Epoxy injection is one of the most common ways of repairing narrow cracks. It has been used to repair cracks in buildings, bridges, and dams. To achieve good results, though, requires proper materials and injection techniques and an understanding of what epoxy injection can and cannot do.
Epoxy injection alone cannot solve every crack problem. If a crack is an active crack which continues to open or close, then the cause of the crack movement must be removed or a control joint must be constructed in the area of the crack. Otherwise, the concrete will crack again nearby after the crack is injected.
HOW TO SELECT AN EPOXY FOR CRACK INJECTION
Epoxies used to inject cracks in concrete should meet the requirements for Type I epoxies described in ASTM C 881. Type I epoxies are designed for bonding hardened concrete to hardened concrete. Three grades based on viscosity and consistency and three classes based on the range of temperatures for which they are suitable are available.
The procedure involves the following steps:
- Clean the cracks
- Seal the surface of each crack
- Install the entry points
- Mix the epoxy
- Inject the epoxy
- Remove the surface seal.