Leak sealing injection – Systems
Both acrylic and PU based resins are effective for repairing cracks in concrete structures. The choice between the two depends on the specific application and the required properties of the resin.
Acrylic Based
Methacrylate based resins are hydrophilic and flexible resins that are used for repairing non-structural cracks and joints. Due to their low viscosity and hydrophilic swelling behavior in contact with water, this type of resin can waterproof leaks and seal even the smallest cracks. Optionally, a fourth component (a polymer) can be added to improve the strength and flexibility of the resin and improve its performance in wet-dry cycles under fluctuating groundwater levels.
PU Based
Polyurethane based injection resins, also known as PU resins, are designed to stop water. They react quickly upon contact with water and increase significantly in volume, creating a high foaming effect. This makes them ideally suited for sealing cracks in dams and bridges, waterproofing in civil engineering and tunnel construction.
Acrylic vs PU based injection resins – differences
Acrylic and PU based resins are two common types of injection resins used for repairing cracks in concrete structures. Although their usage is similar, there are clear distinctions between the two materials.
Composition: Acrylic resins are made of acrylic esters and methyl methacrylate monomers, while PU resins are made of polymeric isocyanates and polyols. This difference in composition affects their chemical and physical properties.
Strength and hardness: PU resins are typically stronger and harder than acrylic resins and can withstand heavier loads and greater stress. This makes them more suitable for repairing cracks in concrete structures that are subject to high loads, such as bridges, dams and industrial floors.
Reaction time: Acrylic resins have a larger window of reaction times, going from very slow to very fast.
Viscosity: Acrylic resins typically have lower viscosities than polyurethane injection resins. This means that they can flow more easily and penetrate smaller cracks and voids, but may not be as effective at filling larger gaps.
Aspect: PU resins are foams or elastomers whereas acrylic resins are gels. They do not expand as most of the PU resins tend to do.
