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Article

Considering the Effect of Various Silica Types on Chemical, Physical and Mechanical Properties in Cement Mortar Production via Substitution with Cement Content

by
Osman Hansu
Department of Civil Engineering, Gaziantep Islam Science and Technology University, 27000 Gaziantep, Turkey
Buildings 2025, 15(1), 74; https://doi.org/10.3390/buildings15010074
Submission received: 9 November 2024 / Revised: 16 December 2024 / Accepted: 26 December 2024 / Published: 29 December 2024
(This article belongs to the Special Issue Study on Concrete Structures)
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Abstract

The main objective of this study is to reduce CO2 emissions resulting from rapidly increasing cement production and utilization rates worldwide. For this purpose, the effects of NS (nano-silica) and SF (silica fume) materials, which are the post-production wastes of industrial products, the substitute material obtained by grinding SG (silica gel) wastes used for packaging purposes in the preservation of industrial electronic products and many other areas, and MLS (micritic limestone) obtained by grinding limestone, a natural resource, on mortars after cement substitutions were evaluated. MLS and SG contents were sieved through a 0.063 mm sieve and substituted into the mixtures, while specific surface area values for SF and NS were obtained as 23 m2/g and 150 m2/g. Each of these materials was used in mortars by substituting between 0% and 10% cement by weight. The samples were subjected to consistency determination and then evaluated for setting time. Subsequently, flexural tests were carried out on 40 mm × 40 mm × 160 mm specimens placed in molds, and compressive tests were carried out on prism fragments broken after flexural tests. The experimental results showed that substitution of SG substitutes with cement at 3–10 wt% was highly effective against SF, NS and MLS in terms of strength and workability properties.

1. Introduction

During the design of special or ordinary concrete/reinforced concrete structures from an engineering point of view, the use of materials suitable for the purpose of design (ambient conditions, service life, environmental impact, etc.) is of great importance. On the other hand, environmentally friendly and sustainable material solutions for use in fabrications, included in applied designs, are, to a large extent, the main target in the construction sector today, especially as regards cement-based fabrications. This situation leads the authors to aim for the most economical solution as much as possible as well as for the most positive contribution in terms of environmental pollution and sensitivity. On the other hand, it is often stated in the literature that the easiest and most practical solution to this situation is to recycle waste or reduce the amount of cement to be used during production. In this case, the aim is to remove the waste from nature as much as possible and to reduce the use of cement by utilizing its ability to be directly or indirectly trapped in concrete or cement paste, and as a result, to reduce the demand for cement [1,2,3,4,5,6,7,8,9,10].
About fifty years ago, self-compacting concrete (SCC) was first studied by Okamura in Japan to improve the performance of its fresh properties and the hardened strength–stability characteristics of conventional concrete (TC). Although SCC and TC are designed to have essentially the same mix content (i.e., aggregate, sand, cement, and water), SCC differs from TC in its fresh properties, with lower coarse aggregate and higher cement content [1,3,4,5,6,11,12,13]. Therefore, it is seen that these two main parameters are the main cost elements in SCC and SCM production and are the main reasons for cost increases, which is a significant disadvantage. As a result, it is calculated that almost the same amount (80%) of CO2 emissions is generated during the production of 1.0 ton of clinker in the cement sector, which is currently trying to respond to increases in cement demand. Considering this situation, increasing CO2 emissions in cement production means increasing the effectiveness of the global greenhouse effect [1,2,3,5,6,14].
In 2022, around 4.1 billion tons of cement were produced globally [1,2,3,5,6] and with the need for shelter increasing in line with the global population growth rate, prospects indicate that production values will increase to 5 and 6 billion tons in 2030 and 2050, respectively, due to increasing demands for construction and infrastructure needs [15,16]. In turn, the International Energy Agency projects a significant reduction in global CO2 emissions from cement production in line with its sustainable development scenario (from 2.4 Gt in 2019 to 0.2 Gt by 2070). This is expected to be achieved through measures such as reducing or avoiding cement demand and reducing the clinker-to-cement ratio [17].
To reduce these emissions, researchers have tried to both reduce the use of aggregates and to look for substitutes for cement [2,3,5,8,9,10,18,19]. Inert materials (such as limestone powder, palm oil fuel ash, quartz powder, marble powder, and calcite powder) and/or pozzolanic materials (metakaolin, fly ash, volcanic ash, silica fume, pumice, olive waste, blast furnace slag, etc.) often have properties that can be used for partial substitution with cement to reduce cement dosage during concrete production and overcome problems caused directly or indirectly by over-dosage or environmental impacts [13,17,20,21,22].
Some studies in the literature show that some mineral-based admixtures play a role in increasing cement hydration values. This is usually the case for inert, pure materials consisting of quartz, calcite, rutile and alumina powders [23,24]. However, there are other materials in the literature that have the same effect on pozzolanic additives such as silica fumes, fly ash, natural pozzolans and colloidal silica. This increase in the fineness of the powder grains usually eliminates some of the negative effects of cement dilution that can result from replacing the cement content with mineral admixtures. In addition, the substitution of some powders with products can cause a decrease in the hydration rate, leading to a delay in setting and subsequently affecting the development of short-term pressure increases. This effect was mainly observed in studies with fly ash or silica fume [23,24,25].
Supplementary cement admixtures not only fill the pores in the concrete mass, but also change the chemical reactions in a complex way in relation to the hydration of cement. Due to differences in the pozzolanic reactions of various supplementary cement additives, their use in concrete production is limited. SF is one of the most studied among them. The silicon and ferrosilicon industries produce SF as a by-product during their production processes, which can be used to replace additional cementitious materials, thus reducing the need for increased cement dosage. In addition, this also reduces CO2 emissions. SF has different names according to its content and fineness, such as silica powder, micro silica, and volatile silica. The very small particle size of SF allows it to enter micro voids that may occur in the cement matrix and act as a filler in this matrix. Due to its high pozzolanic reactivity, SF has a positive effect on compressive strength and lime-depletion activity and therefore a lower hydration heat, which improves the overall cement matrix and reduces bleeding and permeability [26,27,28].
Silica nanoparticles, also called nano-silica or silicon dioxide particles, have attracted great interest from researchers in recent years given their properties. The properties of NS include high pore volume, optimum surface area, outstanding potential biocompatibility, harmonic pore size and the potential to be used to encapsulate hydrophilic/hydrophobic materials. Another aspect that can be said for NS is that various aspects of NS can be manipulated, such as its shape, crystallinity and porosity, depending on particle size, which has attracted the attention of researchers. The incorporation of small amounts of NS into concrete can change the nanostructure of cementitious materials, providing high durability. Recently, in concrete technology, nano-silica has attracted particular attention due to its very good performance in concrete compared to traditional mineral admixture [29,30].
Since the early 1990s, limestone-derived powdered materials have attracted considerable interest as partial substitutes for cement due to their wide availability, and economic and environmental benefits. Therefore, numerous studies have been conducted to evaluate the effect of limestone grain size and content on the workability, hydration products, porosity, strength and durability of ordinary Portland cement (OPC) concrete to investigate the successful applicability of limestone powder as a complementary cementitious material considering its properties. In the literature, an increase in the workability of OPC concrete has been reported through morphological, filling and dilution studies of finely ground limestone powder. Replacing OPC with up to 15% limestone with high blain values is favorable for increasing the compressive strength of OPC concrete through filling, nucleation and chemical effects. It is also possible that coarse limestone addition may worsen the strength development and durability of OPC due to a dilution effect. Through extensive experimental and practical studies, many countries have established specific standards to promote the use of limestone powder as a supplementary cement admixture in concrete [31,32,33].
Within the scope of this study, an evaluation was made on the use of different types of waste and natural resources that can be substituted for cement. The study presents an evaluation of the production of mortar and its derivatives with appropriate content of waste and natural resources and their subsequent substitution with cement in high-cement-dosage concrete and its derivatives. In this study, both industrial waste, natural resources and technological product waste were evaluated to minimize the waste impact on the environment and reduce CO2 emissions into the atmosphere during the production of cement required for concretes with high dosage levels. In the evaluation, the setting times, which are of great importance both in the production of cement and in its use in the field, were evaluated, and usability in the field for post-production substitution were tested, and the situations in which a normal consistency value could be provided were evaluated; additionally, the cement was checked in regards to its ability to meet the labor requirements at construction sites. While studies on industrially produced nano-silica and silica fume were used as references, silica gel has not been previously evaluated as waste in the literature. During the article writing process, it was verified that there were no examples of the use of micritic limestone, a natural resource, in sizes smaller than 0.063 mm for substitution with cement. Accordingly, the study presents data on different silica-containing and limestone-containing resources in the literature. The materials produced for this purpose were evaluated for changes in setting times, changes in mechanical properties and workability levels. Silica gel, silica fume, nano-silica and micritic limestone substituted mixtures were designed in two groups. First were cement pastes, and then mortar production was carried out. Cement contents were substituted with related materials between 1% and 10% and used in 1% increments. The water/binder ratios in the mixtures were increased or decreased according to the appropriate workability characteristics of the cement paste and mortar tests. Four groups of experiments were carried out on all mixtures produced. These are presented in the study as chemical and microstructure monitoring tests, setting time determination tests, and mechanical tests (flexural strength and compressive strength tests). The predictions of the obtained experiments, that the relevant mix ratios can reduce cement utilization rates and can reduce CO2 emissions from cement, are supported by the study.

