Steel Fiber Reinforced Self-Compacting Concrete: A Comprehensive Review

The slump flow test detects the flowability of SCC. When there are no impediments, the deformability of SCC horizontal free flow (slump flow) is assessed. The procedure is quite similar to the procedure for determining concrete's slump. The distinction is that slump flow is measured as the diameter of the spread concrete in two perpendicular directions as opposed to the height loss. Concrete has a greater capacity to fill formworks when the slump flow is higher. The period needed for the concrete to expand to a diameter of 500 mm during a slump flow test reflects the concrete's viscosity and stability. Greater fluidity or a lesser workability loss is indicated by a shorter time (Gencel et al., 2011). The slump T500 test without aggregate segregation along the borders of the spread-out takes place in the range of 2.2–3.5 s and slump flow widths of 600–700 mm. Consequently, it may be said that all concrete mixes fall within the limit of SCC as predicted, adding fibers decreases SCC slump flow, increasing the probability of obstruction. In general, adding fibers reduced the SCC viscosity because fibers prevent clumps from freely moving (Madandoust et al., 2015). Figs. 2 and 3 show slump flow and slump T500 of SCC with the addition of SF, respectively.

SF with hooked ends that were 30 mm long was utilized by Liao et al. to create SCC with a 600 mm slump flow (Liao et al., 2006). All SCCs show positive findings between 550 and 800 mm, which is a sign of good deformability. To prevent segregation, all mixtures, in other words, required sufficient deformability under their own weight and a reasonable viscosity (Gencel et al., 2011). According to the study, the slump flow diminishes with increasing fiber concentration, notably over 0.75% SF. The slump flow for the concrete blend with 1.25% fiber dropped under the minimum requirement of 600 mm. So, to improve workability, the water–cement ratio and powder content was both slightly raised (Iqbal et al., 2015b). According to Dieb et al., using the greatest SF dose resulted in a decreased slump flow of roughly 12%. (0.52%). A change in admixture dose is necessary if the slump value must be unchanged  (El-Dieb, 2009). The droop flow diminishes as the fiber rises, particularly at 0.75% SF. The slump flow for the concrete blend with 1.25% fiber dropped under the minimum threshold of 600 mm (Iqbal et al., 2015b). A study demonstrates that adding 0.25% hooked end SF to SCC decreased the slump flow by 50 mm; however, adding 0.5% of these fibers resulted in a much greater slump flow reduction of 220 mm (Torrijos et al., 2008).

According to the study, no segregation of aggregates was seen in any of the mixes towards the edge of the spread-out concrete, and the slump flow diameter of the mixes ranged from 560 to 700 mm (Sahmaran & Yaman, 2007). According to (Rambo et al., 2014), the slump flow diameters with 0.5 and 1% addition of SF in SCC were 625–750 mm and 620–720 mm, respectively. Each value fell within the boundaries set by EFNARC (EFNARC, 2002). In contrast, the research found that the flow velocity of SCC dropped with the addition of SF (0.5–2% by volume), and as a result, it cannot be deemed an acceptable combination for divinely reinforced portions since passing through it was impenetrable (Gencel et al., 2011).

Additionally, T500 values raised as coarse particles' maximum size increased. Greater energy loss occurs during the movement of concrete containing bigger aggregate particles, especially when there are more fibers present (Madandoust et al., 2015). The largest increase in slump flow time (T500) was reached when silica fume concentration was increased from 7 to 14% in reinforced self-compacting mixes with a fiber content of 0.75%. This was the result of substituting cement with silica fume (about 25%). Therefore, the use of silica fume and SF further prolonged the slump flow time (T500). The sample containing 0.75% fiber and 14% silica fume had the highest T500 rise when compared to the control combination (Mastali & Dalvand, 2016). The amount of fiber content in the concrete mix cause to decrease in the flow, which occurs when fibers with hooked ends force concrete particles to jam during flow. Workability was shown to diminish as the amount of SF increased (Siddique & Kaur, 2016).

SCC capacity for the filling was assessed using V-funnel testing. The amount of time it took to flow SCC through the device during the test was recorded for flowability. The EFNARC (2002) standard specifies that test time values should fall between 6 and 12 s to get satisfactory characteristics in freshly poured SCC. In accordance with the advice of EFNARC (2002), an L box exam was administered to gauge their aptitude for passing. This test is used to assess the concrete's filling capacity's obstruction. The EFNARC standard requires the filling ability, which is calculated as the ratio of the height of the concrete in H₂ at one end to H₁ at the outlet of the L box (H₁/H₂). This ratio (H₁/H₂) should be in the range of 0.8–1.0, to show the slope of the concrete while at rest (EFNARC, 2002). Figs. 4 and 5 show the V funnel and L box ratio of SCC with the addition of SF, respectively.

