Glossary

Acrylic gels are generally aqueous 3-component injection materials with a very low viscosity of <10 mPa-s. The materials are particularly suitable for sealing thicker masonry and, like the PUR injection resins, have a capillary blocking effect. They can also be used for salt exposure and high levels of moisture penetration, as well as for surface sealing within an open-pored building structure. The material can reversibly absorb and release moisture and should therefore only be used in areas in contact with the ground.

Adhesion is the physical term for the state in which different bodies or substances adhere to each other.

Adhesive tensile strength is the tensile force per unit area that must be applied perpendicular to the contact surface in order to release the adhesive bond between the material and the substrate (e.g. masonry). It is measured to assess the adhesion of coatings or fillers.

Describes the percentage of water vapor in the gas mixture of the air. In the context of coatings, humidity as a function of temperature is an important indicator known as the dew point. For coatings, the building temperature should ideally be at least 3 °C above the dew point in order to avoid condensation.

Only those who know a problem and what causes it can solve it sustainably. This is why a comprehensive building condition analysis is the basis for professional refurbishment.

The analysis of the building condition includes general investigations such as building information on

• Age
• Building condition
• Use of the adjoining rooms
• Humidity and temperature in the rooms
• Groundwater conditions
• PH value of the groundwater
• Indication of acids (increased salt load)
• Assessment of the subsoil

The construction of the building component must also be taken into account:

• Type and structure of the masonry
• Wall thicknesses
• Structure of the masonry (single or multi-shell, with or without air layer)
• Homogeneity
• Strength
• Density and porosity of the wall
• Existing cracks and cavities
• Any component movements
• Foundation structure and position
• Supply connections
• Static evaluation and stability
• Existing barriers
• Positions and condition
• Repairs already carried out

The moisture analysis in the component also allows conclusions to be drawn about the cause of the damage.

For surfaces, the

• the condition of the substrate
• the moisture condition
• surface strength
• the concrete quality and the
• condition of the surface

are determined.

If cracks limit the load-bearing capacity or serviceability of a component, this constitutes a defect or damage.

Banked-up seepage water occurs in very dense and/or cohesive soils (e.g. clay). The surface water can often only drain away slowly and builds up from the bottom upwards, creating hydrostatic pressure.
 

Federal Highway Research Institute (Bundesanstalt für Straßenwesen, BASt), a research institution of the Federal Ministry of Transport and Digital Infrastructure in Germany. The aim of the BASt is to improve safety on Germany's roads.

Bending cracks occur when bending moments arise and usually run perpendicular to the flexural reinforcement. They start at the tensile edge and end in the zero line

A bending tensile stress occurs on the outside of a bent material. As the surface is enlarged on the outer bent side, tensile stress is created. The component's ability to withstand this stress is called bending tensile strength.

Bentonite Swelling Tape is used for sealing construction joints in in-situ concrete structures. In contrast to prefabricated concrete elements, in‑situ concrete is applied at the construction site – i.e. cast-in-place directly on site. Swellable joint fillers are used for joints exposed to ground water, slope water or surface water. It is also suitable for sealing pipe passageways. Bentonite Swelling Tape is characterized by its reliable swelling behavior. It must be firmly surrounded on all sides to be able to build up the necessary swelling pressure. The sodium bentonite swelling tape may therefore only be used for in-situ concrete structures. Thanks to its change in structure from solid to malleable material upon contact with water, cracks and gravel nests/honey combs are sealed effectively and permanently. 

Additional moisture in a building component that penetrates the building material during the construction period. This moisture can escape again in the subsequent period until the equilibrium moisture content is reached.

The DIBt (German Institute for Structual Engineering) publishes a list of building products that comply with the state building regulations and may therefore be used in Germany.

Capillary water absorption is a physical phenomenon that occurs as a result of the surface tension of water in capillaries, e.g. in the concrete structure or masonry.

The carbonation of concrete means that the calcium hydroxide in the concrete absorbs carbonic acid from the air and this can penetrate millimetres to centimetres into the concrete. As a result, limestone forms and the strength of the concrete can even be increased. On the other hand, the loss of the alkaline environment can cause the reinforcement to rust and make the concrete unstable in these areas.