2. Experimental Studies

2.1. Materials

Nano-silica (NS), silica fume (SF), micritic limestone (ML) and silica gel (SG) were substituted with cement in the range of 1% to 10% by weight and cement paste and mortar mixtures were produced (Figure 1). Silica fume is a product consisting of amorphous SiO2 particles in two forms, condensed and non-condensed, used in construction chemicals, and refractory and construction sectors, meeting ASTM C-1240 standards [34]. The product was purchased from DOSTKİMYA factory and product-specific surface area values were obtained as 23 m2/g. The nano-silica material is readily available from the manufacturer as a product called AEROSIL-150. Specific surface area values were obtained by the vendor as 150 m2/g. Due to its three-dimensional structure, nano-silica is known to increase viscosity and cause thixotropic behavior when used as a thickener or filler for the cement matrix. Micritic limestone was taken from the Pülümür valley as a natural source and pieces were taken from the source on the ground and brought to the laboratory. In the laboratory, these pieces were first crushed in a Los Angeles abrasion machine at 500 rpm and then crushed in a ring grinder for 5 min to make the resultant material finer. The powder form of the produced material was sieved with a sieve with a size opening of 0.063 mm and used. Silica gel is used for dehumidification in electronic storage areas and is contained in small packages of electronic products that need to be protected against moisture. The products collected in these small packages in landfills were taken and brought to the laboratory. In the laboratory, these pieces were ground in a ring grinder for 5 min. The powder form of the produced material was sieved with a sieve with a size opening of 0.063 mm and used. RILEM sand (RS) was used in mortars. Aggregates were saved in water for 24 h and then the specific gravity of the saturated surface dry (SSD) was measured. Specific gravity and water absorption were measured as 2.261 and 0.59%, respectively. Specific gravities used for NS, SF, ML and SG were 2.2, 2.22, 2.53 and 1.65, respectively. The chemical components for cement, NS and SF were obtained from the manufacturers, while the chemical properties of ML and SG were obtained from professional laboratories for testing, and all detailed components are given in Table 1. The water, obtained from the drinking water network, was used as mixing water during mortar and cement paste production.
The experimental work which followed the chemical analysis is briefly summarized in “Table 1. Chemical composition” and “Table 2. Chemical composition of the dry mix in the analyses obtained in the study” below. Chemical oxide analyses were carried out in a Thermo Fisher ARL 9900 XRF (X-ray fluorescence), Pazarcık, Turkey. device with wavelength dispersion by preparing the sample by the melting method according to the TS EN 196-2 [35] standard. While preparing the melt sample, 1 g of the cement sample was used and 8 g of lithium tetraborate was melted with a fluxer, and lithium iodide solution was used to prevent adhesion. The melt pellets were analyzed in an XRF device for chemical oxide analysis. Loss on the fire test was carried out in a Protherm-brand muffle furnace according to the TS EN 196-2 [35] standard. One gram of cement (blended powder mixture) was weighed into a preheated and tared crucible. The closed crucible was placed in an electric furnace with a constant temperature of (950 ± 25) °C and heated for 5 min, then the lid was removed, and the crucible was kept in the furnace for another 10 min. The crucible was cooled to room temperature in a desiccator. The constant mass was then determined. In this way, “Table 1. Chemical composition”, and “Table 2. Dry mix chemical composition” and “Table 3. Cement paste designs.” data were obtained at the ÇIMKO Cement and Concrete Industry Trade Inc. laboratories located in Pazarcık district of Kahramanmaraş province.

