2.1. Physical Properties

MSWI-BA is a gray to black amorphous material. Its quality depends on several factors, including (1) the waste content, (2) type of combustion unit, and (3) type of air pollution control device used in the incinerator [33]. According to Dou et al. [34], more than 60% of the particles were in the typical range of NA between 0.02 and 10 mm and around 5–15% were in the form of silt and clay. The authors also disclosed that MSWI-BA may contain up to 30% of particles larger than 10 mm.

Additionally, MSWI-BA has a specific gravity ranging from 1.5 to 2.0 for fine particles and 1.8 to 2.4 for coarse particles [35]. The water absorption ranges from 2.4% to 15%, with an average of 9.7% [20]. Therefore, when compared with typical NA, MSWI-BA has a lower specific gravity but much higher water absorption. However, little effort has been made by researchers to improve the physical properties of MSWI-BA to be utilized as aggregates [36]. The variations in the main physical properties of MSWI-BA are represented in Table 1 based on data selected from the different literature [37,38,39,40,41].

2.2. Chemical Properties

Studies show great variation in the composition of MSWI-BA due to samples obtained from different countries and at different times [42]. Table 2 shows the variation in chemical composition of MSWI-BA selected from different countries [43,44,45,46,47]. Although other samples from different studies might show different content in the material, it can be concluded that the main oxides that comprise MSWI-BA are SiO₂, Al₂O₃, CaO, and Fe₂O₃, regardless of the source of the waste. Also, high loss on ignition (LOI) is detected in some samples.

¹ Loss on ignition.

In addition to the mentioned main elements, there are several toxic elements found in MSWI-BA [20]. Heavy metals such as Pb, Zn, Al and many others are present and may cause leaching problems that have adverse effects on the environment [42]. The leachate pH is considered the most important factor that influences the leaching of heavy metals in MSWI-BA [48]. Ferrous metals are found in the range of 7–15% of the MSWI-BA while non-ferrous metals are only around 2% [49].

4. Limitations for the Use of MSWI-BA as Aggregates in Cementitious Materials

4.1. Expansion Due to Hydrogen Gas

Cement hydration creates an alkaline environment in the cementitious product. Within this environment, the presence of aluminum (Al) or aluminum compounds in aggregates creates the following reaction presented by Equations (1) and (2) [50]:

Anodic reaction: Al + 2H2O ! AlO2 + 3e- (1)
Cathodic reaction: 2H2O + 2e? ! H2 + 2OH- (2)

The product of the cathodic reaction, hydrogen gas, causes expansion especially during setting time of concrete [51]. According to studies from different countries, MSWIBA contains around 0.4% to 2.3% metallic Al by mass [36]. This would cause considerable cracking and spalling in concrete if not treated properly [52].

4.2. Expansion Due to Alkali-Silica Reaction (ASR)

ASR is the reaction between the silica in aggregates and an alkaline solution [53]. The reaction is represented by Equation (3) [36]:

2M+ + 2OH- + H4SiO4 → M2H2SiO4 + 2H2O (3)

The ASR gel produced by this reaction causes slow but severe deterioration of the concrete and results in major structural problems [54]. MSWI-BA can contain up to 60% glass by mass [36], where a high silica content in glass triggers ASR.

4.3. Expansion Due to Ettringite Formation

Ettringite can form in cementitious materials after the hardening process due to the presence of excessive amounts of sulfates (SO₄^2-) within [55]. Sulfate ions react with the calcium aluminate found in the cement paste and result in the following equation, where ettringite is formed [56]:

6Ca₂⁺ + 2Al(OH)^4- + 3SO₄^2- + 4OH^- + 26H₂O → Ca₆[Al(OH)₆]2(SO₄)₃.26H₂O (4)

MSWI-BA can contain up to 5100 mg/kg of sulfates [57]. The formation of ettringite causes significant expansion in concrete, leading to the deterioration of concrete members [58].

4.4. Corrosion of Steel Reinforcement

Corrosion of steel reinforcement is considered a critical issue for the durability of reinforced concrete members. It is an electrochemical process that depends on the pH of the concrete, presence of chlorides, and moisture [59]. The corrosion of steel reinforcement is represented by the following equations [60]:

Anodic reaction: Fe → Fe²⁺ + 2e^- (5)
Cathodic reaction: H₂O + 1/2 O₂ + 2e^- → 2OH^- (6)

MSWI-BA contains some amounts of chlorides, varying between 0.2% and 5% [61]. They are mainly present in the fine portion of the MSWI-BA [62]. The leaching of chloride can activate steel corrosion in concrete [63]. As a result, the concrete cover cracks, and then deterioration takes place [64]. Figure 1 summarizes the main barriers of using MSWI-BA as aggregates in cementitious materials.

Figure 1. Limitations of using MSWI-BA as aggregates in cementitious materials

5. Treatment methods

As mentioned earlier, several limitations hinder the usage of MSWI-BA in cementitious materials. As such, three treatment principles are suggested to improve the quality of the aggregates prior to use in engineering applications: separation processes, solidification and stabilization, and thermal methods [42].

5.1 Separation Process

It is common to start the treatment of MSWI-BA with separation processes [65]. A washing process, for example, intends to remove chlorides and heavy metals by using a leachate such as water [42]. More than 70% of the chlorides can be removed at a liquid/solid ratio of 10:1 [66]. Another study showed that 77% of chlorides are removed by 15 min of water washing and shaking at a liquid/solid ratio of 2.5, but only highly soluble sulfates are dissolved [67]. 

Metals could be present in the MSWI-BA within the aggregate matrix (in mineral form) [68]. As mentioned earlier, metallic Al and Zn causes the formation of hydrogen gas and as a result the expansion of concrete. Sodium carbonate (Na2CO3) can be used as a leachate for the removal of sulfates and metallic Al by increasing the pH level [36]. An alkaline solution, such as sodium hydroxide (NaOH), can also be used for the removal of the remaining metallic Al [69]. In fact, it was found that immersing MSWI-BA in an
alkaline solution for 15 days released all of the hydrogen gas [27]. The main disadvantage of washing processes is the wastewater produced [61].
Another separation process is the electrochemical process. It is a technique that involves extracting heavy metals and reducing their leaching [70]. The method creates an electric potential to stimulate reduction and oxidation reactions, where metals are accumulated on the surface of the cathode [42]. However, the efficiency of this process is low, and an electrodialytic remediation period is required [71]. Therefore, researchers suggested combining washing and remediation for reducing the leaching of heavy metals [72].
The magnetic density separation method can also be used for the separation of metals in the MSWI-BA. The efficiency of the recovery of ferrous metals by this method could reach up to 83% [73]. However, this process is only suitable for particle sizes larger than 2 mm [74]. Magnetic density separators can be designed in different ways and could have a simple geometry consisting only of a magnet and magnetic liquid, where separation takes place vertically (Figure 2) [74]. Eddy current separation is similarly used for the separation of non-ferrous metals. Its efficiency depends on the size of the particles and increases with
the increase in the particles’ size [61].

