A PROCESS FOR SYNTHESIZING GEOPOLYMER CONCRETE INCORPORATING PHOSPHOGYPSUM AND GGBS WITH VARIABLE NAOH CONCENTRATIONS

Abstract

The invention discloses a process for synthesizing geopolymer concrete using phosphogypsum (PG) and ground granulated blast furnace slag (GGBS) as precursors, activated with sodium hydroxide (NaOH) and sodium silicate. By varying GGBS proportions (5%-25%) and NaOH concentrations (6M-16M), the invention optimizes compressive strength, achieving 49.67 MPa at 20% GGBS replacement and 12M NaOH. The process offers an eco-friendly alternative to cement, utilizing industrial by-products to produce durable, high-performance concrete with reduced environmental impact.

Specification

Description:FIELD OF THE INVENTION:
The field of the invention relates to sustainable construction materials, specifically the synthesis of geopolymer concrete. It focuses on utilizing industrial byproducts like phosphogypsum and ground granulated blast furnace slag with varying molar concentrations of sodium hydroxide to enhance mechanical properties and promote eco-friendly alternatives to conventional cement-based concrete.

BACKGROUD OF THE INVENTION:
Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
The invention centers on the development of geopolymer concrete, a sustainable and eco-friendly alternative to conventional cement-based concrete. Geopolymer concrete is synthesized using aluminosilicate-rich precursors activated by alkaline solutions, creating a polymeric structure with enhanced mechanical properties. This alternative has gained significant attention due to its ability to reduce the reliance on Portland cement, whose production is energy-intensive and a major contributor to greenhouse gas emissions. By leveraging industrial byproducts, such as phosphogypsum and ground granulated blast furnace slag, geopolymer concrete presents a dual benefit of waste utilization and environmental conservation.
Phosphogypsum is a byproduct generated during the production of phosphoric acid, commonly used in fertilizers. Despite its abundance, its utilization has been limited due to concerns about impurities and environmental challenges. Phosphogypsum contains silica, calcium, and minor amounts of alumina, making it a suitable precursor material for geopolymer synthesis. On the other hand, ground granulated blast furnace slag, a byproduct of steel manufacturing, is rich in calcium and alumina, offering beneficial properties to enhance the geopolymeric network when combined with other precursors. Together, these materials present an opportunity to reduce industrial waste while producing a durable and high-strength construction material.
The activation process of geopolymer concrete relies on the use of alkali solutions, such as sodium hydroxide and sodium silicate, to induce the polycondensation of aluminosilicate precursors. The concentration of sodium hydroxide plays a crucial role in determining the mechanical properties of the resulting concrete. A higher molar concentration generally enhances the dissolution of precursors, leading to a more robust polymeric structure. However, beyond an optimal concentration, adverse effects may arise due to excessive alkali presence, impacting the workability and strength characteristics of the material. Thus, identifying the ideal concentration of sodium hydroxide is pivotal to achieving the desired balance of strength and durability.
In the present invention, varying concentrations of sodium hydroxide ranging from 6M to 16M were used to explore the effects on compressive strength. Phosphogypsum was partially replaced with ground granulated blast furnace slag in increments of 5%, 10%, 15%, 20%, and 25%, allowing for a detailed investigation of the role of GGBS in enhancing the geopolymeric matrix. Sodium silicate was also incorporated as a secondary activator, maintaining a fixed ratio with sodium hydroxide to ensure consistent polymerization kinetics across all samples.
Experimental results demonstrated that the optimal compressive strength was achieved at a 20% replacement of phosphogypsum with GGBS, coupled with a sodium hydroxide concentration of 12M. At this combination, the geopolymer concrete exhibited a compressive strength of 49.67 MPa, significantly surpassing other compositions. This improvement is attributed to the synergistic interaction between the calcium content from GGBS and the silica and alumina from both precursors, resulting in a densely packed and well-bonded matrix. Conversely, when the sodium hydroxide concentration exceeded 12M, the compressive strength decreased, possibly due to excessive alkali disrupting the formation of a stable polymeric structure.
The adoption of geopolymer concrete synthesized from phosphogypsum and GGBS offers several environmental and economic benefits. By utilizing industrial byproducts, the invention addresses waste management challenges and reduces the need for landfill disposal. Additionally, the reduced reliance on Portland cement contributes to lowering the carbon footprint of construction activities. Geopolymer concrete also exhibits superior durability and resistance to chemical attacks, making it suitable for a wide range of applications, including pavements, precast elements, and structural components.
The innovation also underscores the potential of tailoring geopolymer concrete properties through careful selection of precursors and activators. The replacement levels of phosphogypsum with GGBS and the molar concentration of sodium hydroxide can be optimized to achieve specific performance characteristics, providing flexibility to meet diverse construction requirements. Furthermore, the use of an alkali-to-binder ratio of 0.45 in present invention ensures sufficient workability and strength development, balancing the needs of practical application and material performance.
The study's findings contribute to advancing the understanding of geopolymerization mechanisms and their dependence on precursor composition and activator concentration. It highlights the importance of calcium in enhancing the geopolymer matrix, particularly when derived from GGBS. The presence of calcium facilitates the formation of calcium-alumino-silicate-hydrate (C-A-S-H) gels, which complement the primary geopolymeric gel, improving the overall mechanical properties and durability of the material.
The invention's emphasis on sustainability aligns with global efforts to reduce environmental impacts in the construction sector. By providing an alternative that not only utilizes industrial waste but also outperforms traditional materials in strength and durability, this geopolymer concrete holds significant potential for large-scale adoption. The adaptability of the process to incorporate other industrial byproducts further enhances its appeal as a versatile and eco-friendly solution for modern construction challenges.
Additionally, the ability to customize the properties of geopolymer concrete through precise control of precursor ratios and activator concentrations makes it a valuable material for specialized applications. For instance, the high compressive strength achieved in present invention can be leveraged for structural applications requiring superior load-bearing capacity. At the same time, the reduced environmental impact positions it as an ideal choice for green building initiatives and infrastructure development projects focused on sustainability.
Therefore, present invention demonstrates a significant advancement in the field of geopolymer concrete synthesis, leveraging the unique properties of phosphogypsum and ground granulated blast furnace slag. By optimizing the molar concentration of sodium hydroxide and the replacement levels of precursors, the invention achieves a balance of mechanical performance, environmental sustainability, and economic feasibility. This process not only addresses pressing issues of waste management and carbon emissions but also paves the way for innovative applications in construction, contributing to a more sustainable and resilient built environment.

