SUSTAINABLE HIGH-STRENGTH CONCRETE FORMULATION WITH NANO-SILICA INTEGRATION

Abstract

7. ABSTRACT This invention presents a high-performance concrete formulation incorporating nano-silica (NS) to enhance durability and mechanical strength. By partially replacing traditional cement with NS at optimal dosages between 2% and 5%, the formulation achieves a refined microstructure, reducing porosity and improving compressive and tensile strength. NS's controlled particle size (15-200 nanometers) enables optimal dispersion, contributing to increased resistance to water permeability, chloride ion penetration, and environmental degradation. The method includes precise mixing and curing for specified durations (7, 14, and 28 days), ensuring the concrete’s robust structural integrity and resilience to freeze-thaw cycles and chemical exposure. This innovative concrete design offers significant potential for sustainable construction practices by reducing cement content and carbon emissions while meeting high durability and load-bearing requirements, making it suitable for demanding infrastructure applications. The figure associated with abstract is Fig. 1.

Specification

Description:4. DESCRIPTION
Technical Field of the Invention

The present invention relates to the field of construction materials, specifically focusing on high-strength concrete formulations. More particularly, it involves the integration of nano-silica (NS) to enhance the mechanical properties and durability of concrete while promoting sustainable construction practices.

Background of the Invention

Concrete is the most utilized construction material worldwide, prized for its high compressive strength, versatility, and longevity. However, despite these advantageous properties, conventional concrete formulations exhibit significant drawbacks. High porosity is one of the major concerns, as it can lead to increased water permeability and reduced durability over time. This porosity makes concrete vulnerable to various environmental stressors, including freeze-thaw cycles, chemical attacks, and reinforcement corrosion, which ultimately compromise structural integrity and service life.

Recent advancements in material science have introduced innovative solutions to enhance the performance of concrete. Among these solutions, the incorporation of nano-silica (NS) has gained attention due to its potential to significantly improve the microstructural properties of concrete. Nano-silica particles, typically ranging from 15 to 200 nanometers in size, have a high surface area-to-volume ratio that promotes effective bonding within the cement matrix. When used in controlled dosages, NS can refine the microstructure, reducing porosity and enhancing both compressive and tensile strengths.

Moreover, the addition of nano-silica contributes to the formation of calcium silicate hydrate (C-S-H) gel, which plays a crucial role in binding aggregates and improving the overall toughness of concrete. This enhancement translates into improved resistance against chloride ion penetration, mitigating the risk of reinforcement corrosion, which is particularly critical in infrastructure exposed to harsh environmental conditions.

The need for sustainable construction practices has also prompted a shift towards reducing traditional cement content in concrete formulations. By partially replacing cement with nano-silica and other recycled materials, such as bottom ash, silica fume, or fly ash, it is possible to lower carbon emissions associated with cement production. This not only addresses environmental concerns but also meets the growing demand for durable and resilient infrastructure.

Given these considerations, there is a pressing need for a comprehensive formulation of high-performance concrete that effectively integrates nano-silica to enhance durability and mechanical strength while promoting sustainability. This invention aims to fulfill this need by providing a concrete formulation that leverages the benefits of nano-silica, resulting in improved structural integrity, reduced permeability, and heightened resistance to environmental and chemical stressors.

Brief Summary of the Invention

The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

It is a primary objective of the invention is to develop a high-strength concrete formulation that significantly improves durability against environmental stressors, including freeze-thaw cycles, chemical attacks, and chloride ion penetration.
It is yet another object of the invention to optimize mechanical strength through the incorporation of nano-silica (NS) in controlled dosages, achieving superior compressive and tensile strengths that improve the overall load-bearing capacity of the concrete.

It is yet another object of the invention to refine microstructural properties by utilizing nano-silica to reduce porosity and increase density, thereby contributing to lower water permeability and enhanced structural integrity.

It is yet another object of the invention to promote sustainability by reducing the reliance on traditional cement content through the incorporation of recycled materials and nano-silica, ultimately lowering carbon emissions associated with concrete production.

It is yet another object of the invention to facilitate homogeneous dispersion of nano-silica within the cement matrix by controlling particle size, ensuring optimal integration and preventing agglomeration.

