the chloride migration and diffusion coefficients of some new ternary cements covered by the European standard EN 197-5:2021 .Furthermore, the challenge will be to move from traditional concrete uses to more widespread applications. Accordingly, experimentally determined results of chloride ingress coefficients determined from chloride migration tests are presented and discussed. Results from chloride diffusion tests carried out in accordance with standard NT BUILD 443, and results from non-steady-state chloride migration tests conducted in accordance with standard NT BUILD 492, are also compared.Traditionally, the relevance for safety of concrete structures has been strong, and its mechanical strength will be sufficiently guaranteed by a high safety factor. In contrast, the influence of the reinforced concrete structure degradation has not been considered systematically. Currently, architects and civil engineers are attempting to estimate the whole service life of reinforced concrete structures. This will certainly be hampered by many shortcomings, particularly as the exposure classes are usually not even well-defined and will likely change during the operational period of the reinforced concrete structures. The chloride-induced corrosion of steel reinforcement embedded in reinforced concrete structures is undoubtedly one of the most significant durability concerns . For allIn the operational phase of reinforced concrete structures, the most appropriate means of maintenance and replacement is planned. It is at this point that the information about the degradation effect on the service life must be as accurate as possible. A reinforced concrete structure is built for use for a certain length of a time, for at least 50 years. In addition, it is broadly acknowledged that about 80% of operation, maintenance and repair costs of a building are set in the 20% cost of the design process , i.e., m2) amounts were 3.84% and 35.96%, respectively. Free lime contents in the coal fly ash and Portland cement were 0.5% and 1.31%, respectively.Common ternary cements were made by mixing a CEM I 42.5 R—EN 197-1 , coal si3, Al2O3, Fe2O3, CaO, SiO2, MgO, Na2O, K2O, insoluble residue (IR), loss on ignition (LOI), and Cl− contents have been determined by the analytical methods described in EN 196-2 [The SOEN 196-2 . This st2/g) and coal fly ash (3772 cm2/g). Their densities were 2.4 g/cm3 and 3.12 g/cm3, respectively. The granulated blast-furnace slag was ground until the desired degree of fineness is reached, 3489 cm2/g for SA and 4630 cm2/g for SB.Fineness was determined according to EN 196-6  for the Portland cements manufactured for this research were made up by uniting all the cement constituents, i.e., CEM I 42.5 R, siliceous fly ash (FA) and GGBFS in the proportions provided in Two concrete qualities  have beeCylindrical specimens (∅15 × 30 cm) were made of concrete according to EN 12390-2:2019 . They weThe test to determine the chloride diffusion coefficient was carried out according to the method described in the NT BUILD 443 standard . Four cyx, was measured. The initial chloride content, C0, was determined at a proper depth below the exposed area to the chloride ions solution. The effective chloride transport coefficient, De, and the boundary condition of the chloride profile at the exposed surface, Cs, were calculated. The non-stationary diffusion coefficient, Dns, was determined according to the standard NT BUILD 443 [x, and depth below the exposed surface, x.All the samples were soaked in limewater and then stored in a container. All faces of the concrete except the one to be exposed to the chloride solution were then dried at room temperature until constant weight was achieved. Later, the top of the concrete specimen was exposed to distilled water containing sodium chloride (30 ± 1 g/L NaCl–165 ± 1 g/L NaCl). This solution was replaced every 5 weeks with a new pure one. After specified exposure times of 3, 6, 9 and 12 months, thin layers were ground off parallel to the exposed surface of the concrete specimen and the chloride content of such layers, CIn order to calculate the non-steady-state chloride migration coefficient of concrete the rapid chloride migration (RCM) test was performed according to NT BUILD 492.First, cylindrical concrete specimens with Ø100 × 100 ± 1 mm (diameter × height) were cast and a Ø50 ± 1 mm thick slice was cut from the central part of the cylinder as the test sample. Then, the concrete specimens were kept in a desiccator and vacuumed at 1 kPa/min, thereby providing stable vacuum throughout concrete. They were kept in the desiccator for 4 h, and then, a saturated