OBJECTS OF THE INVENTION:
The prime object of the invention is to provide a process for synthesizing geopolymer concrete incorporating phosphogypsum and ground granulated blast furnace slag, utilizing varying concentrations of sodium hydroxide as an activator, to achieve superior mechanical properties and promote the sustainable use of industrial byproducts.
Another object of the invention is to develop a geopolymer concrete that reduces dependency on traditional Portland cement, thereby minimizing carbon emissions associated with conventional cement production and contributing to environmental sustainability.
Yet another object of the invention is to offer a method for utilizing phosphogypsum and ground granulated blast furnace slag, addressing the challenge of waste disposal from fertilizer and steel industries while creating high-performance construction materials.
Still another object of the invention is to investigate the effects of varying molar concentrations of sodium hydroxide on the strength and durability of geopolymer concrete, optimizing the activator concentration to enhance the geopolymerization process and improve the resulting material properties.
A further object of the invention is to provide a flexible process that allows for the adjustment of precursor ratios and activator concentrations, enabling the customization of geopolymer concrete properties to meet specific construction and structural requirements.
An additional object of the invention is to achieve a significant improvement in the compressive strength of geopolymer concrete by replacing phosphogypsum with ground granulated blast furnace slag in increments, identifying the optimal replacement level for superior performance.
Moreover, another object of the invention is to explore the synergy between calcium and aluminosilicate-rich precursors, facilitating the formation of a well-bonded geopolymeric matrix that enhances the mechanical strength and durability of the concrete.
Still further, the object of the invention is to provide an eco-friendly and economically viable construction material that can be produced using readily available industrial byproducts, offering a sustainable solution for modern construction needs.
Finally, an additional object of the invention is to contribute to the advancement of geopolymer concrete technology by providing insights into the polycondensation reactions and gel formations facilitated by specific combinations of precursors and activators, laying the groundwork for future innovations in sustainable construction materials.

