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Article

The Mechanical Strength of Ecological Cement Mortars Based on Fly Ash from the Combustion of Municipal Waste and Cement Kiln Dust

by
Alina Pietrzak
and
Malgorzata Ulewicz
*
Faculty of Civil Engineering, Czestochowa University of Technology, 42-201 Czestochowa, Poland
*
Author to whom correspondence should be addressed.
Appl. Sci. 2025, 15(6), 3215; https://doi.org/10.3390/app15063215
Submission received: 7 February 2025 / Revised: 9 March 2025 / Accepted: 13 March 2025 / Published: 15 March 2025
(This article belongs to the Section Civil Engineering)
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Abstract

:
The article presents the physico-mechanical properties of cement mortars modified with the addition of fly ash generated from municipal waste incineration (MSWI-FA) and dust from rotary kiln dedusting installations (CKD—cement kiln dust) produced during cement manufacturing. The waste materials were dosed separately and in combination—MSWI-FA in amounts of 10, 15, and 20% of the cement mass, with a volumetric adjustment of the standard sand mass, while CKD was used as a cement replacement in amounts of 10, 15, and 20% of the cement mass. Basic tests were conducted on the prepared mortars, including consistency and flexural and compressive strength after 7 and 28 days of curing, water absorption, bulk density, and resistance to freeze–thaw cycles. The results indicate that the addition of MSWI-FA and CKD reduces the strength of mortars compared to the control series, with CKD proving to be more effective and stable than MSWI-FA, especially over longer curing periods. The combination of MSWI-FA and CKD often resulted in the greatest decline in mechanical parameters, suggesting limited synergy between these materials. The best results were achieved using low additive concentrations, especially in the MSWI-FA-CKD/3–3 (i.e., after 3% of the MSWI-FA and CKD waste) combination. The research confirms the potential of utilizing MSWI-FA and CKD in sustainable cement compositions but highlights the need for further work on optimizing proportions and modification techniques. The importance of these efforts for reducing environmental impact and promoting a circular economy is emphasized.

1. Introduction

Cement remains one of the most widely used materials in construction worldwide. In 2023, global cement production reached approximately 4.1 billion tons, a figure similar to that of 2022 [1]. Since 2013, the annual production of this material has consistently exceeded 4 billion tons globally. In 2022, the European Union produced 176 million tons of cement, underscoring the critical role of this material in European construction [2]. However, cement production significantly impacts the natural environment. Carbon dioxide emissions associated with the process are substantial, and large amounts of waste are generated. One of the by-products of the manufacturing process is rotary kiln dust, known as CKD (cement kiln dust). In some cases, bypass dust, referred to as CBPD (Cement Bypass Dust), is also generated. CKD is a by-product always produced during cement manufacturing, whereas CBPD occurs only when alternative fuels are used or when it is necessary to limit the chlorine and alkali content in the process [3]. The chemical composition and properties of CKD and CBPD can vary depending on the raw materials, fuel, and production technology used. CKD is typically less contaminated, while CBPD is characterized by higher contents of chlorides, potassium oxide, and sulfur trioxide, limiting its usability in other industrial sectors. The amount of by-products such as CKD and CBPD can range from 0% to 25% of the clinker mass, depending on the production technology and raw materials used [4]. In large cement plants, daily CBPD production can reach up to 1000 tons [5].
Waste dust from cement production are classified under waste category 10 13 80. Cement kiln dust (CKD) is finding increasingly diverse applications in various industrial fields, helping to mitigate its negative environmental impact. Cement kiln dust (CKD) has been widely acknowledged as a cost-effective material for soil stabilization in various studies. For instance, Moon et al. examined its role in stabilizing and solidifying polluted soils [6], while Gupta et al. explored its application in inactivating heavy metals present in contaminated soils [7]. Carlson et al. highlighted its effectiveness in improving the engineering properties of soil [8], and Albusoda and Salem applied CKD for the stabilization of dune sands [9]. Similarly, Arulrajah et al. assessed its impact on aggregate stabilization [10], and Ekpo et al. investigated its potential in optimizing the plasticity of tropical soils [11]. Furthermore, Mohamed et al. utilized CKD in the production of building materials and road paving [12], while Mohammadinia et al. focused on its capacity to enhance the stiffness and strength of aggregates [13]. Okafor and Egbe demonstrated its use in improving sub-grade materials [14], and Ebrahimi et al. emphasized its ability to increase soil stiffness [15]. Finally, Sreekrish et al. highlighted CKD’s role in soil treatment [16]. These studies collectively emphasize CKD’s versatility and wide-ranging applications in soil and aggregate stabilization.
CKD has been successfully used as a replacement for cement in various proportions (5–50%) in applications such as self-consolidating concrete [17], concrete paving blocks [18], lightweight concrete [19], concrete and mortar [20,21], and concrete production [22,23,24]. Due to its properties, CKD helps reduce carbon dioxide emissions associated with cement production, making it a more environmentally friendly solution. Additionally, its application can lower production costs in the construction industry, especially in large-scale projects. In the ceramic and brick industry, CKD also finds extensive use as a cementitious material in various proportions (2–50%). It has been used for producing wollastonite ceramics [25], red clay bricks [26], brick production [27], and pressed building bricks [28]. CKD, with its binding properties, enhances the durability and strength of finished products, making it an attractive raw material for the ceramic sector. Furthermore, its usage can contribute to the reduction in industrial waste, supporting circular economy principles. Equally important is the multi-criteria assessment of the efficiency of post-process waste utilization [29].
In the context of a circular economy, increasing attention is being given to the potential use of another material—waste fly ash (MSWI-FA) generated during the incineration of municipal waste. Interest in the thermal treatment of waste is growing as the volume of municipal waste continues to increase. In 2022, the average per capita generation of municipal waste in the European Union was 513 kg, of which 61.1% was recovered, including 20.2% that underwent thermal treatment with energy recovery. Waste fly ash, classified under the code 19 01 13*, is produced as a by-product during the incineration of municipal waste in thermal waste treatment facilities. According to the European waste catalog, this code refers to fly ash containing hazardous substances. Such ash is characterized by a fine grain fraction and a substantial specific surface area, which significantly influence its physicochemical properties. This material can be considered a substitute for natural aggregate in the production of mortars or concrete. This is justified because a number of waste materials, such as fly ash from coal combustion, silica ash, blast furnace slag, and ash from waste incineration, have been successfully used for the production of mortars and concrete [30,31,32,33,34,35,36,37]. Additionally, polymeric materials like PET, polyethylene, and polypropylene have shown similar utility [38,39,40,41,42,43,44]. Several works have also been published on the use of waste such as slag (MSWI-slag), bottom ash (MSWI-BA), and fly ash (MSWI-FA) from the thermal transformation of municipal waste for this purpose [45,46,47]. MSWI-FA has found applications in geopolymers [48,49,50,51] and as an additive in cement [52,53,54]. In some cases, MSWI-FA undergoes a melting process at 1450 °C in an electric furnace for one hour, followed by milling, before being incorporated into slag-cement mortars [55,56]. When partially replacing Portland cement (10–40%) alongside CaCO3 (10–40% by weight), these composites achieve high compressive strength after 90 days of curing. Furthermore, MSWI-FA has been used in concrete [37,39] and mortars [54,57,58,59,60,61,62,63], though it often reduces the compressive strength of mortars compared to control samples. However, incorporating 0.1% polypropylene fibers into concrete containing MSWI-FA has been shown to enhance compressive strength [64,65]. These findings highlight the innovative potential of MSWI-derived materials in sustainable construction, offering environmental and performance benefits.
The article analyzes research on the potential use of fly ash from municipal waste incineration (MSWI-FA) and dust from rotary kiln dedusting installations (CKD) in the production of cement mortars. Incorporating these materials into construction products could reduce the amount of waste sent to landfills and limit the exploitation of natural resources while simultaneously improving the mechanical properties and durability of the products. This strategy supports a circular economy, contributing to sustainable development and minimizing negative environmental impacts. It is worth emphasizing that, as indicated by the cited publications, the studied waste materials have so far been used only individually. This article presents research findings in which, in addition to the individual use of each type of waste, their mixture was also incorporated into the technology of cement mortar production. This approach significantly expands the application possibilities, enabling the effective use of a wider range of waste materials in construction without compromising their mechanical properties.

