SELF-CURING CONCRETE USING SODIUM POLYACRYLATE AND PARTIAL CEMENT REPLACEMENT WITH GROUND GRANULATED BLAST FURNACE SLAG (GGBS)

Abstract

SELF-CURING CONCRETE USING SODIUM POLYACRYLATE AND PARTIAL CEMENT REPLACEMENT WITH GROUND GRANULATED BLAST FURNACE SLAG (GGBS) The present invention provides a novel self-curing concrete composition and method that reduces the reliance on external curing techniques, uses sustainable materials like GGBS, and enhances the performance and durability of concrete. The combination of sodium polyacrylate and ground granulated blast furnace slag (GGBS) offers a cost-effective and environmentally friendly solution to the challenges posed by traditional concrete curing methods. The sodium polyacrylate is present in an amount of 0.2-1.0% by weight of the binder. The GGBS is present in an amount of 30-40% by weight of the binder.

Specification

Description:4. DESCRIPTION

Technical Field of the invention

The present invention relates to self-curing concrete compositions and methods for preparing them. Specifically, the invention pertains to a self-curing concrete formulation that incorporates sodium polyacrylate and uses ground granulated blast furnace slag (GGBS) as a partial replacement for cement, improving both the curing process and the environmental sustainability of the concrete mix.

Background of the invention

Concrete is a commonly used construction material, and its properties, such as strength, durability, and workability, are significantly influenced by the curing process. Traditional curing methods require external water sources to ensure proper hydration of cement particles, which can be challenging in hot climates or large-scale projects due to water scarcity and the high cost of water usage.

Furthermore, the production of cement results in significant carbon emissions due to the calcination of limestone and the energy-intensive process. This has prompted the exploration of alternative materials and methods for improving the sustainability of concrete production.

Ground Granulated Blast Furnace Slag (GGBS) is an industrial byproduct that has gained attention as a partial replacement for Portland cement in concrete mixes. GGBS improves concrete's long-term durability, reduces environmental impact, and enhances the material's resistance to sulfate attack and chloride-induced corrosion.

However, GGBS-based concrete still requires effective hydration management to achieve optimal strength and durability.

There is a need for a concrete mix that:
1. Does not require external curing methods.
2. Utilizes sustainable and low-carbon materials.
3. Reduces the need for water during the curing process while enhancing overall concrete properties.

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.

The present invention addresses the above-mentioned problems by providing a self-curing concrete composition comprising:
1. Cement (Portland cement or any suitable binder),
2. Ground Granulated Blast Furnace Slag (GGBS) as a partial replacement for the cement, and
3. Sodium Polyacrylate as a self-curing agent.

The sodium polyacrylate is an absorbent material that retains water, releasing it gradually during the hydration process of the cement. This leads to enhanced hydration, reduces the need for external curing methods, and improves the overall mechanical properties of the concrete.

Detailed Description of the invention

It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

The use of "including", "comprising" or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "a" and "an" herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. Further, the use of terms "first", "second", and "third", and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

The concrete mixture according to the present invention comprises the following key components:
• Portland Cement (PC): 40-60% by weight of the binder content.
• Ground Granulated Blast Furnace Slag (GGBS): 20-50% by weight of the binder content, replacing Portland cement.
• Sodium Polyacrylate (SPA): 0.1-2% by weight of the total binder content, added to promote water retention and self-curing.
• Water: Sufficient quantity to achieve a workability of the mix (typically in the range of 0.35-0.50 water-to-binder ratio).
• Aggregates: Conventional fine and coarse aggregates, such as sand and gravel, making up the remaining portion of the mix.
The sodium polyacrylate component is a superabsorbent polymer that has the capacity to absorb water several times its weight. It is incorporated into the concrete mix in a dry or pre-hydrated form. When added to the concrete mixture, it retains water within the matrix and releases it over time, facilitating the hydration of the cement particles and promoting curing from within.

