The laboratory evaluation is a central link between materials science and practical execution in deconstruction, demolition works, rock cutting/processing and natural stone extraction. It provides robust characteristic values for concrete, masonry, steel and natural stone, from which safe methods, suitable tools and appropriate hydraulic performance can be derived. For applications such as concrete demolition, special demolition, building gutting and cutting, rock excavation, tunnel construction, natural stone extraction and special applications, it establishes the basis for making targeted decisions under real boundary conditions – for example on the use of concrete pulverizers or rock wedge splitters and concrete splitters, on sizing the hydraulic power pack, and on dealing with reinforcement, cracks, moisture or contamination.
Definition: What is meant by laboratory evaluation
Laboratory evaluation refers to the structured collection, analysis and interpretation of test and measurement data obtained from representative samples of concrete, masonry, steel or natural stone. These include mechanical, chemical, mineralogical and physical parameters (e.g., compressive strength, fabric/matrix, chloride content, moisture content, grain composition) that are determined in the laboratory using standardized or technically accepted methods. The evaluation links measurement results with the structure or rock context and derives concrete statements for planning, occupational safety, tool selection, process parameters and disposal.
Core processes of the laboratory evaluation: from sample to practical value
A robust laboratory evaluation follows a transparent sequence: objective definition and test plan; quality-assured sampling (e.g., concrete cores, rock blocks, reinforcement sections, dust or water samples); sample preparation; execution of mechanical, chemical, petrographic and physical tests; plausibility check; statistical consolidation; interpretation in the context of the structure or rock mass; derivation of measures such as tool strategy, hydraulic demand, cutting or splitting sequences as well as protective measures. Documentation concludes with a clearly structured report that classifies limit and guide values and assesses transferability to the wider area.
Objectives and benefits in concrete demolition, deconstruction and rock processing
The laboratory evaluation provides decision certainty by quantifying material behavior and reducing uncertainties. It helps to plan interventions appropriate to the material and with low emissions, avoid downtimes and limit risks. It is particularly relevant when low vibration levels are required, reinforcement is unclear, composite construction types are present, or an environmental requirement (construction) must be observed. This makes it possible to estimate in advance whether a selective approach with a concrete pulverizer or controlled splitting with rock wedge splitters and concrete splitters is advantageous, what hydraulic performance is required, and how cutting and splitting sequences should be adapted to the material.
Sampling and sample preparation
The quality of the results depends largely on the sample. Samples must be representative, adequately dimensioned and correctly labeled. Heterogeneous zones (e.g., transitions from old concrete to post-cast areas, zones affected by chloride-laden splash water, crack fields, joint systems in rock) are recorded separately. Preparations such as drying, cutting to size, grinding or impregnation (for thin sections) follow the applicable rules. Errors in this step distort parameters such as compressive strength, porosity or moisture content – with direct consequences for tool selection and process planning.
Test methods: mechanical, chemical, petrographic and physical
Mechanical parameters
Compressive and splitting tensile strength, modulus of elasticity, abrasion and wear behavior are key quantities. In concrete demolition, they indicate how brittle or tough a component responds. In rock mechanics, uniaxial compressive strength together with discontinuities (joints, foliation) provides clues to splitability. High compressive strengths with pronounced brittleness favor the use of rock wedge splitters and concrete splitters; tough, heavily reinforced areas can often be structured gently with concrete pulverizers before further steps follow.
Petrography and fabric/matrix
Thin section and fabric analysis clarify grain shape, binder matrix, crack systems, alkali-silica reactions, aggregate types or weathering. In natural stones, mineral composition and joint orientation provide indications of preferred splitting directions. For the hydraulic splitter and wedge placement, this orientation is crucial to efficiently convert modest hydraulic performance into crack propagation.
Chemical parameters
Concrete carbonation depth, chloride contamination, sulfate or pH values influence reinforcement condition, corrosion tendency and possible separation cut concepts. In deconstruction projects, such values also assist with disposal planning. Chemical analyses also support the selection of cutting or pulverizer strategies when corroded reinforcement may release unpredictable stresses.
Physical properties
Bulk density, water absorption, porosity, moisture and temperature profiles provide indications of drillability, cutting resistance and splitting demand. High moisture can delay effective splitting action; highly porous materials often respond more favorably to controlled splitting than to high localized cutting loads.
Non-destructive testing
Supplementary non-destructive methods (e.g., reinforcement localization, rebound principle, ultrasonic pulse velocity) provide an area-wide preliminary assessment. They do not replace laboratory testing, but help to target sampling and identify local weaknesses for pulverizer bites or wedge positions.
