Slab Impulse Response

The Slab Impulse Response method is excellent for evaluating the condition of slab subgrade support.

The Slab Impulse Response (SIR) system is designed to identify subgrade voids below slabs-on-grade less than two feet thick. In addition, the Slab IR test method can be used on other concrete structures to quickly locate areas with delaminations or voids in the concrete, if the damage is relatively shallow. Slab IR can be performed on reinforced and non-reinforced concrete slabs as well as asphalt or asphalt-overlay slabs.

The Slab IR testing method is often used in conjunction with GPR for subgrade void detection and mapping. Collecting Slab IR data at multiple, densely spaced locations can improve the conclusions by mapping relative areas of higher and lower mobility. Relatively low mobility (velocity/force) and flexibility (displacement/force) qualitatively indicates that such an area appears to be more solidly supported than an area with relatively high mobility and flexibility.

Data Platform Required, Sold Separately

Freedom Data PC
NDE-DAQ Platform NDE-DAQ
NDE 360 NDE 360
Applicable On:
  • Concrete Slabs
  • Pavements
  • Pool Bottoms
  • Pond Bottoms
  • Runways
  • Spillways
  • Tunnel Liners
Test For:
  • Delaminations in Decks
  • Soft, Weak Subgrade Support
  • Voids below Slabs/Tunnel Linings
Meets ASTM:
  • N/A
Meets ACI:
  • ACI 228.2R

Key Features & Specifications

System is compact, durable, and easily transported allowing for up to 600 tests per day Real-time waveform display while testing
Short learning curve for data acquisition and basic processing 2-D maps are easily generated from data by exporting the tables from Olson's WinSIR software into Excel
English or Metric units can be used Can be performed on reinforced and non-reinforced concrete slabs as well as asphalt or asphalt-overlay slabs

Hands-on training is available for all of our NDE test methods at our Wheat Ridge, Colorado (USA) location, which is a suburb located approximately 15 minutes northwest of downtown Denver. Training may be available at your location by one of our agents/engineers upon special arrangement.


Save money! Contact Olson when adding on to an existing system, or purchasing multiple systems as some of the components are common to other test methods.

For complete details about any of our products, call our toll free number at 1-888-423-1214 or email Olson Instruments: