Mechanical Performance of Mortars with Partial Replacement of Cement by Aluminum Dross: Inactivation and Particle Size

: Although the use of primary aluminum dross as cement replacement has shown promising results in mortars and concretes, there is a knowledge gap between the effect of the secondary dross inactivation process and particle sizes on the mechanical properties and consistency. So, by using X-ray diffraction, laser granulometry, and scanning electron microscopy, this article describes ﬁrst the inactivation process applied to a secondary aluminum dross. Second, this manuscript presents the fresh and hardened properties of mortar mixes containing 5, 10, and 20% inactivated secondary aluminum dross with three different particle sizes (i.e., ﬁne, intermediate, and coarse). Mortar ﬂow test results indicate that compressive and ﬂexural strengths of mixes containing up to 20% ﬁne and intermediate aluminum dross as cement replacement were satisfactory, respectively. These results have the potential to reduce the environmental and health impacts caused by cement production and secondary aluminum dross disposal, respectively. Moreover, the durability aspects of the mortar mixes, as well as the effectivity of the investigated inactivation process, are identiﬁed as future research topics.


Introduction
Although there are significant environmental impacts at local and global scales, the construction sector is strongly connected to economic growth and social development by promoting a large number of jobs (direct and indirect) and energizing other subsectors of the economy [1].The last is particularly important in developing countries such as Colombia, which was ranked third (13 Mt), after Brazil (56.6 Mt) and Mexico (40.0 Mt), based on cement production in Latin America and the Caribbean [2].So, in order to minimize the environmental impacts while increasing social development and economic growth, the City Hall of Santiago de Cali is evaluating the implementation of a circular economy model for the construction sector, which understands circular economy (CE) as a production and consumption system that promotes efficiency in the use of materials, water, and energy, taking into account the resilience of ecosystems and the circular use of material flows through the implementation of technological innovations, alliances, and collaborations between stakeholders (e.g., raw material producers, building companies, users, and final disposal actors) and the promotion of business models that respond to the fundamentals of sustainable development [3].Among other strategies, the CE model stimulates the use of eco-concretes and eco-mortars that replace cement with by-products from local industries [4].
the use of eco-concretes and eco-mortars that replace cement with by-products from local industries [4].
Aluminum dross is a by-product of aluminum production that can be classified based on the aluminum content in white (15 to 70% Al), black (12 to 18% Al), and salt cake (3 to 5% Al).Most frequently, white aluminum dross is reprocessed due to its high quality.On the other hand, black dross and aluminum salt cake, which are normally landfilled, have been investigated in building materials as additive, calcium aluminate cement, cement, and fine aggregate replacements [5] (Figure 1). Figure 1.Some aluminum dross uses in building materials [5].Pereira et al. (2000) investigated the use of salt cake, containing oxides of aluminum, as a replacement for cement and sand in mortars.They reported satisfactory cement replacement around 10% and sand replacement from 30% to 50% [6].As supplementary cementitious materials, Elinwa and Mbadike (2011) produced concrete by replacing various percentages of cement with aluminum waste.From their results, it was found that the compressive and flexural strengths of concrete with replacement levels of 10 to 15% are comparable to those of control concrete.Another result was that concrete-containing aluminum waste retards the concrete setting times, which is desirable for hot-weather concreting [7].Similarly, Reddy & Neeraja (2016) studied the use of aluminum dross as a cement replacement in concrete.They reported that for up to 15% replacement of cement by secondary aluminum dross, the performance is comparable with conventional concrete [8].In the same way, Mailar et al. (2016) reported superior mechanical and durability properties with a concrete by replacing 20% of the cement with aluminum dross.They also noticed a delay in the setting process [9].Aditionally, Panditharadhya et al. (2018) investigated the partial replacement of Portland cement with aluminum dross (5%, 10%, 15%, and 20%) and its combined use with a pozzolan in concrete.They reported that by increasing the percentage of dross, the mixture required more water to keep a normal consistency.They also found that as the percentage of dross replacement increased, the initial setting time increased, but the final setting time decreased.Regarding the mechanical properties, they observed that as the percentage of cement substitution increased, the compressive, tensile, and flexural strengths decreased, an aspect that was associated with the increase of voids in the mixture by the addition of dross [10].A detailed compilation of these results is presented in Table 1.
Figure 1.Some aluminum dross uses in building materials [5].Pereira et al. (2000) investigated the use of salt cake, containing oxides of aluminum, as a replacement for cement and sand in mortars.They reported satisfactory cement replacement around 10% and sand replacement from 30% to 50% [6].As supplementary cementitious materials, Elinwa and Mbadike (2011) produced concrete by replacing various percentages of cement with aluminum waste.From their results, it was found that the compressive and flexural strengths of concrete with replacement levels of 10 to 15% are comparable to those of control concrete.Another result was that concrete-containing aluminum waste retards the concrete setting times, which is desirable for hot-weather concreting [7].Similarly, Reddy & Neeraja (2016) studied the use of aluminum dross as a cement replacement in concrete.They reported that for up to 15% replacement of cement by secondary aluminum dross, the performance is comparable with conventional concrete [8].In the same way, Mailar et al. (2016) reported superior mechanical and durability properties with a concrete by replacing 20% of the cement with aluminum dross.They also noticed a delay in the setting process [9].Aditionally, Panditharadhya et al. (2018) investigated the partial replacement of Portland cement with aluminum dross (5%, 10%, 15%, and 20%) and its combined use with a pozzolan in concrete.They reported that by increasing the percentage of dross, the mixture required more water to keep a normal consistency.They also found that as the percentage of dross replacement increased, the initial setting time increased, but the final setting time decreased.Regarding the mechanical properties, they observed that as the percentage of cement substitution increased, the compressive, tensile, and flexural strengths decreased, an aspect that was associated with the increase of voids in the mixture by the addition of dross [10].A detailed compilation of these results is presented in Table 1.Although the above-mentioned aluminum dross and salt cake valorization experiences are significantly important for sustainable development, as they reduce Portland cement consumption and mitigate landfill-associated problems, the relationship between the dross characteristics and the mechanical performance of the investigated building materials is not completely clear.In this sense, it is quite important to understand the aluminum dross inactivation process, which will certainly impact the dross properties and, therefore, the mechanical performance of building materials using this by-product.For example, Dai and Apelian (2017) used primary (rich in aluminum and magnesium) and secondary (complex impurities mixture) aluminum dross in cement mortars and studied the effect of particle size, weight fraction, and dross origin on the mechanical properties of mortar specimens.Obtaining only promising results with the primary dross, they concluded that these factors have important effects on the uniformity of the microstructure of mortar specimens [11].Therefore, this research aims to fill the knowledge gap in the relationship between secondary aluminum dross inactivation and particle size and the mechanical performance of mortars containing 5, 10, and 20% aluminum dross as cement replacement.

