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

配置されたコンクリートを固めた後、余分な材料を表面から取り除き、スクリードを使用して型枠の上部に洗い流します。
その後、ブルフロートまたはダービーを使用して、コンクリート表面の高いスポットを下げ、低いスポットを埋め、大きな骨材をコンクリートに埋め込んでから、ブリード水が表面に上昇します。
表面のブリード水からの光沢が蒸発時に消えると、最終的な仕上げの準備が整います。これは、コンクリートのエッジを丸くすることを含むエッジングから始まります。
その後、制御、分離、および建設ジョイントが構造に戦略的に配置されるジョイントが続きます。
次に、ハンドヘルドフロートまたはパワーフロートを使用して、エッジングとジョイントに起因する表面の欠陥を取り除き、骨材をコンクリート内にわずかに埋め込み、余分な水分を取り除き、表面を開いたままにします。
最後に、仕上げられた表面は、こてで硬くて滑らかな表面を作成する、ほうきで粗くて滑りにくいものにする、上部の余分なセメントペーストを洗って露出した外観を作成する、または仕切りストリップを挿入してパターン化することによってテクスチャリングすることができます。

コンクリートの仕上げ

コンクリートの仕上げは、コンクリートを配置して固めた直後に始まります。最初のステップであるスクリードでは、余分な材料を取り除いて型枠の上部と平らになるようにし、コンクリートの表面を整えます。その後、ブルフロートまたはダービーを使用して表面をさらに滑らかにし、高い部分を効果的に下げ、低い部分を埋め、大きな骨材粒子がコンクリート内に埋め込まれるようにします。この準備は、ブリード水が発生する前に行うことが重要です。ブリード水があると、スケールや粉塵が発生する可能性があるためです。


 表面からブリード水がなくなると、コンクリートは最終仕上げの準備が整います。仕上げには、エッジング（スラブの端を丸めて欠けを防ぐ作業）、ジョイント（制御ジョイント、絶縁ジョイント、建設ジョイントを作成してコンクリートの自然な動きを管理し、見た目の悪いひび割れを防ぐ作業）、およびフローティングが含まれます。フローティングは、前の手順で残った欠陥を滑らかにし、骨材を表面の下にわずかに埋め込み、余分な水分を逃がしながら最終仕上げのために表面のモルタルを圧縮します。


 コンクリートの最終的な外観と質感は、表面を滑らかにして硬化させるためのこて塗りや、表面を荒らすためのほうき塗りなど、さまざまな技術によって実現されます。さらに、模様や露出骨材仕上げを施して装飾効果を生み出すこともできます。

配置されたコンクリートを固めた後、余分な材料を表面から取り除き、スクリードを使用して型枠の上部に洗い流します。
その後。。。

Education

JoVE Core

Civil Engineering

土木工学

Unit 1

ユニット1

Mixing, Placing and Curing Concrete 

コンクリートの練混ぜ、打設および養生

KEY TERMS AND CONCEPTS

主要用語および概念

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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