Thickness Measurement

A common problem in construction is to determine the constructed thickness of concrete sections where only one face is exposed. This is easily evaluated by impact-echo technology. The thickness of a concrete section can be determined up to a depth of approximately 6 feet (2 meters). Our company has used this technique to nondestructively determine the construction thickness of many types of structural members including concrete pavements, sidewalks, retaining walls, basement walls, shaft liners, below grade tanks and above ground shotcrete structures.

Concrete Delamination

When embedded reinforcing steel corrodes, it results in expansive forces which separates the concrete surrounding the reinforcing steel in a process known as delamination. Where the concrete surface is exposed, shallow delamination can readily be detected visually or by dragging a chain across it's surface. However, where the delamination crack is deep, or where there is an overlay over the concrete surface, it is not so easily identified. Under these circumstances, impact-echo technology is an ideal instrument to use since it is able to detect delamination cracks over one meter below the surface of the concrete, even when covered by an asphalt overlay. This characteristic of impact-echo signals has been successfully used to determine delamination of asphalt covered bridge decks and parking garage slabs, retaining walls and water retaining structures.

Crack Profile Measurement

The precision and small footprint of the impact-echo signal enables the tracing of the profile of a crack. Accurate data can be obtained of the crack depths by completing tests at narrow intervals. This technique can also be used after crack injection to verify proper filling of the crack.

Detection of Internal Defects

Impact-echo signals are not significantly distorted by the presence of well bonded reinforcing steel. However at locations where small defects are present within the concrete, for example at small pockets of air or where corrosion is initiating cracking
around the reinforcing steel, characteristic signals are produced which are readily identified by trained impact-echo technologists

Chemical Attack &  Frost Damage

Measuring the reduction of section thickness due to degradation is another common structural problem which can be assessed by impact-echo testing. Chemical and sulphate attack on the back face of underground structures has been successfully measured by our company. In a similar manner, the extent of deterioration of the back face of structural members due to freezing and thawing