SUMMARY OF THE INVENTION:
The invention presents a process for synthesizing geopolymer concrete by utilizing phosphogypsum and ground granulated blast furnace slag as primary precursors, activated by sodium hydroxide at varying molar concentrations. This process addresses the dual challenges of reducing industrial waste and creating sustainable construction materials with superior mechanical properties.
An inventive aspect of the invention is to provide a method for substituting phosphogypsum with ground granulated blast furnace slag in increments of 5%, 10%, 15%, 20%, and 25%, allowing for a detailed assessment of the synergistic effects of these precursors on the mechanical properties of geopolymer concrete.
Another inventive aspect of the invention is to provide a process where the molar concentration of sodium hydroxide, ranging from 6M to 16M, is optimized to enhance the dissolution of aluminosilicate precursors, promoting the polycondensation reaction and forming a robust geopolymeric matrix. The optimal concentration of 12M sodium hydroxide was identified to achieve the highest compressive strength.
Yet another inventive aspect of the invention is to provide a geopolymer concrete formulation that achieves a compressive strength of up to 49.67 MPa, which is significantly higher than conventional geopolymer mixes. This strength is attained at a 20% replacement of phosphogypsum with ground granulated blast furnace slag, combined with a 12M sodium hydroxide concentration.
Still another inventive aspect of the invention is to offer a sustainable alternative to Portland cement-based concrete by utilizing industrial byproducts, thus reducing carbon emissions associated with conventional cement production and addressing the disposal issues of phosphogypsum and blast furnace slag.
An additional inventive aspect of the invention is to establish a fixed alkali-to-binder ratio of 0.45 and a sodium silicate-to-sodium hydroxide ratio of 1.5, ensuring consistency in the activation process and optimizing the geopolymerization reaction for better material performance.
Moreover, another inventive aspect of the invention is to provide insights into the formation of calcium-alumino-silicate-hydrate (C-A-S-H) gels as a secondary binding mechanism within the geopolymeric matrix, facilitated by the calcium content in ground granulated blast furnace slag.
A further inventive aspect of the invention is to enable the customization of geopolymer concrete properties by varying precursor ratios and activator concentrations, making it suitable for a wide range of applications, including structural components, pavements, and precast elements.
Yet still another inventive aspect of the invention is to demonstrate that the compressive strength of geopolymer concrete increases with higher molar concentrations of sodium hydroxide up to 12M, but diminishes beyond this point, providing critical insights into the optimal conditions for achieving the best mechanical performance.
Finally, an inventive aspect of the invention is to utilize a process that balances environmental sustainability and economic feasibility by leveraging readily available industrial byproducts, reducing material costs, and contributing to the advancement of sustainable construction technologies.

BRIEF DESCRIPTION OF DRAWINGS:
The accompanying drawings illustrate various embodiments of "A Process for Synthesizing Geopolymer Concrete Incorporating Phosphogypsum and GGBS with Variable NaOH Concentrations," highlighting key aspects of its formulation and testing methods. These figures are intended for illustrative purposes to aid in understanding the invention and are not meant to limit its scope.
FIG. 1 depicts a block diagram of the process for synthesizing geopolymer concrete, showing the key components, including phosphogypsum, ground granulated blast furnace slag, sodium hydroxide, and sodium silicate, along with their interactions during the geopolymerization process, according to an embodiment of the present invention.
The drawings provided will be further described in detail in the following sections. They offer a visual representation of the process steps, material proportions, and resulting concrete properties, helping to clarify and support the detailed description of the invention.

