Name: concrete workability with plasticizers
Uploaded: 2024-11-07T14:48:38.000Z
Duration: 1 min 31 s
Channel: JoVE

주형에서 접근하기 어려운 위치에서 콘크리트를 만드는 것을 고려하십시오. 가소제는 콘크리트가 자체적으로 압축되는 데 도움이 되어 물이나 시멘트를 줄여 작업성을 향상시킵니다.
일반적인 가소제에는 리그노설폰산(lignosulfonic acids)과 하이드록실화 카르복실산(hydroxylated carboxylic acid)이 포함되며, 콘크리트에서 물 사용을 5-15% 줄일 수 있는 환수성 혼화제로 작용합니다.
가소제의 계면 활성제는 비혼합상 사이의 계면력을 변경하고 시멘트 입자에 부착하여 음전하를 부여하고 반발을 촉진하며 기포를 밀어내면서 분산을 안정화합니다.
음전하는 각 입자 주위에 정렬된 물 분자 층을 유도하여 효과적으로 거리를 둡니다.
마지막으로, 입자 이동이 향상되고 클러스터링된 시스템에서 물이 방출되어 혼합을 용이하게 하고 작업성을 개선할 수 있습니다.
가소제는 시멘트 입자의 분산을 향상시켜 수화를 위한 표면적을 증가시킵니다. 이 분산은 혼화제가 없는 혼합물에 비해 조기 연령의 강도를 높입니다.
이러한 혼합물이 강도에 미치는 영향은 트리칼슘 알루미네이트가 낮거나 알칼리 수치가 낮은 시멘트에서 더 두드러집니다.
건설에 가소제를 사용하기 전에 분리, 블리딩 또는 작업성 감소와 같은 문제를 식별하기 위해 테스트가 필수적입니다.

가소제

감수제 또는 가소제는 콘크리트의 강도와 작업성을 개선하기 위해 사용되는 화학 혼합물입니다. 이러한 첨가제는 작업성을 손상시키지 않고 물-시멘트 비율을 낮추고, 동일한 작업성을 유지하면서 시멘트 함량을 낮추거나, 작업성을 높여 접근하기 어려운 구역에 콘크리트를 배치하는 데 도움이 됩니다.


 가소제는 표면 활성제를 사용하여 시멘트 입자 사이에 반발 정전기력을 생성합니다. 이 분산은 콘크리트의 작업성을 향상시키고 물을 혼합할 필요성을 5~15퍼센트 줄입니다. 특정 가소제로 인해 응고 시간이 지연되더라도 시간이 지남에 따라 작업성 손실이 반드시 줄어드는 것은 아닙니다. 콘크리트의 최종 특성에 영향을 미치는 공기 주머니를 도입할 수 있는 공기 연행제와의 호환성을 보장하기 위해 시험 혼합물을 갖는 것이 중요합니다.


 이러한 혼합물의 경우, 시멘트의 수화가 더 균일하기 때문에 특히 초기 단계에서 콘크리트의 강도를 향상시킵니다. 일반적으로 모든 시멘트 유형에서 효과적이며, 트리칼슘 알루미네이트 또는 알칼리 함량이 낮은 시멘트에서 강도가 더 현저하게 증가합니다. 감수제를 올바르게 사용하면 콘크리트의 내구성도 개선할 수 있습니다. 그러나 구현하기 전에 콘크리트 구조의 장기적 실행 가능성을 보장하기 위해 분리 또는 블리딩과 같은 발생 가능한 부정적인 영향을 테스트하는 것이 중요합니다.

주형에서 접근하기 어려운 위치에서 콘크리트를 만드는 것을 고려하십시오. 가소제는 콘크리트가 자체적으로 압축되도록 도와 주며 더 적은 비용으로 작업성을 향상시킵니다.

Education

교육

JoVE Core

Civil Engineering

토목공학

Unit 1

제1단원

Admixtures

혼화제

KEY TERMS AND CONCEPTS

주요 용어 및 개념

Plasticizers

concrete workability with plasticizers

Concrete plasticizers are water-reducing chemical admixtures that improve workability and strength. They help concrete use less water while keeping the same flow, reduce cement content without losing workability, or make mixes easier to place in hard-to-reach areas.