2. Materials and Methods

2.1. Materials

For the cement mortar studies, Portland cement CEM I 42.5R was used, meeting the requirements of the PN-EN 197–1 standard [66], along with standardized quartz sand with a 0–2 mm fraction in accordance with PN-EN 196-1 [67], and tap water from Czestochowa compliant with PN-EN 1008: 2004 [68]. The water contained an average of 37.0 mg/dm3 of nitrates, 31.5 mg/dm3 of chlorides, and 53.8 mg/dm3 of sulfates. Two waste materials were also used: fly ash generated from municipal waste incineration (code 19 01 13*) and dust from rotary kiln dedusting (CKD) used in cement production (code 10 13 80). Both materials were sourced from the local market in Poland (Figure 1). MSWI waste was collected from a municipal solid waste thermal treatment plant located in the Małopolskie Voivodeship (Poland). The waste was collected over a three-month period at the turn of 2023/2024, and the sample for testing was homogenized. The chemical composition of these waste materials (Table 1) was determined using SpectroXEPOS X-ray fluorescence spectroscopy (SPECTRO, Józefów, Poland), and their specific density was measured in accordance with PN-EN 196–6 [69]: 2.32 g/cm3 for fly ash (MSWI-FA) and 2.63 g/cm3 for kiln dust (CKD). The chemical composition determines the suitability of waste for use in cement composites. MSWI-FA was used as a sand substitute because it does not have binding properties at a level that would allow it to replace cement, and CKD (containing over 60% CaO and SiO2, Al2O3) is a cement substitute.
A thermal analysis (TGA-DTA) was performed for the waste materials used in the study using an SDT 650 thermoanalyzer from TA Instruments (New Castle, DE, USA). Thermograms were recorded in a synthetic air atmosphere with a heating rate of 10 °C/min up to 1000 °C. The results include thermogravimetry (TG), differential thermogravimetry (DTG), and differential thermal analysis (DTA). Based on the TG/DTA curves for the MSWI-FA sample (Figure 2), a slight mass loss was observed in the temperature range of 300–400 °C, which may be associated with the loss of physically and chemically bound water. In this temperature range (approximately 300–400 °C), the decomposition of magnesium carbonate (MgCO3) may also occur, as it is reported in the literature to decompose in the range of 170–330 °C. A minor endothermic peak on the DTA curve confirms the carbonate decomposition reaction. Additionally, an endothermic peak observed in the 600–800 °C range on the DTA curve corresponds to the decomposition of calcium carbonates, aligning with the mass loss observed on the TG curve in the same temperature range. According to literature data, calcium carbonate decomposition occurs between 550 °C and 825 °C. For the CKD sample (Figure 3), mass losses were observed in two temperature ranges: approximately 500–600 °C and 700–800 °C. These ranges coincide with two endothermic peaks on the DTA curve, likely associated with the decomposition of calcium carbonates.

2.2. Research Methods

A control mortar was prepared according to the standard [66] along with 14 series of modified mortars incorporating waste materials. Fly ash (MSWI-FA) was added in amounts of 10%, 15%, and 20% of the cement mass, with corresponding adjustments to the volume of standard sand. Cement kiln dust (CKD) was used as a replacement for cement in amounts of 10%, 15%, and 20% of the cement mass. These waste materials were dosed both individually and in combination in various proportions. The compositions of the individual mortars are presented in Table 2. MSWI-FA was used as a sand replacement because it does not possess binding properties (either hydraulic or pozzolanic) at a level that would allow it to replace cement. In contrast, CKD has binding properties and can replace cement, supporting hydration processes. Individual series of mortars were marked as follows: mortars modified with fly ash–MSWI-FA–% content; cement kiln dust–CKD–% content; and ash and dust MSWI-FA-CKD -% content of individual waste.
For the fresh cement mortars, consistency was tested using a flow table in accordance with PN-EN 1015-3 [70]. The PN-EN 1015-3 standard specifies a method for testing the consistency of masonry mortar using a flow table. The consistency of the mortar indicates its ability to flow and determines how easily the mortar can be spread on a surface. For the hardened mortars, compressive and flexural strength tests were conducted, a key parameter for assessing their mechanical properties and ensuring the durability of building structures. The tests were performed using an MMC-3742 testing machine (FPR; ToniTechnik 2030, Berlin, Germany) in accordance with PN-EN 196-1 [67] on prisms measuring 40 × 40 × 160 mm. The compressive and flexural strength tests were carried out after 7 (so-called early strength) and 28 days of sample curing (full strength). The flexural strength test was conducted on three prisms by gradually increasing the load at a rate of 50 ± 10 N/s until the samples broke. The compressive strength test was performed on six halves of the prisms, applying a uniform compressive force increment of 2400 ± 200 N/s to ensure the precise evaluation of the samples’ load resistance. Additionally, water absorption was tested using the soaking method in accordance with PN-B-04500:1985 [71], conducted after 28 days of curing. For this test, three prisms measuring 40 mm × 40 mm × 160 mm were prepared from mortars in each series. The bulk density of the dry cement mortar was also measured in accordance with PN-EN 1015-6:2000 [72]. Freeze–thaw resistance testing was conducted in accordance with PN-B-04500:1985 [71] using a Toropol K-010 chamber (Toropol, Warsaw, Poland). From each mortar series, 12 prisms measuring 40 mm × 40 mm × 160 mm were prepared. Six samples underwent 25 cycles of alternating freezing and thawing, while the remaining prisms served as control samples. Freezing took place in air at a temperature of −18 ± 2 °C and lasted for at least less 4 h. Samples were defrosted in water at +18 ± 2 °C-time 2 h–4 h.