calcium hydroxide solution was added to ensure that all the specimens were immersed. After 1 h, air was entered in the desiccator to recover the atmospheric pressure. Twenty-four hours later, the concrete specimens were clamped, and the entire assembly was put into a test container. The end area was the one to be exposed to the saline solution containing chlorides . The anolyte contains a 0.3 N NaOH solution (about 12 g/L NaOH). Chloride ion transport was accelerated by the application of an electrical field. Concrete samples were located between the anode and cathode. In this arrangement, the cell consists of cathodes and anodes connected to each other and to the external 60 V DC voltage supply (i < 5 mA) at 25 °C b. The inAfter testing, the concrete specimen was axially split, and a 0.1 M silver nitrate solution was sprayed on the freshly split surface. The chloride ingress depth was measured from the formation of silver chloride, which accounts for the appearance of the white salt precipitation. Afterwards, this value of penetration depth is used to calculate the chloride migration coefficient from the non-steady state chloride migration test.In the ASTM C 1202  and NT BMechanical strength of concretes A and B was assessed by compression strength testing at 28- and 90-days, which is the capacity of the concrete to withstand loads tending to reduce size . This pack) for C30/37 concrete grade is 30 MPa, while for C45/55 concrete grade it is 45 MPa. Accordingly, Concrete A is categorized as grade C30/37 and Concrete B as grade C45/55. Ground granulated blast-furnace slag fineness has an effect more noticeable for concrete B than for concrete A .According to the European standard EN 206 , the minWith finer ground granulated blast-furnace slag, the compressive strength of concrete A is generally improved. Ternary cements SA25VA25 and SB25VA25, in both A and B concretes, improved the mechanical performance at 28 and 90 days in relation to the reference concrete made only with CEM I. This fact suggests a synergic effect of the FA and GGBFS .2 = 0.97). Equation (1) shows the mentioned relationship. In contrast, concrete B showed no correlation (R2 = 0.65).The relationship between the 28-days and 90-days compressive strength is shown in Concrete B gains greater strengths with time and is denser than concrete A. However, the development of compressive strength of concrete B is more heterogenous and, consequently, achieving a good correlation between results obtained at 28 and 90 days is more difficult.app), which is the value obtained in a non-steady-state test such as the 90-day ponding test, where chloride binding is occurring simultaneously with the diffusion process. In contrast, the effective diffusion coefficient (Deff) is attained when the chloride diffusion test is carried out under steady-state conditions in concrete previously saturated with chloride ions; accordingly, no chloride binding takes place during diffusion. Therefore, Dapp is normally greater than Deff since the chloride penetration front progresses throughout the concrete retarded by the binding. From the results recorded in the non-steady state chloride diffusion test defined in NT BUILD 443 [eff) for investigated concrete specimens is determined and summarized in One experimental testing method has been used to determine the chloride diffusion coefficient based on Fick’s second law, which is concerned with concentration gradient changes with time. First, it is quite convenient to distinguish between the apparent chloride diffusion coefficient , a wider range was measured in concretes A (4.98 × 10−12 m2/s–7.64 × 10−12 m2/s).As expected, concrete A was inferior to concrete B in resisting chloride diffusion, i.e., they have chloride diffusion coefficients of 17.3 × 10ncrete B . While sThe performance of ternary cements added to concrete B in resisting chloride diffusion improves with the increase of ground granulated blast-furnace slag. This fact is more evident in concrete A.No effect of GGBFS fineness on chloride diffusion coefficient was detected in cements with a high ground granulated blast-furnace slag content (40%). In contrast, with lesser amounts of ground granulated blast-furnace slag (25%), the natural chloride diffusion coefficient is lower for the concrete with the cement containing the coarser ground granulated blast-furnace slag (SB), but it is slightly higher for concrete B. This is probably due to the more efficient and effective synergic effect between the coal fly ash and the coarse ground granulated blast-furnace slag.3, they found a chloride diffusion coefficient with the immersion test of 35.50 × 