Corrosion test refers to the systematic examination of metals and metallic components for corrosion damage, rate, and causes. In the context of concrete demolition, rock excavation, gutting works, and cutting operations, it provides robust decision-making bases: for the structural analysis of corroded reinforcement in concrete, for selecting and safely operating concrete demolition shears, hydraulic rock and concrete splitters, as well as for condition-based maintenance of hydraulic power units, steel shears, tank cutters, combination shears, multi cutters, and stone splitting cylinders.
Definition: What is meant by corrosion test
Corrosion test encompasses methods and procedures for assessing materials and components regarding their susceptibility to different types of corrosion. The goal is condition assessment, root cause analysis, and forecast of further material degradation. In practice, visual, mechanical, electrochemical, and non-destructive tests are combined to detect, for example, pitting, crevice corrosion, galvanic couples, underfilm corrosion, stress corrosion cracking, as well as corrosion-related cross-section losses and crack networks. In concrete structures, this often concerns reinforcement and built-in components; for equipment and tools, the focus is on load-bearing structures, hydraulic components, sealing and connection elements.
Relevance in concrete demolition and special deconstruction
Corrosion dictates the approach in many projects: corroded reinforcement affects load transfer in concrete and thus the safe use of concrete demolition shears or similar tools in selective deconstruction. In humid, chloride-laden environments (for example, in parking structures, wastewater treatment plants, or tunnels) advanced reinforcement corrosion and spalling occur, influencing the choice of separation method and the opening sequence during gutting works and cutting. In rock excavation and tunneling, humid air, splash water, and dust impact steel components of rock and concrete splitters; regular corrosion tests ensure the functionality of cylinders, pins, grippers, cutting edges, and hydraulic connections.
Typical test methods and measured variables
In practice, procedures are combined according to their suitability for the material, component, and environment. Key measured variables are corrosion potential, corrosion current density, coating thicknesses, remaining cross-section, surface roughness depth, crack indications, as well as environmental parameters such as pH value, chloride content, and moisture content.
Visual and mechanical examinations
- Visual inspection with magnifiers/endoscopes to detect rust nests, underfilm corrosion, spalling, and crack indications.
- Mechanical thickness measurements, inspection grinds on replaceable wear parts (e.g., cutting edges, jaws), comparison with wear limits.
- Coating thickness measurement on steel components; adhesion testing (e.g., cross-cut) for protection systems.
Electrochemical methods on steel and reinforcement
- Corrosion potential measurement (for example, half-cell method) to localize active areas in concrete components.
- Linear polarization resistance to estimate the corrosion rate.
- Electrochemical impedance spectroscopy to assess coatings and passive layers.
Non-destructive testing (NDT)
- Ultrasonic testing, eddy current, magnetic particle, and dye penetrant testing for crack and defect detection on steel components, scissor arms, shear blades, and adapter plates.
- Concrete-specific: potential mapping, concrete cover measurement, chloride analysis, and carbonation depth to evaluate reinforcement corrosion.
Laboratory and environmental simulation tests
- Salt spray/salt fog tests and cyclic corrosion tests for comparative evaluation of protection systems.
- Condensation and humidity cycling tests for housings, couplings, and electrical components of hydraulic power packs.
Corrosion types and damage patterns in practice
Corrosion rarely occurs in isolation. Frequently, uniform material loss overlaps with pitting at edges, crevice corrosion in joints, as well as galvanic corrosion between dissimilar metals (e.g., stainless steel insert and unalloyed steel). Tanks that still contain combustible media may be thinned internally by media corrosion; wall thickness must be verified before using tank cutters. In concrete demolition shears, corrosion-assisted microcracks often appear at highly loaded pivot points, growing due to recurrent load cycles. Rock and concrete splitters are prone to corrosion under deposits at piston rods and lines when moisture and dust coincide.
Specific requirements for tools and components
The corrosion test is tailored to the function, material, and loading of the tools. Inspection intervals are pragmatically adapted to operating hours, media contact, and place of use.
Concrete demolition shears: focus areas of the inspection
- Bearings, pins, and bushings: dimensional accuracy, crack indications, corrosion burrs; check lubrication condition.
- Shear and breaking jaws: remaining cutting length, chipping, underfilm corrosion beneath wear protection plates.
