Non-Destructive Testing and Evaluation

By directing an electromagnetic wave into a concrete structure and measuring the response, features such as steel reinforcement, voids, the concrete backwall, and other features of interest can be detected. This work is often completed in scans along a given element on a test grid to generate a 3D view of the features, their depth, and their condition. BDI has developed its own ASNT TC-1A certification program for its GPR professionals and deploys a variety of different technology platforms depending on the speed, precision, or depth of testing needed.

Infrared Thermography is an electromagnetic method that involves measuring the infrared energy emitted from a concrete structure and identifying possible defects such as delamination based on unexpected temperature variations. BDI deploys this method using high-precision IR cameras mounted on drones and vehicles to scan entire structures at high-speed with results generated as feature maps.

By inducing multiple impacts on a concrete structure on a moving platform and measuring the audible response using a microphone array, delaminations in concrete from the resulting frequency response similar to traditional hammer sounding and impact echo. For nearly a decade, BDI has been a pioneer in this technology developing both its own field data collection system and the AI-ML powered analytics model for measuring and mapping delamination on over 60 million square feet of concrete.

Leveraging high-resolution, high-speed cameras mounted on drones and vehicles combined with AI-enabled photogrammetry platforms, BDI can generate 2D orthophoto and 3D renderings of concrete structures to provide context for other services as well as to measure and map defects such as spalls, cracks, exposed reinforcement, and patching with automation.

By directing ultrasonic waves from an array of dry-coupled transducers into concrete, the response can be measured by that array to generate a 2D/3D profile scan that allows for the measurement and mapping of subsurface features such as voids, concrete thickness, and other targets of interest.

By directing an ultrasonic wave from a single transmitter into concrete, the response can be measured by a single receiver, where the configuration of the transmitter and receiver allows for measurement of concrete thickness, concrete continuity, crack depth, and compressive wave speed.

After connecting a test probe to a single exposed point on the steel reinforcement for a section of concrete, a half-cell probe can be used to measure the corrosion potential of the reinforcement through the concrete to generate a map of locations at which steel may be corroding.

By inducing an impact in a given concrete structure, the response can be gathered by an attached accelerometer to measure concrete dimensions, defects, and other features based on the reflections identified in the collected signals. Multiple tests may be taken along a grid to map out variations in dimensions or localize defects.

Using a four-point Wenner probe, the electrical resistivity of the concrete can be measured along test points on a grid to give an indication of possible corrosion taking place at the steel reinforcement.

BDI utilizes a powder sample collection method developed in-house to gather concrete powder samples at varying depths within a concrete slab to measure chloride concentration at each depth to determine their ingress and possible impact on the steel reinforcement.

Hammer sounding and chain drag represent traditional industry standard techniques for surveying concrete by tapping it with a hammer or dragging a chain over it to identify locations with a hollow audible response that indicates delamination.

Visual inspection leverages the expertise and acuity of an experienced technician in evaluating the accessible surface condition of concrete to identify defects and other features of interest. BDI performs this service in line with the standards and definitions laid out by a variety of industry sources (AASHTO MBEI, NBI/SNBI, ACI).