Plasticizers work by using surface-active agents. These agents create repulsive electrostatic forces between cement particles. The particles disperse more evenly, and the concrete needs about 5 to 15 percent less mixing water.

Some plasticizers can delay setting time. Even so, the loss of workability over time is not always reduced. Trial mixes are important to check compatibility with air-entraining agents, which add air pockets that can change the final properties of the concrete.

These admixtures also improve strength, especially early strength, because cement hydrates more uniformly. They are generally effective with all cement types, but the strength gain is often greater in cements with low tricalcium aluminate or low alkali content. When used correctly, water-reducers can also improve durability.

Before using them in a structure, engineers must test for side effects such as segregation or bleeding. Segregation happens when the mix separates, and bleeding is the rise of water to the surface. These checks help confirm that the concrete will perform well over time.

Concrete Workability with Plasticizers

accelerators

Calcium Chloride in Concrete Mixes

Calcium chloride is a concrete admixture that speeds up hardening and helps concrete gain early strength faster. It does not always change the setting time itself, but it can reduce the time needed in practice. This makes it useful in cold weather and in rapid repair work where quick heat generation after mixing is helpful. A common amount is 1 to 2 percent of the cement mass. Its effect can be compared with raising the concrete temperature by 11 degrees Fahrenheit. To spread it evenly through...

retarders

Retarders in Concrete Pouring

Retarders are chemical admixtures used in concrete to slow the setting time. They are especially helpful when one pour must follow another after a delay. By keeping the concrete workable for longer, they can help prevent cold joints and support a more cohesive structure. Retarders can also improve the look of exposed aggregate finishes when they are used in the right amount. Their effect on setting time can be checked with a penetration test. Common retarding substances include sugar,...

plasticizers

Concrete plasticizers are water-reducing chemical admixtures that improve workability and strength. They help concrete use less water while keeping the same flow, reduce cement content without losing workability, or make mixes easier to place in hard-to-reach areas. Plasticizers work by using surface-active agents. These agents create repulsive electrostatic forces between cement particles. The particles disperse more evenly, and the concrete needs about 5 to 15 percent less mixing water. <br...

superplasticizers

Superplasticizers for Stronger Concrete Mixes

Superplasticizers are concrete admixtures that make mixes flow better while using less water. They are strong water reducers, so concrete can be easier to place without losing strength. This makes them useful when concrete must reach tight spaces or heavily reinforced areas without mechanical vibration. These admixtures work through sulfonated melamine or naphthalene formaldehyde condensates. These chemicals give cement particles a negative charge. The particles repel each other and spread out...

additives and fillers in concrete

Concrete Fillers That Improve Performance

Concrete fillers and additives help change how cement paste performs. Pozzolans and blast-furnace slag act as additives or admixtures because they react with calcium hydroxide released during cement hydration. Fine fillers are close in fineness to Portland cement and can improve workability, density, and resistance to capillary bleeding or cracking. Some fillers are hydraulic, which means they can react with water, while others take part in harmless reactions inside the cement paste. A key...

waterproofing and anti-bacterial admixtures in concrete

waterproofing-and-anti-bacterial-admixtures-in-concrete

Concrete Water Resistance and Biological Protection

Concrete can absorb water because of capillary action in the pores of its hydrated cement paste. That movement pulls water into the material. Waterproofing admixtures are added to reduce this penetration and help concrete resist water. The effect of a waterproofing admixture depends on the water pressure acting on the concrete. Rain, capillary rise, and hydrostatic pressure in structures made to hold water can all affect performance. These admixtures make concrete hydrophobic, which means they...

key terms and concepts

Learn how plasticizers reduce water use, improve concrete workability, and boost strength. See why trial mixes and compatibility tests matter.

Concrete Workability with Plasticizers | 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 with Plasticizers

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