3. Results and Discussion

3.1. Consistency

The consistency (PN-EN 1015-3) of all freshly prepared mortars was determined using the flow cone method (Figure 4). The analysis of the consistency results for cement mortars modified with MSWI-FA and CKD waste reveals significant changes in their properties compared to the reference mortar (MS). Mortars with fly ash (MSWI-FA) showed a noticeable decrease in consistency compared to the reference mortar (MS). For MSWI-FA-10, MSWI- MSWI-FA-15, and MSWI-FA-20, the consistency values were 14.9 cm, 14.7 cm, and 14.65 cm, respectively, indicating a deterioration in workability (a key feature of fresh mortar, determining how easy it is to mix, transport, and apply with a minimal risk of segregation of components and loss of homogeneity) with increasing MSWI-FA content. Mortars with cement kiln dust (CKD) exhibited a smaller decrease in consistency compared to MS, with values ranging from 18.2 cm to 19 cm, suggesting a better ability to retain water in the mixture. Combinations of MSWI-FA and CKD (e.g., MSWI-FA-CKD/10-10) affected consistency in varying ways, depending on the proportions of the two components. For example, MSWI-FA-CKD/10-10 had a consistency of 18.5 cm, similar to CKD-10, whereas combinations with higher MSWI-FA content (e.g., MSWI-FA-CKD/20-10) showed lower consistency values. It is notable that the addition of CKD partially compensates for the negative impact of MSWI-FA on consistency. However, this compensatory effect is limited at higher MSWI-FA doses, as shown by MSWI-FA-CKD/17-3, which had a consistency of 13.3 cm.

3.2. Volumetrisity Denesity

The highest bulk density was achieved by the MS sample (2169 kg/m3), indicating its superior structural compactness among all the tested samples (Figure 5). Samples from the MSWI-FA series (with densities ranging from 2121 kg/m3 to 2154 kg/m3) showed slightly lower densities than the control samples. The CKD series exhibited lower density values (2090–2121 kg/m3) compared to the MSWI-FA series but similar to the lower range of the FA series, which may indicate limited effectiveness of CKD in enhancing density. The FA-CKD samples displayed significant variability in density (2052–2132 kg/m3), suggesting that the combination of MSWI-FA and CKD has an inconsistent impact on the structure, depending on the proportions of these components. The lowest densities among the MSWI-FA-CKD samples were observed for MSWI-FA-CKD/20-10 and MSWI-FA-CKD/20-20 (2052 and 2055 kg/m3, respectively), which may indicate a negative effect of certain combinations on the material’s cohesion.

3.3. Water Absorption

The next stage of the study involved testing water absorption. For the control series MS, water absorption was at a level of 8.1% (Figure 6). In mortars modified with MSWI-FA waste (MSWI-FA-10, MSWI-FA-15, and MSWI-FA-20) and CKD waste (CKD-10, CKD-15, and CKD-20), a gradual increase in water absorption was observed, ranging from 7.8% to 10.0% and 7.8% to 9.8%, respectively. This suggests that increasing the amount of waste impacts this parameter. The series where both wastes were used together (MSWI-FA-CKD) showed the highest values, reaching a maximum of 11.1%, indicating a synergistic effect of these components. The greatest variability was noted in the MSWI-FA-CKD group, which may reflect diverse reactions to the tested conditions. Overall, the results demonstrate the significant impact of the combined parameters on the increase in measured water absorption values.

3.4. Compressive Strength

The compressive strength test of cement mortars was conducted after 7 and 28 days of curing. The results are presented in Figure 7. For mortars modified with fly ash (MSWI-FA), compressive strength measured after 7 days of curing showed a decrease in all series compared to the control sample (51.2 MPa). The smallest decrease (22.9%) was observed for MSWI-FA-20, suggesting that an initial increase in MSWI-FA content has a beneficial effect shortly after curing. However, after 28 days, the most stable performance was recorded for the MSWI-FA-10 series, which used 10% waste as a sand replacement, with a reduction of 13.7%. In contrast, the strength of the MSWI-FA-20 series decreased by 28.9%, demonstrating that higher MSWI-FA content worsens long-term strength parameters. The MSWI-FA-15 series showed reductions of 27.8% and 26.2% for the 7- and 28-day periods, respectively, indicating a deterioration of properties in both curing intervals. For mortars modified with cement kiln dust (CKD), the initial reductions were more uniform, ranging from 24.4% to 22.1% for 10%, 15%, and 20% additions. After 28 days, mortars modified with CKD achieved more stable parameters than those modified with MSWI-FA. The smallest reduction was observed in CKD-10 (20.5%), with similar results for CKD-15 and CKD-20 (22.1% and 20.7%, respectively). This indicates that CKD may be a more effective additive for modifying mortar, particularly over longer curing times. In mortars combining MSWI-FA and CKD, the largest strength reductions were recorded in the MSWI-FA-CKD/17-17 series, with a change of 39.6% after 28 days, making it the least effective modification. The best results in this group were achieved by the MSWI-FA-CKD/3-3 series, with reductions of 24.4% after 7 days and 20.9% after 28 days. These results demonstrate that using minimal amounts of both additives may yield more favorable outcomes, although the combined effect is generally detrimental at higher proportions.
Al-Harthy et al. [20] studied the effect of CKD on mortar–concrete mixtures to partially replace Portland cement in concrete. The results showed that the overall compressive strength compared to the control mix decreased with increasing bypass dust content in the tested materials. However, the researchers came to the conclusion that the replacement of as little as 5% of dust with cement did not negatively affect the tested strength parameter. Similarly, Mohammad and Hilal [22] investigated the effect of adding cement kiln dust (CKD) as a partial replacement for cement in amounts of 10%, 30%, and 50% of the cement weight. The obtained results showed a significant decrease in the strength of concrete modified with CKD. After 28 days of curing, the compressive strength was 28 MPa, 25 MPa, and 22 MPa for 10%, 30%, and 50% CKD content, respectively. In comparison, the reference mix (without CKD) achieved a compressive strength of 35 MPa. Marku et al. [21] explored the possibility of using cement kiln dust (CKD) as a partial replacement for cement in the production of mortar and concrete [43]. Various mixtures were developed, containing CKD in proportions ranging from 0% to 45%. In some formulations, CKD was supplemented with fly ash and blast furnace slag. The conducted tests included evaluations of compressive strength, flexural strength, and durability. The results revealed that CKD-OPC blends exhibited limited strength due to the absence of calcium silicates and the low fineness of CKD. Nevertheless, it was demonstrated that CKD can be effectively combined with pozzolanic materials such as blast furnace slag or fly ash.