Materials and Methods
The proposed methodology for this study consisted of five phases, which are (1) Preliminaries, (2) By-product Characterization, (3) Mix Design, (4) Mortars and Properties, and (5) Results Analysis (Figure 2).It is noteworthy that the Colombian norms-NTC standards-are an adaptation of the American Society for Testing and Materials (ASTM) standards (Appendix A) and were used in this project.A brief description of each phase is presented as follows: The first phase included all the preliminary activities to obtain the materials for mortar manufacturing.In this case, river sand from the Cauca River (fine aggregate), high early strength cement (Argos), and aluminum dross-a by-product obtained from a local aluminum industry-were selected.The chemical properties of the cement are presented in Appendix B, which is based on a quality control report done by the producer during the project.
The second phase aimed to exclusively characterize the aluminum dross by means of The first phase included all the preliminary activities to obtain the materials for mortar manufacturing.In this case, river sand from the Cauca River (fine aggregate), high early strength cement (Argos), and aluminum dross-a by-product obtained from a local aluminum industry-were selected.The chemical properties of the cement are presented in Appendix B, which is based on a quality control report done by the producer during the project.
The second phase aimed to exclusively characterize the aluminum dross by means of sieve analysis, X-ray diffraction (Rigaku Multiflex with Search/Match analysis), SEM-Scanning Electron Microscopy (Japanese Manufacturer of Scientific Instruments JEOL Model JSM-6490)-and laser granulometry (Malverm Instruments Model Mastersizer 2000).The X-ray diffraction measurements were obtained with Brag-Brentano geometry and Cu kα.The angular range was 2θ = 6 • -110 • in steps of 0.02 • , and the counting time was 8 s/step.SEM analysis at 100×, 1000×, and 5000× on gold-coated samples was employed to examine the morphology.The particle-size measurements were conducted using the laser diffraction method with wet dispersion in water.The characterization of aluminum dross was done before and after inactivation and also after grinding to obtain the fine (≤75 µm), intermediate (75-150 µm), and coarse particle sizes (150-300 µm).
The aim of the third phase was the mortar mix design using characterization of the fine aggregate and cement.The mix design methodology was developed by Sánchez de Guzmán [13] and requires definition of a goal of compressive strength and consistency, which in this case were 28 MPa and plasticity over 110% in the mortar test flow.Additionally, this methodology requires the characterization of all components, which in this case was done through sieve analyses (NTC 77), absorption and density (NTC 237 and 176), unit weight (NTC 92), and organic matter (NTC 127) for the fine aggregate characterization.Similarly, fineness (NTC 33), setting time (NTC 118), normal consistency (NTC 110), and density (NTC 221) were used for the cement [14-21].
In the fourth phase, after the mix design was obtained for the reference mortar, mixes with cement replacements of 5, 10, and 20% (on a weight basis) using aluminum dross with different particle sizes (fine, intermediate, and coarse) were manufactured.Investigated mixes were then evaluated using three replicates regarding their fresh and hardened properties using the consistency (NTC 5784), density (NTC 1926), compressive and flexural strengths (NTC 220 and NTC 120), SEM analyses, and density and absorption tests [22][23][24][25].Thus, mix designations, descriptions, and sample numbers are presented in Table 2. Lastly, the fifth phase consisted of analyzing the results for selecting the best-performance mortar mixtures in terms of the obtained mechanical properties and consistency.In this case, mix design and application criteria such as NTC-2017 were used to perform the analysis [26].

