Influence of palm oil ash and palm oil clinker on the properties of lightweight concrete

2.1.1 PC

In this study, PC type (CEM I 52.5N) was used, which complies with BS EN 197/1 2011. The physical and chemical characteristics of the PC used are delineated in Table 1.

2.1.2 SF

In this work, SF is a secondary material from a ferrosilicon alloy factory. The SF utilized was locally obtained and is in accordance with ASTM C1240-20 standards. The physical characteristics and chemical attributes of SF from the manufacturer are tabulated in Table 1.

2.1.3 POA

The waste of palm oil comes from companies that make palm oil. The POA for this work came from a palm oil mill in Marsa Matrouh, Egypt. The POA was air-dried in an electrical oven set to 110 ± 5°C for 1 day. It was then put through a 150 mm sieve to get rid of any big or odd particles. The POA that had been sieved was then ground on a grinding machine from Los Angeles to make the particles very small [29]. An electric furnace was used to heat the POA to temperatures of up to 600°C for around 2 h to boost the effectiveness of the POA by eliminating any unburned carbon [24,30]. The equipment that was used in Los Angeles to make POA was also employed in the second step of grinding for the POA that was produced there, and the same method was used in the production of previous studies [29,31]. And finally, the very fine POA was gathered. It meets the standards of BS 3892: Part 1. The POA generated may be classified as classes C and F, in accordance with the ASTM C618-19 standard specifications. Table 1 provides a concise summary of the physical attributes and chemical makeup of POA.

2.1.4 Aggregates

This research used two basic types of fine particles. Concerning the sand, it was used to cast the reference mixtures, while POC wastes as fine aggregates were used to produce LWC mixtures. The utilized fine aggregate (sand or POC) with dimensions varying between 0.15 and 4.75 mm is from the Belbes zone and the Marsa Matrouh zone in Egypt, respectively. Also, two main coarse aggregates (dolomite and POC as lightweight aggregates) were utilized in this work with a maximum particle dimension of 19 mm, and they were obtained from the Attaka zone, Suez, and Marsa Matrouh zone, Egypt, respectively. Some of the previous works investigated the influence of POC on the properties of LWC [32,33]. The properties of aggregates were determined as per ASTM C33/C33M-18. Table 2 presents the outcomes of the physical and mechanical characteristics of the aggregates. Figure 1 displays the gradation shape of the aggregates used.

Figure 1

Gradation shape of aggregates used.

2.1.5 Superplasticizer (SP)

SP (Viscocrete-3425) was used with the aim of obtaining the required workability [34,35]. About 2.9% of SP was utilized in the binder materials. It complies with the specifications for SP as outlined in ASTM-C-494 Type G and BS EN 934 Part 2:2001, with 1.1 specific gravity.

3.1.1 Slump

Figure 2 presents the obtained slump values of full poured LWC mixes. It can be seen that, for CEM-S-D and SF20-FP-CP, the greatest and lowest recorded slump values were, respectively, 132 and 60 mm. The slump values for each group decreased gradually up to a certain point, after which they increased. To give an example, for mixes CEM-S-D, SF10-S-D, SF20-S-D, PA10-S-D, and PA20-S-D, the recorded slump values were 132, 113, 100, 118, and 106 mm. This may be related to the use of a great replacement ratio of SF “20%” by mass from PC, which has a high specific area of 19,995 cm²·g⁻¹” in comparison to the specific area of the used PC, which is 3,525 cm²·g⁻¹. This indicates that a high amount of mixing water was absorbed due to the fineness of the SF particles, which decreased the quantity of free water and reduced the slump values. The reference mix is also shown to have the highest slump value across all groups. Additionally, mixtures with POA have slump values higher than mixtures with SF, where the slump values for mixes CEM-FP-D, SF10-FP-D, SF20-FP-D, PA10-FP-D, and PA20-FP-D were 96, 85, 80, 90, and 86 mm, respectively. This might be related to the material characterization (Table 1) in which the SF-specific area is larger than the POA specific area. Finally, increasing the replacement of sand or dolomite with POC, respectively, at a constant ratio of POA resulted in poor workability, as demonstrated by mixtures PA10-S-D, PA10-FP-D, PA10-S-FP-D-CP, and PA10-FP-CP with associated slump values of 118, 90, 83, and 70 mm, which may occur as a result of increased water absorption (%) of POC than used aggregate, and also the % of clay and fine materials in POC is greater than the utilized aggregate (Table 2). From the preceding discussion, it is obvious that utilizing POA as a replacement for PC in addition to employing POC as a substitute for sand or dolomite creates a negative effect on the workability of LWC, which is consistent with previous studies [42,43].