3.5. Flexural Strength

The flexural strength test of cement mortars was conducted after 7 and 28 days of curing. The results are presented in Figure 8. The control series MS achieved a flexural strength of 7.5 MPa after 7 days of curing and 8.9 MPa after 28 days, representing the highest values among all series.
The series modified with MSWI-FA waste in amounts ranging from 10% to 20% showed a reduction in flexural strength of 25–29% after 7 days compared to the MS series. After 28 days, these results were 22–28% lower than the control. For the series modified with CKD waste, a smaller reduction in the tested parameter was observed compared to the MS series. After 7 days, CKD-10, CKD-15, and CKD-20 achieved values that were 20%, 15%, and 11% lower, respectively. After 28 days, the differences were 19%, 18%, and 17.5%, respectively. In the series using a mixture of MSWI-FA and CKD, the greatest reduction in flexural strength was observed, both after 7 and 28 days. The reductions after 7 days ranged from 31% to 39%, while after 28 days, the decreases were between 30% and 34%. For MSWI-FA-CKD/3-3 and MSWI-FA-CKD/3-17, the reductions after 7 days were 17% and 29%, respectively, compared to the MS series, while after 28 days, the decreases were 20% and 27%, respectively. The results indicate that the addition of CKD in combination with MSWI-FA significantly lowers the flexural strength of mortars, particularly in the early stages of curing.

3.6. Frost Resistance

The analysis of the results of strength tests after assessing frost resistance indicates a varying degree of reduction in compressive strength, bending strength, and weight loss depending on the composition of the mortars (Table 3). The MS control series showed a reduction in compressive strength (−32.66%) and flexural strength (−47.7%), while also showing the highest weight loss (0.82%). The series with MSWI-FA additions demonstrated smaller decreases in mechanical parameters than the series modified with CKD alone. For example, MSWI-FA-20 showed the lowest reductions in compressive strength (−6.10%) and flexural strength (−0.7%), suggesting a positive effect of higher MSWI-FA content on mechanical properties. CKD additions resulted in significant decreases in flexural strength (e.g., CKD-10: −77.9%), but their impact on compressive strength was more varied, ranging from −35.21% (CKD-10) to −19.52% (CKD-20). MSWI-FA-CKD combinations showed mixed results. The MSWI-FA-CKD/20-20 series achieved the smallest reductions in both compressive strength (−1.72%) and flexural strength (−9.9%), along with moderate mass loss (0.24%), indicating favorable effects of this mix. However, some series, such as MSWI-FA-CKD/10-10 and MSWI-FA-CKD/17-17, recorded substantial reductions in flexural strength (−76.6% and −56.6%), suggesting suboptimal proportions of components. The results suggest that an appropriate combination of MSWI-FA and CKD can enhance mechanical properties while minimizing mass loss.

3.7. Evaluation of Results in the Context of Practical Use

The research showed that cement mortar samples containing municipal solid waste incineration fly ash (MSWI-FA), CKD, and a mixture of both wastes achieved the lowest strength parameters compared to the control series samples. In particular, a significant decrease in compressive strength was observed after 7 and 28 days of curing in mortars containing MSWI-FA, which may be caused by the lack of binding properties of this waste. MSWI-FA is characterized by a high chlorine content (4.51%) and alkaline oxides (Na2O + K2O), which may lead to unfavorable chemical reactions weakening the structure of the mortar. The analysis of changes in the mechanical properties of the mortars after 7 and 28 days indicates that MSWI-FA shows a greater reduction in strength in the early curing period than after a longer time. This may result from the slow hydration of components present in the ash and the secondary pozzolanic reaction, which partially compensates for the initial decrease in strength. It is worth noting that after frost resistance tests, mortar samples containing MSWI-FA in amounts of 10%, 20%, and 30% showed an improvement in mechanical parameters. This may be significant for their application in construction, especially in structures exposed to low temperatures. In the future, research should focus on improving the properties of mortars containing MSWI-FA by modifying their composition, both through the optimization of MSWI-FA itself and the addition of appropriate chemical activators. Combining the ash with other mineral additives, such as metakaolin or amorphous silica, may enhance its pozzolanic properties. Alternatively, the introduction of modifiers in the form of polymers or synthetic fibers could improve both cohesion and resistance to environmental factors. Despite the potential environmental benefits of using MSWI-FA and CKD, their practical adaptation in the construction industry may face barriers related to technical standards and material durability limitations. The optimization of composition and further research on the stability of these materials are crucial for their large-scale implementation.

4. Conclusions

The conducted studies and analysis of the results demonstrated that the incorporation of fly ash (MSWI-FA) and cement kiln dust (CKD) as additives in cement mortars significantly influenced their mechanical properties. In mortars with MSWI-FA additions, a reduction in mechanical strength was observed, with the smallest decreases recorded for the lowest MSWI-FA content (10%), indicating an optimal level of addition for short-term mechanical stability. Cement mortar with CKD exhibited greater stability over longer curing periods, with less significant reductions in strength parameters compared to MSWI-FA, except for compressive strength for mortar containing 10% MSWI-FA.
Combinations of MSWI-FA and CKD, although beneficial in reducing emissions and utilizing industrial waste, led to a significant reduction in mechanical properties of the mortars, particularly at higher proportions of both additives. The best results among the mixtures were achieved by the MSWI-FA-CKD/3-3 series (i.e., after 3% of the MSWI-FA and CKD waste), suggesting potential benefits from minimal amounts of these waste materials.
The studies also indicated that mortars with CKD are more resistant to environmental factors, such as cyclic freezing and thawing, compared to those with MSWI-FA. The analysis also showed that mortars containing lower CKD content had comparable or slightly lower mass loss compared to mortars containing MSWI-FA, while the simultaneous use of both types of waste resulted in mostly lower mass loss of the samples compared to the control mortars. In summary, the use of MSWI-FA and CKD as cement replacements could thus be environmentally beneficial, but their impact on mechanical properties requires further investigation, especially regarding their synergy and optimal proportions. The results suggest that separate applications of MSWI-FA and CKD yield better outcomes than their combined use. These observations form a foundation for future work on more sustainable cement compositions.
The incorporation of the discussed waste into the production of building materials reduces the amount of waste deposited in landfills and limits the exploitation of natural resources while simultaneously improving the mechanical properties (after frost resistance tests) and durability of the products. This strategy supports the circular economy, contributing to sustainable development and minimizing environmental impact.

