Name: concrete workability by compacting factor
Uploaded: 2024-11-07T14:48:28.000Z
Duration: 1 min 22 s
Channel: JoVE

다짐 계수 시험은 최대 1.5인치의 골재 크기를 가진 콘크리트의 작업성을 결정합니다.
테스트 장비는 바닥에 힌지 도어가 있는 두 개의 잘린 원뿔 모양의 호퍼와 실린더로 구성되며, 모두 순차적으로 쌓여 있으며 내부 표면은 마찰을 줄이기 위해 광택이 납니다.
콘크리트를 압축하지 않고 상단 호퍼에 배치하고 하단 도어를 열어 콘크리트가 하단 호퍼로 유입되도록 합니다.
다음으로, 하부 호퍼의 하단 도어를 열어 콘크리트가 아래의 실린더로 떨어지도록 하고 여분의 콘크리트를 쳐냅니다.
강철 막대는 테스트 중에 하나 또는 두 호퍼에 끼인 콘크리트를 부드럽게 찌르고 제거하는 데 사용됩니다.
실린더의 설정 부피에서 콘크리트의 최종 중량이 결정되고 부분적으로 압축된 콘크리트의 밀도가 계산됩니다.
완전히 압축된 밀도는 실린더를 4개의 층으로 콘크리트로 채우고 각 층을 탬핑하여 결정됩니다.
마지막으로, 다짐 계수는 완전히 다진 콘크리트의 밀도에 대한 부분적으로 다진 콘크리트의 밀도의 비율로 계산되며, 이는 혼합물의 작업성을 나타냅니다.

압축 인자 테스트

압축 계수 시험은 콘크리트의 작업성을 평가하는 데 사용되는 방법입니다. 특히 최대 3.81cm 크기의 골재를 포함하는 콘크리트 혼합물에 적합합니다. 이 시험에는 두 개의 잘린 원뿔 모양 호퍼와 실린더로 구성된 특수 장비가 포함되며, 모두 마찰을 최소화하기 위해 내부 표면을 연마했습니다.


 절차는 압축 없이 콘크리트를 상부 호퍼에 넣는 것으로 시작합니다. 채워지면 이 호퍼의 바닥 도어가 열려 콘크리트가 하부 호퍼로 흐를 수 있습니다. 하부 호퍼가 채워진 후, 바닥 도어가 열려 콘크리트가 아래에 위치한 실린더로 떨어집니다. 그런 다음 과도한 콘크리트를 제거하여 표면을 평평하게 합니다.


 시험 중에 강철 막대를 사용하여 호퍼에 끼어 있는 콘크리트를 살짝 찔러서 제거할 수 있습니다. 실린더 내부의 콘크리트 무게를 기록하고 부분적으로 압축했을 때의 밀도를 계산합니다. 비교를 위해, 콘크리트의 완전 압축 밀도는 동일한 실린더에 콘크리트를 4겹으로 채우고 각 층을 완전히 다져서 최대 압축을 보장함으로써 결정합니다.


 압축 계수는 부분적으로 압축된 콘크리트의 밀도와 완전히 압축된 콘크리트의 밀도의 비율로 계산됩니다. 이 비율은 콘크리트의 작업성을 나타내는 수치 값을 제공하며, 압축 계수의 다른 수준은 작업성의 다양한 정도를 반영합니다. 이 테스트는 건설 프로젝트 중에 콘크리트가 몰드나 폼에 배치될 때 어떻게 거동하는지 이해하는 데 중요합니다.

다짐 계수 시험은 최대 1.5인치의 골재 크기를 가진 콘크리트의 작업성을 결정합니다.
테스트 장비 ...

Education

교육

JoVE Core

Civil Engineering

토목공학

Unit 1

제1단원

Fresh Concrete

굳지 않은 콘크리트

KEY TERMS AND CONCEPTS

핵심 용어 및 개념

Compacting Factor test

concrete workability by compacting factor

The compacting factor test measures the workability of concrete. Workability describes how easily concrete can move and fill a mold or form during construction. This test is especially suitable for concrete mixes with aggregates up to one and a half inches in size.

The setup uses specialized equipment with two truncated cone-shaped hoppers and a cylinder. All of the inside surfaces are polished to reduce friction. Concrete is first placed into the upper hopper without any compaction. Then the bottom door is opened so the mix can flow into the lower hopper.

After the lower hopper fills, its bottom door is opened. The concrete falls into the cylinder below. Extra concrete is struck off to make the surface level. If concrete gets stuck in the hoppers, a steel rod may be used to gently poke it loose.