Higher SF inclusion in the mix results in a deterioration in the SCC mixes workability. This indicates that the amount of SF utilized in the concrete mix has an inverse link to how well the SCC mixes function (Ghorbani et al., 2020). The time needed to empty the V funnel increased due to increased friction between fibers and aggregates as well as friction between fibers themselves. With the addition and percentage of fiber content in the mixes, V funnel and flow time values increase (Gencel et al., 2011).

A study concluded that for mixes with 0, 0.25, 0.75, and 1.0% fibers, correspondingly, the V-funnel value increased with fiber addition, and the V-funnel times were in the range of 8–13 s. The initial time was quite short, which was attributed to the concrete's greater paste volume and lack of fiber content. However, the impact of fibers on aggregates, which creates obstruction and, therefore, exhibits poorer filling capacity, is what is responsible for the trend of increased V-funnel times (longer v-funnel time). Therefore, increasing the number of SF by 0.25%, 0.5%, 0.75%, and 1.0% causes the V-funnel flow time to increase by 11%, 38%, 50%, and 63%, respectively (Saba et al., 2021). According to research, adding more SF to SCC mixtures causes the friction between the SF and aggregates to increase. As a result, it takes longer to discharge the V funnel (Ghorbani et al., 2020). The sample of SF at 0.9% showed the greatest decrease in slump flow diameter and greatest increases in T50 and V-funnel time in SCC. In certain ways, fibers improved the concrete's surface hardness, which subsequently reduced when fiber volume was raised. The concrete's uniformity was excellent in all mixtures, although somewhat diminished as the proportion of fiber increased, (Sanjeev & Nitesh, 2020). Fly ash, according to a study, aids in the equal distribution of fibers during blending. Fly ash granules that are roughly spherical have sliding impacts on fresh concrete, reducing friction force and improving flow and compaction (Gencel et al., 2011).

According to the investigation, adding silica fume to self-compacting mixes at a rate of between 7 and 14% results in the greatest possible increase in V-funnel time (about 25%). Furthermore, silica fume and recycled SF added together resulted in the largest increase in V-funnel time with a rise of around 85% for specimens containing 0.75% fiber and 14% silica fume in comparison to the control mixture (Mastali & Dalvand, 2016). As fiber content is added to the mixtures, the blocking ratio decreases. All mixtures that meet the SCC blocking ratio approval threshold (less than 0.8), except mixtures with 1% fiber content (Saba et al., 2021). This reduced blocking ratio could be caused by friction and intermeshing that occur along with the inclusion of SF (Borhan et al., 2020). These results imply that finer materials would fulfill the ERNARC (EFNARC, 2002) recommended flowability standards at a greater replacement rate. Table 1 shows the summary of fresh properties of SCC with the addition of SF.

Fig. 6 and Table 2 show the compressive strength (CS) of SCC with the addition of SF. Most researchers noted that SF does not improve the CS of SCC. A decrease in the workability of the concrete may be the cause of a loss of strength. Increasing the amount of SF causes the workability of concrete to decline, which in turn causes the compaction levels of vibrated concrete to decrease (Mohammadi et al., 2008). When no compaction technique is used for molding SCC mixes and just their own weights are used to compress them, this problem might be emphasized. In this context, one should exercise caution when using these kinds of SCCs for substantially reinforced structural sections due to the larger drop in CS at higher SF volume fractions.

The results showed that the maximum CS recorded for the reinforced mixture was associated with the recycled SF volume of 0.5%, but the maximum TS and FS were noted in the reinforced samples with the recycled SF volume of 0.75% (Aghaee et al., 2015). According to research, adding SF to concrete may enhance its mechanical qualities. However, a higher fiber content does not necessarily result in a rise in the improvement in CS (Gencel et al., 2011). The researcher noticed a negligible increase in the CS values when silica fume and SF were added at the same time. The CS is increased by 2.6% when 0.25, 0.50, 0.75, and 1.0% of SF with 20% replacement silica fume is added relative to the control batch. Due to the bridging capacity provided by fibers, adding SF (up to 0.50%) marginally enhances the CS, however, introducing more fibers causes the CS to drop (Saba et al., 2021). CS usually declines a little bit as SF content rises. In this investigation, increasing the amount of SF from 0.5 to 1.25% resulted in a 7% loss in CS (Iqbal et al., 2015a).