DETAILED DESCRIPTION OF THE INVENTION:
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that the embodiments may be combined, or that other embodiments may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.
The present invention is described in brief with reference to the accompanying drawings. Now, refer in more detail to the exemplary drawings for the purposes of illustrating non-limiting embodiments of the present invention.
As used herein, the term "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers or elements but does not exclude the inclusion of one or more further integers or elements.
As used herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. For example, reference to "a device" encompasses a single device as well as two or more devices, and the like.
As used herein, the terms "for example", "like", "such as", or "including" are meant to introduce examples that further clarify more general subject matter. Unless otherwise specified, these examples are provided only as an aid for understanding the applications illustrated in the present disclosure, and are not meant to be limiting in any fashion.
As used herein, the terms ""may", "can", "could", or "might" be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. These exemplary embodiments are provided only for illustrative purposes and so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. The invention disclosed may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
Various modifications will be readily apparent to persons skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention.
Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition and persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
With reference to FIG. 1, in an embodiment of the present invention, the invention describes a process for synthesizing geopolymer concrete using phosphogypsum and ground granulated blast furnace slag as the primary precursors, activated by sodium hydroxide solution at varying molar concentrations ranging from 6M to 16M. The process is designed to develop a high-performance geopolymer concrete with optimized mechanical properties while addressing the utilization of industrial byproducts in an environmentally sustainable manner.
Phosphogypsum and ground granulated blast furnace slag, the key materials in this process, serve as aluminosilicate-rich precursors essential for the geopolymerization reaction. Phosphogypsum, a byproduct of the phosphate fertilizer industry, is abundant and rich in silica and calcium, while GGBS, a steel industry byproduct, provides additional calcium and alumina content. These materials, when combined and activated, undergo a chemical reaction that forms a durable and dense geopolymeric matrix. The process involves substituting phosphogypsum with ground granulated blast furnace slag in varying proportions of 5%, 10%, 15%, 20%, and 25%, enabling a systematic evaluation of their synergistic effects on the resulting concrete's performance.
The activation process is driven by an alkaline activator solution composed of sodium hydroxide and sodium silicate. Sodium hydroxide, a strong base, dissolves the aluminosilicate precursors, initiating the geopolymerization reaction. Sodium silicate, in a fixed ratio of 1.5 with sodium hydroxide, enhances the reaction kinetics and contributes to the formation of a stable and cohesive geopolymer gel. The alkali-to-binder ratio of 0.45 ensures the adequate availability of activators to dissolve and polymerize the precursor materials efficiently, creating a homogeneous geopolymer mix.
To produce the geopolymer concrete, the precursors are thoroughly mixed with the alkaline solution to form a uniform paste. This mixture is then poured into molds and subjected to curing under controlled conditions. The curing process allows the geopolymerization reaction to progress, resulting in the formation of a three-dimensional amorphous network that imparts strength and durability to the concrete. The mechanical properties of the resulting material, including compressive strength, were evaluated at different molar concentrations of sodium hydroxide and varying proportions of GGBS replacement.
Experimental results demonstrated that the molar concentration of sodium hydroxide significantly influences the compressive strength of the geopolymer concrete. As the NaOH concentration increases from 6M to 12M, the compressive strength of the concrete improves, reaching a maximum value of 49.67 MPa at 12M NaOH and 20% GGBS replacement. This improvement is attributed to the enhanced dissolution of aluminosilicates and the subsequent formation of a more densely packed geopolymer matrix. Beyond 12M NaOH concentration, the compressive strength decreases, likely due to the excessive alkalinity disrupting the polymeric network and affecting the material's structural integrity.
The process achieves the best mechanical properties at a replacement level of 20% phosphogypsum with GGBS. At this composition, the synergistic effects of the calcium content in GGBS and the aluminosilicate-rich matrix from phosphogypsum are maximized, leading to the formation of a stable and durable geopolymeric gel. This composition also provides a balance between workability and strength, making it suitable for various construction applications, including structural elements, pavements, and precast components.
An additional feature of the process is its ability to produce geopolymer concrete with superior resistance to chemical attacks and environmental degradation. The dense matrix and the incorporation of calcium-alumino-silicate-hydrate (C-A-S-H) gels, formed through the reaction of calcium with the aluminosilicate network, enhance the material's durability and long-term performance. This makes the geopolymer concrete particularly well-suited for use in harsh environments where resistance to chemicals and environmental stressors is critical.
The eco-friendly nature of the geopolymer concrete synthesized through this process is another significant advantage. By utilizing industrial byproducts such as phosphogypsum and GGBS, the process addresses the dual challenges of waste management and resource conservation. It reduces the dependency on Portland cement, whose production is a major source of carbon emissions, thereby contributing to the mitigation of climate change impacts. The reduction in carbon footprint and the promotion of sustainable construction practices align with global efforts to create greener and more sustainable infrastructure.
The process's adaptability allows for tailoring the properties of the geopolymer concrete to meet specific requirements. By adjusting the proportions of phosphogypsum and GGBS, as well as the molar concentration of sodium hydroxide, the strength and durability of the material can be customized for different applications. This flexibility makes the process versatile and capable of addressing diverse construction needs, from high-strength structural components to cost-effective pavement solutions.
Therefore, present invention represents a significant advancement in the field of sustainable construction materials. It provides a detailed methodology for synthesizing geopolymer concrete using readily available industrial byproducts, achieving superior mechanical properties and environmental benefits. The combination of phosphogypsum and ground granulated blast furnace slag, activated with sodium hydroxide and sodium silicate, creates a durable and high-performance material that meets the demands of modern construction while promoting environmental sustainability. By optimizing the proportions of precursors and activator concentrations, the process ensures maximum efficiency and adaptability, paving the way for widespread adoption of geopolymer concrete in the construction industry.

