Understand the survey
Concrete scanning and GPR glossary
Definitions of GPR, concrete scanning, rebar, cover, voids, delamination and corrosion mapping. Understand your concrete investigation.
- Ground-penetrating radar (GPR)
- An instrument that emits electromagnetic waves and records reflections to help locate embedded items, subject to survey conditions.
- Concrete scanning
- A GPR survey of concrete to help locate embedded objects before coring, cutting, drilling or anchoring.
- Slab scanning
- Concrete scanning applied to a ground-supported or structural slab, often before an opening is made.
- Structural assessment
- Evaluation of a structure using observations and appropriate tests that can inform an engineer’s investigation.
- Concrete assessment
- A common term for structural assessment applied to concrete elements.
- Rebar
- A steel reinforcing bar embedded in concrete, notably to resist tension. Surveys may document its position and estimated depth.
- Concrete cover
- The concrete thickness between the surface and reinforcing steel. GPR estimates depend on data quality.
- Post-tensioning
- A technique in which tendons are tensioned after concrete placement. Work must account for tendon locations and structural requirements.
- Conduit
- A metal or non-metal sleeve for wires or cables. Detectability depends on diameter, contents, depth and contrast with concrete.
- Radiant floor heating
- Heating pipes or cables integrated into a floor; their presence must be considered before drilling.
- Void beneath a slab
- A cavity between a ground-supported slab and its support. Surveys can seek indications, with confirmation as needed.
- Delamination
- An internal separation in concrete, often parallel to its surface.
- Honeycombing
- Concrete with voids between aggregates. A signal anomaly alone may not confirm this condition.
- Corrosion mapping
- A mapped representation of measurements and observations related to reinforcement corrosion, interpreted with the method’s limitations.
- Half-cell potential
- Electrical potential measurements used to investigate reinforcement corrosion activity. Circuit and measurement conditions influence results.
- Chlorides
- Salts that can enter concrete and contribute to reinforcement corrosion; samples can be analysed for chloride content.
- Carbonation
- A reaction with atmospheric carbon dioxide that lowers concrete pH and can affect the protection of reinforcing steel.
- Coring
- Cylindrical sampling or drilling of concrete. Embedded items and structural requirements must be considered first.
- Concrete cutting
- Cutting an opening in a slab or wall. Preliminary investigation helps plan the work.
- Non-destructive testing (NDT)
- A method intended to investigate a structure while limiting damage; some techniques require preparation or local access.
- ASTM D6432
- An ASTM guide addressing surface ground-penetrating radar for subsurface investigation.
- ACI 228.2R
- An American Concrete Institute report on non-destructive evaluation of concrete in structures.