10−12 m2/s, and a chloride migration coefficient of 40.25 × 10−12 m2/s [3), we have determined lower values of chloride diffusion coefficient (17.3 × 10−12 m2/s) and chloride migration coefficient (2.97 × 10−12 m2/s). Frederiksen et al. found chloride migration coefficients higher than the chloride diffusion ones . In cont3 concrete) for the immersion test (16.15 × 10−12 m2/s) and migration test (18.55 × 10−12 m2/s) [3), we have also determined lower values of the chloride diffusion coefficient (8.99 × 10−12 m2/s) and chloride migration coefficient (2.86 × 10−12 m2/s). In any event, it should be noted that the chloride diffusion coefficients of concretes A and B are in the same range as the ones found in the literature. Lower values of 3.10 × 10−12 m2/s [−12 m2/s [3 and 400 kg/m3, respectively.Conversely, they found lower coefficients with denser concretes (water/cement = 0.50 and 327 kg cement/m12 m2/s) . For con−12 m2/s  and 3.13−12 m2/s  have beeThe protective properties of concrete with steel reinforcement depend on the type used in the concrete mix design and it may be evaluated with a chloride diffusion coefficient obtained by using the NT BUILD 443 standard. This experimental procedure refers to the reinforced concrete exposed to saline solutions containing chlorides that are present mainly in deicing salt agents and seawater. Such adverse environments are complex systems, whereby some electrostatic interactions of chloride ions with other ions, such as calcium, sodium, potassium, among others, occur in the concrete pore solution. In most cases, electrostatic interactions are generally combined with other interactions, i.e., chloride ions can be adsorbed on the surface of the hydrated cement constituents and react with some aluminum-containing phases present in the cement. Nevertheless, Fick’s second law can be utilized to model the chloride ion flow through the concrete regardless of the combined physical, chemical, and electrostatic processes involved in the chloride ion ingress. For instance, following the method defined by the NT BUILD 443 standard. The major disadvantage of this method is the length of the test. In contrast, an electric field can be applied to speed up the flow of chloride ions and measure the charge passing through the concrete or calculate the migration coefficient.3 solution to be sprayed on the fracture surface to measure the chloride penetration depth (nssm).Once the rapid chloride migration (RCM) experimental test (which is defined in the NT BUILD 492 standard) has been terminated, the concrete specimens were axially split up into two halves in such a way as to allow the 0.1 M AgNOon depth . Such a nssm) for A and B concrete specimens are given in Non-steady-state migration coefficients .The lowest chloride migration coefficient of 0.53 × 10−12 m2/s and 0.53 × 10−12 m2/s, respectively, which indicates that their resistance to chloride diffusion is very good. This could be attributed to the synergic effect of both cement constituents working together (GGBFS and FA). Similar results (remarkably high resistance to chloride ingress) have been reported with ternary cements composed of 10% of silica fume and 20% of coal fly ash [The concrete mixes with 40% GGBFS (Type A) and 25% FA exhibited improved resistance to chloride ingress since the chloride diffusion and chloride migration coefficients were 2.89 × 10 fly ash .An important influence of the ground granulated blast-furnace slag on the compressive strength and chloride penetration resistance has been reported by Duży et al. . This ca3, respectively. Ground granulated blast-furnace slag replacement levels were 0–70% for the various blends considered. The effective chloride diffusion coefficient ranged from 7.01 × 10−12 to 14.20 × 10−12 m2/s without ground granulated blast-furnace slag. With the incorporation of 50% and 70% ground granulated blast-furnace slag, the effective chloride diffusion coefficient is reduced by more than seven times as the slag content increases. For concretes without Supplementary Cementitious Materials (SCM), a water/cement ratio of 0.55 and cement content of 320 kg/m3, they found an effective chloride diffusion coefficient (NT BUILD 492) of 14.20 × 10−12 m2/s [3), the effective chloride diffusion coefficient was 2.86 × 10−12 m2/s. The presence of 10% of coal fly ash in the cement results in an effective chloride diffusion coefficient of 9.14 × 10−12 m2/s. Furthermore, the incorporation of 50% or 70% results in effective chloride diffusion coefficients of 1.30 × 10−12 m2/s and 0.77 × 10−12 m2/s, respectively. Nevertheless, the coefficient determined in the cement with 10% coal