Figure 2. Principle of magnetic density separation, redrawn from [74].

5.2 Solidification and Stabilization Methods

Solidification and stabilization methods aim to immobilize the hazardous contents found in the MSWI-BA by using additives, binders, or stabilizers [70]. Solidification utilizes certain binders such as cement to improve the physical properties and durability of the MSWI-BA, creating a feasible aggregate for use in engineering applications [34]. For example, it was reported that lightweight artificial aggregates suitable for use in structural concrete can be manufactured by the solidification of MSWI-BA using cement [75,76].

Solidification can be also done by hydrothermal treatment. It is based on solidifying MSWI-BA at 150–200 °C under high pressure [77]. The main advantage of this process is that it can be applied on a large scale, and it reduces heavy metals significantly [78].

5.3 Thermal treatment

Thermal treatment methods involve treating MSWI-BA at very high temperatures ranging from 700 °C to 1500 °C, transforming the ash into less heterogenous slag [79]. The reactions that occur at such temperatures contribute to the removal of organic matter and the immobilization of heavy metals [36]. It also leads to the volatilization of chlorides [62]. Vitrification, for example, transforms the MSWI-BA into a homogenous glassy slag [80]. The leaching levels of the products are much lower than that of MSWI-BA [81]. The main concern of this method is its high cost, gas pollutants, and potential ASR if used in concrete
afterward [36].

Another method that involves thermal treatment is sintering. This method can create a lightweight aggregate from MSWI-BA, having properties comparable to lightweight NA after treating them at a temperature of around 1000 C [82]. Table 3 summarizes the main limitations in MSWI-BA and their corresponding treatment methods mentioned in this section.

Table 3. Limitations and treatment methods of MSWI-BA.

6. Effect on the Properties of Cementitious Materials

6.1. Workability

Ferraris et al. [83] replaced NA with MSWI-BA in concrete at replacement levels of 25, 50, 75, and 100%. The waste used was treated by magnetic separation and vitrification prior to use in the concrete mixtures. All mixtures maintained approximately the same slump, except for one mixture that had both fine and coarse aggregates fully replaced by MSWI-BA. This mixture had a very high workability value, and this was attributed to the loss of cohesion between the aggregates and the cement paste [84]. Müller and Rübner [85] studied the full replacement of NA with MSWI-BA in concrete. The authors reported that the slump value was the same in all mixtures. Shen et al. [47] replaced sand with MSWI-BA up to a 100% replacement level to produce ultra-high performance concrete. The authors reported an increase of slump values at a 25% replacement level, then decreased when higher amounts of MWSI-BA were used, yet they were within acceptable values. The used aggregates were presoaked with water. Tang et al. [86] produced high-performance concrete while replacing sand with MSWI-BA up to a 30% replacement level and observed a decrease in workability with the increase of MSWI-BA content. Specifically, the slump decreased from 21.25 mm for the control mix to 13.25 mm at a 30% replacement level. Similar results were reported in another study [87], where sand was replaced with wet, grinded MSWI-BA up to a 70% replacement level at different water-to-cement ratios. Three main reasons were identified in this study for the reduction of workability with the usage of MSWI-BA: high water absorption, high air content, and finer particles.

Few authors replaced sand with MSWI-BA in cement mortar. Al-Rawas et al. [88] replaced sand with MSWI-BA at 10, 20, 30, and 40% replacement levels in mortar and reported a drastic decrease of slump with the increase of MSWI-BA content. The authors observed a slump of zero mm at 30% and 40% replacement levels (Figure 3) [88]. Cheng [38] replaced sand with MSWI-BA up to a 40% replacement level in mortar and stated that slump values gradually decrease with the increase in MSWI-BA content, probably due to
the irregular shape of its particles.

Figure 3. Slump of cement mortar containing MSWI-BA, with data from [88].

Table 4 shows a comparison between the slump value of cementitious materials, incorporating MSWI-BA as aggregates from the selected literature [38,47,83,85,88]. The comparison takes into consideration the total water-to-binder ratio, the particle size of the MSWI-BA used in the mix, the replacement level of MSWI-BA, and the treatment method. The last column shows the slump value of each mix as a percentage of the control mix. It can be observed that the slump value between the control mix and the mixes containing MSWI-BA was similar, where treatment methods were used or the water-to-binder ratio was increased, whereas it decreased where no treatment method was adopted and the total water-to-binder ratio was kept constant.
In general, it can be inferred that the usage of MSWI-BA as a fine or coarse aggregate in cement-based materials causes a decrease in the workability of the material. This effect is mainly attributed to the high water absorption of MSWI-BA when compared with NA. Using MSWI-BA and having a saturated surface dry condition prior to mixing is suggested to maintain approximately the same slump in mixtures with different contents of MSWI-BA. Another method that could be used is adding and mixing water when using MSWI-BA to maintain the same effective water-to-binder ratio in all mixtures.

¹ Total water-to-binder ratio. ² Saturated surface dry condition.

6.2. Density

Machaka et al. [89] replaced fine aggregates with MSWI-BA at 25% and 50% replacement levels in concrete and reported a slight decrease in the density of the concrete with the increase in MSWI-BA content. The density dropped from 2364 kg/m3 for the control mix to 2269 kg/m3 at a 50% replacement level. Qiao et al. [90] used MSWI-BA to fully replace the fine aggregates in concrete. The MSWI-BA was thermally treated at temperatures ranging from 600 °C to 900 °C, and the results showed that the concrete containing MSWI-BA had a density lower than that of concrete containing NA. In addition, the density of the concrete decreased as the temperature of the thermal treatment of MSWI-BA increased. Holmes et al. [91] produced concrete masonry blocks using MSWI-BA as a partial replacement of fine aggregates up to 100% replacement levels. The authors reported that the density of concrete masonry blocks decreased as the replacement level of MSWI-BA increased.