2.2. Mixture Proportioning and Sample Preparation

A total of 36 mortar (paste) recipes were prepared within the scope of the study. The dosage amounts selected in the study were aimed to reduce the cement content used in concretes such as high-dosage SCC, which is becoming more advanced with today’s concrete technology, by using industrial resource wastes, technological wastes and naturally occurring rocks on the ground surface. In addition to the dosage amount selected for this target, low replacement ratios were selected as it is planned for use as a post-production substitute for cement. These values are based on the setting time and normal consistency values provided for the cement paste as well as the normal consistency conditions of the substitute mixed with cement. Mortar mixtures were produced using the ratios obtained after the calculated consistency–water contents.
The cement pastes and mortar mixtures were prepared using a laboratory-type mortar mixer (Figure 2b) with a capacity of 1 dm3, working on the vertical axis on the bench during production. While evaluating the water/binder ratio in mortar and dough mixtures, the suitability of the flow table diameter values was evaluated according to ASTM C1437 [36]. The appropriate water/binder ratio in the mixtures varied between 0.27 and 0.38. The binder dosage was kept constant as 500 kg/m3. For the cement paste preparation: after drying about half a kilo of cement in an oven until it reached a constant weight, about 25–30% of potable tap water was added to about 300 g of cement (Figure 2a). After kneading the cement and water mixture for 3 min, the resulting cement paste was placed in the Vicat ring after 1 min at the latest. The tip of the probe was lowered into the center of the prepared Vicat ring until it touched the top surface of the dough and was then released freely. A reading was taken from the Vicat device 30 s after the moment of release. This process was repeated with various amounts of water to determine the amount of water required for the cement. Sinking to a depth of 5 mm to 7 mm was considered sufficient for normal consistency.
The cement pastes were evaluated by trying to meet the minimum levels of normal consistency for cement paste. After the obtained normal consistencies were found, mortar production started (Figure 2c). The composition of the mortars was standard. For the production of weighed mortar materials, water and cement are added to the mixing bowl, respectively. The mixer operates at low speed for 30 s, during which the sand is gradually added to the mixer. When all the sand is added, mixing continues for another 1 min and then the mixer is mixed at high speed for another 30 s. The mixer is stopped, and the mortar is allowed to rest for 1 min and then the mixer is started for another 1 min. Thus, in a total of 4 min, the mortar is ready to be put into the molds. The mortar is released from the mixer into the molds and the shaking machine starts and runs for 60 s to complete the placement process (Figure 2).
In the study, firstly, compatibility tests were performed on the cement mortars given in Table 3 with a Vicat instrument, then RILEM sand was added to the cement pastes in this table and new mortar mixtures were formed as a mechanical test set. The reason for using high dosage in this process is that in the developing concrete technology, for example, in SCC type concretes, the use of high dosage with alternative material substitutions is foreseen. In addition, it is aimed at minimizing CO2 emissions and environmental impacts. The slump values measured in the mortars during the experiment were 18 ± 1 cm in the control mix, while the slump values in the mortar mixes with different substitution levels varied between 18 and 21 cm, respectively (Figure 2d). Fresh mortar was poured into steel molds in two layers and vibrated for a few seconds (Figure 2e). The specimens were wrapped in plastic bags and kept in the laboratory for 24 h (Figure 2f). At the end of the laboratory holding period, they were removed from the mold (Figure 2g) and cured in water at 20 ± 2 °C until the test day, according to the test curing time (Figure 2h). To ensure the workability properties of the mortars, the water contents were evaluated within the effect of the respective material type substitution on the workability criteria. This range varied between 1% and 5%, especially for NS content, as 5% and above could not be achieved.
A total of 324 prismatic specimens were produced for the hardened mortar tests. The tests on the hardened mortar were carried out on the 7th, 14th and 28th days. All the 40 × 40 × 160 mm prismatic specimens were tested for tensile strength in flexure and then for compressive strength on broken prism fragments. All mortar specimens were water cured until the test day, before the mechanical tests were performed. Although each experiment consisted of 3 specimens for each mix, the results were calculated as the average of these three specimens.

2.3. Test Procedure

The compressive strength test was carried out on the prism specimens in flexure in accordance with ASTM C348 [37], followed by a tensile strength test in flexure on the fragments resulting from the fracture of the prisms in accordance with ASTM C349 [38]. Therefore, 40 mm × 40 mm × 160 mm prism specimens were used to determine flexural strength and compressive strength at 7, 14 and 28 days of age. Three specimens were tested to determine each test result.

3. Results and Discussion

3.1. Dry Mix Results

X-ray fluorescence (XRF) analyses of the mixtures obtained for NS, SF, ML and SG substituted with cement paste were carried out before the cement paste was prepared. During the analysis, support was obtained from the cement production factory of Çimko Cement and Concrete Industry Trade Inc., located in the Pazarcık district of Kahramanmaraş province. SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, K2O and Na2O contents were measured during the analysis. Other chemical constituents are not recognized as being in the minority and will not be considered in the scope of the study. The results obtained are presented in the table. The highest SiO2 value in the table was obtained in the MCEMSG10 mixture, the highest Al2O3 value in the MCEM mixture and the highest CaO value in the MCEMMLS1 mixture. The MCEMSG10 blend contains 10% SG substitution, and the MCEMMLS1 blend contains 1% MLS substitution.

3.2. Fresh State Results

The mixing water used in the preparation of the mixtures not only affects the workability properties of the mortars to be prepared, but also appears to be an effective parameter with regard to strength. Therefore, it is important to evaluate this parameter in mixtures containing cement. The amounts of water evaluated in the mixtures were calculated as between 27 and 30% for SG, between 27 and 33% for SF substitutes, between 36 and 40% for NS and between 27 and 28% for MLS (Figure 3). Experiments were carried out in accordance with the ASTM C403 [39] standard for the calculation of setting time in fresh property tests of cement paste. For the test method, for the water required for a normal consistency in the hydraulic cement paste, experiments were carried out in accordance with the ASTM C187 [40] standard.
In addition, the amount of water added and substitution ratios also have a significant effect on setting times. In the examination of setting times, initial setting time and final setting time evaluations were made. The setting onset times varied between 120 and 210 min for mixtures containing SG, 200 and 250 min for mixtures containing SF, 245 and 280 min for NS substituents and 170 and 220 min for MLS substituents (Figure 4). The change in setting end times ranged between 245 and 290 min for SG containing mixtures, 265 and 320 min for SF containing mixtures, 280 and 305 min for NS substituents and 245 and 355 min for MLS substituents. The shortest times between the initial and final setting time were calculated as 55 min in the MCEMSG6 mixture, 45 min in the MCEMSG6 and MCEMSG7 mixtures, 25 min in the MCEMNS5 mixture and finally 75 min in the MCEMNS7 and MCEMNS8 mixtures (Figure 4).
When silica fume is used in mixtures at low dosages (<5% replacement by mass of cementitious material), it leads to a reduction in water demand as it displaces entrapped water by filling the voids between water-filled cement grains. At high dosages, particle packing is mostly full and the use of excess silica fume creates more surface area and thus increases the water demand [41], as observed in this study (Figure 3b). As seen in previous studies, nano-silica requires more water than silica fume due to the high specific surface area of the particles [42]. This limited the use of NS substitution after 5% NS substitution in this study (Figure 3c). According to previous studies, increasing the limestone content to 20% and 35% resulted in reduced water requirements. Furthermore, the addition of 5% limestone reduced the water content by an average of 0.5% in absolute terms for dough of standard consistency [43,44]. A similar situation was observed for the MLS substitute (Figure 3d). The SG content used in this study was obtained from the milling of gel-form products with high moisture retention capacity. It can be said that this product, which has a slightly higher water concession, creates a water requirement similar to SF (given its water holding or absorption capacity) (Figure 3a).