Preliminary Activities
The aim of this phase was to obtain high-quality raw materials for the mortars, especially regarding the aluminum dross.Twenty-five kilograms of this by-product was obtained from a local industry that mainly produces aluminum profiles by primary and secondary processes that generate white dross, black dross, and salt cake.The dross used in this study is that which passes through a 2 mm sieve and is collected from different batches following the Orozco-Erazo et al. ( 2022) procedure [27].
At the university laboratory, the aluminum dross inactivation was done by water immersion for 5 days, followed by drying in an oven at 115 to 120 • C for 24 h.In this process, which is represented by equation ( 1), water reacts with aluminum nitride (AlN) to form ammonia (NH 3 ) and aluminum oxide (Al 2 O 3 ), as indicated by Shinzato & Hypolito (2005) [28].Finally, the aluminum dross was exposed to air for 7 days.The whole process was also called dross washing due to the use of water as the main inactivator.
Afterwards, the dross was exposed to abrasion at the Los Angeles machine, which was operated at 1000 rpm with 12 iron balls for 30 min.Then, a separation process with sieves #50 (300 µm opening size), #100 (150 µm opening size), #200 (75 µm opening size), and a bottom sieve was performed to classify the different particle sizes required.More details from the aluminum dross collection and inactivation processes can be observed in Figure 3.The washing process or inactivation of the aluminum dross caused chemical and physical changes that were detected by XRD, SEM, and laser granulometry.First, there was a reduction in aluminum nitride (AlN) and formation of aluminum hydroxide (Al (OH)3).This can be observed when comparing the XRD analyses after (a) and before (b) washing in Figure 4.There was a reduction in and appearance of peaks 2 and 6, respec-

By-Product Characterization 3.2.1. Aluminum Dross Inactivation
The washing process or inactivation of the aluminum dross caused chemical and physical changes that were detected by XRD, SEM, and laser granulometry.First, there was a reduction in aluminum nitride (AlN) and formation of aluminum hydroxide (Al (OH) 3 ).This can be observed when comparing the XRD analyses after (a) and before (b) washing in Figure 4.There was a reduction in and appearance of peaks 2 and 6, respectively.Second, there was agglomeration of the dross particles, which increased the particle size range from 20-800 µm to 100-1000 µm (Figure 5).Also, some morphological changes can be observed in Figure 6 with the SEM analyses at 100×, 1000×, and 5000× from aluminum dross washed (a) and without washing (b).The appearance of larger particles with softer surfaces (fiber type) after the aluminum dross inactivation is noticeable.Similarly, the increase in particle size due to dross inactivation can be observed in the higher specific surface area, uniformity coefficient, and average particle diameter that were calculated from the laser granulometry results and compiled in Table 3.Second, there was agglomeration of the dross particles, which increased the particle size range from 20-800 µm to 100-1000 µm (Figure 5).Also, some morphological changes can be observed in Figure 6 with the SEM analyses at 100×, 1000×, and 5000× from aluminum dross washed (a) and without washing (b).The appearance of larger particles with softer surfaces (fiber type) after the aluminum dross inactivation is noticeable.Similarly, the increase in particle size due to dross inactivation can be observed in the higher specific surface area, uniformity coefficient, and average particle diameter that were calculated from the laser granulometry results and compiled in Table 3.

Aluminum Dross Grinding
Although the aluminum dross grinding did not cause chemical changes, there were significant ones in the physical properties, mainly particle size.Laser granulometry results indicate a particle size between 100 and 600 µm, with an average particle diameter of 234.9 µm for the coarse fraction of the aluminum dross.Similarly, a particle size between 30 and 300 µm, with an average particle diameter of 80.0 µm for the intermediate fraction.Also, a particle size between 1 and 100 µm, with an average particle diameter of 22.9 µm, was determined for the fine fraction (Figure 7).

Aluminum Dross Grinding
Although the aluminum dross grinding did not cause chemical changes, there were significant ones in the physical properties, mainly particle size.Laser granulometry results indicate a particle size between 100 and 600 µm, with an average particle diameter of 234.9 µm for the coarse fraction of the aluminum dross.Similarly, a particle size between 30 and  300 µm, with an average particle diameter of 80.0 µm for the intermediate fraction.Also, a particle size between 1 and 100 µm, with an average particle diameter of 22.9 µm, was determined for the fine fraction (Figure 7).Additionally, a summary of the specific surface areas, uniformity coefficients, and average particle diameters of the three fractions is presented in Table 3. Considering that the aluminum dross will be part of the cementitious phase in this research, it is important to compare these parameters with those obtained for the cement.In this context, with a specific surface of 0.342 m 2 /g (3420 cm 2 /g), cement is much more similar to coarse dross.Considering its uniform coefficient of 0.701, cement is much more similar to intermediate Additionally, a summary of the specific surface areas, uniformity coefficients, and average particle diameters of the three fractions is presented in Table 3. Considering that the aluminum dross will be part of the cementitious phase in this research, it is important to compare these parameters with those obtained for the cement.In this context, with a specific surface of 0.342 m 2 /g (3420 cm 2 /g), cement is much more similar to coarse dross.Considering its uniform coefficient of 0.701, cement is much more similar to intermediate and fine dross.Also, in relation to its average particle diameter, fine dross almost doubles (22.9 µm) that of the used cement (14.36 µm).

Mix Design
Following the corresponding standards, first, the fine aggregate-which is river sand from the Cauca River (Colombia)-was physically characterized by calculating the sand density at saturated and surface-dried conditions, absorption, natural humidity, fineness modulus and nominal max.particle size.These two last parameters were calculated from the sieve analysis and granulometric curve presented in Figure 8.The parameters used in the reference mortar mix design are presented in Table 4.