It is yet another object of the invention to mitigate reinforcement corrosion by enhancing the concrete's resistance to chloride ion penetration, thereby reducing the risk of corrosion of reinforcing steel over prolonged exposure periods.

It is yet another object of the invention to establish optimal curing practices that allow for systematic curing periods (7, 14, and 28 days) to develop a hardened microstructure with enhanced strength and reduced permeability.

It is yet another object of the invention to improve resistance to alkali-silica reaction (ASR), minimizing the potential for expansion and cracking under alkali exposure to ensure long-term stability of the concrete structure.

It is yet another object of the invention to provide a practical application for infrastructure by creating a formulation that addresses the durability and sustainability requirements of demanding construction projects.

According to an aspect of the present invention, a cutting-edge concrete formulation designed to enhance both durability and mechanical strength through the integration of nano-silica (NS). By strategically incorporating NS at dosages ranging from 2% to 5% by weight of the cementitious binder, this formulation refines the concrete's microstructure, leading to reduced porosity and a more compact structure. The resulting improvements in compressive and tensile strength significantly enhance the material's performance in demanding applications.

This innovative concrete formulation employs a systematic approach to mixing, which includes combining Ordinary Portland Cement (OPC) with carefully selected fine and coarse aggregates, water, and nano-silica in colloidal form. The controlled particle size of the nano-silica, specifically between 15 and 200 nanometers, facilitates optimal dispersion within the cement matrix, ensuring uniformity and preventing agglomeration. This level of precision results in a homogenous mix that enhances load-bearing capacity and overall structural integrity.

Furthermore, the invention addresses critical durability concerns by demonstrating improved resistance to water permeability, chloride ion penetration, and environmental degradation. The inclusion of a systematic curing process-selecting periods of 7, 14, or 28 days-allows for the development of a hardened microstructure, which is essential for mitigating the risks associated with freeze-thaw cycles, chemical exposure, and alkali-silica reaction (ASR).

Another noteworthy aspect of this invention is the integration of recycled materials, such as bottom ash, silica fume, or fly ash. By replacing up to 15% of traditional cement content with these sustainable alternatives, the formulation not only reduces environmental impact but also maintains high durability and structural performance.

a sustainable high-strength concrete formulation that effectively combines advanced material science with practical engineering solutions. Its unique properties make it suitable for a wide range of applications, particularly in infrastructure projects where resilience, longevity, and environmental responsibility are paramount. This innovative approach not only enhances the performance of concrete but also aligns with modern sustainable construction practices, paving the way for a greener future in the building industry.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, the detailed description and specific examples, while indicating preferred embodiments of the invention, will be given by way of illustration along with complete specification.

Brief Summary of the Drawings

The invention will be further understood from the following detailed description of a preferred embodiment taken in conjunction with an appended drawing, in which:

Fig. 1 illustrates Ordinary Portland Cement (OPC) comprise fine powder consistency and use in high-strength concrete, in accordance with the exemplary embodiment of the present invention.

Fig. 2 illustrates nano silica, emphasizing its tiny particle size and its role in improving concrete properties, in accordance with the exemplary embodiment of the present invention.

Fig. 3 illustrates the compressive strength of concrete mixes at different curing times, comparing traditional concrete with nanosilica mixes, in accordance with the exemplary embodiment of the present invention.

Fig. 4 illustrates the split tensile strength of various concrete mixes, showing how nanosilica enhances tensile strength over time, in accordance with the exemplary embodiment of the present invention.

Fig. 5 illustrates the relationship between compressive strength and split tensile strength in different mixes, indicating a positive correlation, in accordance with the exemplary embodiment of the present invention.

Fig. 6 illustrates the microstructure of the control concrete mix after 28 days, showing pores and unreacted particles, in accordance with the exemplary embodiment of the present invention.

Fig. 7 illustrates the microstructure of the M3 mix with 4% nanosilica, showing a denser structure with fewer voids, in accordance with the exemplary embodiment of the present invention.

Fig. 8 illustrates the microstructure of the N3 mix with 5% nanosilica, showing improved compactness and reduced porosity, in accordance with the exemplary embodiment of the present invention.


Detailed Description of the Invention

The present disclosure emphasises that its application is not restricted to specific details of construction and component arrangement, as illustrated in the drawings. It is adaptable to various embodiments and implementations. The phraseology and terminology used should be regarded for descriptive purposes, not as limitations.