The working of the invention involves the systematic synthesis of geopolymer concrete using phosphogypsum and ground granulated blast furnace slag as precursors, with sodium hydroxide and sodium silicate as alkaline activators. The process is carried out in several steps to ensure the optimal geopolymerization reaction, resulting in a high-strength and durable concrete material.
Initially, the required quantities of phosphogypsum and ground granulated blast furnace slag are accurately measured. Phosphogypsum serves as the primary precursor, providing silica and alumina, while GGBS acts as a secondary precursor, offering calcium and additional alumina. The precursors are blended in varying proportions, with GGBS replacing phosphogypsum at 5%, 10%, 15%, 20%, and 25%. This variation allows for the exploration of the optimal replacement ratio to maximize the material's strength and durability.
In the next step, an alkaline activator solution is prepared. Sodium hydroxide, in concentrations ranging from 6M to 16M, is dissolved in water to create the primary activator. Sodium silicate is then added to this solution in a fixed ratio of 1.5 to sodium hydroxide. The combined alkaline solution facilitates the dissolution of aluminosilicate precursors and initiates the geopolymerization reaction. The alkali-to-binder ratio is maintained at 0.45 to ensure sufficient activation while retaining workability in the resulting mix.
The prepared precursors are mixed with the alkaline solution in a mechanical mixer to achieve a homogeneous paste. The mixing process ensures uniform distribution of the activators throughout the precursor materials, promoting consistent polymerization. The mixture is then poured into molds of the desired shape and size, which can be tailored to specific applications, such as structural components, paving blocks, or precast elements.
Once the mixture is in the molds, it undergoes a curing process. The curing is typically conducted under controlled temperature and humidity conditions to accelerate the geopolymerization reaction. During curing, the alkaline solution reacts with the aluminosilicates in the precursors, forming a three-dimensional polymeric network. This network imparts strength, durability, and resistance to the concrete. Calcium from GGBS reacts with the aluminosilicates to form secondary calcium-alumino-silicate-hydrate (C-A-S-H) gels, further enhancing the material's mechanical properties.
As the curing progresses, the geopolymer matrix continues to densify, reducing porosity and improving the material's structural integrity. The compressive strength of the concrete is tested at various intervals to monitor its development. Experimental results indicate that the optimal strength is achieved at a 20% replacement of phosphogypsum with GGBS and a sodium hydroxide concentration of 12M. At this combination, the concrete achieves a compressive strength of 49.67 MPa, demonstrating superior performance compared to traditional cement-based concrete.
The working of the invention also involves analyzing the effects of varying sodium hydroxide concentrations on the material's properties. The compressive strength increases with higher molar concentrations of sodium hydroxide up to 12M, as the dissolution of aluminosilicates is enhanced, leading to a more robust geopolymer matrix. However, beyond 12M, the strength decreases, likely due to excessive alkalinity causing disruptions in the polymeric network.
The resulting geopolymer concrete exhibits excellent resistance to chemical attacks, environmental degradation, and mechanical stresses. This makes it suitable for a wide range of applications, including construction in harsh environments and areas requiring high durability. Its eco-friendly nature, achieved by utilizing industrial byproducts and reducing reliance on Portland cement, contributes to sustainable construction practices and addresses environmental challenges.
Overall, the working of this invention integrates precise material selection, optimized activator preparation, and controlled curing processes to create a high-performance geopolymer concrete. The systematic approach ensures reproducibility and adaptability, allowing the material to meet diverse construction needs while promoting environmental sustainability.
ADVANTAGES OF THE INVENTION:
The prime advantage of the invention is to provide a sustainable alternative to Portland cement-based concrete, utilizing industrial byproducts like phosphogypsum and GGBS to reduce environmental impacts and promote efficient waste management practices.