Different results were observed in another study [87], where the density of concrete increased with the increase of the MSWI-BA content. The authors explained the increase by stating that the water absorption of MSWI-BA was much greater than that of the gravel used. Ghanem et al. [46] substituted MSWI-BA for sand at replacement levels 25, 50, and 100% in cement mortar. The authors noticed that the density of the mortar slightly increased at a 25% replacement level, then decreased at 50% and 100% replacement levels. They clarified that this might have been due to the effect of the formation of more calcium silicate hydrate (C-S-H) at certain replacement levels. Figure 4 shows the effect of the MSWI-BA content on the density of the mortar after 28 days of curing [46].

Figure 4. Density of mortar containing MSWI-BA, redrawn from [84]

Usually, the density of the cement mortar and concrete are mainly affected by the mixture ingredients. Owing to its low density when compared with NA, MSWI-BA can be effectively used to produce lighter cement-based materials. This is especially important for structural concrete, where properly utilizing aggregates of lower densities than that of NA contributes in reducing the dead weight of the structural members [92].

6.3. Strength

Abba et al. [93] partially replaced sand and fine gravel with MSWI-BA in concrete and stated that the compressive strength of the concrete was not affected by the utilization of MSWI-BA. However, the concrete mixes containing MSWI-BA had a remarkably higher coefficient of variation of the compressive strength when compared with the control mixes. Kim et al. [37] used MSWI-BA washed with NaOH to replace fine aggregates up to a 50% replacement level in concrete. The authors reported that using MSWI-BA caused a decrease in compressive strength. Yet, concrete containing treated MSWI-BA exhibited a higher compressive strength than that containing untreated MSWI-BA at the same replacement level. For example, at a 30% replacement level, the compressive strength of the concrete mix containing treated MSWI-BA reached 83% of the control mix, while the concrete containing untreated MSWI-BA reached only 76%. This is better illustrated in Figure 5 [37]. Similar results regarding the effect of treatment of MSWI-BA by NaOH on the compressive strength of concrete were reported elsewhere, where other treatment methods such as washing with water and glass separation also contributed in mitigating the reduction in compressive strength [52].

Figure 5. Effect of the chemical treatment of MSWI-BA on the compressive strength of concrete at 28 days, redrawn from [37].

Saad et al. [75] treated MSWI-BA by cement solidification prior to use as a partial replacement of NA in concrete and observed a decrease in compressive strength with the utilization of treated MSWI-BA. Nevertheless, the amount of cement used during the treatment process directly affected the compressive strength of the concrete mixes, as concrete incorporating solidified MSWI-BA with a higher cement content resulted in a lower reduction in compressive strength when compared with concrete containing NA. Sorlini et al. [94] partially replaced NA with MSWI-BA treated by washing and magnetic separation before use in concrete. The authors observed a drop in compressive strength of the concrete when using MSWI-BA. This was more noticeable in concrete mixes containing untreated MSWI-BA. Qiao et al. [90] revealed that concrete mixes including thermally treated MSWI-BA at 600–700 C generated a slightly higher compressive strength than that of the control mix. This is better illustrated in Figure 6 [90]. Baalbaki et al. [41] replaced sand with MSWI-BA at 25% and 50% replacement levels in concrete and reported a slight increase at the 25% replacement level and then a significant drop at the 50% replacement level. Similar results were observed elsewhere [89].

Figure 6. Effect of thermal treatment of MSWI-BA on the compressive strength of concrete at 28 days, redrawn from [90].

MSWI-BA was also substituted for sand in cement mortar by a few authors. Saikia et al. [95] replaced sand with MSWI-BA treated by washing with water at a 25% replacement level in cement mortar. It was reported that using MSWI-BA caused a significant loss of compressive strength of the cement mortar, reaching less than 50% of the compressive strength of the control mix. Yang et al. [39] fully replaced natural sand with MSWI-BA in cement mortar using different mineral admixtures. It was observed that using MSWI-BA caused around a 30% reduction in the compressive strength of the cement mortar. A number of studies also reported a decrease in the tensile and flexural strength when replacing NA with MSWI-BA in concrete and cement mortar [39,86,91,93,94,96].

Table 5 shows a comparison between the 28 day compressive strength of cementitious materials incorporating MSWI-BA as aggregates from the selected literature [38,47,83,85,88]. The comparison takes into consideration the total water-to-binder ratio, the particle size of the MSWI-BA used in the mix, the replacement level of MSWI-BA, and the treatment method. The last column shows the compressive strength value of each mix as a percentage of the control mix. In general, it can be noticed that the value of the compressive strength decreased when replacing NA with MSWI-BA, especially at high replacement levels. Nevertheless, different studies showed that the compressive strength could be maintained
at a 25% replacement level without additional treatments.

Table 5. Compressive strength at 28 days of cementitious materials containing MSWI-BA.

¹ Total water-to-binder ratio. ² Compressive strength at 28 days. ³ Effective water-to-binder ratio.

Lynn et al. [97] developed a model for estimating the compressive strength of the concrete that included MSWI-BA as aggregates. The model is presented in Equation (7), and it is based on a regression model developed by Abrams in 1918 [98]:

fc =A/0.91^w/c

where fc is the compressive strength of the concrete incorporating MSWI-BA as an aggregate at 28 days, w/c is the water-to-cement ratio, and the variable A is calculated using a wide range of parameters involving the control mix strength at 28 days, aggregate replacement level, treatment method, grading of the aggregate, and other physical and chemical characteristics of the MSWI-BA. The model achieved an R2 value of 0.82–0.84, indicating a good correlation.

It can be observed that using MSWI-BA in cement mortar and concrete causes a reduction in the compressive, tensile, and flexural strength. However, this can be alleviated by limiting the replacement level of MSWI-BA to ensure that a considerable drop in strength does not occur or by using treatment methods to improve the properties of the aggregate prior to use.