The terms "including," "comprising," or "having" and variations thereof are meant to encompass listed items and their equivalents, as well as additional items. The terms "a" and "an" do not denote quantity limitations but signify the presence of at least one of the referenced items. Terms like "first," "second," and "third" are used to distinguish elements without implying order, quantity, or importance.

According to the exemplary embodiment of the present invention, a cutting-edge concrete formulation designed to enhance both durability and mechanical strength through the integration of nano-silica (NS). By strategically incorporating NS at dosages ranging from 2% to 5% by weight of the cementitious binder, this formulation refines the concrete's microstructure, leading to reduced porosity and a more compact structure.

In accordance with the exemplary embodiment of the present invention, the concrete formulation begins with a cementitious binder primarily consisting of Ordinary Portland Cement (OPC). This type of cement is widely recognized for its mechanical properties and workability, making it suitable for a variety of construction applications. The addition of nano-silica enhances the performance characteristics of this binder, addressing the increasing demands for durability and strength in modern concrete.

In accordance with the exemplary embodiment of the present invention, nano-silica is incorporated into the concrete mix at dosages ranging from 2% to 5% by weight of the cementitious binder. The nano-silica is utilized in colloidal form, characterized by an average particle size between 15 and 200 nanometers. This specific size range is essential for achieving optimal dispersion within the cement matrix, preventing nanoparticle agglomeration and ensuring uniform distribution throughout the concrete, which in turn leads to a refined microstructure.

In accordance with the exemplary embodiment of the present invention, the inclusion of nano-silica yields several significant benefits. This includes the formation of a denser microstructure that reduces porosity and enhances the interfacial bond between the cement paste and aggregates. As a result, there is a notable improvement in both compressive and tensile strengths, contributing to the overall load-bearing capacity and durability of the concrete formulation.

In accordance with the exemplary embodiment of the present invention, both fine and coarse aggregates are selected to meet specific grading requirements, ensuring structural consistency in the concrete mix. The careful selection of aggregates is critical for achieving a well-balanced formulation that maximizes the compatibility between the binder and nano-silica, enhancing the overall mechanical performance and workability of the concrete.

In accordance with the exemplary embodiment of the present invention, a water-to-binder ratio of 0.5 is maintained throughout the mixing process. This controlled ratio is pivotal for achieving desired workability and ensuring adequate hydration of the cementitious materials. By optimizing the water content, the formulation supports the development of a strong and durable concrete matrix.

In accordance with the exemplary embodiment of the present invention, a systematic curing process is employed, selecting durations of 7, 14, or 28 days. This flexibility in curing time allows the concrete to develop its hardened microstructure effectively. Proper curing is essential for enhancing strength development, reducing water permeability, and improving resistance to chemical attacks.

In accordance with the exemplary embodiment of the present invention, recycled material additives may be included to enhance the sustainability of the concrete formulation. Options such as bottom ash, silica fume, or fly ash can replace up to 15% of the traditional cement content. This integration not only reduces carbon emissions associated with cement production but also contributes to the overall mechanical properties and durability of the concrete.

In accordance with the exemplary embodiment of the present invention, the formulated concrete demonstrates enhanced resistance to critical environmental challenges. These include improved resistance to chloride ion penetration, which mitigates reinforcement corrosion, as well as reduced likelihood of alkali-silica reaction (ASR), minimizing expansion and cracking under alkali exposure. Additionally, the concrete formulation exhibits excellent resistance to freeze-thaw cycles, making it suitable for fluctuating temperature environments.

In accordance with the exemplary embodiment of the present invention, performance metrics indicate that the incorporation of nano-silica and other advanced materials can lead to an increase in split tensile strength by up to 15% compared to standard concrete formulations. This enhancement contributes to improved structural integrity, reducing micro-cracking and promoting long-term durability.
Now referring to the figures, Fig. 1 illustrates Grade 53 Ordinary Portland Cement, a critical component used for high-strength concrete applications. The figure captures the fine powder consistency and characteristic color of the cement, underscoring its suitability for specialized construction projects such as bridges, runways, and reinforced concrete structures. This cement grade is specifically selected for its ability to achieve superior compressive strength, serving as the foundational binding material in the concrete mix.

