Concrete injection: methods, technology

In the field of building and repair, concrete injection is a revolutionary method. This is the procedure that experts frequently use to reinforce shaky foundations or patch cracks in historic concrete buildings. Concrete injection helps preserve structural integrity and prolong the life of different types of concrete surfaces by injecting specific materials into voids or cracks.

This technique is useful for fixing problems like water leaks, structural damage, and settling foundations. It functions by caulking cracks with a material that solidifies and adheres to the surrounding concrete, thereby effectively caulking off issues that might eventually cause more serious harm.

Concrete injection can be done in a variety of ways, each appropriate for a particular set of problems and surface. For small cracks, epoxy resins can be used; for larger voids, stronger materials can be used. Having a basic understanding of these techniques will help you make wise choices whether you’re doing a big renovation or a small repair.

We’ll examine the various concrete injection techniques, their workings, and the underlying technologies in this article. Understanding these ideas can improve your repair abilities and guarantee sturdy, long-lasting results, regardless of whether you’re a DIY enthusiast or a professional in the field.

Method Description
Grout Injection Involves injecting a cement-based mixture to fill cracks and voids in concrete, providing stabilization and preventing further damage.
Epoxy Injection Uses a resin-based product to fill and seal cracks, which helps restore the structural integrity and can also be used for aesthetic purposes.
Polyurethane Injection Injects a polyurethane foam that expands and hardens to fill cracks and voids, often used for waterproofing and ground stabilization.
Pressure Grouting Involves forcing grout into soil or voids under pressure to improve strength and reduce settlement issues.
Chemical Injection Uses chemical solutions to stabilize soil and concrete, often employed in special cases where traditional methods are not effective.
Resin Injection Injects various types of resins to repair and reinforce concrete structures, often used in combination with other methods for better results.

General information

The first step in a successful structure repair is to accurately and correctly assess the structure’s condition and identify the causes of any damage. The resolution of these problems directly affects every step of restoration and protection that comes after.

Types of defects and factors influencing their appearance

There are numerous reasons why buildings that are in use can develop cracks. These defects are classified as structural or non-structural based on the expected risk.

Structural ones can result from the following and have an impact on the structure’s strength:

  • design errors;
  • construction miscalculations;
  • soil movement;
  • foundation settlement.

Non-structural cracks are the most prevalent kind and can appear as:

  • superficial;
  • through;
  • internal.

The following elements affect how these defects form:

  • shrinkage;
  • internal stresses occurring during cement hydration;
  • temperature deformations;
  • humidity fluctuations;
  • reinforcement corrosion;
  • mechanical impacts.

The technique and materials for monolith injection are chosen based on the reason for formation and the size of the crack opening.

When selecting a repair technique, it’s crucial to take into account:

  • defect mobility;
  • crack opening size;
  • aggressiveness index of the environment in which the structures are operated;
  • temperature of the repaired coatings;
  • parameters of repair mixtures (compliance with the conditions of use).

Methods for eliminating defects

Injecting concrete is not a novel technique for coating restoration. This procedure’s mechanism hasn’t changed in a long time. The only things that have been upgraded are the tools and supplies.

Every technique has a unique name that is determined by the materials that are used:

  1. Cementation is a method of eliminating defects using cement mixtures. The solution is produced on the basis of water, oil well cement or Portland cement – grades not lower than M400.
  2. Resinization is a method of introducing epoxy resin compositions into cracks, which is an effective way to increase the strength of structures.
  3. Bituminization is performed by injecting bitumen heated to 200 ° C into structures. Bituminization itself does not increase strength, but significantly increases the water resistance of products.
  4. The process of silicification includes two stages. First, liquid glass is injected into the cracks, and then calcium chloride is introduced. As a result of the chemical reaction between these reagents, poorly soluble substances are formed, which fill all the resulting voids.

New materials and techniques are being used in object reconstruction to extend the useful life and boost the dependability of buildings.

The most promising areas in injection technology are polymer and geopolymer compositions based on:

  • polyurethane resins;
  • epoxy resins;
  • microcements;
  • acrylate gels.

Characteristics of materials for the production of works

Polymer-based injection materials are extensively used for void filling and structural element repair, and they meet the requirements of the European standard EN 1504.

Mixtures fall into three categories based on this standard’s classification:

  1. "F" — epoxy-based solutions used to repair load-bearing structural elements at civil and industrial construction sites, such as floor slabs, beams, columns, etc.
  2. «D» — materials based on polyurethane components. Used to seal active expanding cracks in structures that do not perform load-bearing functions.
  3. "S" — acrylic and polyurethane based mixtures used for sealing and eliminating active leaks. Can be used in combination with materials of groups "F" and "D", which act in this combination as finishing materials.

The materials in the aforementioned categories must all adhere to the following specifications:

  • have constant elasticity;
  • have waterproofing ability;
  • the curing time of the composition must correspond to the technical conditions of use;
  • have sufficient viscosity (fluidity) for defects of varying depths and expansion;
  • high adhesive and mechanical strength;
  • versatility of use (dry, wet substrates, etc.).).

In addition to these specifications, the following elements need to be considered when selecting mixtures:

  • affordable price;
  • material consumption;
  • experience using the selected brand;
  • ability to use in specific conditions of the construction site;
  • resistance to operating conditions:
  • there should be instructions for do-it-yourself use for this material.

There are a lot of options for injection, and even more so when considering the aforementioned suggestions; each unique situation calls for a different choice of material. Any material used for this kind of work has two main goals: waterproofing and restoring the structural integrity of the buildings. Additionally, customers are free to choose other features.

