Glossar
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Acidizing
With the help of an acid gel, it is possible to process the concrete surface after curing. This exposes the aggregate. However, the same washing depths cannot be achieved compared to washing.
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Aggregate composition
Also called "grading curve." It should be selected to give the highest possible packing density.
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Aggregate mixture
Aggregate consisting of a mixture of coarse and fine aggregates suitable for concrete production without addition of other aggregates. Note: A mixed aggregate may be produced both without prior division into coarse and fine fractions and by combining coarse and fine aggregates as a factory-mixed aggregate.
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Air entraining agent
Introduction of uniformly distributed small air voids, e.g. to increase the frost and freeze-thaw resistance of concrete.
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Architectural concrete
This usually refers to a method of concreting that emphasizes the selected structure of a formwork. Layers close to the surface are made with particularly fine concrete, which, due to its flowability and fineness, [...]
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artico neo
The term "artico neo" is a synonym for the term "photo concrete". With the help of wash-out processes on the exposed concrete surface, it is possible to create photo-like images.
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CEB
CEB is the abbreviation for Comité Euro-International du Béton (Euro-International Concrete Committee).
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Cement
Cement is a hydraulic binder. That means that after being mixed with water, cement hardens both in the air and under water. After hardening, it remains solid and stable in space even under water.
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Cement paste content
The cement paste content must be adjusted to the grain composition (the so-called grading curve). Too little results in poor bonding of the aggregates, too much in a concrete that is too soft.
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Characteristic strength
The strength value below which 5% of the population of all possible strength determinations of the concrete under consideration are expected to lie.
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Chromate reducer
Chromate reducers reduce the water-soluble chromate content of cementitious products. They are used in the processing of concrete and mortar with direct skin contact.
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Colour pigments
Pigments (Latin "pigmentum" for color) are colour-providing substances that are used in technical applications.
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Compaction
Reduction of voids in soils, building materials, or mixtures of building materials by mechanical action to achieve greater storage density.
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Concrete
The word concrete comes from the French. It was first mentioned by Bernard de Bélidor in a book on architecture. Concrete is a mixture of cement, aggregate or concrete aggregate (sand and gravel or crushed stone) and [...]
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Concrete additives
Concrete admixtures are fine inorganic or organic substances used in concrete to specifically improve or achieve certain properties. Unlike concrete admixtures, they are to be considered as volume constituents in the material space calculation. Concrete admixtures include rock flour, pigments, trass and fly ash.
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Concrete admixtures
Concrete admixtures are liquid, powdery or granular substances that are added to the concrete in small quantities during mixing, based on the cement content. They influence the properties of the fresh and/or hardened concrete by chemical and/or physical action.
There 18 different groups/types of action:
Concrete plasticizer - Superplasticizer - Superplasticizer/ Retarder - Air entraining agent - Sealant - Retarder - Hardening accelerator - Setting accelerator - Setting accelerator for shotcrete - Press-in aid - Stabilizer - Sedimentation reducer - Chromate reducer - Foaming agent - Elastic - Expansion aid - Passivator.
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Concrete paving stones
Concrete product manufactured in the factory for the production of paved surfaces in exterior and interior areas.
It must meet the following conditions:
- At a distance of 50 mm from each edge, no cross section has a horizontal dimension of less than 50 mm.
- Its total length divided by its thickness is less than or equal to four.
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Concrete sealants
Concrete sealants improve the water impermeability of the hardened cement paste and thus of the concrete. This is achieved by a certain water-repellent effect of the concrete admixture.
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Density
Quotient of mass and volume. For soil: mass of moist soil including pores filled with liquid and gas, excluding intrinsic and pile spores. For natural stone and aggregates: dry mass excluding any pore space present, including intrinsic and pile spores.
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Exposed concrete
Exposed concrete is the term used to describe concrete surfaces whose surfaces remain visible and which are subject to certain requirements in terms of appearance. (see also "architectural concrete").