Causes of cracks can result from the concrete properties, e.g.

• Heat of hydration and cooling,
• Shrinkage,
• Creep or swelling

originate. Or from stresses such as

• Load,
• Hindered deformations,
• Temperature influences,
• Settlements,
• Ground deformation or
• Carbonation

An air or gas-filled space in a component is filled using injection materials to prevent subsequent instability of the component.

Construction products that are covered by a harmonized standard will be marked with a CE mark. CE stands for “Conformité Européene”. CE certified goods may be placed on the market within the European Economic Area. By affixing the CE mark, the manufacturer or distributor declares that the product complies with the applicable requirements of the harmonized standard.

Compressive strength is the maximum resistance of a material to pressure, the unit is N/mm². The compressive strength is the quotient of the breaking load and the cross-sectional area of a test specimen.

Concrete is a building material made from a mixture of cement, water and aggregates, with or without the addition of other additives.

Cavities in the concrete component caused by insufficient compaction or mixing of the concrete. As a result, water and oxygen can penetrate the component and the steel can start to rust.

A crack monitor is used to quantitatively record movements or deformations in structures and offers the advantage of precise measurement compared to a plaster mark. The measuring system consists of two overlapping plates that can be moved against each other: The lower one bears a scale, the upper one a transparent crosshair. After adjustment in the zero position, the crack monitor is fixed on both sides of the crack with adhesive. Movements in the horizontal or vertical direction can then be read directly from the crosshairs.

Crack monitors are used in particular to document settlements or deformations at critical component connections such as floor slab-wall, wall-floor slab or building corners.

Crack width w (in mm) is the measured distance between the crack edges on the non-mechanically processed component surface. Crack gauges or crack magnifiers, for example, can be used to determine the crack width.

Crack width changes can occur on one side with a constant increase or decrease in crack widths or recurring. Recurring crack width changes can be

• Short-term (as a result of traffic loads),
• Daily (as a result of day/night cycles or solar radiation) or
• Long-term (e.g. due to seasonal factors)

can be caused. These influences often overlap with irreversible changes in length such as shrinkage shortening. Knowledge of the change in crack width is of particular importance for the selection of suitable expandable crack filling materials and the associated success of a repair measure.

Crack gauges or crack magnifiers for determining the width of a crack.
 

Cracking caused by settlement, temperature fluctuations or shrinkage - a typical phenomenon in buildings.

Subsequent sealing of undergrade building components by inserting a gel creep between the soil and the component is known as curtain injection.

Curtain injection is mainly used when components cannot be sealed from the outside or can only be sealed with disproportionate effort.

The expected highest level of groundwater, stratum water, backwater, seepage water or flood water to be expected during the service life.

The dew point temperature is the temperature at which condensation (condensation water) forms on a component. Cooler air can absorb less moisture, so water condenses on the surface of the component. The dew point temperature depends on the relative humidity and the air temperature; the corresponding values can be found in the dew point table. To prevent condensation from forming when coating components, for example, the component temperature must be 3 °C above the dew point. For example: at an air temperature of 22 °C and a relative humidity of 60 %, the dew point is 14 °C, i.e. the temperature of the component to be processed must be at least 17 °C.

German Institute for Structual Engineering

German Institute for Standardization

Drill hole packers are cylindrical injection packers that are inserted and clamped in drill holes. 
A distinction is made between mechanical packers, which are anchored in the drill hole by screwing; in this case, the drill hole must be drilled 1 mm larger than the diameter of the packer. 
On the other hand, there are hammer-in packers, which are hammered into the drill hole and anchored in the drill hole by annularly arranged lamellas; the component must have sufficient strength. For hammer-in packers, the recommended drill hole size corresponds to the diameter of the packer.

Efflorescence is a crystalline salt deposit that occurs when water-soluble salts such as saltpetre (calcium nitrate), calcium sulphate, sodium carbonate, calcium carbonate etc. are transported outwards with water in mineral building materials. When the water evaporates from the surface, the salts remain as deposits.