6.4. Water absorption

Baalbaki et al. [41] indicated that the water absorption of concrete increased with the increase in MSWI-BA content. This was explained by the higher surface area of MSWI-BA, contributing to higher water absorption. However, the water absorption of the concrete decreased with the increase of the curing age. Machaka et al. [89] reported that the water absorption of the concrete slightly increased when replacing sand with MSWI-BA at 25% and 50% replacement levels after 28 days of curing. Saad et al. [75] determined the water absorption of concrete including MSWI-BA solidified by cement and noticed that the concrete mixes containing MSWI-BA had much higher water absorption than that containing NA. Holmes et al. [91] reported that the water absorption of a concrete masonry block gradually increased with the increase in MSWI-BA content. However, according to the ASTM C90-11b standard of 12% water absorption in masonry blocks [99], replacing sand with MSWI-BA up to 20% is satisfactory. This is better illustrated in Figure 7 [91]. Similar results were reported elsewhere [100]. Ghanem et al. [46] reported an increase in the water absorption of the cement mortar with the increase in MSWI-BA content. However, the water absorption of the cement mortar mixes surprisingly increased and then decreased with the curing age. This was probably due to the hydration product distribution becoming a more dominant factor in the porosity of the mortar mixes in the late curing periods.

Figure 7. Water absorption of concrete masonry blocks, redrawn from [91].

Since it has relatively high water absorption when compared with NA, MSWI-BA is expected to contribute to the increase of water absorption in cement water and concrete. High water absorption in concrete negatively affects its durability, as the concrete becomes exposed for sulfate and chloride attacks [101].

6.5. Porosity

Pavlik et al. [102] substituted MSWI-BA for sand at 10% and 40% replacement levels in cement mortar and reported an increase in porosity from 20.9% in the control mix to 27.9% at a 40% replacement level. However, it was observed that the MSWI-BA did not affect the number of large pores, which remained approximately the same in all mixes. Müller and Rübner [85] observed that the particle size of MSWI-BA fully replacing NA affected the porosity of the concrete mixes, where the porosity increased from 11.7% in control mix to 17% when using MSWI-BA of a 0–8 mm size and 22.5% when using MSWI-BA of a 2–32 mm size. Tang et al. [86] noticed a gradual increase in porosity with the increase in MSWI-BA content in the concrete, ranging from 13.3% in the control mix to 18.3% at a 30% replacement level (Figure 8) [86]. Rübner et al. [52] observed that the porosity of the concrete doubled when using MSWI-BA as a replacement for NA and that different types of treatments, including washing with water, washing with NaOH, and glass separation, did not affect the behavior of MSWI-BA regarding the porosity.

Figure 8. Porosity of concrete containing MSWI-BA, with data from [86].

In general, the utilization of MSWI-BA as an aggregate causes an increase in the air porosity of the cement mortar and concrete. This is mainly due to the high porosity of MSWI-BA when compared with NA. Although it is unfavorable in structural concrete due to its negative impact on the strength, a high porosity can be beneficial in some applications, such as autoclaved aerated concrete [45,103] and pervious concrete [104].

6.6. Drying shrinkage

Shen et al. [47] reported an influence of MSWI-BA on the drying shrinkage of ultrahigh performance concrete, where the drying shrinkage increased with the increase in MSWI-BA content. The authors argued that the water used to presoak the MSWI-BA was released before the setting of the concrete, leading to an increase in the water-to-binder ratio of the cement paste rather than internal curing [105]. Cheng et al. [38] observed a gradual increase in the drying shrinkage of the cement mortar with the increase in the replacement level of MSWI-BA, where the differences became more significant in the late curing periods. Xuan et al. [44] fully replaced sand with MSWI-BA in cement mortar using different casting methods and curing conditions. It was reported that a substantial increase in the drying shrinkage of the cement mortar took place when the specimens were cured in an 80 °C NaOH solution with different casting methods, whereas the drying shrinkage slightly increased when the cement mortar was cured in 80 °C water when compared with 20 °C water. This is better illustrated in Figure 9 [44].

Figure 9. Drying shrinkage of dry-mixed cement mortar containing MSWI-BA, subjected to different curing regimes. Redrawn from [44].

7. Concluding remarks

The aim of this paper was to present MSWI-BA as a potential material for incorporation in cementitious materials. When compared with NA, MSWI-BA has a lower density and much higher water absorption. The chemical composition of MSWI-BA depends mainly on its source and usually contains amounts of heavy metals, sulfates, and chlorides. These elements can be deleterious when present in aggregates used in cementitious materials. Separation processes such as washing and magnetic density separation are beneficial for dealing with heavy metals and metallic aluminum and zinc. Solidification methods are efficient at immobilizing hazardous materials present in MSWI-BA. Thermal treatment is effective against chlorides and sulfates.

When used in cementitious materials, MSWI-BA usually causes a decrease in workability that could reach zero slump in some cases due to its high water absorption and lead to a drop in density. In addition, it causes a reduction in the compressive, tensile, and flexural strength. The water absorption and porosity understandably increase with the inclusion of MSWI-BA. Drying shrinkage increases as well. Although the effects of MSWIBA on the fresh, mechanical, and durability properties of cementitious materials are, in general, not favorable, the use of MSWI-BA as a partial replacement of NA is still possible. Different treatment methods could be used to upgrade the quality of this aggregate, and limited replacement levels could be applied to guarantee that the required properties of the cementitious materials are maintained.

Future research could include a wider exploration of possible industry-scale treatment methods, where the properties of MSWI-BA can be comparable to those of NA already in use in cementitious materials. Moreover, further study on promising applications of MSWI-BA, such as aerated, autoclaved concrete and pervious concrete, is essential for better interpretation of the effects of this waste material on the properties of these types of concrete. In addition, the possibility of using MSWI-BA as a precursor in alkali-activated concrete should be thoroughly addressed. 

Author Contributions: Conceptualization, J.B.; methodology, J.B.; validation, J.K. and S.K.; formal
analysis, S.K. and M.S.; investigation, J.B.; resources, J.B.; data curation, J.B. and S.K.; writing—original
draft preparation, J.B.; writing—review and editing, J.K.; visualization, M.S.; supervision, J.K.; project
administration, J.K. All authors have read and agreed to the published version of the manuscript.

Funding: This research received no external funding.

Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.
Data Availability Statement: Data sharing not applicable.
Acknowledgments: The authors would like to acknowledge the administrative and technical support offered by the Faculty of Engineering in Beirut Arab University.
Conflicts of Interest: The authors declare no conflict of interest.