The research looked at how hooked-shape SF affected the rheological and mechanical characteristics of SCC with various strength classes of 40 MPa and 60 MPa and utilizing four different SF volume fractions of 0.5–2%. The findings show that the presence of SF decreases the workability of SCC, which in turn leads to a drop in vibrated concrete's compaction levels. This decreases the CS in both strength classes (Khaloo et al., 2014). Atis et al., conclude that the addition of SF to concrete have little to no effect on its CS (Atiş & Karahan, 2009). The CS is unaltered by the insertion of SFs, according to study results utilizing fibers with lengths ranging from 22 to 44 mm; however, compression failure mode changes from brittle to ductile with the specimens retaining their integrity throughout the test (Olivito & Zuccarello, 2010). According to findings, the insertion of SF reduced the CS of high-strength SCC by around 7.5% (Khaloo et al., 2014). Song et al. noted that CS rises as SF content rises to 1.5%volume fraction before dropping down somewhat to 2%, although it still stands at 12.9% more than the CS of concrete without fibers (Song & Hwang, 2004). The research found that adding 0–2% short SF with a 13 mm length and 65 aspect ratio increased the CS of various concretes by 19–42% (Ma et al., 2013). The CS nonetheless decreased by 6.3 and 9.5%, respectively, with further additions of SF (0.75 and 1.0%). This decrease is related to SCC mixes' decreased workability and filling capacity, which caused them to lose their self-compacting capabilities (Mardani-Aghabaglou et al., 2013).

According to findings (El-Dieb, 2009), the most notable testing finding is the concrete's failure mode significantly changes as SF is added to the mix and as the volume percentages of SF rise. Fig. 7 shows the cube specimens for the various mixtures following failure. The cracking changes from an abrupt explosive failure that destroys the specimen to a more ductile failure in which the specimen is still intact. It is possible to see that specimens are more intact as the fiber volume percentage rises. This is a result of the ability of the fibers to avoid unexpected abrupt collapse of the concrete and their tight connection with it.

Self-lightweight compacting concrete combined with SFs has excellent integrity of compressive failure morphology following compression fracturing. The sample took a long time to break under the influence of the compression force, and the cracking sound was loud and unpleasant. The position of the crack opening also revealed the SF that connects the broken surface (Li et al., 2021). It was determined that fiber bridging mechanisms across the fracture surfaces allowed SF to convert from brittle to ductile compression failure (Caggiano et al., 2012). This occurred as a result of the hoop effect, which limited the cracking and transverse expansion of the concrete specimen, produced by the three-dimensional network structure of fibers.

Fig. 8 and Table 2 show the results of the tensile strength (TS) of SCC with the addition of SF.SF bridge the space between the two sides of the fracture formation to increase the TS. Adding hooked end fiber increased the TS (Haddadou et al., 2014). When compared to the control mix of SCC, the increase in TS with 0.5%, 1.0%, and 1.5% fiber content was 11.6%, 32.1%, and 38.7%, respectively. SF ability to stop fracture advancement is thought to be the cause of the improvement in strength. The presence of fibers prevents the formation of internal microcracks, which increases the TS. Additionally, the enhanced bonding of the fiber–matrix, which is supplied by SF with hooked ends, increases pull-out strength and yields a high rise in strength as a result of an increase in fiber content (Siddique & Kaur, 2016). According to TS tests, a 0.75% increase in SF content results in a rise in TS of around 18% (Iqbal et al., 2015a). In comparison to standard SCC without fibers, the researchers found that using 1.5% SF by volume increased FS and TS by around 33% and 24%, correspondingly (Siddique & Kaur, 2016).

The high parameters of SFs, such as aspect ratio, modulus of elasticity, and TS of fiber, are responsible for the improvement in concrete TS because they allow SF to bridge concrete microscopic cracks effectively (Tabatabaeian et al., 2017). When the proportion of SF increases, the ductility in the region of elastic deformation increases which results in more TS (Ali et al., 2020a; b). According to the finding, there is a definite rise in the TS of the concrete mixes with an increase in SF. Results indicate that increasing the SF content of the tested samples from 0.5% to 1.25% increases their TS by around 18% (Iqbal et al., 2015a).