An injection method according to ZTV-Ing and DAfStb guidelines for the injection/sealing of cracks and cavities/voids with epoxy resin.

Epoxy resins are polymeric reactive resins that are formed by the chemical reaction of at least two epoxy groups with a hardener. 
They are used as a structural connection in the renovation and repair of buildings. Epoxy resins are characterized by their high resistance to mechanical or chemical stress as well as their very good penetration properties during injection.

Equilibrium moisture corresponds to the degree of moisture of a fabric at which it no longer absorbs or releases moisture from the ambient air. The moisture of the fabric is in equilibrium with the humidity of the air.

Structures that do not lead to cracking of the crack filling material, even with expansion and compression movements over the entire crack area, are necessary for filling with limited expansion.

PU resins react with water and form fine bubbles. It is these small bubbles that can absorb small volume changes in cracks that extend over a large area when stretched or compressed. Together with the good adhesion to the crack flanks, this “limited ductility” allows changes in crack width due to temperature changes and/or recurring loads to be bridged. Re-opening of the crack is prevented.

Joints in the space between components to compensate for temperature fluctuations and the associated expansion and shrinkage of the component.

Subsequently sealing components in contact with the ground against moisture can be very time-consuming or even impossible for design reasons (partial basements, leaks in floor slabs, underpasses). Inaccessible components exposed to moisture can be sealed without digging by curtain injection with acrylate gels.

The manufacturer checks the manufactured products, intermediate products and raw materials to ensure that they meet the specified properties. Production control checks whether everything is running according to plan in the various areas.

Material with which the injection is carried out e.g. polyurethane resins, polyurethane foams, epoxy resins and cement suspensions

Process of crack injection; casting, injecting or grouting.

Also known as sealing or curtain injection; refers to the subsequent sealing of undergrade building components.

Building products and types of construction for which there are no standardized rules (e.g. DIN) or which deviate from the standardized rules receive a general building approval (abZ) from the Deutsches Institut für Bautechnik DiBt. The abZ assesses products or types of construction with regard to their building authority requirements.
 

The general building authority test certificate (abP) is proof of the usability of construction products and is issued by the German Institute for Building Technology DiBt. There are no standardized rules, such as generally accepted technical rules or DIN standards, for the construction products or types of construction tested in this way. The general building authority test certificates are issued by material testing institutes such as the MFPA/MPA, which are authorized by the DiBt (Deutsches Institut für Bautechnik).
 

Established technical rules for the execution of construction activities. Techniques that are recognized as customary in the industry and have proven to be technically suitable and necessary based on practical experience.

In general, the water that accumulates in the soil due to precipitation.

Plastic packer for driving into the component, which is anchored in the drill hole by annularly arranged lamellae. The recommended drill hole size corresponds to the diameter of the packer.

A hammer-in profile is a joint filler or joint profile used to backfill deep expansion and connection joints. A hammer-in profile can take various forms, but is typically a round profile, also known as a ring cord. A hammer-in profile can be used to limit the depth of a joint, thereby providing a solid abutment. The advantages: The joint becomes more stable and cracks are prevented. This means less sealant is required in the subsequent steps for sealing the joint. If the material of the profiles is ethylene-propylene-diene monomer foam, it is referred to as a hammer-in profile EPDM.

Damp proof courses (dpc) in masonry prevent moisture from the soil from rising capillary in the masonry.

In new buildings, mechanical damp proof courses (dpc) are installed, e.g. made of stainless steel sheets, wallboard or foils. In older existing buildings, there is often no damp proof course (dpc) at all or the existing one is damaged and moisture can rise capillary in the masonry. In this case, a post-construction damp proof course (dpc) can be installed. As with new buildings, there are also mechanical methods: Drill core method, wall sawing method, wall replacement method or hammering in metal sheets or steel plates.

These mechanical methods are very time-consuming, the statics are weakened during installation and cracks can occur in the building component. Incorrect installation can lead to bonding problems between the masonry and the installed parts.

