Please wait, loading...
Please wait, loading...
Introduction – The Importance of Concrete Curing
In the field of civil engineering and concrete technology, considerable focus is always placed on selecting appropriate materials for concrete production, accurately designing mix proportions in the laboratory, using advanced equipment for mixing, and employing chemical admixtures to enhance concrete performance. Additionally, efforts are made to ensure that the fresh concrete mixture is transported to the construction site under optimal conditions and placed into the forms using standard procedures and in full compliance with technical guidelines. However, despite the attention and costs invested in these steps, the final quality of concrete in many projects—specifically in terms of durability, mechanical strength, cohesion, and impermeability—often fails to meet expectations or shows a noticeable gap compared to the specified performance criteria.
The main reason for this discrepancy is the neglect, underestimation, or unprofessional execution of the critical curing process. Even if all previous stages of concrete production are carried out properly and to a high standard, without a professional curing system and adequate moisture retention during the ongoing cement hydration, the resulting hardened concrete will suffer from significant reductions in mechanical properties and increased permeability.
The reality is that everything done during the production and placement of concrete only accounts for half of the path toward ensuring its final quality. The second half, which is often overlooked in many construction projects, is the curing of the freshly cast concrete. Effective curing—by maintaining appropriate moisture and temperature—completes the cement hydration process and significantly improves the durability, strength, and long-term performance of the concrete.
Therefore, if we aim to achieve concrete that is cohesive, durable, and meets the desired performance specifications, we must pay special attention to the curing phase and recognize it as an integral part of the concrete production and implementation process.
Origin of the Idea: Designing Gel-Based Internal Curing Additives
The design and development of internal curing additives for concrete is the result of the integration of expertise, technical knowledge, and social responsibility at ABADGARAN Construction Chemical Company. This innovation was born from a deep analysis of on-site challenges in Iran’s construction industry and shaped around three key pillars:
In many civil engineering projects, despite the use of high-quality materials and precise execution, the final concrete often fails to achieve the desired strength and durability. This is largely due to factors such as rapid moisture loss, poor curing practices, and surface cracking.
In hot and dry climates, these issues become even more pronounced, increasing the vulnerability of structures. In response, ABADGARAN set out to develop a solution that ensures internal concrete quality, independent of external environmental conditions.
In a country like Iran, which is facing an escalating water crisis, the daily use of millions of liters of fresh water for curing concrete is not only economically unfeasible but also environmentally unsustainable.
Given that traditional curing methods often result in significant water waste, ABADGARAN sought to create a material that could enable the curing process from within the concrete itself, eliminating the need for repeated external water application.
ABADGARAN has always considered itself committed to developing construction additives that not only enhance technical performance but also address broader national challenges. The idea of designing an internal curing additive represents not just a technical innovation, but a true expression of social responsibility. This initiative supports natural resource preservation, reduction of the concrete industry’s environmental footprint, and the protection of future generations.
Freshwater from an International Perspective
International organizations such as the United Nations (UN) and UNESCO place strong emphasis on the protection of freshwater resources, particularly in industrial sectors. This concern is reflected in several major reports and initiatives, some of which are outlined below:
As part of the UN’s Sustainable Development Goals, Goal 6 is dedicated to ensuring access to clean water and sanitation for all. One of its sub-targets is to increase water-use efficiency across all sectors, including industry, by 2030. This goal highlights the importance of reducing both water consumption and waste in industrial processes.
These annual reports, published by UNESCO, assess the state of global water resources. Recent editions have emphasized the industrial sector’s role in water consumption and the need for sustainable water resource management. The reports recommend that industries adopt advanced technologies and improve operational processes to minimize water use and prevent waste.
As the only comprehensive scientific program on water within the UN system, the IHP promotes sustainable water resource management. It supports the development of policies and technologies aimed at reducing water consumption, particularly in industrial applications.
This initiative, under the UN Global Compact, encourages companies to manage water resources responsibly. Its objectives include reducing water use, improving water quality, and preventing water loss in industrial processes. Over 430 companies worldwide have joined this initiative to date.
Conventions such as the Convention on the Protection and Use of Transboundary Watercourses and International Lakes and the Convention on the Law of the Non-Navigational Uses of International Watercourses stress the importance of sustainable water management and international cooperation. These agreements require countries to implement measures that reduce water usage and prevent waste across various sectors, including industry.
These global frameworks reflect the international community’s commitment to preserving freshwater resources and minimizing their loss, especially in industrial contexts. The use of innovative technologies—such as iSC Intelligent Self-Curing concrete additives—can play a significant role in advancing these global sustainability goals.
Summary of Internal Curing Technology in Concrete
Mechanism of Action of Intelligent Gel in Concrete
The mechanism behind the formation of super-hydrophilic nanopolymers within the concrete matrix—and their role in enabling internal self-curing—represents a high-tech scientific innovation born from the synergy of chemistry, polymer science, materials engineering, and concrete technology.