Figure 2

Outcomes of slump values of LWC.

3.2.1 Dry density

Figure 3 displays the dry density test outcomes for combined clinker and palm oil samples as a replacement for fine and coarse aggregates, as well as the use of POA as a sectional replacement for PC at 28 days. It is noted that the production of LWC using POA or SF at replacement rates of 0, 10, and 20% by mass of PC resulted in an average dry density of 2,245–2,210 kg·m⁻³ at 28 days. In contrast, the CS ranged between 71.5 and 81.7 MPa at a test age of 28 days. It is noticed that utilizing POA or SF as a sectional replacement for PC did not change much in the density of LWC; on the contrary, it led to a slight enhancement in the dry density of LWC compared to the reference mixture, whereas replacing 50% of the sand with POC causes a decrease in the dry density of the LWC. The dry density of LWC ranged from 1,950, 1,975, 1,990, 1,965, and 1,960 kg·m⁻³ for CEM-FP-D, SF10-FP-D, SF20-FP-D, PA10-FP-D, and PA20-FP-D kg·m⁻³, respectively. It is noted that this decrease in dry density meets the requirements of LWC based on the BS EN specifications, which require that the dry density of LWC be lower than 2,000 kg·m⁻³. In addition, replacing 25% sand and 25% coarse aggregate with POC creates a more pronounced decrease in dry LWC density than when replacing 50% sand with POC alone. In this case, the density of dry LWC conforms to the basic requirements for LWC in BS EN and ACI specifications. The results for the dry density of the LWC were less than 1,920 kg·m⁻³ at 28 days. In the case of substituting 50% sand and 50% coarse aggregate by POC, it resulted in a decrease in the dry density of LWC by 23.7, 22.3, 21.9, 23.3, and 23.5% for CEM-FP-CP, SF10-FP-CP, SF20-FP-CP, PA10-FP-CP, and PA20-FP-CP mixtures compared to CEM-S-D (reference mixture). Therefore, the density of dry LWC, which includes the replacement of 50% sand and 50% coarse aggregate by POC, meets the LWC requirements of BS EN and ACI specifications. The dry density results for LWC in this case ranged between 1,685 and 1,725 kg·m⁻³ at 28 days.

Figure 3

Outcomes of the dry density of LWC.

Figure 4 illustrates the relationship between the dry density and CS of LWC at 28 days. The relationship shows a strong correlation (R = 0.95) between the dry density and CS of the LWC at 28 days. The lower the drying density, the lower the CS. The CEM-FP-CP mixture showed the lowest dry density of 1,685 kg·m⁻³ and the lowest CS of 34.1 MPa among all the mixtures applied in this work. Generally, the outcomes are consistent with the results of prior investigations that studied the impact of low dry density on CS. The utilization of lightweight materials as a sectional replacement for aggregates has a positive influence on reducing density and, on the other hand, a harmful impact on strength, transport, and durability properties. On the other hand, the utilization of POA and SF as a sectional substitute for PC contributed to the preservation of better engineering properties compared to the control mix [44,45].

Figure 4

Relationship between dry density and CS of LWC.