Author Contributions

Conceptualization, M.U.; Methodology, A.P. and M.U.; Software, A.P.; Validation, A.P.; Formal analysis, A.P. and M.U.; Investigation, A.P.; Resources, M.U.; Writing—original draft, A.P.; Writing—review & editing, M.U.; Supervision, M.U. 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

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Acknowledgments

We would like to thank local companies that provided us with waste materials free of charge for testing.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Available online: https://www.statista.com/statistics/1087115/global-cement-production-Volume/ (accessed on 5 September 2024).
  2. Cemburean. Activity Report 2023; Cemburean the European Cement Association: Bruxelles, Belgium, 2023. [Google Scholar]
  3. Al-Jabri, K.S.; Taha, R.A.; Al-Hashmi, A.; Al-Harthy, A.S. Effect of copper slag and cement by-pass dust addition on mechanical properties of concreto. Constr. Build. Mater. 2006, 20, 322–331. [Google Scholar] [CrossRef]
  4. Al-Jabri, K.S.; Taha, R.A.; Al-Ghassani, M. Use of copper slag and cement by-pass dust as cementitious materials. Cem. Concr. Aggreg. 2002, 24, 7–12. [Google Scholar] [CrossRef]
  5. European Council; European Parliament. Directive (Eu) 2018/851 of the European Parliament and of the Council of 30 May 2018 Amending Directive 2008/98/EC on Waste; European Union: Bruxelles, Belgium, 2018. [Google Scholar]
  6. Moon, D.H.; Wazne, M.; Yoon, I.H.; Grubb, D.G. Assessment of Cement Kiln Dust (CKD) for Stabilization/Solidification (S/S) of Arsenic Contaminated Soils. J. Hazard. Mater. 2008, 159, 512–518. [Google Scholar] [CrossRef] [PubMed]
  7. Gupta, S.; Pandey, M.K.; Srivastava, R.K. Evaluation of Cement Kiln Dust Stabilized Heavy Metals Contaminated Expansive Soil-A Laboratory. Study Eur. J. Adv. Eng. Technol. 2015, 2, 37–42. [Google Scholar]
  8. Carlson, K.; Sariosseiri, F.; Muhunthan, B. Engineering Properties of Cement Kiln Dust-Modified Soils in Western Washington State. Geotech. Geol. Eng. 2011, 29, 837–844. [Google Scholar] [CrossRef]
  9. Albusoda, B.S.; Salem, L.A.K. Stabilization of Dune Sand by Using Cement Kiln Dust (CKD). J. Earth Sci. Geotech. Eng. 2012, 2, 131–143. [Google Scholar]
  10. Arulrajah, A.; Mohammadinia, A.; D’Amico, A.; Horpibulsuk, S. Cement Kiln Dust and Fly Ash Blends as an Alternative Binder for the Stabilization of Demolition Aggregates. Constr. Build. Mater. 2017, 145, 218–225. [Google Scholar] [CrossRef]
  11. Ekpo, D.U.; Fajobi, A.B.; Ayodele, A.L.; Etim, R.K. Potentials of Cement Kiln Dust-Periwinkle Shell Ash Blends on Plasticity Properties of Two Selected Tropical Soils for Use as Sustainable Construction Materials. In Proceedings of the IOP Conference Series: Materials Science and Engineering, Ota, Nigeria, 27–28 July 2020; IOP Publishing: Bristol, UK, 2021; Volume 1036, p. 012033. [Google Scholar]
  12. Mohamed, A.M.O.; El Gamal, M.M. Solidification of Cement Kiln Dust Using Sulfur Binder. J. Hazard. Mater. 2011, 192, 576–584. [Google Scholar] [CrossRef]
  13. Mohammadinia, A.; Arulrajah, A.; D’Amico, A.; Horpibulsuk, S. Alkali-Activation of Fly Ash and Cement Kiln Dust Mixtures for Stabilization of Demolition Aggregates. Constr. Build. Mater. 2018, 186, 71–78. [Google Scholar] [CrossRef]
  14. Okafor, F.O.; Egbe, E.A. Potentials of Cement Kiln Dust in Sub-Grade Improvement. Niger. J. Technol. 2013, 32, 109–116. [Google Scholar]
  15. Ebrahimi, A.; Edil, T.B.; Son, Y.-H. Effectiveness of Cement Kiln Dust in Stabilizing Recycled Base Materials. J. Mater. Civ. Eng. 2012, 24, 1059–1066. [Google Scholar] [CrossRef]
  16. Sreekrishnavilasam, A.; Rahardja, S.; Kmetz, R.; Santagata, M. Soil Treatment Using Fresh and Landfilled Cement Kiln Dust. Constr. Build. Mater. 2007, 21, 318–327. [Google Scholar] [CrossRef]
  17. El-Mohsen, M.A.; Anwar, A.M.; Adam, I.A. Mechanical Properties of Self-Consolidating Concrete Incorporating Cement Kiln Dust. HBRC J. 2015, 11, 1–6. [Google Scholar] [CrossRef]
  18. Sadek, D.M.; El-Attar, M.M.; Ali, A.M. Physico-Mechanical and Durability Characteristics of Concrete Paving Blocks Incorporating Cement Kiln Dust. Constr. Build. Mater. 2017, 157, 300–312. [Google Scholar] [CrossRef]
  19. Saleh, H.M.; Salman, A.A.; Faheim, A.A.; El-Sayed, A.M. Sustainable Composite of Improved Lightweight Concrete from Cement Kiln Dust with Grated Poly (Styrene). J. Clean. Prod. 2020, 277, 123491. [Google Scholar] [CrossRef]
  20. Al-Harthy, A.S.; Taha, R.; Al-Maamary, F. Effect of Cement Kiln Dust (CKD) on Mortar and Concrete Mixtures. Constr. Build. Mater. 2003, 17, 353–360. [Google Scholar] [CrossRef]
  21. Marku, J.; Dumi, I.; Lico, E.; Dilo, T.; Çakaj, O. Ckd in Mortar & Conc Prodctn. Mater. Prot. 2012, 53, 334–345. [Google Scholar]
  22. Mohammad, A.M.; Hilal, N. Re-Using The By-Product of Cement Industry (Cement Kiln Dust) To Produce The Concrete. Anbar J. Eng. Sci. 2010, 3, 1–14. [Google Scholar] [CrossRef]
  23. Bagheri, S.M.; Koushkbaghi, M.; Mohseni, E.; Koushkbaghi, S.; Tahmouresi, B. Evaluation of Environment and Economy Viable Recycling Cement Kiln Dust for Use in Green Concrete. J. Build. Eng. 2020, 32, 101809. [Google Scholar] [CrossRef]
