There are multiple methods for the repair, maintenance and protection of concrete structures. The correct choice of application, products and methodology can be complex, but the right selection is fundamental to the project success, both financially and from a safety perspective. A structural asset condition survey provides valuable insight into how to proceed with a concrete repair plan.
Condition surveys are essential to understand the nature and extent of deterioration, materials and conditions of a concrete structure before starting a repair project.
Site owners have a multitude of factors influencing their concrete repair and protection strategy – from no action at all, to protection only, to partial refurbishment or even full reconstruction. A requirement of BS EN 1504, an adequate concrete survey enables the most appropriate, cost-effective and long-lasting solution to be chosen.
As members of the Concrete Repair Association, we understand the value that a correctly-implemented survey can bring to a project, allowing us to correctly outline our findings and present the best repair strategy option to client before planning and execution.
As a minimum, a structural asset survey should include reporting on:
Along with other methodology, a concrete condition survey could typically include the following tests and techniques.
Logging of all defects visually is key, using a systematic and standardised system, to identify both the extent and the likely cause of the defects. The visual survey often gives the first clues as to the extent of concrete damage and condition and should always be carried out by an experienced concrete inspector, with certain signs and clues they are trained to spot. A trained professional’s eye can spot the degree of concrete spalling, for example, and equate this to how long the structure may have been subject to deterioration. Close inspection of cracks, corrosion and other evidence of concrete damage will all be logged at this stage to give a picture of the concrete condition. A visual survey can be used to create a Bill of Quantities, in line with guidance from the Concrete Repair Association.
Cover Meter Survey
A cover meter survey measures the covering of concrete over the steel frame. This can be done using electromagnetic devices to assess bar sizes and locations and discover where areas of insufficient concrete cover exist.
Whether concrete corrosion is due to chloride contamination or carbonation will dictate how the concrete should be repaired. It is consequently important to distinguish the corrosion source. Carbonation pH testing can be used to evaluate the alkalinity of concrete samples, where a lower level would indicate carbonation and the risk of depassivation of reinforcement.
Concrete Resistivity Measurement
Electrical resistivity can inform an inspector of the level of corrosion depending on the results given on moisture and pore volume within the concrete, typically through a four-probe meter for increased accuracy.
Similar to carbonation, testing for chlorides consists of sampling the concrete at key points and testing for the presence of chlorides, which are a key catalyst in corrosion of steel-enforced structures.
Used to assess sub-surface cracking due to reinforcement corrosion, this element of inspection allows for the identification of planar fractures, which often supersede more extensive concrete damage and corrosion within steel-enforced concrete structures. Ultrasonics, radar or simply a hammer test are used to identify hollow-sounding sections of the concrete.
Other methodology such as half-cell potential surveys, petrographic examination and general concrete sampling will also play a part in a comprehensive inspection process.
Following the survey, you should receive a detailed report, outlining all defects and results of concrete condition observations, testing and analysis.
The report will also identify the repair options available to you, along with the recommendation for which should be implemented, any associated budgets and timings, material specifications, Bill of Quantities and a Schedule of Rates. If any make-safe works were implemented during the survey phase then these will also be included.
All of this detail should be included to allow the site owner to make a quick determination in selecting the appropriate schedule of repair work.
Only fully-qualified and professional teams should carry out a structural asset condition survey. Years of experience can provide vital, enhanced ability to decipher visual clues and testing results, which can fundamentally change the recommended route of repair and ongoing protection.
The survey may also require lab testing and/or offsite diagnosis for accurate diagnosis of damage and causes.
At CSC Services not only can we complete your structural asset condition survey, we can also carry out the specified concrete repair and protection schedule of work. With over 20 years at the forefront of concrete repair across a range of industries, our operatives are members of the CRA and hold all the required accreditations to ensure a reliable, cost-effective and, above all, safe programme of work on your site.
Our service offering includes the following core services, meaning a one-stop shop for your condition survey and recommended programme of concrete repair and protection work. Condition surveys can be built in and negotiated into schedules of work, which can save time and costs for the overall project.