3.2.2 CS

Figure 5 shows the results of the CS test of LWC including the substitution of PC with SF and POA, in addition to the replacement of sand and coarse aggregate with POC at 7, 28, and 91 days. SF and POA were used as partial replacements at a ratio of 10 and 20% by weight of PC, and POC was employed as a substitute for both sand and coarse aggregates at rates of 50 and 100% by volume. The findings indicate that incorporating SF and POA as partial substitutes for PC yielded positive results, as evidenced by an improvement in CS compared to the reference mix. The substitution of 10 and 20% PC with SF resulted in a 14.3 and 11.3% increase in CS, respectively. Similarly, substituting 10 and 20% PC with POA led to a 7.4 and 3.8% increase in CS, respectively, when compared to the reference mixture. Referring to Table 1, POA has pozzolanic properties with a chemical structure of SiO₂, Al₂O₃, and Fe₂O₃ of 74.6% and a loss of ignition (LOI) of 3.2% by weight. Therefore, the incorporation of POA as a sectional substitute for PC enhanced the CS of LWC because of the interaction of pozzolanic with Ca(OH)₂, which generated an extra additional calcium silicate hydrate (C–S–H) gel. This is consistent with the investigation by Tangchirapat et al. [46], which states that replacing 10–30% of the PC weight with fine POA increases CS compared to the reference mix. POA’s high SiO₂ content and high fineness increased the response between SiO₂ and calcium hydroxide to generate more C–S–H, which increased CS. On the other hand, POC utilization as an alternative for sand and coarse aggregates caused a decrease in CS. There is an inverse relationship between the replacement rate and the CS, whereby an enhancement in the substitution rate leads to a reduction in the CS. The substitution of 100% sand and 100% coarse aggregates with POC resulted in the greatest reduction in the CS of the CEM-FP-CP mixture by 52.3% compared to the reference mixture. While the rates of reduction in CS varied according to the rate of substitution of sand and coarse aggregate with POC and the level of substitution of PC by SF or POA, they ranged from 8.9 to 52.3%, with an age of 28 days. It is also observed that the utilization of SF or POA as a sectional replacement for PC contributed to reducing the damage to the CS as a result of the utilization of POC as a substitute for coarse aggregate and sand. The findings align with the research investigated by Ibrahim et al. [47], which indicates that substituting aggregates with POC for the manufacture of LWC creates a decrease in CS. Furthermore, the reduction in CS is observed to increase as the rate of aggregate replacement increases.

Figure 5

Outcomes of CS of LWC.

Figure 6 presents the amount of change in the CS of LWC because of utilizing SF and POA as a sectional substitution for PC and using POC as a replacement for coarse aggregate and sand with a test age of 28 days.

Figure 6

Outcomes of CS of LWC at 28 days.

3.2.3 STS

The STS results at 28 days are delineated in Figure 7 for all LWC mixtures. The effect of replacing PC with SF or POA at levels of 10, 20% by weight, and sand and coarse aggregate with POC at rates of 50 and 100% by volume on the STS is investigated. By referring to Figure 7, the STS for the reference mix was 6.53 MPa; in addition, the maximum and minimum splitting tensile values were 7.19 and 3.24 MPa for mixtures SF10-S-D and CEM-FP-CP, respectively. The best results for STS were achieved in each group at a replacement ratio of 10% using SF, which means using SF as a replacement for PC is preferable to using POA, where the STS for SF10-S-D and PA10-S-D increased by about 10.1 and 5.51%, respectively. That may refer to the SF particles being finer than POA particles based on the material characteristics shown in Table 1. Furthermore, adding 20% SF or 10% POA to LWC mixes gives very similar results for STS values, e.g., the STS values for mixes SF20-FP-D and PA10-FP-D were 7.85 and 7.87 MPa, respectively. On the other side, replacing sand and dolomite with POC at different levels at the same level of replacement of PC by SF or POA has an adverse impact on splitting tensile values; increasing the replacement ratios increase the reduction in STS values. For example, the splitting tensile values for mixes SF20-S-D, SF20-FP-D, SF20-S-FP-D-CP, and SF20-FP-CP were 6.85, 5.55, 5.09, and 3.38 MPa, respectively. These outcomes may be related to the crushing value (%) and Los Angles abrasion loss (%) of coarse particles of POC, which are higher than their counterparts in the used dolomite (Table 2). The obtained outcomes agree with the research conducted by Ibrahim et al. [47], which indicates that when POC was used in place of aggregates in the manufacturing of LWC, there was a decrease in the STS of the material. Furthermore, the rate of aggregate replacement significantly contributes to the material’s STS decline.

Figure 7

Outcomes of STS of LWC at 28 days.