A study found that the amount of SF in hardened concrete had a variety of effects, including increasing SF content from 0.5% to 1.25%, which decreased CS to 7%and 18% and enhanced TS and FS to 70%, respectively (Sun et al., 2015). Higher content may, thus, contribute to improved cracking processes as well as improved flexural and TS. The method by which SF bridge the space between two sides of a crack opening is unquestionably relevant to the strength improvement brought on by the presence of SF. The fibers help concrete gain more TS by preventing the emergence of interior microcracks. Additionally, the form of the SF and increased pull-out strength may be credited for better fiber–matrix bonding, which can be seen as crucial to raising TS (Madandoust et al., 2015).

The failed specimen of the tensile test is shown in Fig. 9. As shown in Fig. 9a, the fiber was entirely pulled out of the matrix on both sides, and a piece of the matrix was still connected to the SF. It illustrates the SF and matrix's strong bonding behavior. The quantity of fiber was smaller for the same percentage of the fiber content in recycled SF (extracted from tires) compared to manufacturing SF because of the difference in density. This difference in strength may be the result of SF's larger length, uniform undulating length, and high stiffness compared to recycled SF, which provided greater bridging length and substantially increased fracture resistance (Mastali et al., 2018). According to Sanjeev et al., the collapse in unreinforced concrete happened rapidly; however, in fiber-reinforced concrete, the fibers show many fractures and the concrete has a higher energy absorption than unreinforced concrete, thus the collapse is not brittle (Sanjeev & Nitesh, 2020).

Fig. 10 and Table 2 show that the flexural strength (FS) of SCC improved with the addition of SF. A study claim that although concrete CS was decreased with the addition of SF, but its TS and FS were enhanced. Additionally, the SCC beams' flexural toughness improved as the amount of SF increased (Khaloo et al., 2014). Similar studies claim that fibers improved the flexural capacity of concrete (Ding et al., 2021; Yadav et al., 2020; Łach et al., 2021; Mashrei et al., 2018; Turlapati & Vineel, 2020).

According to findings (Olivito & Zuccarello, 2010), adding SF to concrete boosts its ductility, initial crack strength, and FS while having less of an impact on the CS. Additionally, it was determined that concrete displays hardening behavior with longer fibers whereas softening behavior is produced by the insertion of shorter SFs. The highest value of FS is reached with an SF content of 3.5%. FS of concrete increases as SF content increases. FS is reduced when fiber content is increased more than optimum percentages (Jatale & Mangulkar, 2013).

Concrete TS increased between 19 and 98.3%, while its FS increased between 28 and 266.6% when SF between 0.5 and 2% was added (Song & Hwang, 2004). Concrete reinforced with 1.5% SF showed increases in TS of up to 71% and FS of 30–60% (Atiş & Karahan 2009). It was found that the FS increased with the quantity of SF in concrete, and this was due to the SF random distribution in SCC, which controlled the cracks and stitched them, enhancing the load-bearing capability of tested beams (Gencel et al., 2011). The FS was evaluated throughout the ranges of 0–15% silica fume, 0–1% fiber steel, and 65–80 aspect ratios. The greatest results were achieved at 15% silica fume, 1% fiber steel, and 85 aspect ratios, correspondingly (Saba et al., 2021). Additionally, increasing the volume percentage of the fibers by up to 1.0% might somewhat improve the bending post-cracking strength (Koksal et al., 2008). Although the inclusion of SF might prevent the start and spread of fractures and increase the FS of concrete, it should also be taken into account that the addition of SF would make the concrete matrix less compact, which would negatively impact the FS (Li et al., 2017). Owing to improved concrete qualities that lessen the brittleness of SF SCC, which is a consequence of an increase in TS attributed to the prevalence of SFs, the elastic modulus also increases as the proportion of SF increases (Ali et al., 2020a; b).

Concrete FS increases as the percentage of SF increases, reaching its maximum value at 3.5% SF content. FS is reduced when fiber content is increased more (Jatale & Mangulkar, 2013). With a rise in SF content from 0.5%to 1.25%, the FS significantly improves, by about 70%, while the first crack load only slightly rises, by about 11% (Iqbal et al., 2015a). The use of SF with hooked ends results in enhanced fiber–matrix mortar binding, which boosts FS in specimens containing SFs. SFs’ ability to release fracture energy in the vicinity of crack tips, which is required to extend crack growth by transferring energy from one side to another, is largely responsible for this performance. When tensile stress is transmitted to fibers, the transferred load stops macro fractures from spreading and significantly improves the material (Rambo et al., 2014).

