Corrosion protection

Corrosion accompanies almost all work in construction, deconstruction, and the extraction of natural stone. It affects both structures – for example through reinforcement corrosion in concrete – as well as tools and steel attachments used in harsh environments. For Darda GmbH products such as concrete demolition shears, rock and concrete splitters, hydraulic power packs, combination shears, Multi Cutters, steel shears, tank cutters, and rock wedge splitters, a systematic corrosion protection is an essential basis for safety, availability, and service life. In concrete demolition and special deconstruction, during strip-out and cutting, in rock excavation and tunnel construction, in natural stone extraction, and in special operations, moisture, chlorides, CO2, abrasion, and temperature fluctuations act as drivers of corrosion processes. A practical approach to corrosion protection combines knowledge of the mechanisms, suitable protection systems, and consistent maintenance – always tailored to the application profile and environmental conditions. In addition, design-for-drainage, avoidance of capillary gaps, and condition-based inspection programs help translate protection principles into reliable day-to-day practice.

Definition: What is meant by corrosion protection?

Corrosion protection encompasses all measures that prevent or slow the material change and degradation of metallic materials through chemical or electrochemical reactions with the environment. Typical goals include preventing rust on steel surfaces, preserving the passive film on reinforcing steel in concrete, and ensuring the leak-tightness of hydraulic systems. Protection can be achieved through material selection, design detailing, coatings, inhibitory media, cathodic methods, controlled operating conditions, and appropriate storage. In the context of concrete demolition shears, rock and concrete splitters, and other attachments from Darda GmbH, this means protecting surfaces so that they remain functional over the long term despite mechanical loading, moisture, salt, and dust, while also properly accounting for corrosion on load-bearing components of structures when making deconstruction decisions. In practice, effective concepts combine barrier protection, electrochemical control (passivation or sacrificial action), and preventive design to minimize electrolyte contact and stagnation.

Corrosion mechanisms and protection principles

In practice, corrosion usually arises from the interaction of an electrolyte (e.g., water with dissolved salts), oxygen, and a metallic material. Common forms include uniform corrosion, pitting, crevice corrosion, galvanic corrosion (dissimilar metal couples), and stress corrosion cracking. In concrete, reinforcement corrosion results from carbonation (pH reduction due to CO2) or chloride ingress; in plant and deconstruction environments, condensation, salt-laden spray, cavities, damaged coatings, and conductive deposits promote undercutting of protection systems. In addition, erosion-corrosion from abrasive particles and microbiologically influenced corrosion in stagnant or mineral-rich waters may accelerate local attack. High-strength steels can be susceptible to hydrogen effects under certain conditions and therefore require careful system selection.

Protection principles therefore aim to eliminate at least one reaction partner: keep water out, limit oxygen ingress, passivate the material, equalize electrical potentials, or use sacrificial materials. In application, these principles are implemented through proper materials, surface systems, sealing concepts, fluid care, and scheduled maintenance. Typical triggers in daily operation include:

• Electrolyte presence: splash water, condensate, and saline mists
• Coating defects: sharp edges, pinholes, impact damage
• Design traps: crevices, pockets, and blind holes with poor drainage
• Electrical coupling: dissimilar metals without isolation

Corrosion protection for concrete demolition shears and rock and concrete splitters

Concrete demolition shears and rock and concrete splitters operate in contact with moisture, stone dust, aggregates, and – in winter service or coastal climates – with chlorides. At the same time, high point loads and abrasion act on them. This results in a requirement profile: robust base materials, wear-resistant functional edges, well-adhering coatings in less stressed zones, and a design that minimizes water accumulation and dirt traps. Where feasible, generous radii, sealed interfaces, and defined drainage paths reduce electrolyte dwell time and increase coating durability.