fly ash and 70% ground granulated blast-furnace slag is higher (1.73 × 10−12 m2/s) than the one found in the cement with only 70% ground granulated blast-furnace slag (0.77 × 10−12 m2/s). Accordingly, the combined effect of cements containing ground granulated blast-furnace slag and coal fly ash in the cement is unclear. Similar conclusions have been reached in the present study. Furthermore, it has been reported that chloride migration coefficients determined at 28 and 182 days (NT BUILD 492) in concretes made of CEM III/B 42.5 N (66–70% slag), with water/cement ratio ranging from 0.40 to 0.55 and cement content from 320 to 400 kg/m3 ranged from 0.37 to 6.64 [McNally and Sheils  tested c−12 m2/s . For con to 6.64 .eff and Dnssm [In general, the addition of pozzolanic cementing materials such as ground granulated blast-furnace slag and coal fly ash reduced the diffusion of chloride into concrete, as shown by a decrease recorded in the values of Dnd Dnssm .There was an important discrepancy between the results of the diffusion and migration coefficient, which was between 3 and 8 times lower for the migration coefficient than the diffusion one. It can be assumed that even the same concrete type has very disparate values of chloride penetration resistance when dissimilar testing procedures are utilized.In this paper, the efficiency of the rapid chloride migration (RCM) test, performed in accordance with the test procedure specified in NT BUILD 492, in assessing the chloride penetration resistance of concrete made with ternary cements is presented. Overall, the rapid chloride migration (RCM) test is a reasonable indicator of the chloride ingress resistance of ternary concretes, having been able to distinguish concrete produced with different types of ternary cements. Nevertheless, this test may only be used by materials engineers to compare protective properties, related to the chloride penetration resistance, of tested concretes. Thus, it cannot be used to estimate the service life of reinforced concretes. This test procedure should not be used to determine the period of time after which the chloride ion content achieves the threshold level on the steel reinforcement surface of the reinforced concrete, since the chloride ion penetration throughout the concrete is described by a mechanism of ion flow controlled by diffusion.nssm), determined according to the NT BUILD 492 standard, characterizes the chloride ion penetration into concrete specimens when exposed to an electric field. However, this procedure does not provide the period of time after which the corrosion threshold of chloride ion concentration for corrosion initiation was reached at the surface of the embedded steel bar. Furthermore, the method described in the NT BUILD 492 standard may also be useful to compare the protective properties of concrete. Nevertheless, sometimes chloride ions migration through the concrete could be correlated with the chloride ion diffusion performance for the same concrete mix design. A reasonable correlation between the chloride diffusion from non-steady-state diffusion tests (Dnssm) and the effective chloride diffusion (Deff) has been reported by some authors [ authors ,48,49,50 authors  and NT B authors .In contrast, a lack of connection between natural chloride diffusion and chloride migration was also reported ,52 when Commonly, the definition of the concrete requirements related with the durability of the reinforced concrete structures was by prescription of the 28-day compressive strength test and by the concrete composition (minimum cement content and maximum water/cement ratio) and, only in some cases, limits for some concrete characteristics were established, such as the chloride diffusion coefficient among others.x,t. Numerous publications in connection with the critical chloride content can be found in the literature, whereby a set of values ranging from 0.05% to 8% are given. Most of these values are between 0.1% and 1%. The critical chloride content can be defined as the chloride content required for passivation of the steel or the chloride content associated with acceptable deterioration of the reinforced concrete structure. The critical chloride content normally is expressed as total chloride ion content relative to the weight of the Portland cement, i.e., Cs, of 0.6% to conduct the present study. A large number of critical chloride content or chloride threshold values can be found in the published literature. Most of them are based on Portland cement. In contrast, recent studies on other types of cements have often provided conflicting results. For instance, lower chloride threshold