Inspection of insulated concrete form walls using ground penetrating radar

Insulated Concrete Form (ICF) walls have been increasingly used as an excellent alternative to traditional wall construction. ICF walls are attractive to both owners and contractors due to their superior thermal and structural performance, in addition to significant labor savings and speed of construction. However, potential voids in ICF walls-especially around plastic ties, reinforcing bars, and form corners-have been reported as a result of poor concrete consolidation. These voids could have serious negative impact on the durability, thermal efficiency, and structural performance of ICF walls. In this paper, the use of Ground Penetrating Radar (GPR) for inspecting ICF walls is investigated. GPR is a non-destructive evaluation technique that involves the transmission of electromagnetic waves into the material under investigation and the reflections of these waves at interfaces of embedded objects to determine their location. An ICF specimen was built with air voids, steel bars, and utility pipes, and scanned with GPR to determine the accuracy of GPR in void, bar, and pipe detection. The results have indicated that GPR is an efficient and reliable technique for inspecting ICF walls. A case study of inspecting the bearing lintels in a three-story ICF building using GPR is also presented.