From measurements to decisions: interpretation for practice
The laboratory evaluation condenses individual values into action-guiding statements. The key is linking them to structure or rock geometry, boundary conditions such as vibration and noise requirements, accessibility, as well as safety and environmental goals. The result is a pragmatic, material-sensitive strategy:
- Homogeneous, brittle concrete with moderate reinforcement: controlled splitting with rock wedge splitters and concrete splitters minimizes vibrations; concrete pulverizers help break edges, corners and locally densified zones.
- Highly tough, heavily reinforced concrete: concrete pulverizers for exposure and removal in sequences; subsequent splitting or cutting steps follow the loosened matrix.
- Massive rock with a clear joint system: hydraulic splitter along joint orientation; wedge positions are derived from petrographic and structural findings.
- Inhomogeneous composite construction types: sectional strategy with varying pulverizer and splitting parameters; lab data governs the transitions.
The required hydraulic performance (pressure/flow rate) is derived from strength, component thickness, target split width and tool kinematics. This allows the hydraulic power pack to be sized appropriately to avoid peak loads and stabilize energy use.
Relevance by application area
Concrete demolition and special demolition
Lab data on strength, carbonation and reinforcement condition structures the sequence of pulverizer bites, split boreholes and large-area removal. Vibration-sensitive environments benefit from splitting-based approaches with low vibration levels.
Building gutting and cutting
In selective deconstruction, material parameters determine whether cuts or pulverizer bites at joints, openings and edges are more efficient. Chloride or moisture profiles can influence cutting plans when spark formation or brittle fracture is to be avoided.
Rock excavation and tunnel construction
The combination of compressive strength, joint spacing, crack roughness and stress state governs wedge geometries and splitting spacing. Favorable joint orientations allow lower wedge forces; unfavorable orientations require adapted drilling patterns and higher splitting performance.
Natural stone extraction
Petrography and fabric lead to reproducible split surfaces. The goal is gentle separation along natural weakness zones with high yield and minimal losses.
Special application
For special materials or components with unknown history, laboratory analyses clarify fundamental parameters before working with pulverizers, hydraulic splitters or alternative tools. This reduces unforeseen material reactions and facilitates safety planning.
Report, quality assurance and reference to standards
A good report documents origin, number and location of samples, test methods, raw data, statistical parameters, images and the transparent transfer to the wider area. Quality assurance covers test equipment capability, calibration and internal comparison. Recognized rulebooks are used for classification and limit values; binding assessments are fundamentally made within the framework of the applicable regulations and by the competent authorities. Where appropriate, reference to a DIN standard can support classification.
Occupational safety, environment and emissions
Lab data supports the choice of low-emission methods and appropriate protective measures. Information on dust contents (e.g., silica-bearing), moisture, potential hazardous substance traces or residual media provides guidance on dust extraction, wetting, protective enclosure and disposal. Where uncertainties exist, a conservative approach is indicated; legally binding classifications are made by the competent authorities on the basis of the evidence provided.
Collaboration between laboratory and construction site
Close coordination significantly improves outcomes: the construction team defines objectives and boundary conditions, the laboratory reflects on feasibility and the informative value of the tests. Feedback from execution (e.g., actual pulverizer bite lengths, splitting progress, drillability) flows back into interpretation and sharpens models for subsequent sections.
Practical guide: from parameter to tool
- High strength and brittleness, low joint content: pre-structuring with concrete pulverizers, followed by targeted split boreholes; size hydraulic power packs for peak loads.
- Moderate strength, distinct joint or crack systems: primarily deploy rock wedge splitters and concrete splitters; position wedges along weakness zones, derive drilling patterns from fabric data.
- Heavily reinforced, heterogeneous: sequence of pulverizer (expose, reduce), hydraulic splitter (release) and, if necessary, cutting or hydraulic shear for embedded parts; plan hydraulic performance in stages.
- Natural stone with anisotropic fabric: split along natural anisotropies; the goal is smooth fracture surfaces and high yield.
Typical sources of error and how to avoid them
- Non-representative samples: create a sampling plan, record transition zones separately.
- Unclear transferability: cross-check lab values with non-destructive findings and site observations.
- Isolated consideration: always interpret mechanics, chemistry and fabric together.
- Rigid tool strategy: iteratively adjust pulverizer and splitting parameters based on the laboratory evaluation.
Digital evaluation and trends
Digital test reports, structured datasets and model-based interpretation facilitate transferring laboratory results to structural sections and rock bodies. Together with documented pulverizer and splitting performance, learnable processes emerge that make future projects more predictable and further refine the selection of tools and hydraulic power packs.