Concrete injection is an essential repair method that involves injecting specific materials into damaged concrete to strengthen it and repair cracks. By using this technique, concrete components’ lifespans are increased in addition to their structural integrity being restored. We can comprehend the advantages of these solutions, how they operate, and the best practices for their efficient implementation by investigating different injection techniques and cutting-edge technology. Concrete injection provides a dependable and effective means of maintaining the best possible condition for our concrete structures, regardless of the severity of surface imperfections or structural issues.

Equipment and procedure for performing work

The best repair quality indicators can only be obtained with specialized tools and machinery.

This first pertains to the following devices:

  • packers for concrete injection;
  • pumps for injection of the composition;
  • piping system;
  • control and shut-off equipment.

Concrete injectors, also known as packers, are a particular kind of device that are installed in injection holes or on the surface of objects. They are used in conjunction with supply hose systems to inject a specific solution into structurally compromised areas. As with the materials example, a set of equipment (hoses, packers, pumps, shut-off valves, etc.) is chosen for each unique situation based on the task at hand.

Work procedure

The following operations ought to be incorporated into the crack injection technology:

  • preparatory work;
  • installation of packers;
  • preparation of solutions;
  • Injecting;
  • final works.

Preparation

Determine the number and location of holes by performing a surface study prior to beginning any preparatory work. The locations of the boreholes where there are the most cracks are marked. To fully fill any defective areas, the number of packers and holes for them is calculated.

The following list of required actions makes up the entire preparation process:

  1. Clean the base surfaces from dirt, wipe with a clean rag and blow with air.
  2. Check and install the equipment.
  3. Using a marker and tape measure, mark the points for installing the packers.
  4. Using a magnetic method, conduct a study of the structure for the presence and location of reinforcement. Apply the projection of the reinforcement cage in the form of lines on the surface of the span to avoid damage during hole preparation.
  5. Next, in accordance with the marking, we drill the holes.
  6. It is recommended to place the boreholes in a checkerboard pattern with an interval of 70-100 cm.
  7. The depth of the hole for the injector should be 5-10 mm greater than the inserted length of the parker.
  8. At the end of drilling, blow out all prepared holes with compressed air.

Packer installation

Depending on the kind of defect being removed, different injector types and installation techniques may be used. As a result, we will discuss three primary coating restoration techniques below.

The first instance involves using composite mixtures based on epoxy resin to repair dry cracks.

You will need the following tools and supplies for this operation:

  • quartz sand;

  • single-component electric piston pump;

  • adhesive packer with collet head;

Epoxy mortar combined with sand is used to seal the rupture cavity. Adhesive injectors, which come in plastic or metal forms, are used to remove flaws from densely reinforced structures.

Let’s look at the order of the work:

  1. Adhesive packers are installed using glue or a special sealant directly on the fracture site. Before sticking it, a metal nail is inserted into the cavity of the crack to avoid clogging the channel at the time of coating with sealant. When the glue has set, it is removed.
  2. A pump hose is connected to the first packer, and the check valve on the second is removed and injection is performed (from bottom to top). When liquid appears in the second packer, install a check valve on it and continue injection.
  3. This process is repeated sequentially with other injectors until the entire volume of the crack being repaired is filled with solution.
  4. At the end of the procedure, the packers are removed and the holes are sealed with epoxy mixture.

Be aware that if the repair mixture’s flow rate increases unintentionally without raising the pipeline’s operating pressure, the injection process should be stopped.

Leak-sealed active crack sealing is the second example.

Tools and supplies:

  • polyurethane resin

  • electric piston pump (see photo above);
  • packer with flat or collet head.

Order of work:

  1. The crack cavity is divided with a hammer drill (3×3 cm).. Then putty with repair compounds for active leaks.
  2. On both sides of the rupture line, in a checkerboard pattern and at an angle of 45°, drill holes. The gap between the holes is 15–50 cm. The depth of the holes should be equal to 2/3 of the wall thickness.

  1. Injectors are inserted into the prepared holes and the sealing rings are tightened.

The injection procedure is comparable to the previously mentioned approach. After everything is finished, take the devices out and use repair mortar to seal the holes.

One effective and adaptable method for dealing with a variety of problems in concrete structures is concrete injection. This method has demonstrated efficacy in various applications, such as leak sealing, foundation stabilization, and crack repair. Experts can guarantee that structures stay sturdy and safe for many years to come by employing specific supplies and tools.

Having a thorough understanding of the various techniques and technologies used in concrete injection will enable you to choose the best course of action for your unique requirements. Every method has benefits depending on the circumstance, from polyurethane injections for waterproofing to epoxy injections for repairing cracks. Selecting the appropriate approach is crucial for attaining the intended result and preserving the structural integrity.

All things considered, concrete injection provides a workable fix for a variety of typical concrete issues. By keeping up with the most recent developments and methods in this industry, you can guarantee that your maintenance and repairs are done effectively and efficiently. Concrete injection can prolong the life of your structures and ultimately save you money and time if done properly.

Video on the topic

Injection, concrete repair. Waterproofing, restoration. Dmitry Lebedev, founder of Cetus.PRO

Injection technologies Pit

Waterproofing by injection of concrete structures

Waterproofing of a cold joint, wall-floor junction.

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Marina Petrova

Candidate of Technical Sciences and teacher of the Faculty of Construction. In my articles, I talk about the latest scientific discoveries and innovations in the field of cement and concrete technologies.

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