  24. Hussain, G.S.; Rao, R. Experimental Studies on Concrete Containing Cement Kiln Dust and Fly Ash. Singaporean J. Sci. Res. 2014, 6, 85–88. [Google Scholar]
  25. Ewais, E.M.M.; Ahmed, Y.M.Z.; El-Amir, A.A.M.; El-Didamony, H. Cement Kiln Dust-Quartz Derived Wollastonite Ceramics. J. Ceram. Soc. Jpn. 2015, 123, 527–536. [Google Scholar] [CrossRef]
  26. Ogila, W.A. Recycling of Cement Kiln Dust in Red Clay Bricks and Its Impact on Their Physico-Mechanical Behaviors. Int. J. Sci. Eng. Res. 2014, 5, 1072–1080. [Google Scholar]
  27. El-Attar, M.M.; Sadek, D.M.; Salah, A.M. Recycling of High Volumes of Cement Kiln Dust in Bricks Industry. J. Clean. Prod. 2017, 143, 506–515. [Google Scholar] [CrossRef]
  28. Abdulkareem, A.H.; Eyada, S.O. Production of Building Bricks Using Cement Kiln Dust CKD Waste. In Proceedings of the Sustainable Civil Infrastructures, Cairo, Egypt, 24–28 November 2018; Springer: Cham, Switzerland, 2018; pp. 102–113. [Google Scholar]
  29. Depczyński, R. Assessing raw material efficiency and waste management for Sustainable Development: A VIKOR and TOPSIS Multi-Criteria Decision Analysis. In Production Engineering Archives; Sciendo: Warsaw, Poland, 2024; Volume 30, pp. 537–550. [Google Scholar] [CrossRef]
  30. Ulewicz, M.; Jura, J.; Gnatowski, A. Cement Mortars Based on Polyamide Waste Modified with Fly Ash from Biomass Combustion—A New Material for Sustainable Construction. Sustainability 2024, 16, 3079. [Google Scholar] [CrossRef]
  31. Jura, J. Influence of type of biomass burned on the properties of cement mortar containing fly ash. CoOEP 2020, 9, 77–82. [Google Scholar] [CrossRef]
  32. Jura, J.; Ulewicz, M. Assessment of the possibility of using fly ash from biomass combustion for concrete. Materials 2021, 14, 6708. [Google Scholar] [CrossRef]
  33. Kalak, T.; Szypura, P.; Cierpiszewski, R.; Ulewicz, M. Modification of Concrete Composition Doped by Sewage Sludge Fly Ash and Its Effect on Compressive Strength. Materials 2023, 16, 4043. [Google Scholar] [CrossRef] [PubMed]
  34. Popławski, J.; Lelusz, M. Assessment of Sieving as a Mean to Increase Utilization Rate of Biomass Fly Ash in Cement-Based Composites. Appl. Sci. 2023, 13, 1659. [Google Scholar] [CrossRef]
  35. Popławski, J. Influence of biomass fly-ash blended with bituminous coal fly-ash on properties of concrete. CoOEP 2020, 9, 89–96. [Google Scholar] [CrossRef]
  36. Pribulov, A.; Futas, A.; Baricova, P.D. Processing and utilization of metallurgical slags. In Production Engineering Archives; Sciendo: Warsaw, Poland, 2016; Volume 11, pp. 2–5. [Google Scholar]
  37. Lis, T.; Nowacki, K. Pro-ecological possibilities of using metallurgical waste in the production of aggregates. In Production Engineering Archives; Sciendo: Warsaw, Poland, 2022; Volume 28, pp. 252–256. [Google Scholar] [CrossRef]
  38. Tavakoli, D.; Hashempour, M.; Heidari, A. Use of Waste Materials in Concrete: A review. Pertani. J. Sci. Technol. 2018, 26, 499–522. [Google Scholar]
  39. Saikia, N.; de Brito, J. Use of plastic waste as aggregate in cement mortar and concrete preparation: A review. Constr. Build. Mater. 2012, 34, 385–401. [Google Scholar] [CrossRef]
  40. Bassam, I.A.; Tayeh, A.; Alyousef, R.; Alabduljabbar, H.; Mohamed, A.M.; Alaskar, A. Use of recycled plastic as fine aggregate in cementitious composites: A review. Constr. Build. Mater. 2020, 253, 19146. [Google Scholar] [CrossRef]
  41. Pietrzak, A.; Ulewicz, M. Influence of post-consumer waste thermoplastic elastomers obtained from used car floor mats on concrete properties. Materials 2023, 16, 2231. [Google Scholar] [CrossRef]
  42. Ulewicz, M.; Pietrzak, A. Properties and structure of concretes doped with production waste of thermoplastic elastomers from the production of car floor mats. Materials 2021, 14, 872. [Google Scholar] [CrossRef]
  43. Pietrzak, A. The effect of ashes generated from the combustion of sewage sludge on the basic mechanical properties of concrete’. CoOEP 2019, 8, 29–35. [Google Scholar] [CrossRef]
  44. Helbrych, P. Recycling of sulfur polymers derived from the purification process of copper and other non-ferrous metals in concrete composites. CoOEP 2019, 8, 131–136. [Google Scholar] [CrossRef]
  45. Liu, J.; Wang, Z.; Xie, G.; Li, Z.; Fan, X.; Zhang, W.; Xing, F.; Tang, L.; Ren, J. Resource utilization of municipal solid waste incineration fly ash—cement and alkali-activated cementitious materials: A review. Sci. Total Environ. 2022, 852, 158254. [Google Scholar] [CrossRef]
  46. Ulewicz, M.; Jura, J.; Zieliński, A.; Pietraszek, J. The Application of Converter Sludge and Slag to Produce Ecological Cement Mortars. Materials 2024, 17, 4295. [Google Scholar] [CrossRef] [PubMed]
  47. Chen, D.; Zhang, Y.; Xu, Y.; Nie, Q.; Yang, Z.; Sheng, W.; Qian, G. Municipal solid waste incineration residues recycled for typical construction materials—A review. RSC Adv. 2022, 12, 6279–6291. [Google Scholar] [CrossRef]
  48. Baran, P.; Nazarko, M.; Włosińska, E.; Kanciruk, A.; Zarębska, K. Synthesis of geopolymers derived from fly ash with an addition, of perlite. J. Clean. Prod. 2021, 293, 126112. [Google Scholar] [CrossRef]