The broken beams shown in Fig. 11 demonstrate the ability of the fibers to bridge gaps and effectively increase the mechanical performance of reinforced concrete (Haddadou et al., 2014). According to the study, adding SF is crucial for converting SCCs' brittle failure state into one that is more ductile. Additionally, it may be inferred that shorter fibers in concrete serve as a bridge to lessen microcracks but have little impact on the post-peak behavior of load against displacement at the mid-span of the prism. The longer fibers do not significantly alter the load versus displacement curve of the prisms' post-peak response region, which leads to a high value of FS. However, the longer fibers do influence the creation of microcracks (Haddadou et al., 2014).

Fig. 12 shows that the modulus of elasticity of concrete somewhat decreases as SF content increases, although this decrease is extremely tiny and the values essentially stay the same (Iqbal et al., 2015a).

According to one study, the elastic modulus was improved by increasing the volume percentage of glass fibers in SCC (SCC) from 0 to 1.5% (Atewi et al., 2019). According to the investigation, 0.25% fibers caused a 7% decrease in elasticity when compared to control concrete. Concretes made with glass fibers have a slightly lower modulus of elasticity than concretes made with banana fibers. This is because banana fibers have a higher elastic modulus than glass fibers (Kizilkanat et al., 2015). Results indicate that when SF concentration increases, there is a very minor fluctuation in the modulus of elasticity of concrete, but the cause of this variation is unclear, and the values stay essentially unchanged. The findings suggest that the inclusion of SF does not affect the modulus of elasticity (Iqbal et al., 2015b).

The study also found that SCC-containing fibers had an approximately 10% greater elasticity modulus than plain SCC (Basheerudeen & Anandan, 2015). The results of the laboratory experiments demonstrate that adding fibers has no discernible effect on the concrete's modulus of elasticity. The concrete's elasticity modulus largely decreased with low fiber density (Beigi et al., 2013). The addition of fibers improves elastic modulus by 0.5–5%, and there is little difference between the elastic modulus values of plain concrete and concrete with 1% fibers (Ali et al., 2020a; b). A more thorough study is needed since there are often fewer studies on the elastic modulus of concrete accessible.

Adding steel fiber to SCC improves the amount of charge passed as the volume fraction of fiber increases. However, all mixtures comprising new steel fiber, recycled steel fiber, and control fall within the low to extremely low chloride ion permeability range. With values of 1140, 1227, and 1066.5 C at 28 days, Fig. 13 demonstrates the low chloride ion permeability of the steel fiber mixes of 0.5, 1.0, and 1.5%. However, at a later age of 90 days, all of the mixes, including the control mix, are within the range of extremely low chloride ion porosity. The corrosion that accumulated on the surface of the concrete in the SF samples, whether they were SCC or had a high fiber content, is seen in Fig. 14a, b. However, the portion of the fibers covered in concrete has not shown any deterioration. According to a study (Yehia et al., 2016), the volume proportion of fibers increased along with the total charge transmitted. This may likely be attributed to the electrical conductivity of SFs, and all of the mixtures had extremely low limits of chloride ion penetration.

The development of steel fires in SCC had no impact on the material's ability to withstand chloride penetration. Only a little rise in chloride concentration was seen in the mixture with a volume percentage of 0.7% fiber (Anastasiou et al., 2014). It was discovered that all SCC mixtures had extremely high resistivity values, which suggested very effective protection for steel reinforcement against corrosion. In comparison to the control mix, the maximal chloride ion penetration resistance was 766 Coulombs when SF concentration was 1.5% by volume (Siddique & Kaur, 2016). Even with the inclusion of SFs, research supported their findings that the rate of chloride diffusion was limited owing to the relatively low matrix porosity (Corinaldesi & Moriconi, 2004). The research found that the total charge flowing increased as the amount of SF increased, probably due to the fiber’s electrical conductivity. All of the mixtures also exhibited extremely low levels of chloride ion permeability (El-Dieb, 2009).

The findings indicate that the porosity decreased with aging because of increased or improved hydration and pozzolanic reaction rates. The lowest porosity was attained in the control mix but mix SCC4 (1.5% SF) increased porosity relative to the reference mix by roughly 6%. As seen in Fig. 15, the permeability of concrete gradually decreases as it ages. Research (El-Dieb, 2009) found that no significant change in porosity was seen following fiber insertion after examining specimens at ages 28, 56, and 91 days. This may be because the microstructure of cement paste has a major role in the progression of water. Since the cement paste is roughly the same for all the combinations, the variances were caused by the sensitivity of the experiment. Research (De Oliveira et al., 2013) further shows that the SF fraction has no appreciable impact on the porosity of SCC with fibers.