3.2.4 FS

Figure 8 illustrates the outcomes obtained from the FS test conducted on LWC specimens. The test included the substitution of PC with supplementary cementitious materials, namely, SF and POA, as well as the replacement of sand and coarse aggregate with POC. The samples were tested at 28 days. In the study, the researchers used SF and POA as partial substitutes for PC, with a weight ratio of 10 and 20%, respectively. Additionally, POC was utilized as a substitute for both sand and coarse aggregates, with volume ratios of 50 and 100%, respectively. The findings indicate that the presence of supplementary materials such as SF and POA as sectional replacements for PC yields a favorable outcome. This is supported by an observed improvement in FS when compared to the reference mixture. The incorporation of SF as a substitution for 10 and 20% of PC led to a respective increase of 10.7 and 6.12% in FS. Furthermore, the substitution of 10 and 20% of PC with POA resulted in a corresponding rise of 5.7 and 0.5% in FS, as compared to the control mixture. Referring to the data illustrated in Table 1, POA has pozzolanic characteristics, as indicated by its chemical composition, which includes SiO₂, Al₂O₃, and Fe₂O₃, which together account for 74.6% of its total weight. Additionally, POA shows a LOI of 3.2% by weight. As a result, the inclusion of POA as a sectional replacement for PC led to an increase in the CS of LWC due to the pozzolanic reaction with Ca(OH)₂, resulting in the formation of an extra C–S–H gel. This agrees with the study by Tangchirapat et al. [46]. The elevated SiO₂ concentration and small particle size of POA facilitated the interaction between SiO₂ and calcium hydroxide, resulting in the augmented formation of calcium silicate hydrate. This, in turn, led to an increment in FS. Conversely, the presence of POC as a substitute for sand and coarse aggregates creates a decrease in FS. A negative correlation exists between the replacement rate and the FS, whereby an increase in the replacement rate results in a drop in the FS. The replacement of 100% sand and 100% coarse aggregates with POC resulted in the most significant decrease in the FS of the CEM-FP-CP, exhibiting a loss of 25.24% when compared to the CEM-S-D mixture. The rates of decline in STS exhibited variability depending on the extent of sand and coarse aggregate substitution with POC, as well as the extent of PC substitution with SF or POA. These rates ranged from 10.38 to 25.24% at an age of 28 days. Additionally, it should be acknowledged that including supplementary materials such as SF or POA as a sectional replacement for PC has been shown to have a role in mitigating the adverse impact on FS. This is particularly evident when utilizing POC as an alternative for coarse aggregate. Finally, the FS outcomes follow the same trend as the CS findings, and the FS outcomes agree with the results obtained by Ibrahim et al. [47].

Figure 8

Outcomes of FS of LWC at 28 days.

3.2.5 MOE

MOE is evaluated at 28 days by testing three 150 mm × 300 mm cylinder specimens for each LWC mixture. Figure 9 demonstrates the outcomes of MOE for entire LWC mixtures at 28 days due to the effect of utilizing SF and POA as a substitute for PC with levels of 10 and 20% by weight in addition to replacing aggregates by volume with ratios of 50 and 100% using POC. The obtained findings have the same trend as the CS findings. The reference mix recorded MOE values of 37.01 GPa, while the best and worst values of MOE occurred at mixtures SF10-S-D and CEM-FP-CP, respectively, whereas the MOE values were 39.47 and 25.81 GPa, respectively. It is observed that using SF is better than using POA as a substitution for PC, and that may relate to the good particle characteristics of SF compared with the properties of POA particles, where SF particles are finer than POA particles, and from chemical composition, the SiO₂ content of SF is higher than the SiO₂ content of POA. That increased the reaction between SiO₂ and calcium hydroxide to produce more calcium silicate hydrate, which increased MOE. Furthermore, a 10% SF percentage is considered to be the optimal ratio for achieving high MOE results. For clarification, the recorded MOE results were 10.13, 9.71, 9.68, and 9.20 GPa for mixes SF10-S-D, SF20-S-D, PA10-S-D, and PA20-S-D, respectively. On the other side, the presence of POC as a replacement for aggregates resulted in a decline in MOE values due to the bad characteristics of the used POC compared to the utilized aggregates (Table 2). The MOE values decreased by about 4.62, 8.8, and 25.6% for mixes SF10-FP-D, SF10-S-FP-D-CP, and SF10-FP-CP, respectively, compared to CEM-S-D. In addition, it is seen that using POC as a full substitution for sand is better than utilizing POC as a sectional substitution for sand or dolomite, where the obtained results for mixes CEM-FP-D, CEM-S-FP-D-CP, and CEM-FP-CP were 33.18, 31.72, and 25.81 GPa, respectively. These results agree with that reported by Ibrahim et al. [47].

Figure 9

Outcomes of MOE of LWC at 28 days.