References

1. Al-Ghouti, M.A.; Khan, M.; Nasser, M.S.; Al Saad, K.; Heng, O.E. Recent advances and applications of municipal solid wastes bottom and fly ashes: Insights into sustainable management and conservation of resources. Environ. Technol. Innov. 2020, 21, 101267. [CrossRef]
2. Levine, D. Municipal SolidWaste Management: A Roadmap for Reform for Policy Makers; TheWorld Bank: Washington, DC, USA, 2018.
3. The World Bank. Solid Waste Management. Available online: https://www.worldbank.org/en/topic/urbandevelopment/brief/ solid-waste-management (accessed on 1 March 2021).
4. Xue, W.; Cao, K.; Li,W. Municipal solid waste collection optimization in Singapore. Appl. Geogr. 2015, 62, 182–190. [CrossRef]
5. Harijani, A.M.; Mansour, S.; Karimi, B.; Lee, C.-G. Multi-period sustainable and integrated recycling network for municipal solid waste—A case study in Tehran. J. Clean. Prod. 2017, 151, 96–108. [CrossRef]
6. Das, S.; Lee, S.-H.; Kumar, P.; Kim, K.-H.; Lee, S.S.; Bhattacharya, S.S. Solid waste management: Scope and the challenge of sustainability. J. Clean. Prod. 2019, 228, 658–678. [CrossRef]
7. Tang, C.-S.; Paleologos, E.K.; Vitone, C.; Du, Y.-J.; Li, J.-S.; Jiang, N.-J.; Deng, Y.-F.; Chu, J.; Shen, Z.; Koda, E. Environmental Geotechnics: Challenges and Opportunities in the Post COVID-19 World. Environ. Geotech. 2020, 40, 1–21.
8. Kulkarni, B.N.; Anantharama, V. Repercussions of COVID-19 pandemic on municipal solid waste management: Challenges and opportunities. Sci. Total Environ. 2020, 743, 140693. [CrossRef] [PubMed]
9. Nanda, S.; Berruti, F. Municipal solid waste management and landfilling technologies: A review. Environ. Chem. Lett. 2021, 19, 1433–1456. [CrossRef]
10. Wagner, T.P.; Raymond, T. Landfill mining: Case study of a successful metals recovery project. Waste Manag. 2015, 45, 448–457. [CrossRef]
11. Osinowo, O.O.; Falufosi, M.O.; Omiyale, E.O. Integrated electromagnetic (EM) and Electrical Resistivity Tomography (ERT) geophysical studies of environmental impact of Awotan dumpsite in Ibadan, southwestern Nigeria. J. Afr. Earth Sci. 2018, 140, 42–51. [CrossRef]
12. Mukherjee, S.; Mukhopadhyay, S.; Hashim, M.A.; Sen Gupta, B. Contemporary environmental issues of landfill leachate: Assessment and remedies. Crit. Rev. Environ. Sci. Technol. 2015, 45, 472–590. [CrossRef]
13. Massarutto, A. Economic aspects of thermal treatment of solid waste in a sustainable WM system. Waste Manag. 2015, 37, 45–57. [CrossRef] [PubMed]
14. Lu, J.-W.; Zhang, S.; Hai, J.; Lei, M. Status and perspectives of municipal solid waste incineration in China: A comparison with developed regions. Waste Manag. 2017, 69, 170–186. [CrossRef] [PubMed]
15. Arvanitoyannis, I.S.Waste management for polymers in food packaging industries. In Plastic Films in Food Packaging; Elsevier: Amsterdam, The Netherlands, 2013; pp. 249–310. ISBN 1455731129.
16. Clavier, K.A.; Paris, J.M.; Ferraro, C.C.; Townsend, T.G. Opportunities and challenges associated with using municipal waste incineration ash as a raw ingredient in cement production—A review. Resour. Conserv. Recycl. 2020, 160, 104888. [CrossRef]
17. Setoodeh Jahromy, S.; Jordan, C.; Azam, M.; Werner, A.; Harasek, M.; Winter, F. Fly ash from municipal solid waste incineration as a potential thermochemical energy storage material. Energy Fuels 2019, 33, 5810–5819. [CrossRef]
18. Ferraro, A.; Farina, I.; Race, M.; Colangelo, F.; Cioffi, R.; Fabbricino, M. Pre-treatments of MSWI fly-ashes: A comprehensive review to determine optimal conditions for their reuse and/or environmentally sustainable disposal. Rev. Environ. Sci. Bio/Technol.
2019, 18, 453–471. [CrossRef]
19. Dungca, J.R.; Jao, J.A.L. Strength and permeability characteristics of road base materials blended with fly ash and bottom ash. Int. J. Geomate 2017, 12, 9–15. [CrossRef]
20. Lynn, C.J.; Ghataora, G.S.; Obe, R.K.D. Municipal incinerated bottom ash (MIBA) characteristics and potential for use in road pavements. Int. J. Pavement Res. Technol. 2017, 10, 185–201. [CrossRef]
21. Aberg, A.; Kumpiene, J.; Ecke, H. Evaluation and prediction of emissions from a road built with bottom ash from municipal solid waste incineration (MSWI). Sci. Total Environ. 2006, 355, 1–12. [CrossRef]
22. Gupta, V.K.; Ali, I.; Saini, V.K.; Van Gerven, T.; Van der Bruggen, B.; Vandecasteele, C. Removal of dyes from wastewater using bottom ash. Ind. Eng. Chem. Res. 2005, 44, 3655–3664. [CrossRef]
23. Ducom, G.; Radu-Tirnoveanu, D.; Pascual, C.; Benadda, B.; Germain, P. Biogas—Municipal solid waste incinerator bottom ash interactions: Sulphur compounds removal. J. Hazard. Mater. 2009, 166, 1102–1108. [CrossRef]
24. Andreola, F.; Barbieri, L.; Corradi, A.; Lancellotti, I.; Manfredini, T. The possibility to recycle solid residues of the municipal waste incineration into a ceramic tile body. J. Mater. Sci. 2001, 36, 4869–4873. [CrossRef]

