Identifies damage to the concrete surface. Drummy concrete is typically identified by striking the surface with a hammer and listening for a distinct hollow sound. The hollow sound is a result of the concrete delaminating from the rest of the structure, typically a result of the reinforcement corroding.
Visual assessment of concrete, steel and timber structural elements. Areas of note for concrete elements include joints, cracking, previous repairs and areas of seepage. While steel members include corrosion, protective coating breakdowns, missing members and bolts, non-compliant modifications, cracked welds & loose connections.
Concrete Compressive Strength Measurements
Using a Schmidt hammer also known as a rebound hammer, the concretes compressive strength at the surface is measured.
Locations of leaks and seepage are recorded as it is important to plan for their rectification. Leaks and seepage left unattended will continue to develop resulting in substantial and costly damage.
Concrete Cover Measurements
Concrete cover is the depth of concrete to the reinforcement and is generally measured using a cover meter. The cover meter allows for non-destructive readings of cover to the reinforcement and can also be used for bar layout mapping.
Chloride Ion Survey
Reinforcement within concrete is protected from corrosion by a passive layer which forms around the bar once concrete is placed and cured. Over time chlorides make their way through the porous matrix of concrete and when the chlorides reach the bar the passive layer is breached. This results in the onset of corrosion to the reinforcement. The chloride ion survey gives an indication of the depth the chlorides have penetrated into the concrete. The survey, in conjunction with other test results is useful for identifying root cause of damage, predict future damage locations and time frames. It is also key to identifying the appropriate repair or preventative works program to implement.
Concrete carbonation is where carbon dioxide (CO2) reacts with concrete causing a loss of alkalinity in the concrete and subsequently corrosion of the reinforcement. The process is initiated at the surface and slowly penetrates the cover concrete, eventually reaching the reinforcement. At this point the reinforcements protective passive layer is broken down and corrosion can initiate.
Electrical Potential Survey
The Electrical Potential (EP) survey is used to determine the corrosion state of reinforcement and other steel within concrete structures. Readings are taken on the surface of visually sound concrete using specialist testing equipment. The data gathered, in conjunction with other test results is then used to provide an indication of the corrosion activity, service life estimation and can also be used to confirm CP systems are functioning correctly.
Continuity of the reinforcement is a prerequisite for the effective implementation of cathodic protection. The survey is completed to confirm all reinforcing steel that is to be protected by the system is electrically continuous.
Concrete Resistivity Measurements
Concrete electrical resistivity is obtained by applying a current to the surface of the concrete element and measuring the response voltage. Several methods are available for measuring concrete resistivity, but in the field a system of four probes is setup in a Wenner array. Concrete resistivity measurements assist in the determination of service life estimation and cathodic protection effectiveness.
Using ultrasonic inspection equipment, thickness of steel can be measured to determine accurate section loss to corroded members.
Dry Film Thickness gauge
This is another type of ultrasonic inspection equipment, but more typically used to determine the thickness of protective coatings.
Non Destructive Evaluation
Visual inspections may identify at risk structural elements that require specialist inspection. Magnetic Particle Testing, Ultrasonic Testing, Radiographic Testing and Die Penetrant Testing (MPI, UT, RT, PT) can be used to detect internal or external flaws, to measure geometric characteristics, to determine material structure or composition or to measure or detect some of the material’s properties.
Timber Micro Drilling / Boring
Exploratory boring is used to identify the presence and type of decay and to estimate the remaining sound timber.