A review of condition surveys of concrete structures by non-destructive methods

Speaker:
Perttunen, J.; Kiwa Inspecta; Finland

Authors:
Perttunen, J.; Kiwa Inspecta; Finland

ID: ECNDT-0574-2018

Concrete NDE can be divided into three different parts by its principle: Ultrasonic, electromagnetic and magnetic pulse-induction.
Ultrasonic testing uses the ultrasonic shear-wave tomography technique and it’s suitable for all types of concrete and stone structure examinations with a strength of 50 to 2500 mm.

Ultrasonic testing has been used for example in tensioned road and railroad bridges and water tower surveys to locate flaws in tension cable injections and to locate casting flaws in extremely tight reinforcement areas.

Electromagnetic wave testing uses high frequency electromagnetic waves for detecting metals, non-metals and cavities. It passes through coatings and structural layers up to 300 mm.

Electromagnetic wave testing has been used for example to minimize the risk of hitting concealed objects in diamond drilling and sawing. It has also been used in structural and capacity analyses to find out the actual reinforcement of concrete structures (for example yard decks, midsoles and slabs), especially when designs have been unavailable, or when you need to make sure the structure is implemented as it is designed.

Magnetic pulse-induction testing uses magnetic pulse-induction to locate reinforcement bars and measure concrete covers. It is the quickest and simplest method for locating and measuring rebars, diameters, density and concrete covers up to 160 mm.

Magnetic pulse-induction testing has been used for example in surveys for structures that are exposed to weather when you need to estimate corrosion level by measuring concrete covers (e.g. facades, balconies and bridges).