  49. Zarębska, K.; Zabierowski, P.; Gazda-Grzywacz, M.; Czuma, N.; Baran, P. Fly ash-based geopolymers with refractoriness properties. Clean Technol. Environ. Policy 2022, 24, 2161–2175. [Google Scholar] [CrossRef]
  50. Ulewicz, M.; Jura, J. Influence of mix fly and bottom ashes from biomass on selected properties of cement mortars. Key Eng. Mater. 2020, 828, 14–17. [Google Scholar] [CrossRef]
  51. Cristelo, N.; Segadães, L.; Coelho, J.; Chaves, B.; Sousa, N.R.; de Lurdes Lopes, M. Recycling municipal solid waste incineration slag and fly ash as precursors in low-range alkaline cements. Waste Manag. 2020, 104, 60–73. [Google Scholar] [CrossRef] [PubMed]
  52. Pietrzak, A.; Ulewicz, M.; Kozień, E.; Pietraszek, J. Application of a Mixture of Fly Ash and Solid Waste from Gas Treatment from Municipal Solid Waste Incineration in Cement Mortar. Materials 2025, 18, 481. [Google Scholar] [CrossRef] [PubMed]
  53. Zheng, L.; Gao, X.; Wang, W.; Li, Z.; Zhang, L.; Cheng, S. Utilization of MSWI fly ash as partial cement or sand substitute with focus on cementing efficiency and health risk assessment. Front. Environ. Sci. Eng. 2020, 14, 5. [Google Scholar] [CrossRef]
  54. Siddique, R. Utilization of MSWI ash in cement and mortar. Resour. Conserv. Recy. 2010, 54, 1037–1047. [Google Scholar] [CrossRef]
  55. Wang, L.; Jin, Y.; Nie, Y.; Li, R. Recycling of municipal solid waste incineration fly ash for ordinary Portland cement production: A real-scale test. Resour. Conserv. Recycl. 2010, 54, 1428–1435. [Google Scholar] [CrossRef]
  56. Lee, T.C.; Wanga, W.J.; Shih, P.Y.; Lin, K.L. Enhancement in early strengths of slag-cement mortars by adjusting basicity of the slag prepared from fly-ash of MSWI. Cem. Concr. Res. 2009, 39, 651–658. [Google Scholar] [CrossRef]
  57. Li, J. Municipal Solid Waste Incineration Ash-Incorporated Concrete: One Step towards Environmental Justice. Buildings 2021, 11, 495. [Google Scholar] [CrossRef]
  58. Bertolini, L.; Carsana, M.; Cassago, D.; Curzio, A.Q.; Collepardi, M. MSWI ashes as mineral additions in concrete. Cem. Concr. Res. 2004, 34, 1899–1906. [Google Scholar] [CrossRef]
  59. Aubert, J.E.; Husson, B.; Sarramone, N. Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement Part 2. Mechanical strength of mortars and environmental impact. J. Hazard. Mater. 2007, 146, 12–19. [Google Scholar] [CrossRef]
  60. Poranek, N.; Pizoń, J.; Łaźniewska-Piekarczyk, B.; Czajkowski, A.; Lagashkin, R. Recycle Option for Municipal Solid Waste Incineration Fly Ash (MSWIFA) as a Partial Replacement for Cement in Mortars Containing Calcium Sulfoaluminate Cement (CSA) and Portland Cement to Save the Environment and Natural Resources. Materials 2024, 17, 39. [Google Scholar] [CrossRef] [PubMed]
  61. Thomas, M.; Ślosarczyk, A. Effect of Municipal Solid Waste Slag on the Durability of Cementitious Composites in Terms of Resistance to Freeze–Thaw Cycling. Materials 2023, 16, 626. [Google Scholar] [CrossRef]
  62. Lin, K.L.; Wang, K.S.; Tzeng, B.Y.; Lin, C.Y. The reuse of municipal solid waste incinerator fly ash slag as a cement substitute. Resour. Conserv. Recycl. 2003, 39, 315–324. [Google Scholar] [CrossRef]
  63. Rémond, S.; Pimient, P.; Bentz, D.P. Effects of the incorporation of Municipal Solid Waste Incineration fly ash in cement pastes and mortars: I. Experimental study. Cem. Concr. Res. 2002, 32, 303–311. [Google Scholar] [CrossRef]
  64. Abdi, E.; Asadollahfardi, G.; Salehi, A.; Akbardoost, J.; Esmaeili, N.; Panahandeh, A. Using Municipal Solid-Waste Incinerator Fly Ash, Wash Water, and Propylene Fibers in Self-Compacting Repair Mortar, Greenhouse Gas Emissions Potential. Int. J. Concr. Struct. Mater. 2024, 18, 57. [Google Scholar] [CrossRef]
  65. Bertoldo, N.; Qureshi, T.; Simpkins, D.; Arrigoni, A.; Dotelli, G. Concrete with Organic Waste Materials as Aggregate Replacement. Appl. Sci. 2024, 14, 108. [Google Scholar] [CrossRef]
  66. PN-EN 197-1:2012; Cement—Cement—Part 1. Composition, Requirements and Compliance Criteria for Common-Use Cements. Polish Committee for Standardization: Warsaw, Poland, 2012.
  67. PN-EN 196-1:2016; Cement Test Methods—Part 1: Determination of Strength. Polish Committee for Standardization: Warsaw, Poland, 2016.
  68. PN-EN 1008:2004; Mixing Water for Concrete—Specification for Sampling, Testing and Assessment of Suitability of Mixing Water for Concrete, Including Water Recovered from Concrete Production Processes. Polish Committee for Standardization: Warsaw, Poland, 2004.
  69. PN-EN 196-6:2019-01; Cement Testing Methods—Part 6: Determination of Fineness of Grinding. Polish Committee for Standardization: Warsaw, Poland, 2019.
  70. PN-EN 1015-3:2000; Test Methods for Mortars for Walls—Determination of the Consistency of Fresh Mortar (Using A Flow Table). Polish Committee for Standardization: Warsaw, Poland, 2000.
  71. PN-B-04500:1985; Building Mortars—Testing of Physical and Strength Properties. Polish Committee for Standardization: Warsaw, Poland, 1985.
  72. PN-EN 1015-6:2000; Testing the Bulk Density of Cement Mortar in A Dry State in Accordance with the Standard. Polish Committee for Standardization: Warsaw, Poland, 2000.