Dross Condition
Specific Surface (m

Mix Design
Following the corresponding standards, first, the fine aggregate-which from the Cauca River (Colombia)-was physically characterized by calculat density at saturated and surface-dried conditions, absorption, natural humid modulus and nominal max.particle size.These two last parameters were cal the sieve analysis and granulometric curve presented in Figure 8.The param the reference mortar mix design are presented in Table 4.  Second, the reference mortar composition was determined by the mix de proposed by Sanchez Guzman (2011) [13], which requires defining the strength (28 MPa) and consistency (plastic) of the mortar.So, using the phy terization of the fine aggregate and cement, the following mix composition for one cubic meter of reference mortar (Table 5).Then, mixes with cement r  Second, the reference mortar composition was determined by the mix design method proposed by Sanchez Guzman (2011) [13], which requires defining the compressive strength (28 MPa) and consistency (plastic) of the mortar.So, using the physical characterization of the fine aggregate and cement, the following mix composition was defined for one cubic meter of reference mortar (Table 5).Then, mixes with cement replacements of 5, 10, and 20% aluminum dross (fine, intermediate, and coarse) were performed to this mix design.a Fine aggregate at saturated and surface-dried conditions.

Fresh and Hardened Properties of Mortars
Mortar flow results show that mortar mixes with aluminum dross content up to 20% did not substantially affect their design consistencies, which were over 110% in all cases.However, there was a slight consistency decrease when increasing the aluminum dross content in the mortar mixes.These results are in agreement with those reported in [10], where there was a decrease in the consistency, indicated by a decrease in the final setting time.
On the other hand, the mechanical properties indicated by the compressive strength at 7, 28, and 56 days of the investigated mortar mixes are presented in Figure 9. Results show that mortar mixes containing up to 20% fine aluminum dross satisfy the required 28 MPa compressive strength after 28 and 56 days.On the contrary, samples using 20% aluminum dross with coarse and intermediate particle sizes did not satisfy the compressive strength required in the mix design.Although there was an increase in the mechanical performance after 7, 28, and 56 days of casting, this was not enough to achieve the required performance in these samples.This trend was also reported by Panditharadhya, Mulangi, and Shankar (2019), who studied concrete with 5%, 10%, 15%, and 20% aluminum dross [10].a Fine aggregate at saturated and surface-dried conditions.