- Hydraulics: inspect lines, couplings, and cylinder heads for rust, weeping points, contact corrosion, and underfilm paint corrosion.
Rock and concrete splitters: hydraulics and cylinders
- Piston rods: surface condition, scoring, pitting; condition of sealing lips.
- Splitting wedges and springs: corrosion notches and dimensional accuracy, especially after contact with moist drill cuttings.
- Distributor blocks and power packs: condensate formation, brackets, protective caps; check electrical plug connections for corrosion.
Other tools in deconstruction
- Steel shears and multi cutters: crack testing on shear blades, pitting at cutting edges, fastening bolts.
- Combination shears: transitions between material pairings; minimize galvanic couples.
- Tank cutters: wall thickness measurement and media-induced internal corrosion; atmospheric external corrosion under insulation.
Influencing factors: environment, media, and operating profile
Corrosion progression strongly depends on climate and use. High humidity, chlorides (de-icing salt, marine proximity), sulfates, CO₂-induced carbonation of concrete, temperature fluctuations, and abrasive dusts increase the risk. In tunneling, condensate and aerosols promote coating underfilm corrosion; in natural stone quarries, rain, mud, and UV radiation act. In special applications with chemical media, chemical resistance must also be considered.
Test planning, documentation, and condition assessment
A robust corrosion test follows a structured plan with clear inspection points, evaluation criteria, and documentation.
- Define objectives: structural stability, functional safety, maintenance needs, remaining service life.
- Select methods: a combination of visual, NDT, and electrochemical methods, adapted to the component and accessibility.
- Measurement strategy: grid, reference points, repeatability; record environmental parameters.
- Evaluation: classify into condition categories, define measures (continued operation, repair, replacement).
- Documentation: photo records, measurement logs, test reports, and recommendations for inspection intervals.
Normative and technical foundations
There are recognized standards and guidelines for corrosion tests and corrosion protection, for example, rule sets on terminology, salt spray and cyclic tests, qualification of NDT personnel, concrete technology and repair, as well as coating systems for steel surfaces. The exact application varies depending on the project, component, and national regulations. Tests should always be expertly planned and executed.
Relation to areas of application: practical examples
Concrete demolition and special deconstruction
Before separating load-bearing components, corrosion mapping of reinforcement provides indications of cross-section losses and potential unexpected load redistributions. This influences gripping and cutting strategies of concrete demolition shears as well as the sequence of cuts.
Gutting works and cutting
In existing buildings with moisture damage, reinforcement can be locally heavily corroded. NDT and potential measurements help identify critical zones. At cutting tools, bearings and hydraulics are checked in parallel for signs of corrosion to avoid failures during ongoing operations.
Rock excavation and tunneling
Humid, saline aerosols accelerate corrosion on exposed steel parts. Regular inspections on rock and concrete splitters, especially on piston rods, fastenings, and protective caps, stabilize operational safety.
Natural stone extraction
Mud and mineral dusts promote crevice corrosion in joints. Cleaning and visual inspection intervals should be adjusted accordingly; replaceable wear parts are evaluated against defined limits.
Special operations
For work on tanks and systems with chemical pre-exposure, internal media corrosion must be expected. Wall thicknesses must be verified before separation work, and potential ignition sources minimized; tests are performed cautiously and adapted to the media.
Prevention, maintenance, and inspection intervals
Corrosion can be significantly slowed by coordinated measures. The combination of suitable protection, proper application, and regular inspection is decisive.
- Surface protection: coatings, galvanic protection systems, suitable material pairings; treat edges and joints with particular care.
- Design protection: avoid water traps, provide run-off and drip edges, covers for exposure phases.
- Operation: cleaning after deployments in saline/muddy environments; drying, preservative lubrication at bearings.
- Hydraulics: media cleanliness, water content, filtration; use corrosion inhibitors as approved.
- Inspection intervals: stagger by operating hours and exposure; initially shorter, later extended or shortened based on condition.
Safety and responsibility
Corrosion test serves hazard prevention and health protection. Results flow into work and assembly instructions and support the selection of suitable tools, such as concrete demolition shears or rock and concrete splitters, for the specific component and environment. Legal requirements may vary by country and project; inspection and maintenance obligations must be observed carefully. Statements in this contribution are of a general nature and do not replace individual assessment.