Table 1: Tests results on cement:
S.NO TESTS RESULTS
1 Initial setting time 45min
Final setting time 1hr 40min
2 Consistency 30%
3 Specific Gravity 3.15
4 Fineness 8%
5 Compressive strength for 7, 14,
28 days 17 N/mm²,
19 N/mm²,
25 N/mm²

Fine Aggregates: Fine aggregates were selected based on specific grading criteria, ensuring that no more than 45% of the aggregate passes through one sieve while being retained on the sieve after it. The fineness modulus of the fine aggregate must be greater than 3.1 and less than 2.3, with no variation exceeding 0.20. According to IS 383, fine aggregates are classified into four zones, with particle size distribution getting progressively finer from grading zone I to grading zone IV. The shape and surface roughness of fine aggregates influence the void ratio and water demand in concrete mixes. For this experimental study, Zone II fine aggregates were chosen based on these guidelines.




Table 2: Test Results on Fine Aggregates:
S. No Tests Results
1 Fineness modulus 4
2 Specific gravity 2.6
3 Water Absorption 0.43%
4 Bulk density 1596 kg/m³

Coarse Aggregates: Coarse aggregates are crucial in concrete production, comprising materials like gravel, crushed stone, and recycled concrete. Typically, coarse aggregate sizes range from 3/8 inch to 1.5 inches in diameter, and they are essential raw ingredients in concrete mix design. Aggregates classified as coarse have a particle size range between 4.75 mm and 40 mm.

Table 3: Test Results on Coarse Aggregates
S. No Tests Results
1 Fineness modulus 4.23
2 Specific gravity 2.74
3 Water absorption 0.2%


Fig. 2 illustrates nano silica, highlighting its incredibly fine particle size, which averages around 40 nm. The image showcases a micrograph that emphasizes the granular nature of nano silica, portraying its role as a pozzolanic material in the concrete mix. Nano silica, also known as crystalline SiO₂, is incorporated to enhance mechanical properties by filling micro voids and improving bonding within the concrete matrix. This figure effectively emphasizes the unique characteristics of nano silica that significantly contribute to the study's objectives, showcasing its effectiveness as a performance-enhancing additive in concrete production.

Nano silica, often referred to as quartz dust or silica dust, is characterized by a high SiO₂ percentage exceeding 99%. Its incorporation reduces the overall volume of cement while completing the grading curve of the aggregate mix in the smallest particle size range. The primary purpose of nano silica is to produce a filler effect, filling in gaps and thereby increasing the compactness of the concrete. Consequently, when nano silica is used in the manufacturing of ultra-high-performance concrete (UHPC), there is a greater demand for water or superplasticizers (SPs), and the setting process may be delayed. Nano silica is available in 26 nominal sizes ranging from 15 to 200 mm.

Table 4: Physical Characteristics of Nano silica:
Property Value
Average particle size (mm) 15 to 200
Density (g/cm³) 2.4
Molar Mass (g/mol) 59.96
Melting Point (°C) 1,610
Boiling Point (°C) 2,230
Specific gravity 2.4

The compressive strength of concrete cubes was assessed in accordance with IS 2250-1981, while the split tensile strength was evaluated at 3, 7, and 28 days of curing, following IS 5816-1999. Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX) analysis was utilized to explore the microstructural characteristics of the concrete mix.

Fig. 3 illustrates the compressive strength of concrete specimens at various curing ages of 7, 14, and 28 days. This figure presents a comparative analysis of the compressive strength values for traditional control concrete (CM) and concrete mixes incorporating nanosilica (M1 and M2). The graph indicates a clear trend, showcasing the enhanced compressive strength of nanosilica-modified concrete compared to the control mix.

The results reveal that the compressive strength of concrete is influenced primarily by the water-cement ratio, the quality of the aggregates, and the curing duration. In this study, the concrete mix was formulated using a water-cement ratio of 0.5, adhering to the guidelines set forth by IS 10262-2019. The presence of nanosilica in the concrete mix significantly contributed to the increased strength observed over the curing periods. Table 5 displays the details of the mix design. The traditional control concrete mix is designated as CM, the combination of nanosilica & CM varies from 2%to 5%. The fresh and hardened properties are examined for each concrete mix as specified in table 5.