3.3. Flexural Strength Results

At this stage, three 40 × 40 × 160 mm specimens of each mortar mix were taken and tested. The specimens were tested in accordance with ASTM C348 [37], which is given as the standard test method for flexural strength of hydraulic cement mortars. The results in flexural tensile strength tests of the prism mortar specimens are summarized in this section. When the first group of mixtures was evaluated, the highest flexural tensile strength values for the specimens cured at 7, 14 and 28 days of age were obtained from MCEMSG5, MCEMSG6 and MCEMSG6 mixtures, respectively. The obtained strengths were calculated as 12.23, 9.07 and 10.04 MPa for these mixtures, respectively. Again, in the SG-containing group, the lowest flexural tensile strength values of the specimens cured at 7, 14 and 28 days of age were obtained in the groups containing 10% SG. In these mixtures, the lowest strength values obtained at 7, 14 and 28 days of age were calculated as 4.19, 5.49 and 7.26 MPa, respectively (Figure 5). The highest flexural tensile strength values calculated for specimens cured at 7, 14 and 28 days of age in mixtures containing SF were obtained in the 3% SF substitution group. The strengths obtained in this mixture group were calculated as 8, 8.6 and 9.5 MPa for 7, 14 and 28 days of age, respectively. In the SF-containing group, the lowest flexural tensile strength values calculated for the specimens tested at 7, 14 and 28 days of age were obtained in mixtures containing 10% SF and the strength values obtained in these mixtures at 7, 14 and 28 days of age were calculated as 4.78, 5.7 and 6.81 MPa, respectively (Figure 5). In another group, NS-substituted mixtures, the highest flexural tensile strength values, calculated for 7, 14 and 28 days of age, were obtained in the group with 1% NS, and the strengths obtained were 4.5, 4.5 and 4.3 MPa for the given order of days. The lowest strengths for this mixed group were obtained in the groups containing 5% NS for 7 days and 4% NS for 14 and 28 days. The obtained flexural tensile strengths were calculated as 1.8, 1.74 and 1.6 MPa at 7, 14 and 28 days of age, respectively (Figure 5). For MLS, which was used as the last substitution product, the maximum values obtained were in mixtures with 2% substitution, and the minimum values were in mixtures with 10% substitution. The highest flexural tensile strength values calculated for 7, 14 and 28 days of age were 7.6, 8.65 and 9.5 MPa for the given order of days. On the other hand, the lowest flexural tensile strength values obtained were 4.32, 3.39 and 2.39 MPa at 7, 14 and 28 days of age, respectively (Figure 5).
Although silica fume itself cannot directly hydrate with water, the reaction of cement hydration products with Ca(OH)2 under alkaline conditions can lead to an increase in C-S-H gel formation, due to the so-called pozzolanic effect. Such a reaction increases the volume of C-S-H gel in the mortar. As the component providing the main strength increases, the strength of the mortar matrix also increases. To generalize further, silica fume can serve as a reactive micro filler. The filling effect of silica fume can be utilized for the porous structure of the cement mortar, which varies with the w/c ratio. Silica fume can be used to effectively fill and refine pores of different sizes in the matrix, thus improving the overall performance [31,45,46]. It can be predicted that the matrix structure is strengthened, reflected as an increase in tensile strength in bending due to the increase in C-S-H in the voids and support for the formation of ettringite.

3.4. Compressive Strength Results

ASTM C349 [38] was used as the Standard Test Method for Compressive Strength of Cement Mortars. In this method, the compressive strength of mortars was calculated by using the fractured parts of the prisms in flexure. The results obtained from these tests were evaluated in four groups of mixtures. In the first group, with SG substitution, the lowest values on the 7th, 14th and 28th days were obtained at 10% substitution rate. The results obtained on these days were calculated as 28.6, 33.22 and 42.47 MPa, respectively. The highest values were obtained from mixtures with 4%, 5% and 6% substitution on the 7th, 14th and 28th days, respectively. The results obtained for compressive strength were 48.7, 56.5 and 74.75 for days 7, 14 and 28, respectively (Figure 6). In the second mix, in the second group with SF substitution, the lowest values were obtained on days 7, 14 and 28 at 10% substitution rate. The results obtained on days 7, 14 and 28 were calculated as 32.15, 33.22 and 36.71 MPa, respectively. On the 7th, 14th and 28th days, the highest values were obtained from the tests performed on 4%, 5% and 4% substitution mixtures, respectively. The compressive strengths were 48.7, 56.5 and 74.75 for 4%, 5% and 4% substituted mixtures on days 7, 14 and 28, respectively (Figure 6). The maximum compressive strength values obtained with NS substitutes, which are materials with high silica content, and other mixtures containing nanoparticles, were obtained at 2% substitution rates. The results obtained at 7, 14 and 28 days are 48, 54.4 and 58 MPa, respectively. The lowest compressive strengths were calculated at a 5% NS substitution rate for the same test days. These values were 24.4, 26.6 and 34.9 MPa, respectively (Figure 6). The maximum compressive strength values obtained in other mixtures containing MLS substitute, a naturally occurring limestone-based material, were obtained at a 3% substitution rate. The compressive strengths were 43.1, 49 and 55 MPa for days 7, 14 and 28, respectively. The lowest compressive strengths were calculated at a 10% MLS substitution rate for the same test days. These values are 22.6, 31.2 and 38.68 MPa, respectively (Figure 6). Silica content has been shown to become a nucleation center for cement hydrates and to accelerate hydration through this mobilization. The mechanism is related to the non-agglomerated structure of silica derivatives (well-dispersed particles) and the increased surface area, which works as a nucleation site for the precipitation of additional C-S-H gel. The additional C-S-H formation occupies the available space, leading to a denser structure [46]. This can be considered as an indication of the compressive strength increases in the study.
The graphs of the variation between the compressive and flexural tensile strengths of mortars produced with SG, SF, NS and MLS evaluated in the study are given in Figure 7. When the results obtained were evaluated, the ratios of 0.16, 0.15, 0.09 and 0.13 were found between the compressive and flexural tensile strengths of SG, SF, NS and MLS. The R2 values, which are statistically collinearization coefficients of these ratios, were calculated as 0.99, 0.99, 0.87 and 0.92, respectively. There is a very significant correlation between SG and SF compressive and flexural tensile strengths. There are dense data on the mechanical properties of concrete and the relationships between them are well documented in the literature, and empirical formulas have been detailed in various designs or standards and codes. Although the tensile strength of concrete is moderately low, it is reported to be about 10% to 15% of the compressive strength and in very rare cases can be as high as 20% [47,48]. However, it has also been reported that there is no direct proportionality between the two mechanical properties, but , in general, when the compressive strength increases, the tensile strength may also increase or decrease [49]. Similarly, it has been suggested that the results for flexural strength can generally be about 10% of the compressive strength value [50], but the data do not establish a linear process in this relationship. On the other hand, for concretes produced with low compressive strength, this ratio can be up to about 30% [51]. However, it is important to note that this ratio is greatly influenced by the composition of the concrete, the type of aggregate and the curing and testing conditions [52]. In parallel with this situation, considering that the mortars produced reflect the basic properties of the concretes, it can be said that a relationship between 9% and 15%, obtained in the study, is consistent with the data obtained.
Reducing the desired useful service life of reinforced concrete structures during their design is a major problem facing the developing construction industry worldwide. Concrete deterioration due to reinforcement corrosion is significant in temperate climates of the world, while in hot and arid regions the problem is caused by a combination of environmental conditions, marginal aggregates and improperly selected construction methods. The repair and rehabilitation of deteriorated concrete structures also consumes a significant number of resources [53]. The SF- and SG-containing mortars produced in this study appear to be highly suitable for these repairs due to their high compressive and tensile strengths.