Material selection and surface systems

High-strength quenched and tempered steels at cutting edges or splitting wedges provide the necessary strength, while load-bearing structures can be combined with tough fine-grain steels. For corrosion protection, a layered concept has proven effective: areas subject to heavy mechanical loads often remain uncoated and are protected through regular care (cleaning, targeted oiling); adjacent zones receive robust primers and topcoats. Duplex systems consisting of zinc plus an organic topcoat can increase service life in exposed environments. Critical factors include careful edge rounding, suitable surface preparation, and sufficient film thicknesses at geometrically challenging locations. Good practice also encompasses:

• Stripe coats at welds, edges, and fastener heads to boost edge retention
• Compatible systems for touch-up that match hardness and flexibility of the main coating
• Targeted sealing of joints and covers to prevent crevice formation

Hydraulic systems and fluids

Hydraulic power packs, lines, and cylinders are sensitive to moisture, condensate, and fluid aging. Water content in the oil promotes internal corrosion and reduces lubrication performance. Leak-tightness, filtration, regular oil maintenance, corrosion-resistant couplings, and condensate management are therefore key elements. External steel components on cylinders benefit from smooth, well-cleaned surfaces and spot preservation after use. Additional measures such as monitoring particle load and water content, protecting quick couplers with caps, and drying cavities before storage reduce the risk of internal and external corrosion.

Rebar corrosion in concrete and implications for deconstruction

In concrete demolition and special deconstruction, the condition of the reinforcement governs the approach. Carbonation lowers the pH, the passive film collapses, and rusting begins; chlorides from de-icing salts or marine climates can cause pitting. Rust expansion leads to spalling, cracking, and cross-section loss. This affects both structural stability and the choice of demolition method – for example, whether concrete demolition shears should cut the section in a controlled manner or whether rock wedge splitters should expand the concrete without explosives. A structured pre-assessment of cover depth, visible distress, and likely load paths informs sequencing, temporary support, and tool selection.

Carbonation and chlorides

Carbonation progresses depending on concrete quality, moisture, and CO2 content. Chlorides act locally, often in splash zones. Both mechanisms reduce reserve capacity. In practice, this means identifying corroded zones, taking restraint effects and voids into account, and planning the intervention to keep load redistribution under control. Tools such as concrete demolition shears enable cold, low-spark separations in reinforced concrete and support controlled deconstruction when structural stability is limited. Indicative measurements (e.g., carbonation depth or chloride presence at reinforcement level) help set working lines and define exclusion areas.

Deconstruction planning and occupational safety

Corrosion can expose hidden conditions or keep defects concealed. Before starting work, material condition, loss of cross-section, and anchorage locations must be assessed. Corroded reinforcement exhibits sharp fracture surfaces; edge loads and drop edges must be secured. When cutting exposed steels, steel shears and Multi Cutters are options; sparking should be minimized depending on the environment. In general: always plan measures specific to the asset and apply proven methods. Temporary propping, defined cut sequences, and controlled debris handling mitigate the risk of progressive collapse where reinforcement has lost section.

Corrosion in rock excavation, tunnel construction and natural stone extraction

Underground and in quarries, fluctuating humidity, abrasive dusts, and often saline waters prevail. Attachments such as combination shears, rock wedge splitters, and steel shears benefit from protective detailing: protected bearing points, sealed cavities, and drain holes to prevent water pooling. After use, cleaning, drying, and light preservation accelerate dry-back and reduce undercutting. In tunnel atmospheres with elevated chloride or sulfate content, maintenance intervals should be shortened and visual inspections for underfilm corrosion intensified. Where groundwater carries elevated minerals or organic load, deposits and microbiological activity can intensify localized attack – frequent rinsing and prompt removal of residues are advantageous.

Surface preparation and coating systems

The durability of coatings is determined during preparation. The goal is a clean, sound, and sufficiently rough surface. Mechanical loading in service also demands tough, repair-friendly systems. On Darda GmbH attachments, mixed constructions of uncoated functional edges and coated surfaces are common; touch-up coatings should fit the overall system. Environmental conditions during application – substrate temperature, relative humidity, and dew point distance – must be within specification to avoid condensation and poor adhesion.

Preparation steps

• Degreasing: Thoroughly remove oils, greases, and hydraulic fluids to ensure wettability.
• Derusting/roughening: Mechanically clean or blast as required; remove all loose layers completely.
• Edge rounding: Break sharp edges to achieve adequate film thickness at edges.
• Drying: Avoid residual moisture; consider temperature and dew point to prevent condensation.
• Masking/protection: Shield functional interfaces, labels, and precision fits from abrasion and overspray.

