{"id":20107,"date":"2026-01-20T08:11:03","date_gmt":"2026-01-20T07:11:03","guid":{"rendered":"https:\/\/www.darda.de\/?page_id=20107"},"modified":"2026-01-20T08:11:03","modified_gmt":"2026-01-20T07:11:03","slug":"grouting-technique","status":"publish","type":"page","link":"https:\/\/www.darda.de\/en\/knowledge\/grouting-technique","title":{"rendered":"Grouting technique"},"content":{"rendered":"
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Grouting technique comprises underpouring, casting, and pressure grouting of voids, joints, and boreholes using mineral or reactive systems. The objectives are bonded, load-transferring bedding, the durable filling of voids, sealing against water and other media, and the anchoring of structural elements. In conjunction with concrete demolition and special deconstruction<\/a>, special demolition, and rock excavation it provides a clean technical closure of interventions previously executed with concrete demolition shears, hydraulic rock and concrete splitters<\/a>, or cutting and shearing tools. In this way, structural elements are stabilized after deconstruction, anchors are bonded in a load\u2011transferring manner, and boreholes are professionally closed.<\/p>\n

Definition: What is meant by grouting technique<\/h2>\n

Grouting technique refers to the totality of methods for placing grout mortars<\/strong>, injection resins, and injection systems into cracks, joints, drill holes, and beneath bearing surfaces. Technically, a distinction is made between undergrouting<\/em> (e.g., under machine foundations), anchor grouting<\/em> (e.g., for rock and concrete anchors), void filling<\/em> (e.g., after drilling and splitting operations), and sealing injection<\/em> (e.g., against water ingress). Key requirements include flowability, low shrinkage tendency, adequate compressive strength, good bond, and an E\u2011modulus suited to the intended use.<\/p>\n

Materials and systems at a glance<\/h2>\n

The selection of the system is guided by loads, environmental conditions, and application method. In the deconstruction and rock context the following groups have become established:<\/p>\n

Cement\u2011based grout mortars<\/h3>\n

Used as low\u2011shrinkage or expansive systems with a graded particle-size distribution. Typical are high compressive strengths, good flow values, and robust placement even in larger cross\u2011sections. They are suitable for undergrouting of foundation slabs, filling split and drill holes, and for anchor grouting in concrete and rock.<\/p>\n

Microfine and ultrafine cement<\/h3>\n

For injections into fine cracks and rock pores, for example in tunnel construction for consolidation or to reduce water inflows. The small particle size enables penetration into capillary structures; stability and filtration behavior must be considered.<\/p>\n

Reactive resins (epoxy, polyurethane)<\/h3>\n

Epoxy resins provide very high bond (pull\u2011off) and compressive strengths as well as low creep; they are used for highly loaded undergrouting, anchors in dynamically loaded areas, or for thin bearing joints. Polyurethanes are primarily used for sealing injections, especially in the presence of water ingress. Exothermy, temperature control, and emissions must be carefully managed.<\/p>\n

Thixotropic and vertically stable systems<\/h3>\n

For overhead or vertical applications, such as grouting core drill holes in walls or slabs after using concrete demolition shears and cutting methods. Here, thixotropic additives prevent run\u2011off while still providing sufficient working time.<\/p>\n

Design and planning in the deconstruction context<\/h2>\n

In projects involving concrete demolition and special demolition, proper planning of the grouting technique governs load behavior, tightness, and durability. Load paths, contact surfaces, and temperature histories must be defined in advance.<\/p>\n

Undergrouting of bearings and equipment<\/h3>\n

When undergrouting machine plates, rails, and pedestals\u2014such as for mobile hydraulic power units<\/a> that are operated temporarily or permanently on foundations\u2014a flowable, low\u2011shrinkage grout mortar is selected. Important parameters are the E\u2011modulus, compressive strength, and the ability to fill the bearing area without voids.<\/p>\n

Anchor grouting in concrete and rock<\/h3>\n

After removal with concrete demolition shears or splitting with hydraulic wedge splitters for stone and concrete, temporary or permanent anchors are often installed. The grout must reliably transfer loads, make use of borehole roughness, and respect edge distance. In wet boreholes, water\u2011tolerant systems must be provided.<\/p>\n

Process chain: preparation, placement, curing<\/h2>\n

Reproducible quality arises from a structured approach from substrate preparation through to documentation.<\/p>\n

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  1. Prepare the substrate: expose concrete, remove loose material, clean bonding surfaces, pre\u2011wet mineral systems (saturated surface\u2011dry).<\/li>\n
  2. Set formwork and dams: tight and stable; plan vent paths and pour openings; provide a gradient for material flow.<\/li>\n
  3. Mixing: adhere precisely to water addition, observe mixing time, ensure freedom from lumps and control temperature; for resins, keep component ratio exact.<\/li>\n
  4. Placement: place continuously from one side, promote venting, avoid material changes; respect the placement time (pot life).<\/li>\n
  5. Curing: protect early against drying, frost, or heat; control exothermic reactions; rework edge areas.<\/li>\n
  6. Control: record flow spread, air temperature, component temperature, compressive strength of fresh mortar\/hardened concrete, and, where applicable, pull\u2011off tests or an anchor pull-out test.<\/li>\n<\/ol>\n

    Grouting technique in conjunction with stone and concrete splitting devices<\/h2>\n

    Stone and concrete splitting devices create defined splits via wedge\u2011based stresses in predrilled holes. The resulting voids, split joints, and bore channels are often grouted for structural or building\u2011physics reasons, following the wedge principle.<\/p>\n

    Borehole and split\u2011joint grouting<\/h3>\n

    After controlled splitting in natural stone extraction or in concrete demolition, boreholes can be filled with low\u2011shrinkage mortars to homogenize surfaces, block water paths, or set anchors with a bonded load transfer. In water\u2011bearing areas, consolidating injections with microfine cement or water\u2011reactive systems are appropriate.<\/p>\n

    Crack injection for stabilization<\/h3>\n

    For secondary cracks resulting from load redistribution, injections with low\u2011viscosity systems can restore integrity. Decisive factors include suitable packer arrangement, controlled pressure, and monitoring of material intake.<\/p>\n

    Applications with concrete demolition shears, hydraulic demolition shears and multi cutters<\/h2>\n

    Selective dismantling with concrete demolition shears exposes reinforcement, produces edge breakouts, and creates local voids. Proper closure includes grouting of:<\/p>\n