3.2.6 Relationship of mechanical properties with CS

Figure 10(a)–(c) shows the relationship between CS and tensile strength (TS), FS, and MOE, respectively. The correlation strength between the mechanical properties of concrete is exceptional, remaining above 99% for all relationships, including those between CS and TS, FS, and MOE. This confirms that CS expresses other properties in a percentage that exceeds 99% of the results. The American Concrete Institute’s (ACI 318-11) code also supports this, which is consistent with most of the prior research [48,49]. The following relationships serve as evidence that the ACI 318-11 affirms a strong correlation between CS and other mechanical properties.

Figure 10

The relationship between CS and TS, FS, and MOE. (a) The relationship between CS and TS. (b) The relationship between CS and FS. (c) The relationship between CS and MOE.

This study estimated that the TS of concrete samples is directly proportional to their CS, as shown in Eq. (1).

The FS of concrete samples was also estimated to be directly proportional to their CS as shown in Eq. (2).

The MOE of concrete samples was also estimated to be directly proportional to their CS as shown in Eq. (3).

3.3.1 Chloride permeability

Figure 11 illustrates the chloride permeability test outcomes for LWC specimens at 28 days. The samples were prepared with partial substitutions of SF and POA for PC and POC as a replacement for coarse aggregate and sand. The results clearly fall into three categories. First, the use of SF and POA as partial substitutes at levels of 10 and 20% of the PC mass. In this case, the results showed a slight improvement in the transport characteristics, as the chloride permeability values decreased by 3–6% compared to the reference mixture. The chloride permeability values of the SF10-S-D, SF20-S-D, PA10-S-D, and PA20-S-D mixtures were lower by 4.8, 6.4, 3.2, and 4.6%, respectively, when fine pozzolanic materials like SF and POA were used. The enhancement in transport characteristics may be attributed to the role of pozzolanic materials (SF and POA) in interaction with Ca(OH)₂ and the presence of extra gel C–S–H. In addition to filling efficiency, both effects contributed to closing the pores and increasing the density of the LWC matrix, which impeded the chloride permeability inside the LWC. This agrees with most of the prior investigations that confirmed the role of soft and ultra-fine pozzolanic materials in reducing chloride permeability through LWC [50,51].

Figure 11

Outcomes of chloride permeability of LWC at 28 days.

Second, using POC as an alternative to fine aggregate and coarse aggregate at rates of 50 and 100% of the aggregate volume. In this case, the results showed damage to the transport properties, as the chloride permeability values increased by 14.8–51.9% compared to the reference mixture. Compared to the control mixture, using POC as substitutes for fine aggregate and coarse aggregate raised the chloride permeability values of the CEM-FP-D, CEM-S-FP-D-CP, and CEM-FP-CP mixtures by 14.8, 22.9, and 51.9%, respectively. POC’s porous structure, which allowed for higher chloride permeability compared to natural aggregates, may have contributed to the decline in transport properties. This agrees with most of the prior research, which confirms that the use of lightweight aggregates as a replacement for natural aggregates leads to worse transport properties and increases the permeability of chloride and water through LWC [52,53].

Third, using POC as an alternative for fine and coarse aggregates in proportions of 50 and 100% by volume, as well as using SF and POA as partial substitutes in proportions of 10 and 20% by mass of PC. In this case, the outcomes showed a very slight improvement in transport properties, with chloride permeability values decreasing by 3.2–6.6% compared to mixtures that included only POC as a substitute for the normal aggregate. The observed phenomenon can be attributed to the effects of filling efficiency and the pozzolanic reactivity of supplementary cementitious materials such as SF and POA. However, the porous structure of POC limits these two effects. Hence, in this particular case, the influence of POC outweighed the influence of pozzolanic materials, resulting in a greater degree of chloride permeability compared to the reference mixture [53,54].