Coating selection

• Primer with active anti-corrosion pigment or zinc-bearing: improves barrier and cathodic action.
• Intermediate and topcoat with high abrasion resistance: protects in dusty, mechanically stressed environments.
• Repair systems: easy to apply for partial areas after use; compatible with the existing coating.
• Duplex approach: combine metallic and organic protection mechanisms where possible.
• Stripe coat at edges, welds, and fasteners to reinforce weak spots and reduce early undercutting.

Compliance with specified dry film thicknesses, recoat intervals, and curing conditions is crucial to avoid undercutting and edge rust. Requirements for surface preparation and coating systems should follow recognized state-of-the-art practice. Verification via simple checks – such as surface cleanliness tests, profile assessment, and dry film thickness measurement – increases process reliability.

Corrosion protection during cutting operations on steel and tanks

During strip-out and cutting of steel sections or vessels, wall-thickness reductions caused by corrosion are safety-relevant. Tank cutters and steel shears are selected so that cutting forces and possible residual stresses remain manageable. In preparation, check material condition, connection points, and any residual contents in the vessel. Corroded areas tend to develop unpredictable cracks; therefore, a controlled cutting path and secure support are advisable. Low-spark methods can be advantageous in sensitive environments; suitability must be assessed for the specific asset. For tanks and enclosed items, safe preparation includes cleaning and ventilation, removal of residues, and gas measurement to rule out flammable or toxic atmospheres before starting work.

Material combinations and galvanic corrosion on attachments

When different metals meet in a conductive environment, galvanic corrosion can occur. Typical examples include bolted joints, bearing housings, or repair zones. Protection is achieved through targeted material pairing, electrical isolation (e.g., seals and washers), tightly sealing coatings, and avoiding crevices where electrolytes can stagnate. For hydraulic connectors and couplings, regular inspection of contact surfaces and coating integrity helps. The exposed area ratio matters: a small less noble component coupled to a large more noble partner corrodes faster – isolation and robust sealing are therefore priorities at mixed-metal interfaces.

Maintenance, inspection intervals and storage

Effective corrosion protection relies on routines. Post-use checks, periodic maintenance, and a suitable storage environment prevent consequential damage and ensure the readiness of concrete demolition shears, rock and concrete splitters, and other Darda GmbH tools. Clear intervals, defined acceptance criteria, and traceable documentation support consistent quality over the service life.

Practical measures

1. After use: Remove coarse dirt, rinse with clean water, dry; lightly preserve functional surfaces.
2. Visual inspection: Identify damaged coatings, rust onset, and undercutting and repair promptly.
3. Hydraulic care: Check for leaks, replace filters and oil as specified; monitor water content and particles.
4. Screw and bolt connections: Check for corrosion in clamping areas and contact surfaces; apply torques per specification.
5. Storage: Dry, ventilated, low-condensation; avoid direct floor contact and water ponding.
6. Documentation: Record maintenance, coating repairs, and inspections in a traceable manner.
7. Seasonal lay-up: For extended idle periods, clean, dry, preserve, cover, and rotate moving parts at intervals to prevent sticking and hidden corrosion.

Environmental and sustainability aspects

Corrosion protection and environmental protection can be aligned: durable systems reduce maintenance, and proper cleaning minimizes the introduction of dusts and old coatings into the environment. When selecting cleaning and coating materials, ensure proper application and compliance with applicable environmental and occupational safety requirements. Seals and containment during cleaning and coating prevent particles and fluids from entering soil or water bodies. Preference for low-VOC or waterborne systems, segregated waste handling, and reuse of wash media where feasible contribute to resource efficiency without compromising protection goals.

Documentation and condition assessment

A structured condition assessment helps identify corrosion risks early: condition classes for surfaces, defined inspection points at exposed locations, photo documentation, and clear criteria for repairs create transparency. For structures, non-destructive testing methods and indicative measurements (e.g., carbonation depth or chloride content) support deconstruction planning. For attachments, recurring inspections provide reliable data to proactively plan maintenance windows, spare parts needs, and protection measures. Trend analyses across inspection cycles and a concise defect taxonomy (location, type, severity) enable focused remediation and measurable improvement of availability and lifecycle cost.