Infrastructures are constructed with reinforced and prestressed concrete. For quality assurance and quality control, non-destructive techniques are adopted. In India, rebound hammer and ultrasonic pulse velocity test are widely used. Most of the time, it becomes necessary to find the reinforcements and ducts present in the concrete structure. Ground Penetrating Radar (GPR), shortly called radar, is one of the advanced non-destructive techniques, used for inspection of concrete structures, pavements and to detect reinforcements and ducts in concrete. It is also used for quality assessment and to locate flaws inside the concrete. It is based on the propagation of short electromagnetic waves of frequency 1.0 GHz to 2.5 GHz. This paper focuses on the detection of reinforcements and ducts which are present inside the concrete and simulated specimens. The effect of grid spacing during the collection of data is an important parameter in locating the reinforcements and ducts. The effect of grid spacing that is effective in identifying the reinforcements and ducts was studied and reported.

The identification of reinforcements in the structures becomes essential. So GPR can be used for detecting reinforcement and ducts in a shorter time duration with higher accuracy. The grid spacing is an important parameter in locating reinforcements and ducts. Hence, an attempt has been made in this research to find the optimal grid spacing in identifying the reinforcements and ducts through an experimental study. This has been achieved by conducting tests on concrete specimens with reinforcement mesh and also on simulated sand specimen concrete reinforcement mesh and duct.

The RADAR (acronym for Radio Detection and Ranging) technology is used to perform investigation on reinforced concrete structures to detect reinforcements and defects, such as voids and honeycombs, and is derived from the radar used for undergoing surveys called Georadar. The radar method has several advantages in Non-Destructive Testing (NDT). Concrete thickness determination is a basic but important application in the use of radar for NDT of concrete systems. GPR has many advantages previously unavailable to individuals working in the areas of engineering, environmental management and geology. One advantage is that the scale of features resolvable using GPR can range from a few centimeters to tens or hundreds of meters using the selection of antennas available. Another distinct advantage is the ability of GPR to provide high-resolution continuous profiling of an area. The great majority of radar applications in civil engineering is aimed at the geometrical characterization of the investigated structure.

Structural Engineering Journal, Non-destructive testing, Ground Penetrating Radar (GPR), Concrete, Reinforcement spacing, Ducts.