Next, the weight of the concrete in the cylinder is recorded. This gives the density of the partially compacted concrete. For comparison, the same cylinder is filled with concrete in four layers and each layer is tamped thoroughly to reach maximum compaction. The compacting factor is then calculated as the ratio of the partially compacted density to the fully compacted density. This number shows the workability of the concrete and helps predict how the mix will behave in forms.

Concrete Workability by Compacting Factor

concrete-workability-by-compacting-factor

workability of concrete

Concrete Flow and Compaction Factors

Concrete workability is the ease with which fresh concrete can be mixed, placed, compacted, and finished. It is an important property during construction because it affects how well the material moves into position and how easily it can be shaped. Workability depends on the internal friction within the mix and the resistance it meets from molds and reinforcements. When the ingredients resist one another, concrete moves less easily. The same is true when it has to pass around barriers in the...

factors affecting workability

Concrete Workability and Mix Design Factors

Concrete workability depends on mix design factors that change how easily the material can be mixed, handled, and finished. The mix needs enough flow so it can move and be placed without losing quality. Water is a key part of this because it acts as a lubricant between the ingredients. The amount of water needed can change with the aggregates, or the solid particles in the mix. Finer particles and angular, rough-textured aggregates need more water than smooth, rounded ones because they have...

segregation in fresh concrete

How Concrete Mixes Separate During Placement

Fresh concrete can separate during placement, which changes how the mix is spread and can weaken the finished structure. This separation is called segregation. It happens when the parts of the mix no longer stay evenly blended. Segregation often occurs when concrete moves too much inside a form. It can also happen when the mix is dropped from a great height or pushed through narrow paths with sharp turns. In these cases, the heavier coarse aggregate settles at the bottom, while lighter...

bleeding in fresh concrete

Bleeding Water and Laitance in Fresh Concrete

Bleeding in fresh concrete happens when water from the mix rises to the surface after placement. The solid parts of the mix do not hold all the water as they settle, so separation occurs and water collects on top. Engineers can measure the severity of bleeding by checking total settlement or by noting how much the concrete height drops per unit height. Bleeding can create weak spots inside the concrete. Rising water may get trapped under large aggregate particles or reinforcement bars, which...

slump test

Concrete Workability Check with Slump

The slump test checks the workability of fresh concrete. Workability means how easy the mix is to place and handle. The test uses a 12-inch-high truncated cone mold that narrows from eight inches at the base to four inches at the top. Before testing, the mold is fixed to a flat base and dampened. Concrete is added in three layers. Each layer is compacted 25 times with a steel tamping rod that is five-eighths of an inch in diameter and has a rounded end. This helps spread the concrete evenly...

compacting factor test

The compacting factor test measures the workability of concrete. Workability describes how easily concrete can move and fill a mold or form during construction. This test is especially suitable for concrete mixes with aggregates up to one and a half inches in size. The setup uses specialized equipment with two truncated cone-shaped hoppers and a cylinder. All of the inside surfaces are polished to reduce friction. Concrete is first placed into the upper hopper without any compaction. Then the...

vebe test

Concrete Workability with the Vebe Test

The Vebe test measures the workability of concrete, especially for dry mixes. Workability means how easy concrete is to handle and compact. The test uses a cylindrical chamber, a standard slump cone, and a transparent disc-shaped rider mounted on a vibrating table. The cylindrical chamber measures nine and a half inches in diameter and eight inches in height. Concrete is placed into the slump cone in layers and compacted in the standard way. After the cone is removed, the concrete stays in the...

flow table test

Concrete Spread Measured by Flow Table

The flow table test measures how far fresh concrete spreads, which helps assess workability. Workability means how easily concrete can flow and settle under its own weight. The method is useful for highly flowable concrete mixes. The test uses a flow table made from a wooden board with a steel plate on top. Together, the parts weigh 35 pounds. The board is hinged to a base and measures 27.6 inches on each side. A truncated cone mold is also used. It is 8 inches high, with an 8-inch base...

key terms and concepts

Measure concrete workability with the compacting factor test using hoppers and a cylinder. Learn how partially and fully compacted densities are compared.

Concrete Workability by Compacting Factor | JoVE K12

JoVE Core Civil Engineering offers a foundational exploration of essential construction materials such as bricks, stones, steel, wood, and concrete, along with fluid mechanics topics like flow over immersed bodies, open channel flow, and dimensional modeling. It also covers key surveying concepts, including leveling, traverse adjustments, curve design, topographic mapping, and geospatial technologies (GPS & GIS). Science-in-action videos showcase laboratory research on materials, fluids, and surveying practices in real-world engineering systems.

civil engineering

Concrete Workability by Compacting Factor

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