The test cut is a targeted, small-scale intervention in concrete, masonry, or rock to examine a component’s build-up, the position of reinforcement, and the material’s response to separating or splitting methods. In the practice of concrete demolition and special demolition, gutting works and cutting, rock excavation and tunnel construction, and natural stone extraction, it serves as a methodological preliminary investigation. The findings directly influence the selection and application of hydraulic tools such as concrete demolition shears or hydraulic wedge splitters and the configuration of the associated hydraulic power pack from Darda GmbH.
Definition: What is meant by test cut
A test cut is a test cut or exploratory cut for the structural and technological investigation of a structural or rock cross-section. It is executed as small as possible and as large as necessary to identify material composition (aggregate grading, binder, matrix), reinforcement layout (diameter, position, density), bond, and any prestressing. In rock, the test cut aims to capture joint systems, bedding planes, and stratification boundaries. The results support controlled crack guidance, the selection of suitable separating or splitting methods, and safe segmentation for subsequent deconstruction or extraction.
Objectives, benefits, and typical questions
A test cut provides reliable information before large areas are cut, split, or removed. Typical objectives include:
- Determination of concrete cover, bar diameters, and spacings in reinforced concrete members
- Verification of the presence of prestressing or concealed inserts (cables, built-in components)
- Assessment of material quality (compressive strength, aggregate, concrete carbonation, voids)
- Determination of governing crack and joint orientation in rock and natural stone
- Validation of drilling patterns and wedge arrangements for hydraulic wedge splitters
- Adjustment of the gripping and cutting strategy for concrete demolition shears, combination shears, multi cutters, and steel shears
- Forecast of emissions (dust, noise, vibrations) and derivation of organizational measures
- Definition of hydraulic performance parameters (oil flow rate, working pressure) at the hydraulic power pack
Methods of the test cut in concrete, masonry, and rock
Test cut in concrete demolition and special demolition
In reinforced concrete, the test cut is performed with minimal vibration and combined with stepwise exposure:
- Create an exploratory opening at an edge zone, e.g., by selective nibbling with a concrete demolition shear to reveal concrete cover and reinforcement layout.
- Apply limited core drilling or a short separation cut if necessary to create a defined edge.
- Perform a trial split with a hydraulic wedge splitter: choose drilling pattern and wedge orientation to probe the natural crack direction.
- Document behavior: crack path, secondary breakage, force demand, and the response of reinforcement and built-in components.
Test cut in gutting works and cutting
In selective deconstruction of existing structures, the test cut clarifies which cutting sequence and tools are appropriate. Thin-walled components or plates can be opened on a trial basis with multi cutters, steel shears, or—for cylindrical vessels—with tank cutters to check wall build-up, coatings, and residual contents. On this basis, subsequent segmentation is defined.
Test cut in rock excavation and tunnel construction
In rock, the test cut aligns operations with joints and bedding planes. Short, targeted splits with hydraulic rock and concrete splitters show whether planned drilling patterns produce the desired crack pattern. The positioning of splitting wedges is selected to utilize principal joint systems and avoid overloads.
Test cut in natural stone extraction
In the deposit, a small-format test cut checks block yield along bedding and joint planes. Crack propagation reveals the spacing of splitting points and the required drive power to win economical raw blocks with minimal secondary breakage.
Tool selection: from test cut to process planning
The results of the test cut lead to well-founded tool and parameter choices:
- Concrete demolition shears: select jaw geometry, cutting edge shape, and opening width according to reinforcement density and member thickness; define the sequence of gripping, crushing, and controlled severing.
- Hydraulic wedge splitters: determine drill diameter, wedge sizes, and spread distance based on the identified strength and crack orientation; align wedge orientation to the desired crack line.
- Hydraulic power pack: set the required oil flow rate and working pressure so the tool operates stably and thermally safe under continuous load.
- Combination shears, multi cutters, steel shears, tank cutters: for metallic inserts, plates, or vessels, use the test cut to determine wall thicknesses and composite conditions and derive the cutting sequence from this.
Evaluation and documentation
Systematic documentation makes the test cut reproducible and plannable:
- Sketches/photos of the position of reinforcement, built-in components, joints, and rock fractures
- Dimensions: concrete cover, bar diameters, spacings, member thicknesses
- Behavioral data: crack path, secondary breakage, required hydraulic pressure, number of working strokes
- Work and environmental conditions: moisture, temperature, accessibility, required shoring
These details flow into the deconstruction concept, segmentation, and the selection of subsequent tools. This shortens setup times and avoids unwanted secondary damage.
Occupational safety and environmental aspects
The test cut supports safe working practices. If prestressing, residual media in vessels, or hazardous substances are suspected, proceed with especially careful openings, stepwise load increases, and appropriate cordoning. Plan dust suppression and noise reduction measures, protection against falling parts, and orderly handling of resulting pieces early. Low-vibration methods with hydraulic splitting and shear tools help protect adjacent components.
Practical tips for clean edges and controlled crack guidance
- In concrete: edge relief by keeping separation cuts short or by targeted breaks with the concrete demolition shear minimizes spalling.
- Align drilling patterns for hydraulic wedge splitters with the material structure and desired separation line; keep borehole depth uniform.
- Stagger wedges and increase the load stepwise to guide the crack front.
- Keep contact surfaces free of loose particles so splitting forces are introduced in a defined manner.
- In masonry, work along bed joints; in mixed masonry, probe material transitions first.
Frequent material and structural features revealed by the test cut
- Strongly varying concrete cover or reinforcement congestion requiring an adjusted shear strategy
- Gravel pockets, voids, or weak bond zones with an increased risk of secondary breakage
- Concealed built-in components, utility lines, or anchors suggesting a different segmentation
- Unexpected joint and bedding orientations in rock influencing splitting wedge positioning
Relation to typical application areas
In concrete demolition and special demolition, the test cut clarifies reinforcement layout and guides the choice of concrete demolition shears or splitting methods. In gutting works and cutting, it defines safe openings and the cutting sequence for multi cutters, steel shears, and tank cutters. In rock excavation and tunnel construction, it sets drilling patterns and splitting sequences for rock wedge splitters. In natural stone extraction, it ensures block yield along bedding. For special demolition—for example with hard-to-access components—it enables tailored, low-vibration methods.