Fresh and Hardened Properties of Mortars
Mortar flow results show that mortar mixes with aluminum dross content up to 20% did not substantially affect their design consistencies, which were over 110% in all cases.However, there was a slight consistency decrease when increasing the aluminum dross content in the mortar mixes.These results are in agreement with those reported in [10], where there was a decrease in the consistency, indicated by a decrease in the final setting time.
On the other hand, the mechanical properties indicated by the compressive strength at 7, 28, and 56 days of the investigated mortar mixes are presented in Figure 9. Results show that mortar mixes containing up to 20% fine aluminum dross satisfy the required 28 MPa compressive strength after 28 and 56 days.On the contrary, samples using 20% aluminum dross with coarse and intermediate particle sizes did not satisfy the compressive strength required in the mix design.Although there was an increase in the mechanical performance after 7, 28, and 56 days of casting, this was not enough to achieve the required performance in these samples.This trend was also reported by Panditharadhya, Mulangi, and Shankar (2019), who studied concrete with 5%, 10%, 15%, and 20% aluminum dross [10].Similar to the compressive strength, the flexural strength decreased with the aluminum dross content used in the mortar samples (Figure 10).In this case, mortar mixes containing up to 20% aluminum dross with fine and intermediate particle sizes have acceptable mechanical performances.For example, these satisfactorily comply with the minimum Similar to the compressive strength, the flexural strength decreased with the aluminum dross content used in the mortar samples (Figure 10).In this case, mortar mixes containing up to 20% aluminum dross with fine and intermediate particle sizes have acceptable mechanical performances.For example, these satisfactorily comply with the minimum mechanical resistance required for paving stones (4.2 MPa according to the NTC 2017 standard).Similar flexural strengths were obtained recently by one of the authors using recycled aggregates obtained from old paving stones in Cauca (Colombia) [29].mechanical resistance required for paving stones (4.2 MPa according to the NTC 2017 standard).Similar flexural strengths were obtained recently by one of the authors using recycled aggregates obtained from old paving stones in Cauca (Colombia) [29].Moreover, when analyzing the correlation between the compressive and flexural strengths (Figure 11), it is observed that the compressive strength is between five and seven times the flexural strength, which is in agreement with other reported results.Similarly, the decreasing trend in the flexural and compressive strengths when increasing the amount of aluminum dross from 0% (REF) to 20% can be explained by the combined effect of the mortar porosity and dross particle sizes.Indeed, although not reflected in the density and absorption tests, there was a slight porosity increase observed in the SEM images at 100×, 2000×, and 5000× of mortar samples (Figure 12).This porosity was produced by the residual gases (e.g., NH3) released during the curing process by the aluminum dross.This can be confirmed through the XRD analyses (Figure 4), where there was a reduction in peaks 2 and 6, but still, there was not complete elimination of the aluminum nitride.However, compressive and flexural strengths reported here with the secondary aluminum dross are significantly higher than those reported by Dai and Apelian (2017) when evaluating mortars with 20% secondary dross.They reported a decrease in the mortar flexural strengths from 86 to 100% for fine and coarse particle sizes, respectively [11].Moreover, when analyzing the correlation between the compressive and flexural strengths (Figure 11), it is observed that the compressive strength is between five and seven times the flexural strength, which is in agreement with other reported results.Similarly, the decreasing trend in the flexural and compressive strengths when increasing the amount of aluminum dross from 0% (REF) to 20% can be explained by the combined effect of the mortar porosity and dross particle sizes.Indeed, although not reflected in the density and absorption tests, there was a slight porosity increase observed in the SEM images at 100×, 2000×, and 5000× of mortar samples (Figure 12).This porosity was produced by the residual gases (e.g., NH 3 ) released during the curing process by the aluminum dross.This can be confirmed through the XRD analyses (Figure 4), where there was a reduction in peaks 2 and 6, but still, there was not complete elimination of the aluminum nitride.However, compressive and flexural strengths reported here with the secondary aluminum dross are significantly higher than those reported by Dai and Apelian (2017) when evaluating mortars with 20% secondary dross.They reported a decrease in the mortar flexural strengths from 86 to 100% for fine and coarse particle sizes, respectively [11].Finally, it must be pointed out that prior to real-scale application of the investigated mortars, their durability aspects and environmental impacts should be investigated to include a complete life-cycle approach to evaluation.Also, optimization of the dross inactivation process is identified as a key factor in significantly contributing to the net zero carbon program signed by Santiago de Cali, which is aimed at reducing the current and projected consumption of cement in Colombia, the third-largest CO2 producer from cement   Finally, it must be pointed out that prior to real-scale application of the investigated mortars, their durability aspects and environmental impacts should be investigated to include a complete life-cycle approach to evaluation.Also, optimization of the dross inactivation process is identified as a key factor in significantly contributing to the net zero carbon program signed by Santiago de Cali, which is aimed at reducing the current and projected consumption of cement in Colombia, the third-largest CO 2 producer from cement in the Latin America region, after Brazil and Mexico (Figure 13) [30,31].So, simultaneous research is currently being performed by the authors on the design of an industrial-scale production process and a financial feasibility analysis for a specific case study.The findings validated the potential of the proposed recovery process and provided insights into determining the market price for the resulting product [32].