The advanced polymeric materials used in the formulation of the intelligent gel additive possess the ability to retain and release mixing water in a controlled manner. During concrete production, these materials are added to the mix along with the gel additive and remain embedded in the concrete structure.One of their key functions is the absorption and internal retention of excess water within the concrete. During the mixing stage, the super-hydrophilic nanopolymers dissolve into the free water present in the concrete. They raise the boiling point of the mix water to around 100°C and lower the freezing point to approximately –10°C, without altering the setting time or interfering with the hydration process.
After initial setting, these materials gradually begin to release the stored water in sync with the cement hydration reaction. This gradual water release helps prevent surface evaporation and, in cold environments, inhibits internal water from freezing and expanding. This continuous hydration results in better cohesion of the mix and enhanced strength development. As hydration progresses, osmotic and thermal pressure builds up around cement particles. In response, the nanopolymers release their stored water progressively, maintaining localized moisture balance around the cement grains. This behavior effectively prevents early-age shrinkage cracking and the formation of capillary voids in the hardened concrete matrix.
After initial setting, these materials gradually begin to release the stored water in sync with the cement hydration reaction. This gradual water release helps prevent surface evaporation and, in cold environments, inhibits internal water from freezing and expanding. This continuous hydration results in better cohesion of the mix and enhanced strength development. As hydration progresses, osmotic and thermal pressure builds up around cement particles. In response, the nanopolymers release their stored water progressively, maintaining localized moisture balance around the cement grains. This behavior effectively prevents early-age shrinkage cracking and the formation of capillary voids in the hardened concrete matrix.
The controlled water release by nanopolymers indirectly reduces plastic and drying shrinkage, supports uniform C–S–H (calcium silicate hydrate) phase development, and minimizes porosity. This marks a significant advancement over traditional curing methods, which often fail to deliver uniform moisture distribution for effective hydration. These intelligent materials are particularly effective in hot, arid climates or in large and mass concrete pours. As a result, the mechanical strength and durability of concrete are enhanced without the need for external curing. With the application of these smart additives, conventional curing practices such as water spraying or wet coverings are no longer necessary. Moreover, this technology is highly practical for structures where access to poured concrete sections is limited, making it ideal for complex, inaccessible, or large-scale concrete elements.
Comparison of Intelligent Gel with Conventional Silica-Based Gels
Conventional micro-silica gels are among the most widely used additives in the concrete industry, primarily employed to enhance mechanical properties and durability. The micro-silica contained in these gels—also known as silica fume—consists of ultra-fine, reactive particles predominantly made of amorphous silica.
When added to concrete, silica fume reacts with the calcium hydroxide (portlandite) released during cement hydration to form calcium silicate hydrate (C–S–H) gel, a stable and durable compound that significantly improves concrete strength and density. These gels contribute to:
The formulations of conventional micro-silica gels are designed to:
Collectively, micro-silica gels play a vital role in improving concrete mix quality, transportation efficiency, and extending the service life of concrete structures.
However, conventional silica gels are not without limitations. Despite their valuable technical benefits, they lack internal self-curing capability—a critical feature that will be discussed in the next section. This limitation becomes especially evident in environments where external curing is difficult or inconsistent, and it has a direct impact on the final performance and long-term quality of concrete.
Key Features of POWER GEL-iSC and MS-5-iSC
The primary distinguishing feature of these intelligent gels is their notable improvement in compressive strength when compared to control samples. This has been verified through standardized testing in accordance with Iran National Standard INSO 1608-3, using a concrete compression testing machine at 1, 3, 7, and 28 days of curing.
This enhancement in compressive strength is attributed to the internal curing mechanism embedded within the concrete matrix. Unlike traditional methods—such as water spraying, immersion, or external curing—the intelligent gel ensures continuous and sufficient water supply for the cement hydration process. This guarantees optimal development of the concrete’s internal structure, even in the absence of external curing.
In addition to strength improvement, workability (flowability) of the concrete is significantly increased, as confirmed by tests based on INSO 3203-2.
Furthermore, air content tests conducted in accordance with INSO 15904 showed no significant effect of the new polymer-based materials on the amount of entrapped or entrained air in the concrete.
Another critical performance parameter tested was water penetration depth, evaluated according to INSO 1608-8. This test reflects the concrete’s long-term durability and resistance to water ingress, and the results demonstrate that iSC gels contribute to superior water tightness.
Finally, a major advantage of the iSC intelligent gels is their competitive cost. Given the nature of the material and its target market, the low production cost plays a decisive role in reducing the overall project expenditure, making them an economically viable solution for a wide range of concrete applications.
Physical and Chemical Properties
POWER GEL-iSC
MS-5-iSC
