NONDESTRUCTIVE TESTING
Nondestructive Testing (NDT) methods are used to characterize concrete properties and to evaluate the condition of concrete structures. Durability Engineers uses NDT methods for quality control of new construction, assessment of new and existing structures, and evaluations of structures for rehabilitation.
GROUND PENETRATING RADAR
GPR
Durability Engineers utilizes ground penetrating radar (GPR) for assessments of as-built conditions. Capable of identifying presence and location of reinforcing steel, verifying member thickness, and identifying inclusions and voids below the concrete surface, GRP provides rapid, real-time information requiring minimal calibration and delays.
GPR may be used in the field to:
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Locate Reinforcing Steel, Conduits and Tendons
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Estimate As-Built Conditions such as Member Dimensions and Cover Depth
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Locate Voids and Discontinuities
IMPULSE RESPONSE
IR
Impulse Response (IR) is a particularly effective technique for investigating plate-like elements containing construction defects, voids and poor consolidation. Structures with access restrictions or limitations on invasive drilling required for calibration with other forms of NDT benefit from this testing technique.
IR is performed in general accordance with ASTM C1740, "Standard Practice for Evaluating the Condition of Concrete Plates Using the Impulse-Response Method" and may be used to establish concrete properties such as:
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Relative Strength
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Delaminations
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Underlayment Support
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Cold Joints
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Voids
ULTRASONIC PULSE VELOCITY
UPV
In instances where concrete elements have concerns for poor consolidation or large voids, Durability Engineers can instrument the sections through ultrasonic pulse velocity (UPV) to identify problem areas throughout the member in question.
UPV is performed in general accordance with ASTM C597, "Standard Test Method for Pulse Velocity Through Concrete," and is often used for identifying various issues, including but not limited to:
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Relative Strength
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Cracks and Crack Depth
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Concrete Consolidation
PHASE ARRAY TOMOGRAPHY
UST
The phased array tomography technique utilizes a grid of transducers, where each signal response is interpreted through the synthetic aperture focusing technique (SAFT)3
Durability Engineers employs UST for investigations on large concrete structures to investigate various issues, including but not limited to:
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In-Situ Strength
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Dying & Plastic Shrinkage
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Delamination
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Blitering
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Scaling
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Mixture Compliance
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Poor Consolidation
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Honeycoming / Small Voids
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SURFACE RESISTIVITY, HALF-CELL & CORROSION RATE
CORROSION ANALYSIS
Durability Engineers complements its extensive NDE suite through its capabilities in the investigation and assessment of structural reinforcing steel via half-cell, resistivity and corrosion rate equipment in order to determine the current and potential corrosion of existing reinforcing steel.
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Chemically Unstable Minerals
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Volumetrically Unstable Materials
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Staining & Surface Color Change
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Materials Susceptible to Deicers
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Freeze-Thaw Susceptibility
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Aesthetic Changes due to Weathering
PROJECTS
This past year, Durability Engineers was brought onto a project to assess the strength of an existing concrete structure. Our team assessed the in-situ strength, determined the as-built conditions of the structure, potential for corrosion, and extracted cores to identify durability controlling factors.
Through our site evaluation efforts, Durability Engineers was able to assess the structure's service life and develop an appropriate repair remotely, through the aid of the additional information collected in the field. Our additional efforts helped streamline the repair process and provide the client with peace of mind the the new modifications will be able to continue maintaining the future integrity and serviceability of the structure.
