Colloidal Silica Hydrogels for Retrofitting Marine Base Structures
Marine base structures, such as ports and offshore platforms, are subject to harsh environmental conditions due to constant exposure to saltwater and severe weather. As a result, they are prone to corrosion and damage which can weaken their structural integrity over time. This not only poses a safety risk for those working on these structures but also leads to high maintenance costs and potential downtime for repairs. In this article, we talk about how colloidal silica hydrogels can be used to improve resilience and combat deterioration of concrete used in forming these structures.
Marine Base Structure Deterioration
Damage to concrete in a marine environment can occur due to physical and chemical attacks. Effects include fatigue, where repeated loadings weaken the concrete by exceeding the strength of the material, and chemical attack, a process that chemically alters the binding matrix or aggregate skeleton of concrete to a weaker and/or greater voluminous version than the original concrete or aggregate skeleton.
Chemical and physical attacks produce cracking and microcracking, increasing the rate of water and salt migration into the concrete. This increase accelerates the potential for ASR, which is defined as a “chemical reaction in either concrete or mortar between hydroxyl reaction, ASR ions (OH-) of the alkalis (sodium and potassium) from hydraulic cement (or other sources), and certain siliceous rocks and minerals, such as opal, chert, microcrystalline quartz, and acidic volcanic glass, present in some aggregates. This reaction and the development of the alkali-silica gel reaction product can, under certain circumstances, lead to abnormal expansion and cracking of the concrete” (FHWA, 2013).
How Colloidal Silica Hydrogels Work
Colloidal Silica Hydrogels are a dispersion of nano sized particles which consume excess water and alkalis that reside in concrete pores and cracks and produces a denser concrete. Concrete is a hardened sponge with channels that allows water to leach through the body of the concrete to the concrete surface while also allowing deleterious chemicals to flow into the concrete. Colloidal Silica Hydrogels are a spray on technology which creates a more homogenous and stable concrete structure that is less prone to excessive degradation from chemical and physical attack. When hydrogels are added, a reaction occurs that chemically binds the concrete pore water solution. In doing so, this converts the pore solution into a bridging technology that spans the crack and pores that would cause further concrete deterioration. Furthermore, this technology in combination with the pore water solution develops into calcium silicate hydrate (“C-S-H”). C-S-H is the backbone of concrete strength and therefore, concrete enhanced with Colloidal Silica Hydrogels is denser and less permeable. This results in the decrease of water and alkalis to the surface as well as the decrease in harmful chemicals that are able to leach from the surface into the body of the concrete.
Advantages of Using Colloidal Silica Hydrogels
Compared to traditional retrofitting materials such as cement or epoxy resins, Colloidal Silica Hydrogels offer several advantages:
Easy Application: The gel can be applied as a spray on technology with 100 to 300 psi sprayers available at local hardware stores.
High Penetration: Due to the small size of the particles, Colloidal Silica Hydrogels can penetrate even the tiniest cracks and pores in the structure, ensuring comprehensive reinforcement.
Strong Bonding: The gel bonds well with both concrete and steel, providing a strong and durable retrofitting solution.
Chemical Resistance: Colloidal Silica Hydrogels are resistant to chemical corrosion, making them suitable for use in marine environments.
Improved Longevity: By strengthening the structure from within, these hydrogels can significantly prolong the life of marine base structures.
Conclusion
Colloidal silica hydrogels offer a highly effective and efficient solution for retrofitting marine base structures. With their unique properties and advantages, they have become an increasingly popular choice for enhancing the strength and stability of these vital structures. As technology continues to evolve, we can expect to see further advancements and applications of colloidal silica hydrogels in the marine industry. Using colloidal silica hydrogels is a sustainable option for renovating marine base structures that are exposed to harsh environmental conditions.