Edge protection in construction, deconstruction, and stone processing refers to all measures that protect edges and edge zones of components made of concrete, reinforced concrete, masonry, or natural stone against spalling, edge breakage, uncontrolled cracking, and secondary damage. It is a central component of a component-friendly and low-emission workflow—especially where hydraulic demolition and separation tools such as concrete demolition shears or hydraulic rock and concrete splitters are used. Edge protection equally serves the preservation of adjacent components, safety at the workplace, and the quality of the outcome.
Definition: What is meant by edge protection
Edge protection is understood as the planning and practical bundle of precautions to specifically stabilize and preserve the edge areas and edge zones of a component or block. These include:
- constructive measures (e.g., sufficient edge distances, temporary shoring, chamfers),
- procedural measures (e.g., sequence of work, force-controlled tool guidance, pre- and post-processing),
- mechanical protective means (e.g., protective strips, elastic pads, coverings, splash protection),
- quality-assurance measures (e.g., visual inspection, measurement, documentation).
In the context of controlled deconstruction with hydraulic tools, edge protection particularly means controlling the introduction of forces, vibrations, and wedge effects so that component edges do not break out unintentionally and adjacent structures remain intact.
Objectives and fields of application of edge protection
Edge protection pursues three main objectives: component preservation, safety, and quality. It is used in all application areas where powerful yet controlled methods are employed:
Concrete demolition and special deconstruction
During selective separation of concrete components, edge-protective measures prevent spalling at visible edges, reduce secondary damage in adjacent fields, and minimize rework. Concrete demolition shears, combination shears, and multi cutters are then preferably guided so that forces are introduced into zones with sufficient load-bearing capacity. These practices align with concrete demolition and special deconstruction.
Strip-out and cutting
When sawing, drilling, and separating, pre-cuts, chamfers, and load relief during the cut are crucial to avoid edge breakouts. Mechanical coverings prevent flaking at edges and retain chips.
Rock demolition and tunnel construction
In rock and for natural stone blocks, defined drilling patterns, controlled splitting sequences, and intermediate shoring ensure edge stability. Stone and concrete splitters as well as stone splitting cylinders are planned with regard to edge distances and rock joints.
Natural stone extraction
Clean fracture edges increase yield. Here, edge protection means guiding the break along preferred lines, maintaining minimum distances to the block edge, and avoiding constraint.
Special applications
In sensitive environments—such as existing load-bearing structures, tanks, or plants—procedural edge protection concepts take center stage: low vibration, controlled force peaks, and effective shielding.
Material and edge zone behavior: Why edges are particularly sensitive
Edge zones are more brittle due to geometry and material behavior and are more susceptible to tensile stresses. Stresses concentrate at sharp edges; microcracks can quickly develop into spalling under excessive point load. In concrete, compressive strength, aggregate, moisture, reinforcement layout, and age influence edge stability; in natural stone, joints, texture, and grain bonding are decisive. Edge protection reduces local stress peaks, distributes loads over larger areas, and limits dynamic effects.
Methods of edge protection in practice
Constructive edge protection
- Maintain minimum edge distances for drilling, splitting wedges, and gripping points.
- Temporary chamfers or scoring of the edge before separation to prevent spalling.
- Shoring, packing, and load bedding under edges and cantilevers.
Mechanical edge protection
- Elastic protective strips, hardwood or rubber buffers at tool bearing points.
- Coverings made of robust fabrics or boards to bind splinters.
- Splash protection to control water, slurry, and fine particles at cut edges.
Procedural edge protection
- Build up forces slowly; pre-tension instead of loading abruptly.
- Sequence work from the load-bearing field toward the edge rather than the reverse.
- Use small step lengths; perform separation or splitting in stages.
Edge protection with concrete demolition shears: procedure and settings
Concrete demolition shears enable controlled “biting off” of concrete structures. Edge protection here begins with the selection of suitable engagement points and a force-regulated working method.
- Gripper positioning: Do not place the shear directly on the visible edge, but keep sufficient edge distance; relieve edges first.
- Bedding: Elastically pad the bearing points of the components to reduce notch stresses.
- Smaller bites: Work in several small bites to prevent edge breakage.
- Consider reinforcement: Position teeth so that tensile forces in the reinforcement are intercepted; pre-cut near reinforcement if necessary.
- Force build-up: Ramp up hydraulic pressure moderately; avoid load peaks.
In confined situations, combination shears and multi cutters support gentle exposure before larger cross-sections are processed. Hydraulic Power Units with sensitive control facilitate gentle force build-up.