25. Andreola, N.M.; Barbieri, L.; Lancellotti, I.; Pozzi, P. Recycling industrial waste in brick manufacture. Part 1. Mater. Constr. 2005, 55, 5–16.
26. Andreola, F.; Barbieri, L.; Hreglich, S.; Lancellotti, I.; Morselli, L.; Passarini, F.; Vassura, I. Reuse of incinerator bottom and fly ashes to obtain glassy materials. J. Hazard. Mater. 2008, 153, 1270–1274. [CrossRef] [PubMed]
27. Pera, J.; Coutaz, L.; Ambroise, J.; Chababbet, M. Use of incinerator bottom ash in concrete. Cem. Concr. Res. 1997, 27, 1–5. [CrossRef]
28. Jansegers, E. The Use of MSWI Bottom Ash in Hollow Construction Materials. In Waste Materials in Construction; Goumans, J.J.J.M., Senden, G.J., van der Sloot, H.A.B.T.-S., Eds.; Elsevier: Amsterdam, The Netherlands, 1997; Volume 71, pp. 431–436.
29. Schneider, M.; Romer, M.; Tschudin, M.; Bolio, H. Sustainable cement production—Present and future. Cem. Concr. Res. 2011, 41, 642–650. [CrossRef]
30. Collivignarelli, M.C.; Cillari, G.; Ricciardi, P.; Miino, M.C.; Torretta, V.; Rada, E.C.; Abbà, A. The Production of Sustainable Concrete with the Use of Alternative Aggregates: A Review. Sustainability 2020, 12, 7903. [CrossRef]
31. Sonak, S.; Pangam, P.; Sonak, M.; Mayekar, D. Impact of sand mining on local ecology. In Multiple Dimensions of Global Environmental Change; Sonak, S., Ed.; TERI Press: New Delhi, India, 2006; pp. 101–121.
32. Coppola, L.; Bellezze, T.; Belli, A.; Bignozzi, M.C.; Bolzoni, F.; Brenna, A.; Cabrini, M.; Candamano, S.; Cappai, M.; Caputo, D. et al. Binders alternative to Portland cement and waste management for sustainable construction—Part 2. J. Appl. Biomater. Funct. Mater. 2018, 16, 207–221. [CrossRef]
33. Siddique, R. Use of municipal solid waste ash in concrete. Resour. Conserv. Recycl. 2010, 55, 83–91. [CrossRef]
34. Dou, X.; Ren, F.; Nguyen, M.Q.; Ahamed, A.; Yin, K.; Chan,W.P.; Chang, V.W.-C. Review of MSWI bottom ash utilization from perspectives of collective characterization, treatment and existing application. Renew. Sustain. Energy Rev. 2017, 79, 24–38. [CrossRef]
35. Wiles, C.C. Municipal solid waste combustion ash: State-of-the-knowledge. J. Hazard. Mater. 1996, 47, 325–344. [CrossRef]
36. Xuan, D.; Tang, P.; Poon, C.S. Limitations and quality upgrading techniques for utilization of MSW incineration bottom ash in engineering applications—A review. Constr. Build. Mater. 2018, 190, 1091–1102. [CrossRef]
37. Kim, J.; Nam, B.H.; Al Muhit, B.A.; Tasneem, K.M.; An, J. Effect of chemical treatment of MSWI bottom ash for its use in concrete. Mag. Concr. Res. 2015, 67, 179–186. [CrossRef]
38. Cheng, A. Effect of incinerator bottom ash properties on mechanical and pore size of blended cement mortars. Mater. Des. 2012, 36, 859–864. [CrossRef]
39. Yang, M.-J.; Wang, H.-Y.; Liang, C.-F. Effects on strengths of cement mortar when using incinerator bottom ash as fine aggregate. World J. Eng. Technol. 2014, 2, 42–47. [CrossRef]
40. Al Muhit, B.A.; An, J.; Nam, B.H. Recycling of Municipal SolidWaste Incineration (MSWI) Ash as Aggregate Replacement in Concrete. In Proceedings of the IFCEE 2015, Reston, VA, USA, 17–21 March 2015; pp. 2797–2806.
41. Baalbaki, O.; Elkordi, A.; Ghanem, H.; Machaka, M.; Khatib, J.M. Properties of concrete made of fine aggregates partially replaced by incinerated municipal solid waste bottom ash. Acad. J. Civ. Eng. 2019, 37, 532–538.
42. Lam, C.H.K.; Ip, A.W.M.; Barford, J.P.; McKay, G. Use of Incineration MSW Ash: A Review. Sustainability 2010, 2, 1943–1968. [CrossRef]
43. Saikia, N.; Mertens, G.; Van Balen, K.; Elsen, J.; Van Gerven, T.; Vandecasteele, C. Pre-treatment of municipal solid waste incineration (MSWI) bottom ash for utilisation in cement mortar. Constr. Build. Mater. 2015, 96, 76–85. [CrossRef]
44. Xuan, D.; Tang, P.; Poon, C.S. Effect of casting methods and SCMs on properties of mortars prepared with fine MSW incineration bottom ash. Constr. Build. Mater. 2018, 167, 890–898. [CrossRef]
45. Li, X.; Liu, Z.; Lv, Y.; Cai, L.; Jiang, D.; Jiang,W.; Jian, S. Utilization of municipal solid waste incineration bottom ash in autoclaved aerated concrete. Constr. Build. Mater. 2018, 178, 175–182. [CrossRef]
46. Ghanem, H.; Khatib, J.; Elkordi, A. Effect of partial replacement of sand by mswi-ba on the properties of mortar. BAU J.—Sci. Technol. 2020, 1, 4.
47. Shen, P.; Zheng, H.; Xuan, D.; Lu, J.-X.; Poon, C.S. Feasible use of municipal solid waste incineration bottom ash in ultra-high performance concrete. Cem. Concr. Compos. 2020, 114, 103814. [CrossRef]
48. Zhang, H.; He, P.-J.; Shao, L.-M.; Li, X.-J. Leaching behavior of heavy metals from municipal solid waste incineration bottom ash and its geochemical modeling. J. Mater. Cycles Waste Manag. 2008, 10, 7–13. [CrossRef]
49. Grosso, M.; Biganzoli, L.; Rigamonti, L. A quantitative estimate of potential aluminium recovery from incineration bottom ashes. Resour. Conserv. Recycl. 2011, 55, 1178–1184. [CrossRef]
50. Shreir, L.L.; Jarman, R.A.; Burstein, G.T. Corrosion, 3rd ed.; Butterworth-Heinemann: Oxford, UK, 1994; ISBN 0750610778.
51. Bertolini, L.; Carsana, M.; Cassago, D.; Quadrio Curzio, A.; Collepardi, M. MSWI ashes as mineral additions in concrete. Cem. Concr. Res. 2004, 34, 1899–1906. [CrossRef]
52. Rübner, K.; Haamkens, F.; Linde, O. Use of municipal solid waste incinerator bottom ash as aggregate in concrete. Q. J. Eng. Geol. Hydrogeol. 2008, 41, 459–464. [CrossRef]
53. Ichikawa, T.; Miura, M. Modified model of alkali-silica reaction. Cem. Concr. Res. 2007, 37, 1291–1297. [CrossRef]
54. Karthik, M.M.; Mander, J.B.; Hurlebaus, S. ASR/DEF related expansion in structural concrete: Model development and validation. Constr. Build. Mater. 2016, 128, 238–247. [CrossRef]
55. Taylor, H.F.W.; Famy, C.; Scrivener, K.L. Delayed ettringite formation. Cem. Concr. Res. 2001, 31, 683–693. [CrossRef]

