Low-Pressure And High Pressure Injection
In the early days of epoxy injection when resins were thicker with relatively short pot lives, high-pressure machines were developed for injection into relatively wide cracks. The hairline cracks that we commonly inject today were often bypassed. If injected, they seldom received full penetration due to the thicker and quicker to cure resins despite the high pressure used. Flow into the hairline cracks was reduced significantly due to the resulting skin friction in the narrow crack.
With the development of today’s low viscosity and long pot life resins and utilizing low-pressure injection, full depth penetration in hairline cracks can be achieved. Much, if not most, of leak remediation involves hair-line cracks (e.g., a leak through a hairline crack in a below-grade concrete wall). We typically use low pressure injection in these cracks utilizing the newer resins.