2. Properties of Self-Curing Concrete:
• Water Retention: Sodium polyacrylate (SPA) absorbs water during the mixing phase and releases it slowly during the hydration process, reducing the reliance on external curing methods and minimizing surface cracking.
• Enhanced Durability: The partial replacement of cement with GGBS improves the long-term durability of concrete. GGBS reacts with calcium hydroxide produced during hydration, leading to the formation of additional calcium silicate hydrate (C-S-H) gel, which increases concrete's resistance to chemical attacks and reduces porosity.
• Environmental Benefits: The use of GGBS reduces the carbon footprint of the concrete by replacing a portion of the energy-intensive Portland cement. Additionally, the use of sodium polyacrylate reduces the amount of water needed for curing, further contributing to the sustainability of the concrete mix.
• Reduced Shrinkage and Cracking: The self-curing property of the concrete mix, enabled by sodium polyacrylate, helps minimize early-age shrinkage and cracking, which can occur when water evaporates too quickly from the surface.

3. Method of Preparing the Self-Curing Concrete:
The method of preparing the self-curing concrete comprises the following steps:
1. Mixing the Dry Components: The Portland cement (or suitable binder), GGBS, fine and coarse aggregates, and sodium polyacrylate are mixed in dry form until a uniform mixture is achieved.
2. Addition of Water: Water is added to the dry mixture in an amount sufficient to achieve the desired workability. The water should be added in a controlled manner to ensure that the sodium polyacrylate absorbs a significant portion, retaining it for release during the hydration process.
3. Mixing to Consistency: The entire mixture is then blended to achieve a uniform consistency, ensuring the even distribution of sodium polyacrylate and water retention capabilities throughout the concrete.
4. Placement and Molding: The concrete is placed in molds or used as desired for construction purposes. The water retained in the mix by sodium polyacrylate will gradually be released during the curing period, ensuring sufficient hydration without the need for external water or traditional curing methods.
5. Curing: The concrete is allowed to cure naturally without the need for external water or wet curing techniques. The sodium polyacrylate provides internal moisture during the hydration process, improving both the speed and completeness of curing.

4. Benefits of the Invention:
• Water Savings: The self-curing nature reduces the requirement for water during traditional curing, thus saving significant amounts of water.
• Environmental Impact: The use of GGBS reduces the carbon footprint associated with concrete production, making it more environmentally friendly compared to conventional cement-based mixes.
• Improved Durability: The inclusion of GGBS enhances the long-term durability and strength of the concrete, making it more resistant to chemical and physical deterioration.
• Ease of Application: The concrete mixture is easy to handle and does not require additional curing infrastructure, which can be costly and time-consuming.
It will be recognized that the above described subject matter may be embodied in other specific forms without departing from the scope or essential characteristics of the disclosure. Thus, it is understood that, the subject matter is not to be limited by the foregoing illustrative details, but it is rather to be defined by the appended claims.

While specific embodiments of the invention have been shown and described in detail to illustrate the novel and inventive features of the invention, it is understood that the invention may be embodied otherwise without departing from such principles.
, Claims:We Claim
1. A self-curing concrete composition comprising:
a) Portland cement or suitable binder;
b) Ground Granulated Blast Furnace Slag (GGBS) in the range of 20-50% by weight of the binder;
c) Sodium polyacrylate in the range of 0.1-2% by weight of the binder; and
d) Water in an amount sufficient to achieve desired workability.

2. The concrete composition as claimed in claim 1, wherein the sodium polyacrylate is present in an amount of 0.2-1.0% by weight of the binder.

3. The concrete composition as claimed in claim 1, wherein the GGBS is present in an amount of 30-40% by weight of the binder.

4. A method for preparing self-curing concrete, comprising:
a) mixing Portland cement or suitable binder, GGBS, sodium polyacrylate, and aggregates in dry form;
b) adding water to the dry mixture to achieve desired workability; and
c) mixing the components until a uniform consistency is achieved.

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