Name: concrete surface finishing steps
Uploaded: 2024-11-07T14:48:35.000Z
Duration: 1 min 18 s
Channel: JoVE

Nach der Verfestigung des eingebauten Betons wird überschüssiges Material von der Oberfläche entfernt und mit einem Estrich mit der Schalungsoberseite bündig.
Anschließend werden mit einem Bull Float oder Darby die hohen Stellen auf der Betonoberfläche abgesenkt, die niedrigen Stellen verfüllt und große Zuschlagstoffe in den Beton eingebettet, bevor das Zapfwasser an die Oberfläche steigt.
Sobald der Glanz des Zapfwassers auf der Oberfläche beim Verdampfen verschwindet, ist es bereit für die endgültige Veredelung. Das beginnt bei der Einfassung, bei der die Kanten des Betons abgerundet werden.
Es folgt die Fugenbildung, bei der Kontroll-, Isolations- und Arbeitsfugen strategisch in der Struktur platziert sind.
Als nächstes wird ein Handschwimmer oder Elektroschwimmer verwendet, um Oberflächenfehler zu entfernen, die sich aus Kanten und Fugen ergeben, die Zuschlagstoffe leicht in den Beton einzubetten und das überschüssige Wasser zu entfernen, wobei die Oberfläche offen bleibt.
Schließlich kann die fertige Oberfläche durch Spachteln strukturiert werden, um eine harte und glatte Oberfläche zu erzeugen, durch Besen, um sie rau und rutschfest zu machen, durch Waschen des überschüssigen Zementleims auf der Oberseite, um ein freiliegendes Aussehen zu erzeugen, oder durch Einfügen von Trennstreifen gemustert.

betonveredelung

Die Betonveredelung beginnt unmittelbar, nachdem der Beton eingebracht und verdichtet wurde. Der erste Schritt, das Abziehen, umfasst das Nivellieren der Betonoberfläche durch Entfernen überschüssigen Materials, um sie bündig mit der Oberseite der Schalung abzuschließen. Anschließend wird die Oberfläche mit einer Glättkelle oder einem Abzieher weiter geglättet, hohe Stellen effektiv abgesenkt, tiefe Bereiche aufgefüllt und sichergestellt, dass größere Zuschlagstoffpartikel im Beton eingebettet werden. Diese Vorbereitung ist entscheidend, bevor Wasserabsonderungen auftreten, da deren Vorhandensein zu Ablagerungen und Staubbildung führen kann.


 Sobald die Oberfläche frei von Wasserabsonderungen ist, ist der Beton bereit für die Endbearbeitung. Dazu gehört das Kantenschleifen, bei dem die Kanten der Platte abgerundet werden, um Absplitterungen zu vermeiden; das Verfugen, bei dem Kontroll-, Isolations- und Arbeitsfugen geschaffen werden, um die natürlichen Bewegungen des Betons zu steuern und unansehnliche Risse zu vermeiden; und das Glätten. Letzteres glättet alle Unebenheiten, die durch die vorherigen Schritte entstanden sind, bettet die Zuschlagstoffe leicht unter der Oberfläche ein und verdichtet den Mörtel an der Oberfläche für die Endbearbeitung, während überschüssige Feuchtigkeit entweichen kann.


 Das endgültige Aussehen und die Textur des Betons werden durch verschiedene Techniken erreicht, beispielsweise durch Glätten und Härten der Oberfläche mit der Kelle oder durch Aufrauen mit dem Besen. Darüber hinaus können Muster oder freiliegende Zuschlagstoffe aufgetragen werden, um dekorative Effekte zu erzielen.

Betonveredelung

Nach der Verfestigung des eingebauten Betons wird überschüssiges Material von der Oberfläche entfernt und mit einem Estrich mit der Schalungsoberseite bündig.
Später...

Education

Lehre

JoVE Core

Civil Engineering

Bauingenieurwesen

Unit 1

Einheit 1

Mixing, Placing and Curing Concrete 

Mischen, Einbauen und Nachbehandeln von Beton

KEY TERMS AND CONCEPTS

ZENTRALE BEGRIFFE UND KONZEPTE

Finishing Concrete

concrete surface finishing steps

Concrete surface finishing begins right after the concrete has been placed and consolidated. The first step is screeding, which levels the surface by removing extra material until it is even with the top of the formwork. A screed is a straight edge used for this leveling step.

After screeding, a bull float or darby is used to smooth the surface further. These tools help lower high spots, fill low areas, and push larger aggregate particles deeper into the concrete. This preparation should happen before bleed water appears. Bleed water is the water that rises to the top of fresh concrete, and if it is handled too soon, it can lead to scaling and dusting.

When the surface is free of bleed water, the slab is ready for final finishing. Edging rounds the slab edges so they are less likely to chip. Jointing creates control, isolation, and construction joints. These joints help manage the concrete’s natural movement and reduce unsightly cracking.

Floating is another finishing step that smooths small imperfections left by earlier work. It also slightly embeds the aggregate below the surface and compacts the mortar at the top. This still allows excess moisture to escape before the final surface treatment is applied.

The last stage shapes the concrete’s final look and texture. Troweling smooths and hardens the surface, while brooming makes it rougher. Patterns or exposed aggregate finishes can also be added for decoration.