values for ground granulated blast-furnace slag containing concrete in comparison with CEM I concrete have been reported in some studies , whereasSince the objective of this study is to evaluate the achievement of GGBFS-FA cements regarding their chloride penetration, the chloride diffusion coefficient of ternary cement concretes was utilized to assess their potential for improvement. Consequently, the minimum cover of concrete, which is required to prevent corrosion induced by chlorides, was taken as reference figure.Finally, these results will be useful to material and civil engineers in designing reinforced concrete made with ternary cements. In any case, the service life of a building depends mainly on its chief structural materials and the environment in which it is placed.The following conclusions can be drawn based on the experimental data and analysis of the diffusion and migration coefficients conducted in the present study.No relationship between diffusion and migration coefficients was found since the tested concretes belong to different “concrete families”, i.e., each ternary cement originates a peculiar concrete type.As expected, the supplementary cementing materials (25% FA and 25% or 40% GGBFS) in the cement improved the chloride resistance of concrete, which was evidenced by very low diffusion and migration coefficients (2–5 times less than that in CEM I concrete). Furthermore, the performance of 40% ground granulated blast-furnace slag cement concrete (SB40VA25) is better than that of 25% GGBFS and 25% FA (SB25VA25) cement concretes.−12 m2/s (concrete B), while the highest chloride migration coefficient was measured in SB25VA25 ternary cement concrete made with 25% GGBFS and 25% FA which is 1.27 × 10−12 m2/s. Accordingly, the highest chloride migration coefficient value doubles the value of the lowest chloride migration coefficient for the ternary cement concretes. The resistance to chloride ingress in the concrete of specimens SB40VA25 and SB25VA25 is high and moderate, respectively, as per the NT BUILD 492 classification.The lowest chloride migration coefficient was measured in the concrete prepared with SB40VA25 which is 0.59 × 10The diffusion coefficient determined as laid down in the international standard NT BUILD 443 adequately describes the diffusion process of chloride ions through the tested concrete. Therefore, the chloride diffusion coefficient determined with this method can be used for service life estimations. Similar values for the diffusion coefficient were found in concretes made with ternary cements SA40VA25 and SB40VA25.All the above results could be taken into account by concrete designers to build reinforced concrete structures made of concrete containing ternary cements made with ground granulated blast-furnace slag (GGBFS) and coal fly ash (FA).


Geopolymer is widely used as a supplement to cementitious composites because of its advantages of low carbon and environmental protection, and geopolymer concrete is also broadly used in practical engineering. In recent years, geopolymer concrete has attracted increasing interest owing to its superior mechanical properties, and a series of research results have been obtained. In this paper, from the preparation of geopolymer concrete, based on the characteristics that geopolymer concrete is brittle and easy to crack, the types and basic properties of fibers to enhance the toughness of concrete are analyzed, the advantages and disadvantages of different fibers used as a material to enhance the toughness of concrete are summarized, and we review the effects of type, shape, volume rate, aspect ratio, and hybrid fiber combinations on the static mechanical properties. The results indicate that fibers have significant potential to enhance the compressive strength, splitting tensile strength, flexural strength, and fracture toughness of geopolymer concrete, and the optimal fiber volume rate seems to be related to the fiber type. Whereas the effect of aspect ratio and hybrid fiber combinations on the properties of geopolymer concrete seems to be obvious. This paper reviews the influence of fiber on the basic mechanical properties of geopolymer concrete, which provides a solid foundation to promote the further development and application of the research on the toughness of fiber-reinforced geopolymer concrete and provides recommendations for future research. With good mechanical properties, traditional concrete materials are regarded as irreplaceable construction materials. Ordinary Portland cement serves as the main raw material for the preparation of concrete; however, a large number of greenhouse gases