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Fibers
Fibers consist of glass, steel or polypropylene. These are added to concrete and improve concrete properties, including strength, compressive values and tensile values.
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Foam generator
Uniformly distributed air voids are introduced by foam generation using a foaming unit.
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Green compressive strength
The strength of concrete before hydration begins. It depends primarily on water content and compaction energy, and secondarily on cement content, cement grind fineness, concrete admixtures, and aggregate grain composition. It can be more than doubled by the addition of fibers. The green compressive strength is generally between 0.1 and 0.5 N/mm².
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Grouting aids
Grouting aids improve flowability, reduce water demand and settling and cause moderate swelling of grout.
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Hardening accelerators
Hardening accelerators accelerate the hardening of concrete. They are used for concreting at low outside temperatures (frost aid) and for concrete products (to increase early strength).
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High-strength concrete
Concrete with a strength class of C55/67 or higher for normal or heavy concrete and a strength class of LC55/60 or higher for lightweight concrete is referred to as high-strength concrete. It is characterized by a dense microstructure with few capillary pores.
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Hydrophobic
Water repellent
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Impregnation
Surface treatment to change its properties, e.g. wettability.
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Insulation material
An insulating material is a material with low thermal conductivity, which is used for thermal insulation in the construction industry, in plant engineering or in the manufacture of refrigerators, freezers or similar. In addition, insulating materials have sound-absorbing and other building-physical properties.
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Micro washout gel
Surface treatment with acid gel. However, the washout depths are much smaller than with normal wash-out.
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Mixing water
Water that must be added during the mixing and preparation of concrete in order to make the material workable and to initiate the setting process. It is added only in the quantity that achieves the consistency required for processing and does not impair the strength of the set material too much.
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Negative process
Application method of the contact retarder during washout. In this case, the retarder is applied to the hidden concrete surfaces of the workpiece by prior treatment of the formwork surfaces.
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Period of use
Period of time during which the properties of a structure or component are sufficient to meet the performance requirements of the structure/component, assuming proper maintenance.
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Photo concrete
With the aid of wash-out processes on the exposed concrete surface, it is possible to produce photo-like images.
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Positive process
Application method of the contact retarder during washout. In this case, the retarder is applied to the exposed concrete surface of the workpiece.
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Powder paints
Finely ground color pigments. When used in concrete, they must be alkali-resistant, lightfast and weather-resistant.
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Precast concrete elements
Precast concrete elements are produced in a factory, stored there, delivered to the construction site and then installed. Ceilings, walls and roofs are made from large-sized precast elements. Precast structures made of columns and beams and ready-made sanitary cells are also part of the construction program. So-called system houses are completely made of precast concrete elements in the course of shell construction.
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Reinforcement
Concrete is excellent at absorbing compressive forces, but has low tensile strength. Concrete is therefore often "reinforced" with rods or fibers made of materials with high tensile strength. These can be, for example, steel fibers, glass fibers or fiber or reinforcement bars made of carbon.
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Release agents
Release agents are used to prevent the mold from sticking to the concrete part during impression processes or to keep objects permanently separable. Therefore, they must be selected depending on the absorbency of the mold skin and must not cause discoloration of the concrete.
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Retarders
Slow down the chemical reaction (hydration) of cement and retard the setting of cement as well as heat generation. Application: Production of larger monolithic components (mass concrete), e.g. in bridge construction, foundations, ready-mix concrete, concreting at high outside temperatures.
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SCC
Self-compacting concrete (SCC) is a concrete that deaerates and encloses the reinforcement by gravity alone. This is made possible by a very flowable consistency, which is achieved by modern high-performance concrete plasticizers based on polycarboxylates.
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Screed
Screeds are mortar layers that are applied as a floor on a load-bearing substrate or on intermediate separating layers or insulation layers.
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Sedimentation reducer
Prevent sedimentation, i.e. the deposition of concrete constituents in fresh concrete.