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Figure 1. The waste materials used were fly ash from municipal waste incineration-MSWI-FA (a) and cement kiln dust-CKD (b).
Figure 1. The waste materials used were fly ash from municipal waste incineration-MSWI-FA (a) and cement kiln dust-CKD (b).
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Figure 2. TGA-DTA thermogram for the MSWI-FA.
Figure 2. TGA-DTA thermogram for the MSWI-FA.
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Figure 3. TGA-DTA thermogram for the CKD.
Figure 3. TGA-DTA thermogram for the CKD.
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Figure 4. Consistency of individual cement mortar series.
Figure 4. Consistency of individual cement mortar series.
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Figure 5. Volumetrisity density of individual cement mortar series.
Figure 5. Volumetrisity density of individual cement mortar series.
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Figure 6. Water absorption of individual cement mortar series.
Figure 6. Water absorption of individual cement mortar series.
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Figure 7. Average compressive strength tested after 7 and 28 days of curing: series where each waste was added separately (a); series where wastes were mixed in the specified proportions (b).
Figure 7. Average compressive strength tested after 7 and 28 days of curing: series where each waste was added separately (a); series where wastes were mixed in the specified proportions (b).
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Figure 8. The average flexural strength tested after 7 and 28 days of sample curing: (a) series where each waste material was dosed separately; (b) series where mixed waste materials were dosed in the adopted proportions.
Figure 8. The average flexural strength tested after 7 and 28 days of sample curing: (a) series where each waste material was dosed separately; (b) series where mixed waste materials were dosed in the adopted proportions.
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Table 1. Chemical composition of investigated MSWI-FA and CKD waste, [%].
Table 1. Chemical composition of investigated MSWI-FA and CKD waste, [%].
WasteSiO2CaOMgOAl2O3F2O3Na2OK2OP2O5SCl
MSWI-FA *17.2237.224.319.622.919.021.451.133.144.51
CKD **8.8762.151.515.451.056.70.87--0.29
WasteMnZnTiPbSnCuCrBaSrBr
MSWI-FA0.090.831.310.930.030.050.010.140.050.02
CKD0.050.010.080.01---0.010.040.02
* fly ash-MSWI-FA; ** cement kiln dust-CKD.
Table 2. Composition of cement mortars–standard and modified (fly ash–MSWI–FA; cement kiln dust-CKD; MSWI-FA-CKD mix).
Table 2. Composition of cement mortars–standard and modified (fly ash–MSWI–FA; cement kiln dust-CKD; MSWI-FA-CKD mix).
Mortar SeriesIngredients
CementSandWaterMSWI-FACKD
[g][g][cm3][g][g]
MS4501350.0225--
MSWI-FA-104501294.222545.0-
MSWI-FA-154501266.322567.5-
MSWI-FA-204501238.3922590.0-
CKD-104051350.0225-45.0
CKD-15382.51350.0225-67.5
CKD-203601350.0225-90.0
MSWI-FA-CKD/10-104051299.7822540.545.0
MSWI-FA-CKD/10-203601305.3622536.090.0
MSWI-FA-CKD/20-104051299.7822581.045.0
MSWI-FA-CKD/20-203601327.6822572.090.0
MSWI-FA-CKD/3-3436.51322.9422513.113.5
MSWI-FA-CKD/3-17373.51326.8422511.2176.5
MSWI-FA-CKD/17-17373.51303.6822563.576.5
MSWI-FA-CKD/17-3436.51250.3322574.2113.5
Table 3. Freeze–thaw resistance test results for individual mortar series.
Table 3. Freeze–thaw resistance test results for individual mortar series.
Mortar SeriesAverage Reduction in Compressive Strength (%)Average Reduction in Flexural Strength (%)Average Mass Loss (%)
MS−32.66−47.70.82
MSWI-FA-10−27.10−15.10.15
MSWI-FA-15−13.70−7.40.18
MSWI-FA-20−6.10−0.70.28
CKD-10−35.21−77.90.15
CKD-15−21.56−73.70.21
CKD-20−19.52−77.30.15
MSWI-FA-CKD/10-10−11.38−76.60.05
MSWI-A-CKD/10-20−8.63−25.60.36
MSWI-FA-CKD/20-10−15.67−48.50.19
MSWI-FA-CKD/20-20−1.72−9.90.24
MSWI-FA-CKD/3-3−5.95−8.20.28
MSWI-FA-CKD/3-17−13.22−44.00.34
MSWI-FA-CKD/17-17−19.95−56.60.17
MSWI-FA-CKD/17-3−3.66−20.20.07
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Pietrzak, A.; Ulewicz, M. The Mechanical Strength of Ecological Cement Mortars Based on Fly Ash from the Combustion of Municipal Waste and Cement Kiln Dust. Appl. Sci. 2025, 15, 3215. https://doi.org/10.3390/app15063215

AMA Style

Pietrzak A, Ulewicz M. The Mechanical Strength of Ecological Cement Mortars Based on Fly Ash from the Combustion of Municipal Waste and Cement Kiln Dust. Applied Sciences. 2025; 15(6):3215. https://doi.org/10.3390/app15063215

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Pietrzak, Alina, and Malgorzata Ulewicz. 2025. "The Mechanical Strength of Ecological Cement Mortars Based on Fly Ash from the Combustion of Municipal Waste and Cement Kiln Dust" Applied Sciences 15, no. 6: 3215. https://doi.org/10.3390/app15063215

APA Style

Pietrzak, A., & Ulewicz, M. (2025). The Mechanical Strength of Ecological Cement Mortars Based on Fly Ash from the Combustion of Municipal Waste and Cement Kiln Dust. Applied Sciences, 15(6), 3215. https://doi.org/10.3390/app15063215

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