Resistivity survey
Concrete surface resistivity measurement provides extremely useful information about the state of a concrete structure. Not only has it been proven to be directly linked to the likelihood of corrosion and the corrosion rate, recent studies have shown that there is a direct correlation between resistivity and chloride diffusion rate, and even to determination of early compressive strength. This makes it one of the most versatile NDT methods for concrete.
Our surveyors use Proceq's Resipod device which is a fully integrated 4-point Wenner probe, designed to measure the electrical resistivity of concrete in a completely non-destructive test. It is the most accurate instrument with the highest resolution available, extremely fast, stable and packaged in a robust, waterproof housing designed to operate in a demanding site environment. The Resipod is available with 1.5" (compliant with the AASHTO standard) or 50 mm probe spacing and is the successor of the classic CNS Farnell Resistivity Meter. This specialist equipment is designed to:
- Estimate the likelihood of corrosion
- Indicate the corrosion rate
- Identify the correlation to chloride permeability
- Provide on site assessment of curing efficiency
- Determine zonal requirements for cathodic protection systems
- Identify wet and dry areas in a concrete structure
- Indicate variations in the water/cement ratios within a concrete structure
- Identify areas within a structure most susceptible to chloride penetration
- Identify the correlation to early compressive strength and to water permeability of rock
