Measuring Effectiveness of Chemical Injection Grouting
Infrared Thermography: Fast and Reliable Assessment of Chemically Grouted Shotcrete Structures
One of the frequently used methods of concrete crack and water infiltration repair of concrete structures is chemical injection grouting.
Non-Destructive | Non-Invasive Testing
In the remediation of any structure, one of our goals is to use non-destructive diagnostic methods and minimally intervene into the concrete structure during surveys.
Researchers are exploring the possibility of using thermography to repair concrete structures using chemical grout injection techniques, as well as the conditions and limitations of using these non-destructive methods.
For more than three decades, Le Fong has been developing concrete repair materials and procedures to achieve proper, effective, and permanent chemical grout placement.
However, verification of proper grouting by non-destructive methods has always been tricky for quality assurance purposes. For quality assurance purposes, infrared thermography (IR) may become a standard tool to help quantify and detect product permeation and travel in grouted walls.
Thermal Imaging | Shotcrete Grout Injection
Construction below grade is becoming increasingly popular with shotcrete. Shotcrete has become a popular alternative to traditional cast-in-place (CIP) concrete due to its lower construction costs and faster construction time.
However, shotcrete construction can result in a less-than-solid structure and may incorporate segregation, honeycombing, and voids, which consequently results in a higher incidence of water ingress into below-grade structures.
The thermal camera pictures clearly show the product permeating the structure, warming the shotcrete as it expands. After the injection gel spreads into cracks and voids, it will eventually cure – sealing the structure.
How Does Thermography Work?
Chemical grout injected into the structure undergoes an exothermic reaction that emits heat. Thermal imaging can be used to detect this heat. It can be used to detect differences in thermal mass or thermal capacity between grouted and ungrouted areas of a structure, as well as to provide a color image that indicates differences in energy/heat emitted from the surface of the structure. A quality assessment regarding the penetration, travel, and effectiveness of the grout injection can be made based on the interpretation of the image.