Damp proof courses (dpc) using injection methods are much less complicated. They offer a solution with significantly less effort and better results than mechanical barriers. The capillary transport of moisture is prevented by injecting reactive materials. Depending on the material used, this is achieved by clogging, constricting or hydrophobizing the capillaries.

Injection lances are extensions with and without holes for filling and/or solidification of the substrate in sandy soils, for example.

The injection pressure is the nominal value of the delivery pressure at which crack filling material is delivered to the filler neck (packer).

Isocyanate is a highly reactive organic compound with the NCO group as a reactive component. Isocyanates are used as hardeners for polyurethane resins.

Spaces between components to compensate for expansion / contraction. Depending on the component type and size, a certain distance between the joints must be selected in order to remain within the permissible framework of the ZTV-Ing and DIN standards.

The following types of masonry are distinguished between single-shell and double-shell masonry, as well as according to the material used and masonry bond

• Dry masonry
• Cyclopean masonry
• Quarry stone masonry
• Hammered masonry
• Irregular layered masonry
• Regular layered masonry
• Ashlar masonry

This is the ratio of the - usually 2-component - injection materials in which the A and B components must be mixed together in order to achieve the best possible curing result. The mixing ratio can be specified both in parts by volume and in parts by weight.

The time it takes to achieve an optimum (homogeneous) mixing result.

The modulus of elasticity (modulus of elasticity) is a material parameter used in materials engineering to describe the stress and strain during the deformation of objects. The lower the value, the easier the deformation of the object. 
The modulus of elasticity decreases at higher temperatures. At 20 °C, steel has a modulus of elasticity of approx. 210,000, whereas concrete only has a value of approx. 27,000 - 37,000.

Dry

• Crack banks and component surface are visually dry, water ingress is not possible
• Influence of water on the crack/cavity area cannot be determined
• Water ingress possible, but can be ruled out for a sufficiently long time

Damp

• Color change due to water (capillary water absorption) in the crack or cavity area, but no water leakage
• Signs of water leakage in the immediate past
• Crack/cavities/voids recognizably damp or matt damp, also on dry drill cores

Wet or unpressurized water-bearing

• Standing water visible in the crack or in fine droplets in the crack area
• Water beads out of the crack area

Flowing water or water under pressure

• Water flows as a continuous stream through the crack or cavities/voids

The degree of moisture saturation (DMS) describes the percentage of moisture in relation to the maximum amount of water that can be absorbed by a component. The actual moisture content can be determined using the Darr method or the CM method, for example. The basis for the calculation, i.e. the maximum moisture value, can be taken from tables, whereupon the degree of moisture penetration can be determined.

Rising damp in masonry is due to the capillary absorbency of mortar and masonry blocks. This works like a sponge, existing water is absorbed and distributed in the building component. 
The extent to which the water can be distributed in the building component essentially depends on the diameter of the capillaries. The smaller the capillaries are, the greater the capillary absorbency and the higher the moisture can rise in the masonry.
No capillary water transport takes place if the pores are either very small and not connected to each other or the radii of the capillaries are larger than approx. 1 mm.

Low-molecular, unsaturated, reactive compounds that form the basic building block for polymers.

The soil is impermeable to the extent that the seepage water can be drained away via a drainage system.

Water that does not exert any pressure on a component.

Injection packers are filler necks that enable the connection of the component and injection pump during injection. Depending on the type of connection to the component, a distinction is made between drill hole packers and surface packers.

Borehole packers

• WEBAC Mechanical Packers Type S
  • Easy to handle
  • Economical use
     
• WEBAC Mechanical Packers Type R
  • Variable use
  • Can also be equipped with button head fittings for higher flow rates
     
• WEBAC Hammer-in Packers 
  • Easy to handle
  • Not suitable for porous masonry/concrete

Surface packers 

• WEBAC Plastic Packers
  • No drilling required (non-destructive injection)
  • Often used on horizontal surfaces

One-day packers

• kein Rückfluss des Materials aus dem Packer, da Rückschlagventil vorhanden
• Rückbau und Verschließen sofort nach der Injektion möglich

Ability of a substance to penetrate a component due to its low viscosity. The lower the viscosity (thinner), the better the penetration ability of the injection material.

