{"id":20213,"date":"2026-01-31T08:48:23","date_gmt":"2026-01-31T07:48:23","guid":{"rendered":"https:\/\/www.darda.de\/?page_id=20213"},"modified":"2026-06-20T16:22:03","modified_gmt":"2026-06-20T14:22:03","slug":"blasting","status":"publish","type":"page","link":"https:\/\/www.darda.de\/en\/knowledge\/blasting","title":{"rendered":"Blasting"},"content":{"rendered":"
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Blasting describes the targeted fracturing of solid material such as concrete, reinforced concrete, or rock by the controlled introduction of energy, in order to convert components, structures, or rock masses into pieces suitable for transport and further processing. In practice, the spectrum ranges from explosive techniques to non-explosive, hydraulic solutions. In concrete demolition, special demolition, rock excavation, tunnel construction, and natural stone extraction, blasting and blasting-related methods are used in combination. Depending on objectives and surroundings, devices such as concrete pulverizers<\/strong> or rock and concrete splitters<\/a> are employed at different process stages. Beyond fragmentation, control of emissions, predictability of outcomes, and compatibility with subsequent process steps<\/em> are central selection criteria.<\/p>\n

Definition: What is meant by blasting?<\/h2>\n

Blasting is understood as the controlled disassembly of massive material by the sudden release of stresses along artificially created zones of weakness. This can be carried out using explosive techniques (for example with explosive charges) or in a non-explosive manner, such as by hydraulic splitting. The goal is defined fragmentation that takes into account geometric specifications, vibration and emission limits, as well as structural and safety boundary conditions. Blasting serves to loosen, separate, pre-break, or deliberately reduce component thicknesses and volumes, often as a preparatory step for mechanical follow-up processing. In a narrower technical sense, the focus lies on inducing tensile stresses<\/strong> that exceed the material strength; in practice, fragment size distribution, flyrock control, and peak particle velocity<\/em> are guiding parameters for design and verification.<\/p>\n

Methods and operating principles of blasting<\/h2>\n

Blasting is based on generating and directing tensile stresses that load the material beyond its strength along desired separation planes. The selection and design of the method depend on material properties (strength, matrix, reinforcement), environmental constraints (vibration, noise, dust), and logistical objectives. Differences between compressive and tensile strength<\/em> of concrete and rock, reinforcement layouts, jointing, and moisture content influence crack initiation and propagation and thus the achievable precision.<\/p>\n

Explosive blasting<\/h3>\n

With explosive techniques, energy is released in a very short time to initiate cracking and fragmentation. The effect can be controlled via drilling pattern, charge arrangement, delay, and shielding. In urban areas and sensitive structures, vibration and emission limits take priority; often the volume is reduced first or components are shielded so that the effects of shock and pressure waves remain controlled. Measures such as stemming, decoupled charges, precise delay intervals, and protective mats<\/strong> help to limit overbreak, noise, and ejected fragments while safeguarding adjacent structures.<\/p>\n

Hydraulic splitting as a non-explosive alternative<\/h3>\n

In hydraulic splitting, rock and concrete splitters<\/strong> as well as rock splitting cylinders<\/strong> generate controlled tensile stresses in the borehole via wedge- or cylinder-shaped pressure bodies. The material breaks along defined axes, fragment size is highly controllable, and vibrations and airborne sound remain very low. This method is particularly proven in inner-city concrete demolition and special demolition<\/em>, during strip-out works, and in rock excavation and tunnel construction<\/em> when regulations constrain explosive methods. Typical parameters such as borehole diameter, spacing, and penetration depth are tailored to the component thickness so that repeatable, low-immission splitting cycles<\/em> are achieved with minimal back-effects.<\/p>\n

Combined methods<\/h3>\n

In practice, methods are combined: pre-drilling and splitting reduce cross-sections and stress states, after which concrete pulverizers<\/strong>, combination shears<\/em> or multi cutters<\/em> undertake structured disassembly. In this way, vibration, dust, and back-effects on adjacent structures can be minimized while optimizing logistics for removal. Coordinated sequencing improves selective dismantling<\/strong>, supports material separation for recycling, and stabilizes cycle times across interfaces.<\/p>\n

Fields of application and typical objectives<\/h2>\n

Depending on the area of use, target geometries, environmental constraints, and equipment differ. Objectives typically include compliance with immission thresholds, structural protection, schedule stability, and recycling-oriented processing<\/em>.<\/p>\n