Another advantage of the invention is its ability to achieve superior compressive strength of up to 49.67 MPa, offering enhanced mechanical performance compared to traditional cement-based materials for various structural and infrastructure applications.
Yet another advantage of the invention is the optimization of sodium hydroxide concentration, enabling precise control over the geopolymerization process and ensuring consistent material quality with improved strength and durability.
Still another advantage of the invention is its resistance to chemical attacks and environmental degradation, making it highly suitable for use in harsh conditions and extending the lifespan of construction materials.
A further advantage of the invention is the flexibility to customize material properties by varying precursor ratios and activator concentrations, enabling tailored solutions for specific construction requirements.
Moreover, another advantage of the invention is its reduced carbon footprint, achieved by replacing energy-intensive cement production with eco-friendly geopolymer concrete synthesis, contributing to global sustainability efforts.
An additional advantage of the invention is its cost-effectiveness, leveraging readily available industrial byproducts to lower raw material costs while delivering high-performance construction materials.
A final advantage of the invention is its adaptability for diverse applications, including precast elements, pavements, and structural components, demonstrating versatility and practical utility in modern construction practices.
, Claims:CLAIM(S):
We Claim:
1. A process for synthesizing geopolymer concrete (100), wherein phosphogypsum (PG) and ground granulated blast furnace slag (GGBS) are utilized as precursors, activated with a sodium hydroxide (NaOH) solution at varying molar concentrations ranging from 6M to 16M, and the process comprises:
a) Mixing phosphogypsum and GGBS in varying proportions of 5%, 10%, 15%, 20%, and 25%, replacing PG with GGBS;
b) Preparing an alkaline activator solution comprising sodium hydroxide and sodium silicate in a fixed ratio of 1.5 (SS/SH);
c) Combining the precursors with the alkaline activator solution in an alkali-to-binder ratio of 0.45 to form a homogeneous geopolymer mix;
d) Curing the mixture to achieve compressive strengths ranging from 32.46 MPa to 49.67 MPa, with the highest strength observed at 12M NaOH and 20% GGBS replacement.
2. The process as claimed in claim 1, wherein the sodium hydroxide concentration is optimized to 12M to enhance the geopolymerization reaction, achieving a maximum compressive strength of 49.67 MPa.
3. The process as claimed in claim 1, wherein the geopolymer concrete formulation exhibits improved mechanical properties due to the synergistic effects of calcium and aluminosilicate-rich precursors from GGBS and PG.
4. The process as claimed in claim 1, wherein the optimal replacement level of PG with GGBS is 20%, providing a balance of workability, strength, and durability.
5. The process as claimed in claim 1, wherein the sodium hydroxide solution acts as the primary activator, and the addition of sodium silicate improves the polymerization kinetics, resulting in enhanced compressive strength and matrix stability.
6. The process as claimed in claim 1, wherein the geopolymer concrete exhibits superior resistance to chemical attacks and environmental degradation, making it suitable for structural applications, pavements, and precast elements.
7. The process as claimed in claim 1, wherein the compressive strength of the geopolymer concrete increases with the molar concentration of NaOH up to 12M but decreases at higher concentrations.
8. The process as claimed in claim 1, wherein the formation of calcium-alumino-silicate-hydrate (C-A-S-H) gel complements the geopolymeric matrix, improving the mechanical properties and durability of the concrete.
9. The process as claimed in claim 1, wherein the geopolymer concrete is synthesized as an eco-friendly alternative to Portland cement, reducing carbon emissions and promoting the use of industrial byproducts.
10. The process as claimed in claim 1, wherein the alkali-to-binder ratio of 0.45 ensures consistent activation and optimal geopolymerization of the precursor materials.

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