The description of the service to be provided by the client for the submission of bids by potential contractors. The construction project should be described as precisely as possible in order to obtain exact information from potential contractors regarding prices and quantities. Any subsequent changes would have to be recorded as an addendum.

A person suitable for specialist planning who can be consulted as an expert in a specific construction phase or for projects through diplomas or additional qualifications.

Polymer Swelling Tape is used for sealing construction joints and joints in precast concrete construction. Polymer swelling tape is permanently dimensionally stable and perfectly suited for repairing expansion joints. Polymer Swelling Tape can even be installed in open joints. The product is also designed for sealing pipe passageways. Polymer Swelling Tape is a swellable filler for joints, it swells upon contact with water. The resulting expansion pressure and the related contact pressure provide for a reliable sealing process. Polymer swelling tape  is characterized by its excellent resistance to chemicals. They can also be used for structural elements exposed to salt or fertilizer.
Swelling Tape is bonded to the substrate with contact adhesive. Especially when using polymer swelling tape vertically it is recommended to install the swellable joint filler mechanically – by means of headless steel nails. No matter if the tape is installed using nails or adhesive: the polymer swelling tape must lie firmly against the entire substrate and be secured against shifting or floating during concreting.

Polymerization is a chemical, exothermic reaction of monomers to form synthetic macromolecular substances (polymers).

Polymers have a high molecular weight due to the combination of many small monomers. Polymers can be divided into natural and synthetic polymers. The common injection products (PU, epoxy and acrylate gels, etc.) consist of liquid monomers that form a polymer solid after reacting with each other.n.

Polyurethanes (PU) are formed by polyaddition of isocyanate (aromatic or aliphatic) with a polyhydric alcohol (polyol) or an amine. Depending on the degree of cross-linking and the structure of the polyol, polyurethanes can range from hard to elastic.

After the actual main injection, the filling material is injected again to fill any leaks that may have occurred during the injection.

Pot life is the period of time during which reactive materials such as epoxy resins can be processed. The pot life of reactive resins is determined in accordance with DIN ISO 9514.

The processing time is the period of time in which a product can be processed after production or mixing.

Cracks are repaired to

• Prevent the ingress of corrosive substances ► Close a crack
• To make a component watertight ► Sealing

Depending on the requirements for the result of the repair, this is achieved by

• Crack fillings that can swell when water is present (reversible) ► Swellable fillings
• Crack fillings that can absorb changes in crack width. For this purpose, the crack flanks are sealed with materials that have limited ductility ► Ductile bonding
• Crack fillings that create a tension- and compression-resistant connection between the crack flanks that also transfers forces

Safety data sheets (SDS) are used to provide safety-related information on substances and mixtures. This provides the professional user with the necessary data and handling recommendations for handling substances and mixtures in order to be able to take the necessary measures for health protection, safety at work and protection of the environment. The content of the safety data sheet is regulated in detail in Annex II of the REACH Regulation (EC) No. 1907/2006.

Water-soluble salts such as nitrates, ammonium, chlorides, carbonates, and sulfates can significantly increase the moisture content in masonry due to their hygroscopic (water-attracting) effect.
The crystallization of salts on the surface of building components leads to efflorescence. This transition from the dissolved to the crystalline form is often associated with a significant increase in volume, whereby the crystallization pressure can cause damage to plaster or masonry. Samples taken from the masonry can be used to analyze the type and quantity of salts and to determine the distribution of the most harmful salts.

Salts are chemical compounds that are made up of positively charged ions (cations) and negatively charged ions (anions). Ionic bonds exist between these ions. In inorganic salts, the cations are often formed by metals and the anions are often formed by non-metals or their oxides. As solids, they form a crystal lattice together. Organic salts are all compounds in which at least one anion or cation is an organic compound.