3.3.2 Water sorptivity

Figure 12 illustrates the results of the water sorptivity test for the LWC samples at 28 days. The specimens were prepared by using SF and POA as substitutes for PC, while POC was utilized as a substitute for both coarse aggregate and sand. According to the research findings, the presence of POA and SF resulted in a significant reduction in water sorptivity in LWC specimens. Furthermore, as the substitution rate increased, the reduction in water sorptivity became more noticeable. The mixture incorporating 20% SF as a partial PC substitute demonstrated superior transport properties compared to all other mixtures examined in this study. The mixtures SF10-S-D, SF20-S-D, PA10-S-D, and PA20-S-D showed water sorptivity values of 0.046, 0.036, 0.055, and 0.048 × 10⁻⁴ (mm·s^−0.5), respectively. While the reference mixture (CEM-S-D) showed water sorptivity value of 0.072 × 10⁻⁴ (mm·s^−0.5). It is also observed that the substitution of sand and coarse aggregate by POC in volume ratios of 50 and 100% led to an enhancement in the water sorptivity values in the LWC specimens. The higher the replacement rate of aggregate, the higher the water sorptivity values. Therefore, the CEM-FP-D, CEM-S-FP-D-CP, and CEM-FP-CP mixtures achieved water sorptivity values of 0.082, 0.088, and 0.109 × 10⁻⁴ (mm·s^−0.5), respectively. On the other hand, adding POA and SF to the LWC samples containing POC as a replacement for aggregate led to a slight enhancement in the transport characteristics. The results that included POA and SF showed a reduction in water sorptivity compared to the samples that only included POC as a substitute for aggregate. The decrease in water sorptivity in LWC samples may be attributed to the positive effects of the pozzolanic reaction and filling efficiency. The efficiency of pozzolanic materials depends on the proportion of amorphous SiO₂ (effective) and the fineness of the material used. The higher the fineness and effective SiO₂ content, the better the transport properties. It also appears from the outcomes of this research that the SF-containing specimens had a higher sorptivity of water than the POA-containing samples. Accordingly, higher efficiency can be achieved by improving ash treatment to achieve higher efficiency, as mentioned in previous research [10,55].

Figure 12

Outcomes of water sorptivity of LWC at 28 days.

3.3.3 Water permeability

Figure 13 demonstrates the outcomes of the water permeability test for LWC samples prepared by combining SF and POA as partial PC substitutes at a rate of 10 and 20% by weight. In addition, POC was utilized as a replacement for both coarse aggregate and sand at 50 and 100% by volume at 28 days. The study’s findings demonstrate that employing POA and SF resulted in a notable decrease in water permeability in the LWC specimens. Furthermore, the decrease in water permeability became more noticeable as the substitution rate increased. The mixture containing 20% SF as a partial PC replacement demonstrated higher transport properties in comparison to all other mixtures studied in this research. The water permeability values of the mixtures SF10-S-D, SF20-S-D, PA10-S-D, and PA20-S-D were 2.48, 2.37, 2.6, and 2.5 × 10^–11 (cm·s⁻¹), respectively. While the water permeability value of the reference mixture (CEM-S-D) was 2.92 × 10^–11 (cm·s⁻¹). Moreover, substituting fine and coarse aggregates with POC at volume ratios of 50 and 100% had an adverse impact on the transport characteristics of the LWC. This was evidenced by an increase in the water permeability values observed in the LWC samples. As the rate of aggregate replacement by the POC increases, the water permeability values also increase. The water permeability values of the LWC samples CEM-FP-D, CEM-S-FP-D-CP, and CEM-FP-CP were measured to be 3.35, 3.58, and 4.24 × 10⁻¹¹ (cm·s⁻¹), respectively. In contrast, incorporating POA and SF into LWC samples containing POC as a substitution for aggregate resulted in a modest enhancement of the transport properties. In addition, the findings indicated that incorporating POA and SF as partial replacements for PC in LWC specimens containing POC as an alternative for aggregate resulted in a minor increase in transport properties, as evidenced by a decrease in water permeability values. The decrease in water permeability rate of the LWC samples was due to the pozzolanic reaction and the filling efficiency of the materials (SF and POA) used as partial PC substitutes. Prior investigations have shown that the effectiveness of pozzolanic materials is influenced by their chemical composition, the percentage of amorphous SiO₂, and the particle size. The efficiency of the pozzolanic reaction increases with decreasing particle size (higher fineness) and higher active SiO₂ content. Consequently, the pozzolanic reaction leads to an increase in gel production, density of the PC matrix, and impermeability of LWC. The study’s findings indicate that the samples containing SF exhibited superior strength and transport properties in comparison to the samples containing POA. Prior investigations have reported that the effectiveness of ash can be enhanced through heat treatment and grinding [55,56]. On the other hand, the outcomes of this work are consistent with prior research, according to which utilizing lightweight aggregates as a substitute for coarse or fine natural aggregates leads to a reduction in strength and an improvement in permeability. The reason for the deterioration of the engineering properties of LWC is its weak and mostly porous structure [52,57]. This required conducting many studies to try to enhance the characteristics of LWC, including this research.

Figure 13

Outcomes of water permeability of LWC at 28 days.