Demolition material is generated during deconstruction, gutting works, and rock or concrete removal. It comprises mineral materials such as concrete, reinforced concrete, masonry, and natural stone as well as metals, asphalt, wood, or plastics. Process-reliable methods and suitable tools are crucial for proper separation, size reduction, and recycling. Especially in concrete demolition, special demolition, or tunnel and rock construction, controlled methods with hydraulic tools—such as concrete pulverizers or rock and concrete splitters—enable precise, low-vibration results and provide defined fractions for further processing.
Definition: What is meant by demolition material
Demolition material refers to the materials arising from deconstruction and removal works on building structures and infrastructure. This includes components detached by breaking and cutting techniques from concrete, reinforced concrete, masonry, natural stone, asphalt, metal as well as installations and layers. The material occurs in different sizes—from large component remnants to crushed fractions—and is directed to reuse or recycling depending on quality, purity, and suitability. Selective separation directly at the source increases material quality and reduces processing steps.
Origin and formation processes of demolition material
Demolition material is generated in several process steps. In primary demolition, components are detached, cut, or split. This is followed by secondary demolition with targeted size reduction, exposure of reinforcement, and sorting. In practice, different methods are used depending on the construction task: controlled splitting for massive components, work with pulverizers on reinforced concrete, shearing and cutting on metals or tanks, as well as natural stone extraction. In these phases, hydraulic tools—supplied via hydraulic power packs—deliver defined piece sizes and support source-separated sorting as the basis for high-quality recycled construction materials.
Material types and typical compositions
Material streams in deconstruction are heterogeneous. A structured view of the main fractions facilitates planning, separation, and processing.
- Concrete and reinforced concrete: mineral main fraction, often with reinforcing steel; suitable for size reduction and processing into recycled aggregates.
- Masonry: brick, calcium silicate brick, autoclaved aerated concrete (AAC); depending on construction type, well crushable and screenable.
- Natural stone: granite, limestone, sandstone; in rock excavation and tunnel construction as hard rock with high compressive strengths.
- Asphalt: bitumen-bound layers from road construction; thermal and mechanical processing possible.
- Metals: reinforcing steel, beams, sheets, and tanks; separate collection improves material value recovery.
- Wood, plastics, insulation materials: to be collected separately; often with specific recovery routes.
Particularities of reinforced concrete
Reinforced concrete combines high compressive strength with tensile load-bearing capacity through reinforcement. Tools such as concrete pulverizers separate the mineral matrix and expose reinforcing steel, which is then cut to transportable lengths using steel shears or combination shears. The resulting mineral demolition material can be provided as a defined input material for crushing and screening plants.
Recovery and initial size reduction on site
The quality of the demolition material is determined as early as the recovery phase. Low-vibration, controlled methods minimize damage to adjacent structures and optimize subsequent processing.
- Concrete demolition and special demolition: concrete pulverizers for load-bearing and non-load-bearing components, exposure of reinforcement, reduced dust and noise emissions compared to impact tools.
- Rock excavation and tunnel construction: rock and concrete splitters and rock splitting cylinders create predetermined breaking planes in hard rock; low vibrations and precise block sizes support safe underground operations.
- Gutting works and cutting: multi cutters and combination shears for separation cuts and detaching installations; tank cutters for specific special tasks on vessels, with appropriate protective measures observed.
Hydraulic supply
Hydraulic power units provide regulated flow and pressure to efficiently operate pulverizers, shears, and splitting cylinders. Proper sizing supports uniform cutting and splitting operations as well as reproducible fragment sizes.
Grain sizes, fractions, and quality characteristics
Demolition material is divided into fractions for further use. Common are fine fractions (e.g., 0/4), mixes (e.g., 0/32), and coarse aggregates (e.g., 32/63 and larger). Important quality characteristics are particle shape, strength, purity, and the share of foreign and interfering substances. The more source-separated the material is right after removal, the higher the quality of the recycled construction materials obtained. For mineral fractions, recognized tests—depending on project requirements—may include compressive strength, freeze–thaw resistance with de-icing salts, or water absorption.