3.5. Micro-Structure Results

SEM (Figure 8), EDX (Figure 9) and XRD (Figure 10) analyses were performed for cement, NS, SF, SG and MLS, and material characterizations were defined. In the results obtained, the high silica content for NS, SF and SG and CaO content in MLS and cement are especially noteworthy. The changes in the strengths obtained from the materials also follow the results obtained from these contents. Compressive strength gains are remarkable in mixtures with SG content, which are mixed sets with more pronounced silica peak values.
EDX analysis of the SF, NS and SG evaluated in the study shows prominent peaks for silicon (Figure 8). Silicon was also observed as a low peak for MLS. The calcium peak for MLS was more clearly observed in EDX analysis. In EDX analysis, the silicon peak in SG appears to have larger values. This can be considered as another indicator of the effectiveness of the change in mechanical properties against other silicon contents.
The high peak between 20° and 30° angles indicates the presence of amorphous silica in the material [54]. It is also known from XRD analysis that some of the crystalline silica (cristobalite) detected for SF, SG and NS may be due to impurities in the content. The XRD results in Figure 9 show the presence of amorphous silica between 20° and 30° angles in the XRD patterns for SF, SG and NS. Therefore, the fact that the XRD results show a broad hump peak indicates that almost all the quartz in these silicates is amorphous.

4. Conclusions

Within the scope of this study, an evaluation of the usage properties of NS- and SF-containing materials that can be obtained as a sub-industry in industrial production, SG, obtained by grinding after waste supply as recycling, and MLS plies, obtained by grinding limestone, which is a natural resource, with cement, was attempted. Also within the scope of the study, standard cement tests such as consistency determination, initial and final setting time, and mechanical tests such as flexural and compressive tests were performed. Silica gel, silica fume, nano-silica and micritic limestone were used as substitutes between 0% and 10%, by weight, in cement pastes and mortars designed and prepared with these materials. Considering the quantities associated with the reduction of carbon dioxide emissions and the use of individual cement substitutes, it was found that the use of SG as a cement substitute at 5–7% by weight, after it has been obtained as waste and milled, would have a positive environmental impact due to both the environmental impact of SG and the reduction in the amount of CO2 emitted when reducing the amount of cement used. Similarly, SF substitution also gives positive results in the range of 5–7%. At these ratios, both substitution rates used are high, and the mechanical property improvements are at optimum levels. The following evaluations were made based on experimental studies on hardened mortar.
  • Among the substitutes used, the highest water demand is observed in mixtures containing NS. This is also the biggest cause of strength losses; the main reason for the water requirement may be due to the specific surface area. On the other hand, there is no significant difference in water demand for the SG substitute.
  • Regarding setting time, which is an important parameter in field studies, increases in SG content show significant gains in final setting time. In MLS substitutions, the final setting time values increase and the time between the initial and final setting times increases.
    The largest flexural strength gains were obtained for SG substitutes collected as waste. Substitutions of around 5% for SG result in significant gains. SF and MLS also show increases in flexural tensile strength tests, but substitution rates of only 3% in these materials provide optimum gains in both replacement amounts and strength.
  • The largest gains in compressive strength were obtained for SG substitutions, as in flexural tensile strength. In contrast to flexural tensile strength, substitutions of around 6% for SG result in significant gains. SF and MLS also show increases in compressive strength tests, but these materials show optimum gains in strength and amount of substitution at around 4% and 3% substitution rates, respectively.
  • In terms of strength and workability properties of SG substitutes, it is revealed that 3–10% by-weight substitution with cement is highly effective relative to SF, NS and MLS.

Funding

This research received no external funding.

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors on request.