Salts can significantly impair the substance of buildings. Salts that are harmful to buildings include sulphates, chlorides and nitrates in particular. These can be naturally present in mineral building materials in varying concentrations - for example in masonry, bricks or plaster or masonry mortar.
If moisture penetrates the building component, salts can be transported in dissolved form with the water. Prolonged exposure to moisture also leads to the mobilization of salts already present in the building material. These dissolved salts reach the component surface via capillary transport processes, where the moisture evaporates and the salts crystallize. Due to their larger volume, the resulting crystals cause considerable compressive stresses in the pore structure, which can lead to cracks, spalling and structural damage.

Damaged structural and expansion joints can be subsequently sealed with little effort by backfilling with acrylate gels. The injection material not only fills part of the joint space, but also forms a gel veil in the adjacent soil, which is able to absorb even larger joint movements. In this way, it is possible, for example, to repair circumferential movement in damaged internal waterstops. This method is particularly suitable for the subsequent sealing of so-called “white tubs” where the planned joint seals have been installed incorrectly.

Separation cracks are cracks due to the low tensile strength of the concrete. They affect significant parts of the cross-section or separate the entire cross-section.

The cause of the formation of separating cracks in concrete components results from cooling (dissipation of the hydration heat) and shrinkage deformations (during hardening) and the resulting restraint stresses.

Settlement cracks are caused by uneven settlement and displacement in the subsoil.

Hardness generally characterizes the resistance of a material to mechanical penetration by another body. The Shore hardness is a number on a scale of 0-100 that indicates the hardness of elastic materials. The lower the value, the lower the hardness. According to DIN 53505, a distinction is made between the SHORE A, C and D methods.

Connection piece between button head fitting and injection adapter of the pump
 

Depending on the moisture load, damp rooms are divided into 8 stress classes.

Moderately stressed rooms in stress classes 0, A01, A02 and B0 are mainly found in private homes. Highly stressed areas are regulated by the building authorities and classified as follows:

• Stress class A1
• Wall surfaces with high exposure to cleaning and process water, e.g. in public showers
• Exposure class A2
• Floors with high exposure to cleaning and process water, e.g. in public showers and swimming pools
• Stress class B
• Wall and floor surfaces in swimming pools (water pressing from the inside)
• Stress class C
• Wall and floor surfaces subject to high water stress in combination with chemical stress, e.g. from chlorine solution, disinfectants

Creation of the monolithic construction state through a compression, shear and pressure-resistant connection in crack or concrete flanks with strength properties. 
Low-viscosity, solvent-free 2C epoxy injection resins are predominantly used for structural bonding (filling) in concrete construction. The good spreading and flow properties of these crack filling materials enable the injection of cracks with crack widths > 0.1 mm and penetration into the finest ramifications. With their high inherent and adhesive strengths, they permanently restore the structural bond of the separated structure and thus the monolithic load-bearing behavior of the component.

Surface-like fine cracks < 0.1 mm, such as craquelure, usually do not restrict the usability of the component and do not need to be treated. They generally run above the reinforcement layers and are almost exclusively caused by excessive temperature differences between the core and shell in the concrete.

Surface packers are bonded directly to the crack on the component surface, no drilling is required (non-destructive injection).

Construction chemistry systems, usually based on epoxy resins, to protect surfaces from stress or strain.

Tie Points and penetrations are commonplace in concrete and reinforced concrete construction. They must be reliably sealed—especially in buildings at risk of water pressure. Plugs, rings, and flanges are swellable sealings that can be used to create watertight seals at tension points. This works even with negative water pressure. These sealing solutions can be installed without adhesive—the seal can be quickly and easily set in place with a hammer.
 

Tubbings are concrete or steel components used to reinforce the inside of a tunnel. Usually consisting of seven parts, they form the inner wall of the tunnel, but are subsequently sealed for further solidification in order to close leaking joints and cracks.

Viscosity describes how thick or viscous a liquid is. The higher the viscosity, the thicker the material.

Waterproofing methods against seepage or groundwater

• Integral waterproofing with watertight concrete (‘white tank’ method).
• Black tank: watertight enclosure of a building, e.g. with bitumen thick coating below the ground surface