56. Collepardi, M. A state-of-the-art review on delayed ettringite attack on concrete. Cem. Concr. Compos. 2003, 25, 401–407. [CrossRef]
57. Tang, P.; Florea, M.V.A.; Spiesz, P.; Brouwers, H.J.H. Characteristics and application potential of municipal solid waste incineration (MSWI) bottom ashes from two waste-to-energy plants. Constr. Build. Mater. 2015, 83, 77–94. [CrossRef]
58. Thomas, M.; Folliard, K.; Drimalas, T.; Ramlochan, T. Diagnosing delayed ettringite formation in concrete structures. Cem. Concr. Res. 2008, 38, 841–847. [CrossRef]
59. Apostolopoulos, C.A.; Demis, S.; Papadakis, V.G. Chloride-induced corrosion of steel reinforcement—Mechanical performance and pit depth analysis. Constr. Build. Mater. 2013, 38, 139–146. [CrossRef]
60. Ahmad, S. Reinforcement corrosion in concrete structures, its monitoring and service life prediction—A review. Cem. Concr. Compos. 2003, 25, 459–471. [CrossRef]
61. Joseph, A.M.; Snellings, R.; Van den Heede, P.; Matthys, S.; De Belie, N. The use of municipal solid waste incineration ash in various building materials: A Belgian point of view. Materials 2018, 11, 141. [CrossRef] [PubMed]
62. Yang, S.; Saffarzadeh, A.; Shimaoka, T.; Kawano, T. Existence of Cl in municipal solid waste incineration bottom ash and dechlorination effect of thermal treatment. J. Hazard. Mater. 2014, 267, 214–220. [CrossRef]
63. Lidelöw, S.; Lagerkvist, A. Evaluation of leachate emissions from crushed rock and municipal solid waste incineration bottom ash used in road construction. Waste Manag. 2007, 27, 1356–1365. [CrossRef]
64. Abou Shakra, J.; Joumblat, R.; Khatib, J.; Elkordi, A. Corrosion of coated and uncoated steel reinforcement in concrete. BAU J.-Sci. Technol. 2020, 2, 4.
65. Mangialardi, T. Disposal of MSWI fly ash through a combined washing-immobilisation process. J. Hazard. Mater. 2003, 98, 225–240. [CrossRef]
66. Jiang, Y.; Xi, B.; Li, X.; Zhang, L.; Wei, Z. Effect of water-extraction on characteristics of melting and solidification of fly ash from municipal solid waste incinerator. J. Hazard. Mater. 2009, 161, 871–877. [CrossRef]
67. Kim, S.-Y.; Matsuto, T.; Tanaka, N. Evaluation of pre-treatment methods for landfill disposal of residues from municipal solid waste incineration. Waste Manag. Res. 2003, 21, 416–423. [CrossRef]
68. Zhang, H.; He, P.-J.; Shao, L.-M. Fate of heavy metals during municipal solid waste incineration in Shanghai. J. Hazard. Mater. 2008, 156, 365–373. [CrossRef] [PubMed]
69. Xuan, D.; Poon, C.S. Removal of metallic Al and Al/Zn alloys in MSWI bottom ash by alkaline treatment. J. Hazard. Mater. 2018, 344, 73–80. [CrossRef]
70. Luo, H.; Cheng, Y.; He, D.; Yang, E.-H. Review of leaching behavior of municipal solid waste incineration (MSWI) ash. Sci. Total Environ. 2019, 668, 90–103. [CrossRef] [PubMed]
71. Ferreira, C.; Jensen, P.; Ottosen, L.; Ribeiro, A. Removal of selected heavy metals from MSW fly ash by the electrodialytic process. Eng. Geol. 2005, 77, 339–347. [CrossRef]
72. Jensen, P.E.; Kirkelund, G.M.; Pedersen, K.B.; Dias-Ferreira, C.; Ottosen, L.M. Electrodialytic upgrading of three different municipal solid waste incineration residue types with focus on Cr, Pb, Zn, Mn, Mo, Sb, Se, V, Cl and SO4. Electrochim. Acta 2015, 181, 167–178. [CrossRef]
73. Xia, Y.; He, P.; Shao, L.; Zhang, H. Metal distribution characteristic of MSWI bottom ash in view of metal recovery. J. Environ. Sci. 2017, 52, 178–189. [CrossRef]
74. Muchova, L.; Bakker, E.; Rem, P. Precious metals in municipal solid waste incineration bottom ash. Water Air Soil Pollut. Focus 2009, 9, 107–116. [CrossRef]
75. Saad, M.; Baalbaki, O.; Khatib, J.; El Kordi, A.; Masri, A. Manufacturing of Lightweight Aggregates from Municipal Solid Waste Incineration Bottom Ash and their Impacts on Concrete Properties. In Proceedings of the 2nd International Congress on Engineering and Architecture, Marmaris, Turkey, 22–24 April 2019; pp. 1638–1649.
76. Cioffi, R.; Colangelo, F.; Montagnaro, F.; Santoro, L. Manufacture of artificial aggregate using MSWI bottom ash. Waste Manag. 2011, 31, 281–288. [CrossRef]
77. Shi, D.; Hu, C.; Zhang, J.; Li, P.; Zhang, C.; Wang, X.; Ma, H. Silicon-aluminum additives assisted hydrothermal process for stabilization of heavy metals in fly ash from MSW incineration. Fuel Process. Technol. 2017, 165, 44–53. [CrossRef]
78. Jing, Z.; Matsuoka, N.; Jin, F.; Hashida, T.; Yamasaki, N. Municipal incineration bottom ash treatment using hydrothermal solidification. Waste Manag. 2007, 27, 287–293. [CrossRef] [PubMed]
79. Roessler, J.G.; Olivera, F.D.;Wasman, S.J.; Townsend, T.G.; McVay, M.C.; Ferraro, C.C.; Blaisi, N.I. Construction material properties of slag from the high temperature arc gasification of municipal solid waste. Waste Manag. 2016, 52, 169–179. [CrossRef]
80. Xiao, Y.; Oorsprong, M.; Yang, Y.; Voncken, J.H.L. Vitrification of bottom ash from a municipal solid waste incinerator. Waste Manag. 2008, 28, 1020–1026. [CrossRef] [PubMed]
81. Ecke, H.; Sakanakura, H.; Matsuto, T.; Tanaka, N.; Lagerkvist, A. State-of-the-art treatment processes for municipal solid waste incineration residues in Japan. Waste Manag. Res. 2000, 18, 41–51. [CrossRef]
82. Cheeseman, C.R.; Makinde, A.; Bethanis, S. Properties of lightweight aggregate produced by rapid sintering of incinerator bottom ash. Resour. Conserv. Recycl. 2005, 43, 147–162. [CrossRef]
83. Ferraris, M.; Salvo, M.; Ventrella, A.; Buzzi, L.; Veglia, M. Use of vitrified MSWI bottom ashes for concrete production. Waste Manag. 2009, 29, 1041–1047. [CrossRef]
84. Terro, M.J. Properties of concrete made with recycled crushed glass at elevated temperatures. Build. Environ. 2006, 41, 633–639. [CrossRef]