Acknowledgments

This study is supported by ÇIMKO Cement and Concrete Industry Trade Inc. located in Pazarcık district of Kahramanmaraş province.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Etli, S.; Yılmaz, T.; Hansu, O. Effect of White-Portland Cement Containing Micro and Nano Silica on the Mechanical and Freeze-Thaw Properties of Self Compacting Mortars. Eng. Sci. Technol. Int. J. 2024, 50, 101614. [Google Scholar] [CrossRef]
  2. Etli, S. Effect of Glass Sand Used as Aggregate on Micro-Concrete Properties. J. Croat. Assoc. Civ. Eng. 2023, 75, 39–51. [Google Scholar] [CrossRef]
  3. Etli, S. Mechanical Properties of Self-Compacting Mortars Containing Rubber Waste Particles as Fine Aggregate in Freeze–Thaw Cycles. J. Mater. Civ. Eng. 2024, 36, 04024246. [Google Scholar] [CrossRef]
  4. Akgül, M.; Etli, S. Investigation of the Variation of Mechanical and Durability Properties of Elements Manufactured with Rubber Substituted SCMs with Element Height. Constr. Build. Mater. 2024, 428, 136300. [Google Scholar] [CrossRef]
  5. Etli, S. Effect of Recycled Brick Powder on the Properties of Self-Compacting Fiber Reinforced Mortars Produced with Different Cement Types. Front. Struct. Civ. Eng. 2024, 18, 743–759. [Google Scholar] [CrossRef]
  6. Etli, S. Evaluation of the Effect of Silica Fume on the Fresh, Mechanical and Durability Properties of Self-Compacting Concrete Produced by Using Waste Rubber as Fine Aggregate. J. Clean. Prod. 2023, 384, 135590. [Google Scholar] [CrossRef]
  7. Cemalgil, S.; Onat, O.; Tanaydın, M.K.; Etli, S. Effect of Waste Textile Dye Adsorbed Almond Shell on Self Compacting Mortar. Constr. Build. Mater. 2021, 300, 123978. [Google Scholar] [CrossRef]
  8. Cemalgil, S.; Etli, S.; Onat, O. Curing Effect on Mortar Properties Produced with Styrene-Butadiene Rubber. Comput. Concr. 2018, 21, 705–715. [Google Scholar] [CrossRef]
  9. Gesoglu, M.; Güneyisi, E.; Hansu, O.; Etli, S.; Alhassan, M. Mechanical and Fracture Characteristics of Self-Compacting Concretes Containing Different Percentage of Plastic Waste Powder. Constr. Build. Mater. 2017, 140, 562–569. [Google Scholar] [CrossRef]
  10. Etli, S.; Cemalgil, S.; Onat, O. Effect of Pumice Powder and Artificial Lightweight Fine Aggregate on Self-Compacting Mortar. Comput. Concr. 2021, 27, 241–252. [Google Scholar] [CrossRef]
  11. Quercia, G.; Spiesz, P.; Hüsken, G.; Brouwers, H.J.H. SCC Modification by Use of Amorphous Nano-Silica. Cem. Concr. Compos. 2014, 45, 69–81. [Google Scholar] [CrossRef]
  12. Shokravi, H.; Mohammadyan-Yasouj, S.E.; Koloor, S.S.R.; Petrů, M.; Heidarrezaei, M. Effect of Alumina Additives on Mechanical and Fresh Properties of Self-Compacting Concrete: A Review. Processes 2021, 9, 554. [Google Scholar] [CrossRef]
  13. Nasr, D.; Behforouz, B.; Borujeni, P.R.; Borujeni, S.A.; Zehtab, B. Effect of Nano-Silica on Mechanical Properties and Durability of Self-Compacting Mortar Containing Natural Zeolite: Experimental Investigations and Artificial Neural Network Modeling. Constr. Build. Mater. 2019, 229, 116888. [Google Scholar] [CrossRef]
  14. Gupta, N.; Siddique, R.; Belarbi, R. Sustainable and Greener Self-Compacting Concrete Incorporating Industrial By-Products: A Review. J. Clean. Prod. 2021, 284, 124803. [Google Scholar] [CrossRef]
  15. Amran, M.; Makul, N.; Fediuk, R.; Lee, Y.H.; Vatin, N.I.; Lee, Y.Y.; Mohammed, K. Global Carbon Recoverability Experiences from the Cement Industry. Case Stud. Constr. Mater. 2022, 17, e01439. [Google Scholar] [CrossRef]
  16. Bekun, F.V.; Alola, A.A.; Gyamfi, B.A.; Kwakwa, P.A.; Uzuner, G. Econometrics Analysis on Cement Production and Environmental Quality in European Union Countries. Int. J. Environ. Sci. Technol. 2023, 20, 4265–4280. [Google Scholar] [CrossRef]
  17. Guo, Y.; Luo, L.; Liu, T.; Hao, L.; Li, Y.; Liu, P.; Zhu, T. A Review of Low-Carbon Technologies and Projects for the Global Cement Industry. J. Environ. Sci. 2024, 136, 682–697. [Google Scholar] [CrossRef]
  18. Etli, S. Investigation of the Effect of Glass Sand Used in SCC on the Behavior of the SCC Stress-Strain Relationship. Int. J. Innov. Eng. Appl. 2022, 6, 237–244. [Google Scholar] [CrossRef]
  19. Etli, S. Evaluation of Curing Time for Micro Concrete Mixes Containing Silica Fume, Nano-Silica And Fly Ash. İstanbul Ticaret Üniversitesi Fen. Bilim. Derg. 2022, 21, 304–316. [Google Scholar] [CrossRef]
  20. Hani, N.; Nawawy, O.; Ragab, K.S.; Kohail, M. The Effect of Different Water/Binder Ratio and Nano-Silica Dosage on the Fresh and Hardened Properties of Self-Compacting Concrete. Constr. Build. Mater. 2018, 165, 504–513. [Google Scholar] [CrossRef]
  21. Badogiannis, E.G.; Sfikas, I.P.; Voukia, D.V.; Trezos, K.G.; Tsivilis, S.G. Durability of Metakaolin Self-Compacting Concrete. Constr. Build. Mater. 2015, 82, 133–141. [Google Scholar] [CrossRef]
  22. Askarian, M.; Fakhretaha Aval, S.; Joshaghani, A. A Comprehensive Experimental Study on the Performance of Pumice Powder in Self-Compacting Concrete (SCC). J. Sustain. Cem. Based Mater. 2018, 7, 340–356. [Google Scholar] [CrossRef]
  23. Tome, S.; Nana, A.; Tchakouté, H.K.; Temuujin, J.; Rüscher, C.H. Mineralogical Evolution of Raw Materials Transformed to Geopolymer Materials: A Review. Ceram. Int. 2024, 50, 35855–35868. [Google Scholar] [CrossRef]
  24. Lawrence, P.; Cyr, M.; Ringot, E. Mineral Admixtures in Mortars. Cem. Concr. Res. 2003, 33, 1939–1947. [Google Scholar] [CrossRef]
  25. Rashad, A.M.; Mosleh, Y.A.; Mokhtar, M.M. Thermal Insulation and Durability of Alkali-Activated Lightweight Slag Mortar Modified with Silica Fume and Fly Ash. Constr. Build. Mater. 2024, 411, 134255. [Google Scholar] [CrossRef]
  26. Singh, A.; Singh, N. Mechanical Properties of Silica Fume Based Concrete: A Review. Mater. Today Proc. 2024. [Google Scholar] [CrossRef]
  27. Fattouh, M.S.; Tayeh, B.A.; Agwa, I.S.; Elsayed, E.K. Improvement in the Flexural Behaviour of Road Pavement Slab Concrete Containing Steel Fibre and Silica Fume. Case Stud. Constr. Mater. 2023, 18, e01720. [Google Scholar] [CrossRef]
  28. Amin, M.; Zeyad, A.M.; Tayeh, B.A.; Saad Agwa, I. Effect of Ferrosilicon and Silica Fume on Mechanical, Durability, and Microstructure Characteristics of Ultra High-Performance Concrete. Constr. Build. Mater. 2022, 320, 126233. [Google Scholar] [CrossRef]