The uniformity of plain concrete may be decreased by adding fibers. Fig. 16a, b provides the traditional concrete and SCC UPV and rebound numbers. According to the relevant standard codes, the UPV values and rebound numbers are used to grade concrete. The SF concrete matrix's surface hardness was noted as a material surface. Additionally, the surface hardness of the glass fiber concrete was lower than that of SF-reinforced concrete and was rated as a good layer. In contrast to regular concrete, reinforced concrete often has a lower uniformity. As the amount of fiber rise, the UPV dropped. Concrete with SF has a lower UPV than concrete with glass fiber (Sanjeev & Nitesh, 2020). In comparison to traditional reinforced concrete, the reinforced SCC showed more homogeneity. The fiber-reinforced concrete matrix was rated as an acceptable layer since its surface hardness was less than that of RCC. Reinforced concrete has less uniformity than regular concrete. The study's uniformity was increased using reinforced concrete with a considerable fiber volume. Fiber-reinforced SCC had greater homogeneity as compared to reinforced vibrated concrete (Sanjeev & Nitesh, 2020).

The control mix obtained a maximum pulse velocity of 4.7 km/s, but the mix (1.5% SF) only managed a minimum pulse velocity of 3.9 km/s, which is 17% less than the control (Siddique & Kaur, 2016). In accordance with ASTM C597 (ASTM 2009), concretes are classified as excellent, good, questionable, poor, and extremely poor for pulse velocity values of 4.5 km/s and above, 3.50–4.50, 3.0–3.5, 2.0–3.0, and 2.0 km/s and below, respectively. Between pulse velocity values of 4.1 and 4.7 km/s, the lower border of excellent-grade concrete is located. At the age of 28 days, every concrete sample created for this study is of high quality.

The accessibility of voids in the mixes containing SF more so than in the control mix may be the source of the decreased pulse velocity, which will shorten the time needed for an ultrasonic wave to bypass (Gencel et al., 2011). Additionally, since the SF in cubes is randomly oriented, waves that pass through them may, to a limited degree, be diverted in different ways rather than traveling straight ahead to the other end of the cube. However, researchers (Sahmaran & Yaman, 2007) found that adding SF to SCC mixes did not affect the pulse velocity, in contrast. Acebes et al. (2011) concluded that the presence of SF reduced pulse velocity. The ultrasonic pulse velocity of mortar with long fibers decreased by around 8.3% in comparison to normal mortar.

Steel fiber (SF) had a considerable impact on drying and autogenous shrinkages. According to Fig. 17, drying shrinkages both linearly dropped as fiber content increased, and they roughly decreased at a rate of 170 × 10⁶% more SFs. This is most likely due to the self-compacting fiber concrete having a greater paste content and being more sensitive to fiber content than regular fiber concrete. Research (Miao et al., 2003) indicates that the addition of fiber lowers the percentage of fractures. With 0.30% fiber, plastic shrinkage cracks were completely invisible (by volume).

In research, it was discovered that the dry shrinkage deformations of fiber concrete were less than those of the basic concrete without fibers, suggesting that they were more stable. By strengthening their bond with the concrete matrix and reducing dry shrinkage during the drying process, fibers may assist reduce shrinkage in concrete (Li et al., 2006). The most important feature of concrete fibers to limit shrinkage is fracture prevention, which has a substantial impact on fibers in concrete (Ahmad et al., 2022a, b; Barr et al., 2003). These findings are consistent with those made by other researchers who found that adding fibers to a composite may aid to lessen cracking brought on by dry shrinkage in a composite (Kaikea et al., 2014).

The addition of 0.10–0.25% fibers dramatically decreased the crack width as compared to the control sample. The fracture width shrank by 72–93% with the addition of fiber up to 0.25%. Shrinkage cracking is reduced by 50–99% by adding fibers up to 0.30% (Islam et al., 2016). Research also found that adding polypropylene fiber outperformed adding SF in terms of avoiding shrinkage cracking. Concrete's cracking area was decreased by 98% when polypropylene fibers were added at a concentration of 0.5% (Sivakumar & Santhanam, 2007). When contrasted to plain prepacked aggregate concrete specimens, it has been found that the dry shrinkage values of all prepacked aggregates of fiber-reinforced concrete samples with blended polypropylene fibers were much reduced up to 180 days. Fibers stop the development of microcracks on the concrete's surface, which stops the mobility of dangerous components in the sample. As a consequence, the adverse effects of dry shrinkage are minimized and the fracture density and size are decreased (Alrshoudi et al., 2020).