Processing: crushing, splitting, cutting, screening, and sorting
Processing typically follows a multi-stage chain of preconditioning, metal separation, and screening. Efficient preconditioning with concrete pulverizers or rock and concrete splitters reduces crushing resistance and improves particle shape.
- Preconditioning: targeted detachment of large pieces, releasing slabs and beams, controlled splitting of massive components.
- Metal separation: exposing and cutting reinforcement using shears; magnetic separation in stationary processing.
- Screening: classification into defined fractions; recirculation of oversize back into the size-reduction process.
- Quality control: sampling, documentation of fraction quality for the intended use.
Importance of preconditioning
If concrete is structurally weakened with pulverizers or divided into target sizes with splitting cylinders before crushing, energy demand in the crushing stage decreases. At the same time, undesirable fines are reduced, improving the quality of the grading curves.
Recycling: application options for recycled construction materials
After appropriate processing, mineral demolition material can be used as recycled construction material, for example in road and path construction, in civil works (unbound layers), as sub-base and frost protection layer, or—depending on evidence and project-specific requirements—as aggregates in concrete. The specific suitability is determined by the technical requirements of each application. Careful separation and process control on the construction site form the basis for high-quality recycling options.
Environmental and occupational safety when handling demolition material
Dust, noise, and vibrations are key aspects. Methods with controlled splitting and pulverizer work can limit vibrations and reduce dust generation, especially in sensitive environments. Dust suppression (e.g., water mist), organized airflow management indoors, and appropriate personal protective equipment are essential elements of occupational safety. For potentially hazardous materials, careful, expert evaluation and separate collection are required; binding specifications must be checked on a project-specific basis.
Logistics, documentation, and traceability
Efficient logistics reduces downtime and transport distances. Clear material flow planning—container and skip concepts, intermediate storage, haul routes—facilitates source-separated collection. Documentation of material flows and fraction qualities supports traceability and eases subsequent use as recycled construction material. On-site digital capture, coupled with weighing and batch data from processing, creates transparency on quality and costs.
Typical challenges and practical solutions
- Steel-intensive components: pulverizers open the concrete cover, shears cut reinforcement; this creates clean mineral fractions and source-separated metals.
- Confined space and sensitive neighborhoods: low-vibration splitting and pulverizer techniques, adapted sequencing, and noise-reduced work windows.
- Thick, high-strength concrete: a combination of pre-drilling and splitting to initiate cracks, followed by secondary size reduction with pulverizers.
- Tunnel construction and rock removal: defined block sizes achieved with rock and concrete splitters facilitate haulage and dosing into processing.
- Installations and tanks: controlled cutting with suitable tools, separate collection of metal fractions.
Quality control and test parameters
The suitability of demolition material for specific uses is described by material-technical parameters. These include density, particle strength, Los Angeles value, freeze–thaw resistance with de-icing salts, particle shape indices, and fines content. Regular sampling and structured documentation facilitate compliance with project-specific requirements. For concrete recyclates, foreign material contents (e.g., wood, bitumen, gypsum) must also be minimized to ensure durability and workability.
Economic efficiency and life-cycle considerations
A high share of in-house reuse and source-separated collection already during deconstruction lowers transport and disposal costs. Tool change times, the energy demand of processing, and the quality of the generated fractions significantly influence total costs. Processes that convert materials into defined piece sizes with concrete pulverizers or rock and concrete splitters can ease subsequent crushing stages and improve economic efficiency.
Best practice in concrete demolition, special demolition, and tunnel construction
In structures with high requirements for vibration and noise protection, a sequential approach is recommended: relieve, score, split, remove with pulverizers, sort. In tunnel construction and rock removal, controlled splitting techniques provide predictable fracture surfaces and safe block sizes. In gutting works, compact hydraulic tools support precise cuts and separated detachment of component layers. These approaches deliver demolition material with defined quality and simplify subsequent processing into usable recycled construction materials—from the construction site to the plant.
Term delimitation and interfaces
Demolition material includes both directly reusable components and materials that are routed to processing. Whether a material is classified as waste, a by-product, or a recycled construction material depends on conditions and documentation and must be carefully evaluated in the project context. As a rule, the earlier selective separation takes place in the process, the higher the chances for high-quality material recycling and stable quality of the produced fractions.