  29. Abhilash, P.P.; Nayak, D.K.; Sangoju, B.; Kumar, R.; Kumar, V. Effect of Nano-Silica in Concrete; a Review. Constr. Build. Mater. 2021, 278, 122347. [Google Scholar] [CrossRef]
  30. Mohtasham Moein, M.; Rahmati, K.; Saradar, A.; Moon, J.; Karakouzian, M. A Critical Review Examining the Characteristics of Modified Concretes with Different Nanomaterials. Materials 2024, 17, 409. [Google Scholar] [CrossRef] [PubMed]
  31. Hamdadou, M.N.; Bignonnet, F.; Deboucha, W.; Ranaivomanana, H.; Leklou, N.; Arroudj, K. Hydration, Mechanical and Transfer Properties of Blended Cement Pastes and Mortars Prepared with Recycled Powder or Limestone Filler. J. Build. Eng. 2023, 78, 107541. [Google Scholar] [CrossRef]
  32. Radović, A.; Carević, V.; Marinković, S.; Plavšić, J.; Tešić, K. Prediction Model for Calculation of the Limestone Powder Concrete Carbonation Depth. J. Build. Eng. 2024, 86, 108776. [Google Scholar] [CrossRef]
  33. Her, S.-W.; Yang, K.-H.; Bae, S.-C.; Kwon, S.-J.; Wang, X.-Y. Effect of Particle Size Distribution and Content of Limestone Powder on Compressive Response of High-Early-Strength Cement Mortars. J. Build. Eng. 2024, 97, 110964. [Google Scholar] [CrossRef]
  34. ASTM C1240-20; Standard Specification for Silica Fume Used in Cementitious Mixtures. American Society for Testing and Materials International: West Conshohocken, PA, USA, 2020.
  35. TSI TS EN 196-2; Methods of Testing Cement. Part 2: Chemical Analysis of Cement. Turkish Standards Institution: Ankara, Turkey, 2002.
  36. ASTM C1437-20; Standard Test Method for Flow of Hydraulic Cement Mortar. American Society for Testing and Materials International: West Conshohocken, PA, USA, 2020.
  37. ASTM C348; Standard Test Method for Flexural Strength of Hydraulic-Cement Mortars. American Society for Testing and Materials International: West Conshohocken, PA, USA, 2008.
  38. ASTM C349; Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50-Mm] Cube Specimens). American Society for Testing and Materials International: West Conshohocken, PA, USA, 2013.
  39. ASTM C403; Standard Test Method for Time of Setting of Concrete Mixtures by Penetration Resistance. American Society for Testing and Materials International: West Conshohocken, PA, USA, 2008.
  40. ASTM C187; Standard Test Method for Amount of Water Required for Normal Consistency of Hydraulic Cement Paste. American Society for Testing and Materials International: West Conshohocken, PA, USA, 2011.
  41. Mather, B.; Ozyildirim, C. SP-1 (02): Concrete Primer; American Concrete Institute: SP0102; American Concrete Institute: Farmington Hills, MI, USA, 2002; Available online: https://www.concrete.org/store (accessed on 8 November 2024).
  42. Liew, J.Y.R.; Xiong, M.-X.; Lai, B.-L. Design of Steel-Concrete Composite Structures Using High-Strength Materials; Elsevier: Amsterdam, The Netherlands, 2021; ISBN 9780128233962. [Google Scholar]
  43. Fagerlund, G. Imaginable Effects of Limestone Filler on Chloride Transport; Lund University: Lund, Sweden, 2005. [Google Scholar]
  44. Dhir, R.K.; Limbachiya, M.C.; McCarthy, M.J.; Chaipanich, A. Evaluation of Portland Limestone Cements for Use in Concrete Construction. Mater. Struct. 2007, 40, 459–473. [Google Scholar] [CrossRef]
  45. Lin, Y.; Alengaram, U.J.; Ibrahim, Z. Effect of Treated and Untreated Rice Husk Ash, Palm Oil Fuel Ash, and Sugarcane Bagasse Ash on the Mechanical, Durability, and Microstructure Characteristics of Blended Concrete—A Comprehensive Review. J. Build. Eng. 2023, 78, 107500. [Google Scholar] [CrossRef]
  46. Singh, L.P.; Goel, A.; Bhattachharyya, S.K.; Ahalawat, S.; Sharma, U.; Mishra, G. Effect of Morphology and Dispersibility of Silica Nanoparticles on the Mechanical Behaviour of Cement Mortar. Int. J. Concr. Struct. Mater. 2015, 9, 207–217. [Google Scholar] [CrossRef]
  47. Franklin, S.O.; Kangootui, F.I. Tensile/Compressive/Flexural Strength Relationships for Concrete Using Kgale Aggregates with Botchem as Binder. Int. J. Sci. Eng. Res. 2020, 11. [Google Scholar]
  48. Marín-Uribe, C.R.; Navarro-Gaete, R. Empirical Relationships between Compressive and Flexural Strength of Concrete Containing Recycled Asphalt Material for Pavement Applications Using Different Specimen Configurations. Mater. De. Construcción 2021, 71, e249. [Google Scholar] [CrossRef]
  49. Neville, A.M. Properties of Concrete; Ad Wes Lon Higher ed: West London, UK, 1995. [Google Scholar]
  50. Ahmed, M.; El Hadi, K.M.; Hasan, M.A.; Mallick, J.; Ahmed, A. Evaluating the Co-Relationship between Concrete Flexural Tensile Strength and Compressive Strength. Int. J. Struct. Eng. 2014, 5, 115–131. [Google Scholar] [CrossRef]
  51. Popovics, S. Strength and Related Properties of Concrete: A Quantitative Approach; John Wiley & Sons: Hoboken, NJ, USA, 1998. [Google Scholar]
  52. Ahmed, M.; Mallick, J.; Hasan, M.A. A Study of Factors Affecting the Flexural Tensile Strength of Concrete. J. King Saud. Univ. -Eng. Sci. 2016, 28, 147–156. [Google Scholar] [CrossRef]
  53. Moropoulou, A.; Bakolas, A.; Moundoulas, P.; Aggelakopoulou, E.; Anagnostopoulou, S. Strength Development and Lime Reaction in Mortars for Repairing Historic Masonries. Cem. Concr. Compos. 2005, 27, 289–294. [Google Scholar] [CrossRef]
  54. Malathy, R.; Shanmugam, R.; Chung, I.-M.; Kim, S.-H.; Prabakaran, M. Mechanical and Microstructural Properties of Composite Mortars with Lime, Silica Fume and Rice Husk Ash. Processes 2022, 10, 1424. [Google Scholar] [CrossRef]
Buildings 15 00074 g001
Figure 1. (a) NS, (b) SF, (c) ML, (d) SG (before grinding), (e) SG (after grinding), (f) RILEM sand, and (g) cement.
Figure 1. (a) NS, (b) SF, (c) ML, (d) SG (before grinding), (e) SG (after grinding), (f) RILEM sand, and (g) cement.
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Figure 2. (a) Weighing ingredients, (b) mixer, (c) Vicat normal consistency test, (d) slump flow test, (e) shaking of samples, (f) molding, (g) demolding and (h) curing.
Figure 2. (a) Weighing ingredients, (b) mixer, (c) Vicat normal consistency test, (d) slump flow test, (e) shaking of samples, (f) molding, (g) demolding and (h) curing.
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Figure 3. Mix–water ratios: (a) SG, (b) SF, (c) NS and (d) MLS.
Figure 3. Mix–water ratios: (a) SG, (b) SF, (c) NS and (d) MLS.
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Figure 4. Setting times: (a) SG, (b) SF, (c) NS and (d) MLS.