Concrete demolition and special demolition<\/h3>\n

Massive foundations, bridges, or bunker structures are often reduced volumetrically first. Concrete pulverizers<\/strong> separate reinforcement and concrete in the course of dismantling, while rock and concrete splitters<\/strong> pre-break components along defined lines. This facilitates low-dust, low-vibration step-by-step dismantling. Load paths and temporary supports must be maintained to avoid unintended component behavior during each cycle.<\/p>\n

Strip-out and cutting<\/h3>\n

In buildings with confined space conditions, non-explosive methods are essential. Hydraulic splitting systems create separation joints before multi cutters<\/em> or combination shears<\/em> process lines, beams, and mixed constructions. Controlled removal supports clean material separation for recycling. Compact power supplies and short tool change times<\/strong> enable efficient work in narrow time windows and reduce disturbance in ongoing operations.<\/p>\n

Rock excavation and tunnel construction<\/h3>\n

In rock, pre-fragmentation facilitates extraction or profiling: splitting cylinders establish defined separation planes, blasting or mechanical processing then handles removal. In sensitive areas, for example near existing structures, non-explosive methods are used to meet vibration limits. Profile accuracy and limitation of overbreak are crucial for final lining fit, waterproofing interfaces, and downstream construction quality<\/em>.<\/p>\n

Natural stone extraction<\/h3>\n

Controlled crack guidance is crucial for block quality and yield. Hydraulic splitting produces smooth separation faces; subsequent work with steel shears<\/em> or multi cutters<\/em> squares edges and reduces blocks to transport size. Consideration of bedding planes, anisotropies, and natural fissures<\/strong> improves recovery rate and reduces waste.<\/p>\n

Special applications<\/h3>\n

In facilities with elevated safety requirements or in potentially explosive environments, non-explosive solutions are preferred. Tank cutters<\/em> and shear-based systems complement controlled pre-breaking without introducing ignition sources. Additional precautions include gas monitoring, inerting concepts, and strict hot-work controls<\/strong>.<\/p>\n

Equipment and tools around blasting<\/h2>\n

Equipment selection follows the material, accessibility, and emission requirements. Hydraulics provide the energy in many projects; hydraulic power units<\/a> feed the end tools and enable modular setups. Key parameters are operating pressure, flow rate, and duty cycle<\/em>, which must align with the intended tool forces and planned cycle frequency.<\/p>\n

Rock and concrete splitters<\/h3>\n

Splitters and rock splitting cylinders<\/strong> work gently on the material and generate defined cracks with high repeatability. Typical tasks include pre-breaking foundations, loosening rock in excavation pits, and creating separation joints in deconstruction. Advantages comprise precise crack control, low vibration levels, and scalable force application<\/em> through modular wedge or cylinder assemblies.<\/p>\n

Concrete pulverizers<\/h3>\n

Concrete pulverizers<\/strong> combine crushing and cutting action: concrete is crushed, reinforcement is separated. In combination with pre-drilled and tensioned separation planes, they accelerate removal without generating high vibrations. Optimized jaw geometries and high closing forces increase throughput and help produce uniform, transportable fragment sizes<\/strong>.<\/p>\n

Combination shears and multi cutters<\/h3>\n

These tools cover different material types, such as mixed constructions of concrete, masonry, and steel. They are positioned in the follow-up process to blasting or pre-breaking and support structured dismantling. Interchangeable jaw concepts and targeted bite strategies<\/em> help adapt to changing cross-sections along the process chain.<\/p>\n

Steel shears and tank cutters<\/h3>\n

Steel shears<\/em> cut profiles, beams, and reinforcement. Tank cutters<\/em> are used where thermal cutting methods are not permitted due to fire and explosion protection. Cold-cutting approaches minimize ignition risks and reduce secondary fume formation<\/strong>.<\/p>\n

Planning, safety, and regulatory framework<\/h2>\n

Blasting and blasting-related methods require careful planning. The protection of people, adjacent buildings, and the environment takes top priority. Depending on the method, qualifications and permits are necessary; compliance with applicable legal requirements lies with those executing the work. Robust risk assessments, method statements, and emergency plans<\/em> form the backbone of safe execution.<\/p>\n

Essential planning steps<\/h3>\n