Olson Slab Impulse Response

The method is excellent for evaluating the repair of slab sub-grade support conditions by comparing the support conditions before and after repair

The Slab IR test method can also be used on concrete structures to quickly locate areas of de-lamination or void 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 elements that can be tested include, concrete slabs, pavements, runways, spillways, pond and pool bottoms, and tunnel liners. The Slab IR method is often used in conjunction with GPR for sub-grade void detection and mapping. Testing can locate:

• Erosion beneath concrete slabs in highways, spillways and floors
• Curling of plates
• Anchoring of panels
• De-laminations and honeycombing in bridge decks, slabs, walls and large structures such as dams, chimney stacks and silos
• Freeze-thaw damage
• Presence of Alkali–silica reaction
• De-bonding of asphalt, concrete overlays and patches from concrete substrates
• Quality of stress transfer through load transfer systems across joints in concrete structures

Access

The Slab IR method requires access to the top surface for receiver locations and hammer hitting. The receiver is mounted to the surface of the slab adjacent to the impact location and generally 10-15 cm away. In easy access areas, 400-600 Slab IR tests can be performed in an 8 hour work day.

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