and harmful emissions are generated in the entire production process of cement generates , includiThe use of geopolymer concrete can reduce carbon dioxide emissions and energy consumption in cement production and utilization in the construction industry ,11. With2 emissions of ordinary Portland cement and geopolymer is shown in 2 emissions and energy consumption of geopolymers are much lower than ordinary Portland cement.The research shows that the carbon dioxide emission of geopolymer concrete manufacturing is far lower than that of ordinary Portland cement concrete because the raw materials of geopolymer concrete do not need high-temperature calcination ,16. In aCompared with ordinary Portland cement concrete, geopolymer concrete not only has favorable environmental friendliness but also has high early strength, high durability, and low shrinkage ,20,21. HIn recent years, the effect of various types of fibers on the mechanical properties of geopolymer concrete has been the subject of many studies ,28,29. FAlthough several review articles have been published in the research area of geopolymer composites, they are focused on presenting research works regarding the development history, engineering applications, and durability of geopolymer concrete. The research on fiber-reinforced geopolymer concrete and improving its performance must be supplemented. Therefore, based on the research on the mechanical properties of geopolymer concrete in recent years, this paper reviews the preparation process of geopolymer concrete, analyzes the types and basic properties of fibers to improve the toughness of concrete, and puts forward the advantages and disadvantages of different fibers used as materials to enhance the toughness of concrete. By collecting experimental data from the published literature, a database of basic mechanical properties of fiber-reinforced geopolymer concrete with a relatively large sample size is established, and the effect of type, shape, volume rate, aspect ratio, and hybrid effect of fiber on the basic mechanical properties of geopolymer concrete is discussed. The purpose of this paper is to integrate the current research on fiber-reinforced geopolymer concrete and provide ideas for the green and sustainable development of geopolymer concrete in the future.2SiO3) and the combination of potassium hydroxide (KOH) and potassium silicate (K2SiO3) [“Geopolymer”, first named by Davidovits in the late 1970s, is a green material synthesized from a variety of aluminosilicate materials rich in aluminum and silicon . The alu(K2SiO3) . The pre(K2SiO3) ,40.The comparison of chemical composition between the geopolymer used currently and ordinary Portland cement is shown in It can be seen from Generally speaking, the types of fibers used to improve the performance of geopolymer concrete can be divided into two categories, including artificial fiber and natural fiber . ArtificSteel fiber is mainly made of cold-drawn steel wire, steel plate, or other forms of steel, and its cross-sectional shape is mainly round, square, and rectangular ,54. SteeImprove the ductility, toughness, and flexural strength of cementitious materials;Absorb energy, play the role of bridge connection between cracks, transfer loads;Reduce shrinkage, creep, and permeability of concrete;Improve the fatigue resistance and impact resistance of concrete.The addition of steel fiber has been proven to help control the formation and development of cracks and can make geopolymer concrete, a brittle material, obtain higher crack resistance, and the benefits of using steel fiber to modify the properties of geopolymer concrete are mainly manifested in the following aspects ,52:Impro3.In addition, the physical properties of steel fiber also affect the overall mechanical properties of steel fiber-reinforced geopolymer concrete. At present, the main characteristics of steel fibers used more in geopolymer concrete research are shown in Inorganic fiber is a type of chemical fiber made from minerals. The main varieties are basalt fiber, glass fiber, and carbon fiber. Typical inorganic fibers and the types of polymer are shown in Basalt fiber is composed of basalt gravel, which is environmentally friendly and has good mechanical properties . Basalt Basalt fiber is also often used in the manufacture of basalt fiber-reinforced polymer (BFRP) bars . With th3 and 1.82 g/cm3, the tensile strength of carbon fiber can reach 4558 MPa, and the elastic modulus of carbon fiber can reach about 230 GPa. Many studies have proved that the addition of carbon fiber into concrete can not only significantly improve its toughness, split tensile strength, and flexural strength [Carbon fiber is a type of lightweight and high-strength inorganic fiber material, which is mainly composed of carbon atoms . Over thstrength  but alsostrength ,72.Carbon fiber is also often used in the manufacture of carbon fiber-reinforced polymer (CFRP) . A typicGlass fiber is an inorganic non-metallic material with excellent performance. Its advantages are good insulation, strong heat resistance, good corrosion resistance, and high mechanical strength, but its disadvantages are brittleness and poor wear resistance . The glaThe research showed that glass fiber can eliminate microcracks in geopolymer concrete . TherefoGlass fiber is also often used in the production of glass fiber-reinforced polymer (GFRP). The typical picture of GFRP used in the project is shown in Synthetic fiber is mainly made of macromolecular compounds. In 1965, a researcher first proposed to apply synthetic fiber to cementitious composites . In rece3 and 1.30 g/cm3. Compared with steel fibers and inorganic fibers, the tensile strength and elastic modulus of synthetic fibers are lower. However, with the development of society, the processing technology of synthetic fibers is improving, the varieties of synthetic fibers are gradually increasing, the mechanical properties of synthetic fibers are also further optimized, and the development prospects of synthetic fibers will be better and better. The use of synthetic fibers to improve the properties of concrete can obtain higher economic benefits and better mechanical properties.The properties of synthetic fibers have a great difference, especially in terms of tensile strength and modulus of elasticity, and the mechanical properties of several typical synthetic fibers are shown in Natural fibers mainly come from three main sources: plant, animal, and mineral . Plant fPlant fiber is a biological resource, which is mainly composed of cellulose, pectin, and lignin . DiffereThe mechanical properties of plant fibers also depend on the physical characteristics of the fibers, such as diameter and length. The tensile strengths of plant fibers decrease with the increase in fiber length because longer fibers may have more defects and therefore may fail prematurely compared to shorter fibers. The basic mechanical properties of typical natural fibers are listed in The mechanical properties of plant fibers are lower compared with those of conventional fibers;In an alkaline environment, plant fibers precipitate some carbohydrates, such as cellulose, hemicellulose, and lignin, which will inhibit the strength development of the gelling material;The high water absorption and variability of plant fibers lead to poor adhesion of geopolymer-based gelling materials;Plant fibers are easily degraded in alkaline matrices, which affects the long-term performance of the composites.However, plant fibers also have the following limitations :The mechBy combing the experimental data of the mechanical properties of fiber-reinforced geopolymer concrete in the published literature, the effects of fiber types on the compressive strength, splitting tensile strength, and flexural strength of geopolymer concrete are counted in Based on the experimental data in Based on the experimental data in Based on the experimental data in Based on the experimental data in Based on the experimental data in In the case of hybrid fiber-reinforced geopolymer concrete, for the replacement type, Based on the experimental data in It can be seen from Based on the experimental data in Based on the experimental data in Based on the experimental data in Based on the experimental data in Based on the experimental data in Based on the experimental data in Based on the experimental data in Based on the experimental data in Based on the experimental data in From the perspective of engineering safety, the ideal damage mode of the structure should be accompanied by toughness damage with large deformation and high energy consumption. Geopolymer concrete has the disadvantage of being brittle and prone to cracking in use. Fibers, as a reinforcing material, have a more significant role in improving the brittleness and increasing the toughness of geopolymer concrete. In order to further understand the effect of fiber volume rate on the fracture toughness of geopolymer concrete, this paper analyzes the relative fracture toughness and relative fracture energy to eliminate the influence of different calculation methods. Based on the existing experimental research, the trend of the relative fracture toughness and relative fracture energy of geopolymer concrete with the fiber volume rate is shown in According to