s’MASH uses a low-strain impact, produced by an instrumented rubber tipped hammer, to send stress waves through the tested element and make it vibrate in a bending mode while a velocity geophone transducer measures the amplitude of the response. The ratio of the resultant spectrums, velocity and impact force, gives the mobility as a function of frequency. The software processes the information into 4 parameters (average mobility, mobility slope, dynamic stiffness and void index) presented with contour plots that are used for integrity evaluation of the test area.
Applications
• Detecting voids beneath concrete slabs.
• Detecting curling of slabs on ground.
• Locating delaminations and honeycombing in bridge decks, slabs, walls and large structures such as dams, chimney stacks, and silos.
• Detecting the presence of damage due to freezing and thawing.
• Detecting the presence of alkali-silica reaction (ASR).
• Detecting debonding of asphalt or concrete overlays and repair patches from concrete substrates.
• Evaluating the integrity of anchoring systems of wall panels.
• Evaluating the effectiveness of the load transfer system in transmitting frorces across joints in concrete structures.
Specifications
- Data Acquisition System:
-
- 2 channels, 4 MB/channel
- 8 bits resolution, 50 MHz bandwidth
- -5V to 5V Input Voltage Range
- USB interface
- Omni-directional (360o) dry contact geophone transducer
- Electric impact hammer with external force sensor
- Windows OS based s’MASH software for real-time waveform displaying and creation of contour plots for visual representation of average mobility, mobility slope, dynamic stiffness and voids ratio
- Operating conditions: Temperature: -10 to 50 °C, RH ≤ 95 %
Standard
ASTM C1740, “Standard Practice for Evaluating the Condition of Concrete Plates Using the Impulse-Response Method.”