MUENOW & ASSOCIATES
Structural Engineers utilizing Non-Destructive
Testing Techiniques
Test Techniques Utilized
Pulse Echo
Purpose:
Detects, delineates, and classifies internal discontinuities in
concrete, asphalt, soil, and wood.
Test Theory:
- Pulse Echo is a relatively low frequency test technique that generates
data when changes in material density are encountered by the propagation and reflected
energy of mechanical stress waves. Pulse Echo is a single transducer test system only
requiring one surface of the structural member to be accessible. Evaluations have been
conducted on a wide range of thicknesses, ranging from 1.5 inches (Such as Overlays) to
375 feet (as in Hydroelectric Structures and Foundation Piles).
Typical Applications Include:
Concrete:
- Compressive Strength
- Thickness of Member
- Voids Beneath Pavements and Slabs
- Honeycombing
- Crack Detection, Orientation, and Width
- Cold Joint Detection and Location
- Epoxy Repair Evaluation
- Internal Void Detection
- Overlay Bonding
- Pile Quality and Length
- Repair Evaluation
Wood:
- Centerline Rot
- Presence of Infestation
- Checking
- General Quality
- Pile Evaluation and Quality
Granite and Marble:
- Uniformity
- Detioration
- Anchors
- Granular Adhesion
Soil:
Asphalt:
- Density
- Thickness
- Uniformity
- Depth of Sub-Base
Impulse Radar
Purpose:
- Evaluates the presence and location of reinforcement steel in concrete
members. Locates any metallic embeddment in concrete. Determines the thickness of concrete
slabs and overlays. Detects the presence and defines the extent of voids under slabs and
roadways.
Test Theory:
- Impulse Radar is a high frequency testing technique which generates data
by the propagation and reflected energy of electromagnetic waves. Changes in concrete
density and material dielectric values can be correlated to internal discontinuities and
material variations.
- Impulse Radar is a single transducer system. This system ranges from a
hand-held instrument that locates reinforcement steel to test instruments that are towed
behind equipment at 15 mph to detect voids under pavements and airport runways.
Other Applications Include:
- Pipeline Location
- Tunnel Surveys
- Landfill Studies
- Buried Drum Detection
- Shallow Seismic Surveys
- Concrete and Asphalt Thickness
- Bridge Deck Evaluations
- Roofing Inspection
- Archaeological Surveys
- Rail Bed Surveys
- Rip Rap Surveys
- Lake and River Profiling
- Mine Detection
- Void Detection Under Pavements
Pulse Velocity:
Purpose:
- Evaluates concrete quality, uniformity, and in situ compressive strength
relative to established standards.
Test Theory:
- Pulse Velocity is a through transmission, double transducer testing
technique that utilizes low frequency stress waves to evaluate in situ concrete. Repeated
pulses of stress waves are introduced to one side of the member. These pulses pass through
the member and are received by a second transducer on the opposite face of the member.
Propagation times, amplitude, frequency, and rise times characteristic for the wave action
are recorded for each test location. From the recorded data, comparative compressive
strengths are calculated, while crack presence and orientation are estimated as well. In
addition, crack width determinations can be made as well. The measure of pulse velocity is
correlated to concrete quality and uniformity.
- There are virtually no size limitations to structural members for
evaluation. Two opposite surfaces of the member must be accessible and the member
thickness must be known.
MAAI Background
º Test Techniques I º Test Techniques II º Problem To Technique Guide
º Job References
Muenow and Associates ° Charleston, SC, USA ° 1-843-768-2314
muenowr@bellsouth.net