the analysis of According to In addition, Ghasemzadeh et al.  studied The above research showed that the addition of fibers can effectively enhance the fracture performance of geopolymer concrete. The main reason is that the bridging, pull-out, and fracture of fibers consumed more energy during the fracture process of fiber-reinforced geopolymer concrete. However, when the fiber volume rate exceeds a certain range, the formation of fiber clusters leads to the formation of internal defects in the geopolymer concrete, reducing the energy consumption to the extent that the fracture performance of some specimens decreases.As a new type of composite material with the advantages of high strength, low carbon, and environmental protection, geopolymer concrete has been widely used in the repair and reinforcement of concrete structures in recent years. In order to overcome the disadvantages of geopolymer concrete, such as brittleness and susceptibility to cracking, research on fiber-reinforced geopolymer concrete has received extensive attention in recent years. Considering the space in the existing literature, this paper presents an extensive review of the basic mechanical properties and fracture toughness of fiber-reinforced geopolymer concrete, using a systematic review approach. The following conclusions are obtained.2 emission, and setting time.Nowadays, the most used sources of silicate materials are mainly fly ash, silica fume, metakaolin, ground blast furnace slag, and slag, among which fly ash is mainly used. Under the same circumstances, geopolymer concrete performs better than ordinary Portland cement concrete in compressive strength, tensile strength, durability, fire resistance, COMany studies have shown that the addition of fiber-reinforced materials has a positive effect on the compressive strength of geopolymer concrete, but some researchers have come to the opposite conclusion. The main reason for this phenomenon is that the influence of fiber on the compressive strength of geopolymer concrete is less than that of the water-binder ratio, age, curing environment, and aggregate type.The splitting tensile strength and flexural strength of geopolymer concrete are closely related to the type, shape, volume rate, and aspect ratio of fiber. PFs has a good effect on the splitting tensile strength and flexural strength of geopolymer concrete. The performance of hooked-end SFs is better under the same volume rate. In general, the fiber volume rate and aspect ratio that have the best effect on improving the splitting tensile strength and flexural strength of geopolymer concrete also depends on the type of fiber.The combination of SFs and PPFs can improve the mechanical properties of geopolymer concrete. The compressive strength, splitting tensile strength, and flexural strength of geopolymer concrete show an increasing trend with the increase in steel fiber content.The effect of fibers on the fracture toughness of geopolymer concrete is obvious. Within a certain range, the fracture toughness of geopolymer concrete increases with the increase in fiber volume rate; when the fiber volume rate exceeds a certain range, the fracture toughness of geopolymer concrete decreases with the increase in fiber volume rate.In this paper, based on the experimental data in the published literature, a basic mechanical properties test database of fiber-reinforced geopolymer concrete with a relatively large sample size is established. The database can be used to study the basic mechanical properties of geopolymers, and the results obtained can be used as a basis for further research on structural properties, numerical simulation, and fracture mechanics of geopolymer concrete.This paper only analyzes the macroscopic mechanical properties of fiber-reinforced geopolymer concrete. A more comprehensive study on the microstructure of fiber-reinforced geopolymer concrete can be further conducted, and the relationship between macroscopic properties and the microstructure of fiber-reinforced geopolymer concrete can be established.Fiber-reinforced geopolymer concrete has evolved from a new material to a successful and widely applied material due to its mechanical properties and advantages over conventional concrete, but the higher production cost of fiber-reinforced geopolymer concrete has limited its usage in the public works sector. Compared to normal concrete, the addition of fibers raises the production cost of fiber-reinforced geopolymer concrete. Thus, finding sustainable, environmentally friendly, and cost-reducing methods is one of the directions for further applications of fiber-reinforced geopolymer concrete.