Table 5: Concrete mix details per cubic meter:

S.NO
Mix Proportions
Cement kg/m² Fine aggregate kg/m² Coarse aggregate kg/m²
Nano
Silica
kg/m²
W/C liters
1. CM 349 204.48 685.54 1113.8 -
2. CM+2%(M1) 342.02 204.48 685.54 1113.8 6.98
3. CM+3%(M2) 338.53 204.48 685.54 1113.8 10.47
4. CM+4%(M3) 335.04 204.48 685.54 1113.8 13.96
5. CM+5%(M4) 331.55 204.48 685.54 1113.8 17.45

As indicated in Table 6, the average compressive strength of the control mix at 7, 14, and 28 days was recorded at 11.1 N/mm², 14.1 N/mm², and 16.0 N/mm², respectively. In contrast, the M1 mix, which incorporated 2% nanosilica, demonstrated a marked increase in strength, reaching 13.3 N/mm² at 7 days, and ultimately 17.3 N/mm² by the 28-day mark. The graphical representation in Fig. 3 effectively highlights these findings, illustrating the potential benefits of integrating nanosilica in concrete mixtures to improve mechanical performance.
Table 6: Compressive Strength Values:

S.NO Type of concrete
Compressive strength(N/mm²)



1.


CM 7 days Avg 14 days Avg 28 days Avg
11.1

11.2 13.3

14.1 16

15.8
11.5 14.6 15.5
11.1 14.6 16


2.

M1 13.3

14.33 16

16.13 17.3

17.2
14.6 16 16.8
15.1 16.4 17.7


Fig. 4 illustrates the split tensile strength of various concrete mixes at different curing ages: 7, 14, and 28 days. This figure highlights the importance of tensile strength as a critical property of concrete that significantly influences the cracking behaviour in structural applications. Given the inherent brittleness of concrete, it is typically weak in tension, which necessitates a careful evaluation of its tensile capacity to understand at what load concrete members may start to crack.

In this study, split tensile strength tests were performed on concrete cylinders prepared with different mix proportions, including traditional control concrete (CM) and mixes containing nanosilica (M1, M2, M3, and M4). The results demonstrate that the incorporation of nanosilica enhances the tensile strength of concrete, making it more resistant to cracking under tensile loads.
Table 7: Split tensile strength values:

S.NO Type of concrete
Split tensile strength(N/mm²)



1.


CM 7 days Avg 14 days Avg 28 days Avg
2.30

2.28 3.06

3.07 4.52

4.52
2.26 3.08 4.50
2.28 3.07 4.54


2.

M1 2.43

2.45 3.24

3.21 4.81

4.82
2.47 3.18 4.79
2.46 3.22 4.86

As detailed in Table 7, the split tensile strength values for the control mix at 7, 14, and 28 days were recorded as 2.30 N/mm², 3.06 N/mm², and 4.52 N/mm², respectively. In comparison, the M1 mix, which included nanosilica, showed improved performance, achieving split tensile strengths of 2.43 N/mm² at 7 days and rising to 4.81 N/mm² by 28 days. The graph effectively captures these results, emphasizing the role of nanosilica in enhancing the tensile properties of concrete.

Fig. 5 illustrates a scatter plot that depicts the correlation between compressive strength (X-axis) and split tensile strength (Y-axis) for all concrete mixes at different curing ages. The trendline and associated coefficient of determination (R²) values provide a statistical representation of the relationship between these two fundamental properties. The high R² values indicate a strong correlation, suggesting that as compressive strength increases, so does split tensile strength across all tested mixes. This analysis is vital for validating the findings of the study, establishing a clear link between the mechanical properties of concrete and demonstrating the effectiveness of nanosilica in enhancing overall performance.

Fig. 6 illustrates high-resolution scanning electron microscopy (SEM) images of the control mix (CM) specimen after 28 days of curing. The micrographs capture the concrete's microstructure, showcasing various phases such as pores, unreacted cement particles, and hydration products. The presence of pores and a heterogeneous matrix indicates potential weaknesses in the control mix, highlighting areas for improvement. This figure is essential for understanding the microstructural characteristics of the concrete and provides a baseline for comparing the effects of nanosilica on the performance of other mixes.