Figure 4. Setting times: (a) SG, (b) SF, (c) NS and (d) MLS.
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Figure 5. Flexural tensile strength: (a) SG, (b) SF, (c) NS and (d) MLS.
Figure 5. Flexural tensile strength: (a) SG, (b) SF, (c) NS and (d) MLS.
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Figure 6. Compressive strength: (a) SG, (b) SF, (c) NS and (d) MLS.
Figure 6. Compressive strength: (a) SG, (b) SF, (c) NS and (d) MLS.
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Figure 7. Compressive strength vs. flexural strength: (a) SG, (b) SF, (c) NS and (d) MLS.
Figure 7. Compressive strength vs. flexural strength: (a) SG, (b) SF, (c) NS and (d) MLS.
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Figure 8. SEM images of (a) cement, (b) silica gel, (c) silica fume, (d) nano-silica and (e) micritic limestone.
Figure 8. SEM images of (a) cement, (b) silica gel, (c) silica fume, (d) nano-silica and (e) micritic limestone.
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Figure 9. EDX results for (a) cement, (b) silica gel, (c) silica fume, (d) nano-silica and (e) micritic limestone.
Figure 9. EDX results for (a) cement, (b) silica gel, (c) silica fume, (d) nano-silica and (e) micritic limestone.
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Figure 10. XRD results of (a) cement, (b) silica gel, (c) silica fume, (d) nano-silica and (e) micritic limestone.
Figure 10. XRD results of (a) cement, (b) silica gel, (c) silica fume, (d) nano-silica and (e) micritic limestone.
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Table 1. Chemical composition (%) of Portland cement, silica gel, silica fume, nano-silica and micritic limestone.
Table 1. Chemical composition (%) of Portland cement, silica gel, silica fume, nano-silica and micritic limestone.
CementSilica GelSilica FumeNano-SilicaMicritic Limestone
SiO218.0086.4794.6496.4916.87
Al2O34.790.410.590.050.82
Fe2O33.270.000.570.000.23
CaO63.060.000.540.0043.62
MgO3.190.000.810.002.28
SO32.790.020.000.010.46
K2O0.550.030.970.040.21
Na2O0.390.200.390.060.06
Ignition loss2.8314.091.741.9835.52
Table 2. Dry mix chemical composition.
Table 2. Dry mix chemical composition.
MIXSiO2 (%)Al2O3 (%)Fe2O3 (%)CaO (%)MgO (%)SO3 (%)K2O (%)Na2O (%)Other Components (%)Ignition Loss (%)Blaine (cm2/g)
MCEM184.793.2763.063.192.790.550.390.943.023380
MCEMSG1194.633.2161.953.112.660.540.381.363.163400
MCEMSG2204.643.1961.553.112.740.510.330.83.133530
MCEMSG320.94.573.1960.853.042.730.520.360.633.213560
MCEMSG421.74.563.1660.713.052.640.510.410.043.223650
MCEMSG522.254.493.1159.5132.660.510.370.833.273710
MCEMSG623.334.443.0959.052.972.630.50.380.123.493781
MCEMSG724.24.383.0758.322.932.610.490.380.033.593851
MCEMSG824.964.333.0457.692.892.590.480.380.053.593920
MCEMSG925.94.283.0156.952.852.560.470.380.013.593990
MCEMSG1026.594.232.9856.122.732.510.460.390.13.894059
MCEMSF119.824.723.2362.083.162.780.560.420.362.873640
MCEMSF220.214.643.2361.843.152.690.550.40.462.833840
MCEMSF320.394.633.2361.753.122.680.560.390.52.754050
MCEMSF421.894.623.1960.333.082.710.570.420.442.754310
MCEMSF522.724.543.1760.033.072.650.550.390.042.844460
MCEMSF623.254.523.1659.163.042.630.560.390.522.774693
MCEMSF7244.483.1559.043.022.60.560.390.012.754904
MCEMSF824.754.443.1358.122.992.580.560.380.312.745115
MCEMSF925.194.43.1158.022.972.560.560.380.092.725326
MCEMSF1026.214.363.157.182.942.530.560.380.032.715537
MCEMNS119.144.683.2562.773.162.710.530.390.512.863140
MCEMNS221.164.573.1960.983.072.740.530.380.562.823640
MCEMNS322.514.53.1259.933.033.180.510.310.022.894990
MCEMNS423.824.463.0959.112.992.570.470.30.362.834890
MCEMNS526.714.312.9556.742.832.530.460.310.362.85110
MCEMMLS118.744.763.2563.13.172.70.550.380.213.143370
MCEMMLS218.664.683.1962.653.162.70.540.410.53.513460
MCEMMLS318.714.673.262.393.182.760.530.360.353.853460
MCEMMLS418.444.573.1561.983.12.720.520.340.984.23490
MCEMMLS518.554.553.1461.963.132.730.530.350.514.553580
MCEMMLS618.444.493.1161.533.112.750.520.330.824.93607
MCEMMLS718.384.433.0861.243.092.750.510.320.955.253652
MCEMMLS818.324.383.0660.943.082.760.50.31.055.613697
MCEMMLS918.264.333.0360.653.062.770.50.291.155.963742
MCEMMLS1018.24.28360.353.052.780.490.281.266.313787
Table 3. Cement paste designs.
Table 3. Cement paste designs.
MIXSubstitution Ratio (%)CementSilica GelSilica FumeNano-SilicaMicritic LimestoneWater
MCEM05000000135
MCEMSG114955000135
MCEMSG2249010000140
MCEMSG3348515000140
MCEMSG4448020000140
MCEMSG5547525000140
MCEMSG6647030000143
MCEMSG7746535000144
MCEMSG8846040000145
MCEMSG9945545000146
MCEMSG101045050000147
MCEMSF114950500137
MCEMSF2249001000136
MCEMSF3348501500135
MCEMSF4448002000134
MCEMSF5547502500133
MCEMSF6647003000133
MCEMSF7746503500133
MCEMSF8846004000135
MCEMSF9945504500139
MCEMSF101045005000145
MCEMNS114950050178
MCEMNS2249000100186
MCEMNS3348500150188
MCEMNS4448000200187
MCEMNS5547500250187
MCEMMLS114950005136
MCEMMLS2249000010135
MCEMMLS3348500015134
MCEMMLS4448000020133
MCEMMLS5547500025133
MCEMMLS6647000030132
MCEMMLS7746500035131
MCEMMLS8846000040130
MCEMMLS9945500045130
MCEMMLS101045000050129
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Hansu, O. Considering the Effect of Various Silica Types on Chemical, Physical and Mechanical Properties in Cement Mortar Production via Substitution with Cement Content. Buildings 2025, 15, 74. https://doi.org/10.3390/buildings15010074

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Hansu O. Considering the Effect of Various Silica Types on Chemical, Physical and Mechanical Properties in Cement Mortar Production via Substitution with Cement Content. Buildings. 2025; 15(1):74. https://doi.org/10.3390/buildings15010074

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Hansu, Osman. 2025. "Considering the Effect of Various Silica Types on Chemical, Physical and Mechanical Properties in Cement Mortar Production via Substitution with Cement Content" Buildings 15, no. 1: 74. https://doi.org/10.3390/buildings15010074

APA Style

Hansu, O. (2025). Considering the Effect of Various Silica Types on Chemical, Physical and Mechanical Properties in Cement Mortar Production via Substitution with Cement Content. Buildings, 15(1), 74. https://doi.org/10.3390/buildings15010074

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