Name: superplasticizers for stronger concrete mixes
Uploaded: 2024-11-07T14:48:38.000Z
Duration: 1 min 30 s
Channel: JoVE

초가소제는 금형 내에 조밀한 보강재로 쉽게 배치하거나 바닥 및 포장에 빠르게 배치할 수 있는 유체 콘크리트를 준비하는 데 사용됩니다.
일부 고가소제는 일반적으로 설폰화 멜라민 포름알데히드 또는 설폰화 나프탈렌 포름알데히드 축합물이며, 용량은 콘크리트 입방 야드당 약 0.2-0.6갤런입니다.
고가소제는 설폰산이 시멘트 입자 표면에 흡수되도록 하여 시멘트 분산을 향상시키며, 이는 음전하를 띠고 서로를 밀어냅니다.
이 작업은 물-시멘트 비율을 유지하기 위해 콘크리트의 작업성을 향상시켜 종종 슬럼프를 3인치에서 8인치로 증가시킵니다.
유동 콘크리트의 경우 미세한 골재가 4-5% 증가하며, 길쭉하거나 벗겨지기 쉽거나 매우 각진 골재는 분리와 블리딩을 방지하기 위해 피합니다.
이러한 콘크리트가 거푸집 공사에서 정수압을 가할 수 있다는 점을 고려하는 것이 중요합니다.
고가소제는 물 사용량을 25-35% 줄일 수 있어 물 대 시멘트 비율을 낮추고 콘크리트가 28일 만에 최대 15,000psi의 강도에 도달할 수 있습니다.
초가소제는 콘크리트 타설 직전에 콘크리트에 첨가되는데, 이는 초가소제의 작업성 향상이 일시적이기 때문입니다.

수퍼가소제

Superplasticizers

고성능 감수제는 재료의 강도를 손상시키지 않고 물 함량을 낮춰 콘크리트의 작업성을 향상시키는 고급 혼화제입니다. 이러한 물질은 매우 효과적인 감수제로, 콘크리트 흐름을 개선하고, 작업을 더 쉽게 만들고, 기계적 진동 없이 접근하기 어려운 곳이나 고밀도로 보강된 부분에 도달할 수 있게 합니다. 고성능 감수제의 핵심 성분은 설폰화 멜라민 또는 나프탈렌 포름알데히드 응축물이며, 이는 시멘트 입자에 음전하를 유도하여 상호 반발을 일으키고 혼합물 내에서 분산시킵니다.


 콘크리트에 고성능 감수제를 통합하면 슬럼프가 상당히 증가하여 혼합물이 응집력을 유지하는 동시에 분리 및 유출 문제를 피할 수 있습니다. 이 특성은 특히 물-시멘트 비율이 낮은 고강도 콘크리트를 만드는 데 유용합니다. 물 함량을 25~35% 줄이면 28일 후 최대 1054.60 Kgf/cm^2의 콘크리트 강도를 얻을 수 있습니다. 그러나 고성능 감수제가 제공하는 향상된 작업성은 수명이 짧아 일반적으로 약 30~90분 동안 지속되므로 콘크리트 혼합물에 배치하기 직전에 정확한 타이밍을 맞춰야 합니다. 고성능 감수제를 재투여하는 것은 일반적으로 권장되지 않지만 제한된 시간 동안 작업성을 유지하기 위해 조정할 수 있습니다. 고성능 감수제는 비용이 많이 들지만 고강도의 내구성 있는 콘크리트를 효율적으로 생산할 수 있는 능력으로 인해 가치가 있습니다.

Superplasticizers는 금형 내에서 조밀 한 보강 배열로 쉽게 배치 할 수 있거나 빠르게 배치 할 수있는 유체 콘크리트를 준비하는 데 사용됩니다.

Education

교육

JoVE Core

Civil Engineering

토목공학

Unit 1

제1단원

Admixtures

혼화제

KEY TERMS AND CONCEPTS

주요 용어 및 개념

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 in the mix. As a result, the concrete slump increases, but the mix stays cohesive.

Superplasticizers also help prevent segregation and bleeding. Segregation is when the parts of a concrete mix separate. Bleeding is when water rises to the surface. By lowering water content by about 25 to 35 percent, superplasticizers can support high-strength concrete with low water-to-cement ratios.

The strength gains can be large. Concrete made with superplasticizers can reach up to 15,000 pounds per square inch after 28 days. Their workability is temporary, though. The effect usually lasts only 30 to 90 minutes, so they must be added just before placement.

Re-dosing superplasticizers is generally not recommended, but limited adjustments can help keep the mix workable for a short time. Even though they are expensive, they are valuable for making durable, high-strength concrete efficiently.

Superplasticizers for Stronger Concrete Mixes

superplasticizers-for-stronger-concrete-mixes

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 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. <br...

superplasticizers

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 superplasticizers improve concrete flow, reduce water content, and support high-strength mixes for dense reinforcement and hard-to-reach areas.

Superplasticizers for Stronger Concrete Mixes | 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

Superplasticizers for Stronger Concrete Mixes

Description

Transcript