Conclusions
This article described first the inactivation of aluminum dross and second the ev ation of this aluminum dross with three different particle sizes as supplementary cem tious materials in mortar mixes designed for a compressive strength of 28 MPa and a tic consistency of 110% in the mortar flow test.Mortar flow test results and compre and flexural strengths of mortar mixes containing up to 20% fine and intermediate al num dross as cement replacement were satisfactory.However, mortar mixes contai 20% coarse aluminum dross did not satisfy the design applications.This might b tributed to the combined effect of a higher mortar porosity and large dross particle Mortar porosity was increased by the gases released by the aluminum dross during curing process.Although aluminum nitride reacted with water to form ammonia and minum oxide during the aluminum dross inactivation process, there was still non-rea AlN releasing gaseous NH3 during the curing process of this mortar mix.
Although more research should be performed prior to the mortar's real-scale a cation, this article reports the importance of industrial symbiosis between the constru and aluminum industries from Santiago de Cali (Colombia) in reducing carbon dio emissions due to the lower consumption of cement.Also, this reports the use of alumi dross as a supplementary cementitious material in mortars to reduce the potential imp on the environment and public health caused by aluminum dross disposal.

Conclusions
This article described first the inactivation of aluminum dross and second the evaluation of this aluminum dross with three different particle sizes as supplementary cementitious materials in mortar mixes designed for a compressive strength of 28 MPa and a plastic consistency of 110% in the mortar flow test.Mortar flow test results and compressive and flexural strengths of mortar mixes containing up to 20% fine and intermediate aluminum dross as cement replacement were satisfactory.However, mortar mixes containing 20% coarse aluminum dross did not satisfy the design applications.This might be attributed to the combined effect of a higher mortar porosity and large dross particle size.Mortar porosity was increased by the gases released by the aluminum dross during the curing process.Although aluminum nitride reacted with water to form ammonia and aluminum oxide during the aluminum dross inactivation process, there was still non-reacted AlN releasing gaseous NH 3 during the curing process of this mortar mix.
Although more research should be performed prior to the mortar's real-scale application, this article reports the importance of industrial symbiosis between the construction and aluminum industries from Santiago de Cali (Colombia) in reducing carbon dioxide emissions due to the lower consumption of cement.Also, this reports the use of aluminum dross as a supplementary cementitious material in mortars to reduce the potential impacts on the environment and public health caused by aluminum dross disposal.to 30 September 2021 in the manufacturing plant located in Yumbo (Colombia).Table A2 presents the main cement phases and compounds statistically analyzed from thirty samples of cement.With 68%, C 3 S (alite) and C 2 S (belite) represent the major phases responsible for the mechanical performance.Similarly, the C 3 A (aluminate) phase, which is lower than the maximum allowed (15%), is responsible for the early strength obtained.Finally, it is observed that the chemical compounds are among the limits established for cement durability.This is particularly important regarding MgO (periclase) and alkali compounds (K 2 O and N 2 O).

Sustainability 2023 ,Figure 5 .
Figure 5. Particle-size distribution obtained by laser granulometry from aluminum dross w (a) and without washing (b).

Figure 5 .
Figure 5. Particle-size distribution obtained by laser granulometry from aluminum dross washed (a) and without washing (b).

Sustainability 2023 ,Figure 5 .
Figure 5. Particle-size distribution obtained by laser granulometry from aluminum dross washed (a) and without washing (b).

Sustainability 2023 ,Figure 13 .
Figure 13.CO2 emissions from cement in the Latin America region modified from Our World based on the Global Carbon Budget (2022) [30].

Figure 13 .
Figure 13.CO 2 emissions from cement in the Latin America region modified from Our World Data based on the Global Carbon Budget (2022) [30].

Table 1 .
Results from mortars and concretes using aluminum dross and salt cake as supplementary cementitious materials.

Table 2 .
Mortar mix designation, aluminum dross content, and particle size.

Table 3 .
Specific surface, uniformity coefficient, and average particle diameter of aluminum dross at different conditions.

Table 4 .
Physical parameters of the fine aggregate and cement used in the mortar mix a Fine aggregate at saturated and surface-dried conditions.

Table 4 .
Physical parameters of the fine aggregate and cement used in the mortar mix design.
a Fine aggregate at saturated and surface-dried conditions.

Table 5 .
Components for one cubic meter of reference mortar with a compressive strength of 28 MPa and plastic consistency.

Table 5 .
Components for one cubic meter of reference mortar with a compressive strength of 28 MPa and plastic consistency.

Table A2 .
Main cement phases and compounds of the cement used in this project.