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Setting accelerator
Setting accelerators accelerate the setting (setting time <30 minutes) and the hardening of concrete. They are used for concreting at low outside temperatures (frost aid) and for concrete products (to increase early strength).
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Setting accelerator for shotcrete
Setting accelerators for shotcrete accelerate the setting (setting time <10 minutes) of concrete. They are used, for example, in tunnel construction (shotcrete) and in lightning mortar for sealing water ingress.
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Setting retarder
Retarders cause a delay in the setting of the cement paste and thus allow the workability of concrete to be extended.
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Stabilizers
Reduce the tendency of concrete to bleed and segregate.
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Structurally dense lightweight concrete
A concrete with a lightweight aggregate that is dense and has a completely closed surface. Due to its low dead weight, it can be used advantageously for the construction of long-span bridges, high-rise buildings and precast elements.
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Superplasticizer
Superplasticizers either improve the workability of the concrete at the same water-cement ratio or reduce the water demand and thus the water-cement ratio at the same workability. This leads to an increase in compressive strength and impermeability.
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Surface treatment
Differentiation in mechanical, thermal and/or chemical processing on the hardened concrete. The surface is removed more or less deeply and the color of the aggregate appears. (see also "Acidizing" and "Washing out").
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Tensile strength
Concrete has a particularly high compressive strength, but can only absorb low tensile stresses. The centric tensile strengths of common concretes range between 1.5 and 4 N/mm². Therefore, in reinforced and prestressed concrete, the so-called reinforcement (e.g. special fibers or steel) takes over these forces and thus increases the tensile strength of the composite.
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Texture
Haptic surface design of the concrete surface by reproducing the formwork shape, washing out, acidifying or mechanical processing of the concrete, e.g. stocking and choice of aggregate.
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Trough stone
Factory-produced concrete product for making a trough channel.
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Types of concrete
Fresh concrete - Site concrete - Ready-mix concrete - In-situ concrete - Shotcrete - Underwater concrete - Roller-compacted concrete - Spun concrete - Vacuum concrete - Fiber concrete
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Underwater concrete
Underwater concrete is concrete that is placed under water. To ensure that the concrete does not segregate during concreting, special concreting methods are required, such as the use of stationary hoppers (so-called contractor method). The concrete must have good cohesion and workability. For this purpose, the cement content should be at least 350 kg/m³. Underwater concrete is used in particular for diaphragm walls and in groundwater as a barrier layer for floor slabs.
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Washed concrete paper
Paper coated with a contact retarder. This allows the formwork to be laid out before filling with concrete. Advantage: The concrete can be poured immediately after the exposed aggregate paper has been laid, e.g. in the case of rotary table hermetic presses.
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Washing varnish
When producing finely washed surfaces, the cement slurry on the concrete surface is prevented from hardening by contact retarders. After stripping the precast elements, this uncured surface can be washed off with a water jet. In this way, the colored aggregates [...]
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Washout
During washout, a contact retarder is applied positively or negatively to the concrete. It is important that the application takes place before curing. The surface effect is given by the exposure of the aggregate.
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Water-cement ratio
The water-cement ratio describes the mass ratio of effective water content and cement content. The higher the water-cement ratio, the lower the impermeability and strength of the concrete. Water-cement ratios between 0.40 and 0.60 are favorable.
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Water content
Deviations from the optimum water content impair the green compressive strength. The water content must be related to the compaction method and performance. Water content, consistency and the production process must be coordinated.
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Water permeability
The property of a layer to allow water to pass through open pores.
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Water retention
Property of solid particles to retain the mixing water added during concrete production. In fresh concrete, the water escapes first from the coarse pores. The finer the pores in the mix, the better capillary forces and adsorption forces can retain the water. A high water retention capacity affects the tendency of the fresh concrete to secrete water.
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Weathering
Loss of substance on the surface due to weathering and aging of the building materials.