85. Müller, U.; Rübner, K. The microstructure of concrete made with municipal waste incinerator bottom ash as an aggregate component. Cem. Concr. Res. 2006, 36, 1434–1443. [CrossRef]
86. Tang, P.; Yu, Q.L.; Yu, R.; Brouwers, H.J.H. The application of MSWI bottom ash fines in high performance concrete. In Proceedings of the 1st International Conference on the Chemistry of Construction Materials, Berlin, Germany, 7–9 October 2013; Citeseer: Berlin, Germany, 2013; pp. 435–438.
87. Zhang, T.; Zhao, Z. Optimal Use of MSWI Bottom Ash in Concrete. Int. J. Concr. Struct. Mater. 2014, 8, 173–182. [CrossRef]
88. Al-Rawas, A.A.;Wahid Hago, A.; Taha, R.; Al-Kharousi, K. Use of incinerator ash as a replacement for cement and sand in cement mortars. Build. Environ. 2005, 40, 1261–1266. [CrossRef]
89. Machaka, M.; Khatib, J.; Elkordi, A.; Ghanem, H.; Baalbaki, O. Selected properties of concrete containing Municipal Solid Waste Incineration Bottom Ash (MSWI-BA). In Proceedings of the 5th International Conference on Sustainable Construction Materials and Technologies (SCMT5), London, UK, 14–17 July 2019; Volume 1, pp. 305–317.
90. Qiao, X.C.; Ng, B.R.; Tyrer, M.; Poon, C.S.; Cheeseman, C.R. Production of lightweight concrete using incinerator bottom ash. Constr. Build. Mater. 2008, 22, 473–480. [CrossRef]
91. Holmes, N.; O’Malley, H.; Cribbin, P.; Mullen, H.; Keane, G. Performance of masonry blocks containing different proportions of incinator bottom ash. Sustain. Mater. Technol. 2016, 8, 14–19. [CrossRef]
92. Vijayalakshmi, R.; Ramanagopal, S. Structural concrete using expanded clay aggregate: A review. Indian J. Sci. Technol. 2018, 8, 1–12. [CrossRef]
93. Abbà, A.; Collivignarelli, M.C.; Sorlini, S.; Bruggi, M. On the reliability of reusing bottom ash from municipal solid waste incineration as aggregate in concrete. Compos. Part B Eng. 2014, 58, 502–509. [CrossRef]
94. Sorlini, S.; Abbà, A.; Collivignarelli, C. Recovery of MSWI and soil washing residues as concrete aggregates. Waste Manag. 2011, 31, 289–297. [CrossRef]
95. Saikia, N.; Cornelis, G.; Mertens, G.; Elsen, J.; Van Balen, K.; Van Gerven, T.; Vandecasteele, C. Assessment of Pb-slag, MSWI bottom ash and boiler and fly ash for using as a fine aggregate in cement mortar. J. Hazard. Mater. 2008, 154, 766–777. [CrossRef] [PubMed]
96. Aggarwal, P.; Aggarwal, Y.; Gupta, S.M. Effect of bottom ash as replacement of fine aggregates in concrete. Asian J. Civ. Eng. 2007, 8, 49–62.
97. Lynn, C.J.; Dhir, R.K.; Ghataora, G.S. Use of incinerated ashes as aggregate in concrete: A compressive strength model. Mag. Concr. Res. 2019, 71, 1253–1264. [CrossRef]
98. Abrams, D.A. Effect of Time of Mixing on the Strength and Wear of Concrete. J. Proc. 1918, 14, 22–92.
99. Standard Specification for Loadbearing Concrete Masonry Units; ASTM C90-11b; ASTM International: West Conshohocken, PA, USA, 2011.
100. Abeykoon, A.; Anthony, C.; De Silva, G. Bottom Ash as Replacement of Sand for Manufacturing Masonry Blocks; University Ruhuna:Matara, Sri Lanka, 2012.
101. Zhang, S.P.; Zong, L. Evaluation of relationship between water absorption and durability of concrete materials. Adv. Mater. Sci.  Eng. 2014, 2014, 650373. [CrossRef]
102. Pavlík, Z.; Keppert, M.; Pavlíková, M.; Volfová, P. Application of MSWI bottom ash as alternative aggregate in cement mortar. WIT Trans. Ecol. Environ. 2011, 148, 335–342. [CrossRef]
103. Zhu,W.; Teoh, P.J.; Liu, Y.; Chen, Z.; Yang, E.-H. Strategic utilization of municipal solid waste incineration bottom ash for the synthesis of lightweight aerated alkali-activated materials. J. Clean. Prod. 2019, 235, 603–612. [CrossRef]
104. Kuo,W.-T.; Liu, C.-C.; Su, D.-S. Use of washed municipal solid waste incinerator bottom ash in pervious concrete. Cem. Concr. Compos. 2013, 37, 328–335. [CrossRef]
105. Shen, P.; Lu, L.; Wang, F.; He, Y.; Hu, S.; Lu, J.; Zheng, H. Water desorption characteristics of saturated lightweight fine aggregate in ultra-high performance concrete. Cem. Concr. Compos. 2020, 106, 103456. [CrossRef]