Fig. 7 illustrates SEM images of the M3 concrete specimen (which contains 4% nanosilica) at 28 days. The micrographs reveal a denser microstructure with fewer visible voids compared to the control mix. This enhanced density signifies better interlocking and bonding within the concrete matrix, attributed to the presence of nanosilica. The improved microstructural integrity observed in the M3 specimen is critical for reinforcing the hypothesis that nanosilica contributes to enhanced mechanical properties. This figure provides valuable evidence of how nano silica can positively influence the performance of concrete.

Fig. 8 illustrates SEM images of the N3 concrete specimen (containing 5% nano silica) at 28 days, emphasizing the significant microstructural improvements achieved with a higher concentration of nano silica. The micrographs display a more homogeneous and compact structure, indicating that higher nano silica levels lead to better particle packing and reduced porosity. This enhancement in microstructural quality corroborates the study's findings, demonstrating that the addition of nano silica can substantially elevate the overall performance of concrete. The figure underscores the potential of nano silica to achieve higher strength and durability in concrete applications.
, C , Claims:5. CLAIMS
I/We Claim:
1. A concrete formulation for enhancing durability and mechanical strength, comprising:
a. a cementitious binder, which includes Ordinary Portland Cement (OPC);
b. fine and coarse aggregates meeting specific grading requirements for structural consistency;
c. water to provide a water-to-binder ratio of 0.5
Characterized in that
d. the inclusion of nano-silica (NS) in a controlled range of 2% to 5% by weight of the cementitious binder, wherein:
nano-silica is utilized in colloidal form, with an average particle size ranging between 15 and 200 nanometres to ensure optimal dispersion within the cement matrix,
the specified NS dosage results in refined microstructural properties, leading to reduced porosity and a compacted structure that enhances both compressive and tensile strengths;
e. a systematic curing period selected from 7, 14, and 28 days, which allows the concrete formulation to develop a hardened microstructure with significantly reduced water permeability and enhanced resistance to chemical attacks, environmental stress, and freeze-thaw cycles.

2. The formulation as claimed in claim 1, wherein the nano-silica (NS) dosage is optimized at 3% by weight to maximize compressive strength without leading to nanoparticle agglomeration, thereby preserving material homogeneity.

3. The formulation as claimed in claim 1, wherein the refined microstructure demonstrates improved resistance to chloride ion penetration, thus mitigating reinforcement corrosion over prolonged exposure periods.

4. The formulation as claimed in claim 1, further comprising recycled material additives, selected from bottom ash, silica fume, or fly ash, which reduce the reliance on traditional cement content by up to 15% without compromising durability.

5. The formulation as claimed in claim 1, wherein nano-silica facilitates the formation of a calcium silicate hydrate (C-S-H) gel that further binds aggregates, improving load-bearing capacity and overall toughness.

6. The formulation as claimed in claim 1, wherein the concrete displays enhanced resistance to alkali-silica reaction (ASR), due to reduced free silica in the matrix, resulting in decreased expansion and cracking under alkali exposure.

7. The formulation as claimed in claim 1, where the split tensile strength is increased by up to 15% compared to standard concrete formulations, contributing to reduced micro-cracking and improved structural integrity.

8. The formulation as claimed in claim 1, wherein the formulation's reduced porosity and permeability, facilitated by the nano-silica, supports resistance to freeze-thaw cycles, making it suitable for applications in environments with fluctuating temperatures.

9. A method for preparing a concrete formulation with enhanced durability and mechanical strength according to claim 1, comprising the steps of:
(a) Mixing a cementitious binder, fine aggregates, coarse aggregates, and water at a water-to-binder ratio of 0.5 to form a base concrete mix;

(b) Adding nano-silica in a colloidal form, at a dosage between 2% and 5% by weight of the cementitious binder, wherein the nano-silica particle size is controlled within a range of 15 to 200 nanometers to ensure optimal dispersion and integration within the base concrete mix;

(c) Blending the nano-silica uniformly into the base concrete mix to achieve a homogenous formulation, ensuring nano-silica particles penetrate the cement matrix, refining the microstructure by reducing porosity;

(d) Curing the concrete formulation for a period selected from 7, 14, and 28 days, thereby enabling the development of a hardened microstructure with reduced permeability, improved compressive and tensile strengths, and enhanced resistance to environmental and chemical stressors.

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