Edge protection with stone and concrete splitters and stone splitting cylinders
When splitting with hydraulic cylinders, the drilling pattern is crucial. Edge protection is achieved through spaced, uniform load distribution and a sequential splitting sequence.
- Plan the drilling pattern: Maintain minimum edge distance (depending on strength and reinforcement); choose uniform hole spacing.
- Edge securing: Pack under edges and install coverings to retain splinters.
- Sequence: Position splitting cylinders from the inside out; only release the edge once the field has been weakened.
- Force dosing: Increase pressure step by step; include intermediate pauses for relaxation.
- Control: After each step, visually inspect the edges and monitor crack propagation.
In natural stone blocks, stone splitting cylinders support guidance along natural planes of weakness. Too small an edge distance increases the risk of uncontrolled edge breakage; larger distances increase safety and edge quality.
Edge protection when sawing, drilling, and separating
- Pre-cut/chamfer: Score or chamfer the edge to avoid spalling at breakthrough.
- Load relief: Shore the component during the cut so that the kerf opens in a controlled manner.
- Protect the exit side: When core drilling, cover the exit area and brace from the rear.
- Cooling and flushing: Sufficient cooling reduces thermal stresses and edge spalling.
- Cut sequence: Divide long cuts and close them successively to avoid uncontrolled breaking.
Edge distances, edge stability, and influencing factors
The choice of safe edge distances depends on material, geometry, reinforcement, and load condition. The more brittle the material and the sharper the edge, the larger the distance should be from drill holes, shear grips, and splitting wedges. Influencing factors:
- Concrete and rock strength, moisture, and temperature.
- Reinforcement layout and cover; anchorage lengths near edges.
- Component geometry, chamfers, existing cracks or joints.
- Tool tips, shear jaw contour, and contact areas.
- Working direction, bearing, and shoring.
A simple rule of thumb in practice: it is better to work one step farther from the edge and introduce forces over larger areas than to attack directly at the visible edge.
Edge protection in Darda GmbH’s application areas
Concrete demolition and special deconstruction
Concrete demolition shears allow slabs, walls, and beams to be released step by step from the field. Edge protection results from small bites, gentle pressure build-up, and targeted exposure of reinforcement before edge areas are processed. Hydraulic power packs with sensitive control support precise dosing.
Strip-out and cutting
When opening slab edges, door and window openings, pre-cuts and temporary shoring prevent spalling. Multi cutters and combination shears complement the separation process in densely reinforced zones.
Rock demolition and tunnel construction
Stone and concrete splitters with stone splitting cylinders work with low-vibration, controlled splitting tension. Here, edge protection also means preserving the surrounding structure and not impairing existing supports.
Natural stone extraction
Clean block edges increase usability. Well-coordinated drilling patterns and stepwise splitting produce straight fracture surfaces with minimal breakouts.
Special applications
For tanks and pipelines, steel shears and tank cutters minimize edge deformation when cuts are performed load-free and with suitable bearing. Shields reduce spark emissions and protect adjacent edges.
Quality assurance, documentation, and rework
- Visual inspection of cut and fracture edges after each work step.
- Measurement of edge spalling against project-specific tolerances.
- Documentation of work sequence, tool parameters, and shoring.
- Rework: blunting sharp edges, adding small chamfers, removing loose material.
Structured documentation facilitates the assessment of component preservation and forms the basis for further processing or reuse of components.
Typical mistakes and how to avoid them
- Attacking directly at the visible edge: better start with a setback and work in stages.
- Excessive point load: enlarge contact areas, use elastic pads.
- Insufficient shoring: close load paths, secure cantilevers.
- Missing pre-cut: score or chamfer edges, protect exit sides.
- Overhasty force build-up: increase hydraulic pressure slowly, avoid pressure peaks.
Occupational safety and framework conditions
Edge protection also serves personal protection: intact edges reduce the risk of falling parts and uncontrolled fragments. Protective coverings, splash and chip protection, as well as defined exclusion zones are proven measures. Legal requirements and recognized rules of technology must be considered on a project-specific basis; however, they do not replace expert assessment of individual cases.
Sustainability through component-friendly working
Good edge protection reduces material loss, lowers dust and noise, and increases the reusability of elements. Components with intact edges are easier to further process, saving resources and reducing disposal costs.
Practice-oriented selection of the edge protection strategy
- Analyze component and material: strength, reinforcement, geometry, edge quality.
- Select the method: concrete demolition shear for selective demolition, stone and concrete splitters for quiet separation, supplemented by sawing/drilling.
- Combine protective measures: constructive, mechanical, and procedural.
- Fine-tune parameters: hydraulic pressure, bite size, drilling pattern, cut sequence.
- Check and adapt continuously: short-interval visual inspections and documentation.