Infrared thermal imaging: fast and reliable assessment of chemical grouting shotcrete structures
Chemical grouting is one of the common methods to repair cracks and water penetration in concrete structures.
Minimizing the intervention of concrete structures when conducting surveys and the use of related non-destructive diagnostic methods are one of our goals for repairing any structure.
In the ongoing experimental research using chemical grouting technology to repair concrete structures, the possibility of using thermal imaging technology is being evaluated, and the conditions and limitations of using these non-destructive methods are being explored.
However, for quality assurance purposes, it has always been a challenge to confirm correct grouting through non-destructive measures. The use of infrared thermal imaging (IR) may become a standard tool to help quantify and detect product penetration and travel through grout walls to ensure quality.
Shotcrete is becoming more and more popular in underground construction. The trend of using shotcrete instead of traditional cast-in-place (CIP) concrete can be recognized to reduce overall construction costs and time saved without installing formwork.
However, the use of shotcrete will result in a structure that is less than a solid structure, and segregation, honeycombs, voids and air pockets may appear, resulting in a higher possibility of water ingress in the underground structure.
How does the thermal imager work?
During the exothermic reaction of the chemical grouting injected into the structure, energy is dissipated in the form of heat. This heat can be detected by thermal imaging equipment. Infrared thermal imaging cameras can distinguish the relative difference between the thermal mass or heat capacity of the grouted and ungrouted areas of the structure, and provide a color picture indicating the difference in energy/heat emitted from the surface of the structure. The interpretation of the images can help provide quality assessments that focus on the permeability, stroke, and effectiveness of the pulping process.