Concrete Surface Finishing Steps

mixing concrete

Concrete Mixer Types and Capacity

Concrete mixing creates a uniform blend of cement, aggregates, and paste. The goal is to coat the aggregates evenly with cement paste. Mixers used for this job are usually grouped into two main types: batch mixers and continuous mixers. Batch mixers handle one load at a time. They mix the materials thoroughly, discharge the batch, and then receive the next one. Continuous mixers work differently. They take in a steady flow of ingredients, mix them at a constant rate, and discharge the concrete...

mixing time

Concrete Mixer Charging and Timing

Concrete mixer charging and timing are key to making a uniform concrete mix with the needed strength. Mixing begins only after all ingredients are inside the mixer. The usual charging order starts with 10% of the water, then the solid materials are added steadily, followed by 80% of the water. The last portion of water is added later, within the first quarter of the total mixing period. The minimum mixing time depends on mixer capacity. Mixers with up to 1 cubic yard of capacity need at least...

ready mixed concrete

How Ready-Mixed Concrete Is Delivered

Ready-mixed concrete is prepared at a centralized plant and then delivered by truck to a construction site. It arrives ready for placement, which makes it different from concrete mixed entirely on site. Ready-mixed concrete includes three main forms: central-mixed, truck-mixed, and shrink-mixed. Central-mixed concrete is fully mixed at the plant and carried to the site in agitator trucks. These trucks rotate at 2 to 6 rpm, which helps keep the concrete in motion during transport. Truck-mixed...

pumped concrete

Concrete Pumping for Hard-to-Reach Sites

Concrete pumping moves large amounts of concrete through pipes to places that are hard to reach. It is used for sites such as deep foundation pits and other inaccessible locations. The system includes a hopper, a pump, and pipelines that carry the concrete to the placement point. Direct-acting pumps use a piston to move the concrete. Concrete enters the pump through the inlet valve by gravity and by suction created as the piston moves. The forward movement of the piston then pushes the...

placing concrete

Concrete Placement Methods and Compaction

Concrete placement methods focus on keeping the mix in a uniform shape and position. The concrete is placed as close as possible to its final location to reduce segregation, which is the separation of ingredients. It is then fully compacted to remove trapped air. The next layer is added while the layer below is still plastic, or soft enough to shape. The rate of placing and compacting concrete is kept equal. Concrete is laid in uniform layers, and hand shoveling is avoided. Moving concrete...

vibrating concrete

Concrete Compaction with Vibrators

Concrete compaction with vibrators helps newly poured concrete settle inside formwork and around reinforcement bars. The goal is to remove trapped air pockets and create a dense concrete mass. Mechanical vibration is a key part of that process. One common method uses an internal vibrator, also called a poker vibrator or immersion vibrator. It is quickly inserted through the full depth of the fresh concrete and slightly into the layer below, which is still in a plastic state. The vibrator is...

shotcrete

Shotcrete for Vertical and Overhead Surfaces

Shotcrete is a concrete spraying method used on vertical and overhead surfaces. It uses mortar or small aggregate concrete with a high cement content. The material is sprayed at high velocity, and the impact helps compact it so it can cling without sagging. Builders place shotcrete in layers until it reaches about 4 inches thick. The quality depends strongly on the operator’s skill in managing the nozzle. Careful nozzle control helps the material land evenly and build up properly. Shotcrete...

preplaced aggregate concrete

Concrete Placement for Tight Spaces

Preplaced aggregate concrete is used when a construction site is hard to reach. The process starts by wetting gap-graded coarse aggregates. This helps remove dirt from the stones. The aggregates are then placed in the form and compacted. Next, a mortar mix is pumped under pressure through slotted pipes to fill the spaces between the aggregates. The mortar usually contains Portland cement, pozzolan, fine aggregates, water, and a fluidizing aid. The pozzolan reduces bleeding and segregation and...

finishing concrete

Concrete surface finishing begins right after the concrete has been placed and consolidated. The first step is screeding, which levels the surface by removing extra material until it is even with the top of the formwork. A screed is a straight edge used for this leveling step. After screeding, a bull float or darby is used to smooth the surface further. These tools help lower high spots, fill low areas, and push larger aggregate particles deeper into the concrete. This preparation should...

curing of concrete

How Curing Improves Concrete Strength

Curing helps concrete gain strength after it has set. It keeps the concrete moist and at the right temperature so cement hydration can continue. Hydration is the process where cement reacts with water in the water-filled capillary pores and forms the products that fill spaces in the paste. Dry air can interrupt this process by pulling water from the concrete surface. Concrete with a water-cement ratio below 0.5 can also lose water through self-desiccation, which means internal water is used up...

curing methods

Concrete Curing for Moisture Retention

Concrete curing for moisture retention helps fresh concrete keep the water it needs as it hardens. For members with a small surface-to-volume ratio, the forms are often oiled and moistened before the concrete is placed. These forms may stay in place for a long time to reduce moisture loss. If the form material can be wetted, it can also be kept damp. When forms are removed early, the concrete member is moistened and then covered with polythene sheets. Large horizontal concrete surfaces in dry...

accelerated curing of concrete

How Concrete Gains Strength Faster

Concrete can gain strength faster when heat and extra moisture speed up cement hydration. This faster hydration helps the concrete build early strength sooner than normal curing. The process is used when quicker hardening is needed after casting. One common method is steam curing. Concrete products may move through a chamber on a conveyor belt, or they may be encased in plastic so steam at atmospheric pressure can circulate around them. Steam curing starts with moist curing for about 3 to 5...

key terms and concepts

Learn the steps of concrete surface finishing, from screeding and floating to edging, jointing, troweling, and brooming for different final textures.

Concrete Surface Finishing Steps | JoVE K12

JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

civil engineering

Concrete Surface Finishing Steps

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