Name: special portland cements for durability
Uploaded: 2024-09-12T16:16:36.000Z
Duration: 1 min 22 s
Channel: JoVE

포틀랜드 시멘트 클링커와 제철 공정의 부산물인 과립 용광로 슬래그를 Intergrinding 하면 슬래그 시멘트가 생산됩니다.
그것은 염화물과 황산염의 공격에 저항하도록 설계된 대형 구조물을 건설하는 데 사용할 수 있습니다.
더 적은 양의 철과 망간 산화물을 함유 한 분필과 중국 점토로 만든 백색 시멘트는 독특한 흰색을 띠고 있으며 뛰어난 미학을 가진 정면을 만드는 데 사용할 수 있습니다.
콘크리트에 해롭지 않은 유색 안료를 백색 시멘트로 첨가하면 유색 시멘트가 생성됩니다.
유형 K, M 및 S와 같은 팽창성 시멘트는 포틀랜드 시멘트와 팽창성 제제 및 안정제를 결합하여 생산됩니다. 이는 경화 중 조기 에트링사이트 형성으로 인한 제어된 팽창을 통해 수축 균열을 방지합니다.
공기 혼입 포틀랜드 시멘트는 소량의 공기 연행 재료를 사용하여 시멘트 매트릭스 내에 수백만 개의 미세한 기포를 형성합니다.
이것은 물이 얼 때 팽창할 수 있는 공간을 제공하여 동결-해동 주기로 인한 균열을 방지합니다. 
방수 포틀랜드 시멘트는 발수 물질을 사용하여 습기에 노출된 구조물을 물 침투로부터 보호합니다.

시멘트의 종류 ii

Types of Cement II

포틀랜드 고로 시멘트는 포틀랜드 시멘트의 클링커에 고로 슬래그 미분말을 혼합하여 만드는데, 이는 시멘트 무게의 25~65%를 차지합니다. 보통 포틀랜드(1종) 시멘트와 비슷한 조립률과 응결 시간을 가지지만, 고로 시멘트의 경우 초기 강도는 낮고 이후 비슷한 강도를 달성하게 됩니다. 이 시멘트는 수화열이 낮고 황산염 저항성이 뛰어나 대형 콘크리트 구조물과 해양 환경에 특히 적합합니다.

백색 및 유색 포틀랜드 시멘트는 주로 프리캐스트 커튼월 패널, 외장 패널, 테라조 바닥, 스타코, 마감 코트 플라스터, 타일 그라우트 등과 같이 미적 고려 사항이 중요한 곳에 주로 사용됩니다. 이러한 시멘트는 불순물을 피하고 색상 균일성을 위한 엄격한 생산 요구 사항으로 인해 더 비쌉니다.

팽창 시멘트는 건조 수축을 보상을 위해 초기 경화 기간 동안 팽창합니다. K, M, S의 세 가지 유형이 있으며, 주로 화학 성분이 다릅니다. K형은 일반적인 수축 제어를 위해, M형은 황산염 저항성을 위해, S형은 높은 황산염 노출을 위해 설계되었습니다. 각 유형은 수축의 영향을 상쇄하여 균열을 최소화하도록 설계되었습니다. 이 시멘트는 균열을 방지하기 위해 최소한의 부피 변화가 요구되는 상황에 적합합니다.

포틀랜드 방수 시멘트에는 포틀랜드 시멘트 클링커를 분쇄할 때 스테아르산 칼슘이나 스테아르산 알루미늄과 같은 첨가제를 혼합하여, 시멘트의 습기 침투 저항성을 향상시킵니다.

시멘트의 종류 II

포틀랜드 시멘트 클링커와 제철 공정의 부산물인 과립 용광로 슬래그를 Intergrinding 하면 슬래그 시멘트가 생산됩니다.
그것은 사용할 수 있습니다 ...

Education

교육

JoVE Core

Civil Engineering

토목공학

Unit 1

제1단원

Introduction to Concrete

콘크리트 입문

KEY TERMS AND CONCEPTS

주요 용어 및 개념

special portland cements for durability

Special Portland cements are made for specific building needs, such as added durability, color, or lower cracking risk. One major example is Portland blast-furnace cement. It is made by blending Portland cement clinker with granulated blast-furnace slag, which makes up about 25 to 65 percent of the cement by weight.

Portland blast-furnace cement sets at about the same rate and has about the same fineness as ordinary Portland cement, which is Type I cement. Its early strength is lower, but it reaches similar strength later on. It is useful for mass concrete structures and marine environments because it gives off less heat during hydration and resists sulfate better.

White and colored Portland cements are used when appearance matters most. They are common in precast curtain-wall panels, facing panels, terrazzo floors, stucco, finish-coat plaster, and tile grout. These cements cost more because they must be made with careful control to avoid impurities and keep the color uniform.

Expansive cement is made to expand during early hardening so it can offset drying shrinkage. This helps reduce cracking when minimal volume change is important. Three types are available: K, M, and S. Type K is used for general shrinkage control, Type M is made for sulfate resistance, and Type S is for high sulfate exposure.

Waterproof Portland cement is another special type. It includes additives such as calcium stearate or aluminum stearate mixed into the Portland cement clinker during grinding. These additives improve the cement’s resistance to moisture penetration.

Special Portland Cements for Durability

concrete

Concrete Materials and Reinforcement

Concrete is a major construction material used in buildings, bridges, airfields, highways, dams, and silos. It is valued for strength, durability, and versatility in many structural designs. A concrete mix usually includes Portland cement, coarse gravel, fine sand, and water. Concrete can be mixed by hand or made at industrial plants with computer control. The mix has aggregates and a paste made from water and Portland cement. This paste coats the aggregates. Through hydration, a chemical...

portland cement

How Portland Cement Is Made

Portland cement is the main binding material in concrete. It is made from finely ground ingredients that include lime, iron, silica, and alumina. These materials give cement the properties it needs to hold concrete together. The raw ingredients come from several common natural sources. Lime is obtained mainly from limestone, marble, marl, seashells, and clays. Those same clays can also supply iron and alumina. Silica is sourced from sand, chalk, and bauxite. Making Portland cement starts by...

hydration of cement

Cement Setting and Strength Formation

Cement setting and strength formation begin when water is added to cement particles. The main reaction is called hydration. During hydration, the anhydrous cement compounds react with water and form new solids that help harden the material. Hydration can happen by two main paths: through-solution and topochemical. In through-solution, anhydrous compounds dissolve into their parts, hydrates form in the liquid, and then they come out of a supersaturated solution. In topochemical hydration,...

strength and heat of hydration

Cement Hydration Heat and Strength Gain

Cement hydration produces heat and builds strength at the same time. Hydration is an exothermic reaction, which means it releases heat as cement reacts with water. That heat of hydration is a key part of how cement develops strength. Most of the heat is released early in the process. About half is given off in the first three days, and about 75% is released in the first week. The rate of heat release also affects how much the temperature rises during hydration. Some cement compounds...

fineness of cement

How Cement Particle Size Changes Behavior

Cement particle size changes how cement behaves in concrete. Finer cement has more surface area, so hydration starts faster at the particle surface. This affects the rate of hardening and also influences workability, gypsum requirement, and long-term behavior. Cement fineness is usually described by its specific surface area. This is the total surface area of cement particles per unit mass, and it is often measured in square meters per kilogram. Several methods can be used to determine it,...

setting time of cement

Cement Initial and Final Set

Cement setting time describes how cement paste changes from a plastic state to a solid state. This change matters in construction because it sets the window for placing, compacting, and finishing concrete. The first stage is called the initial set. At that point, the paste becomes unworkable. The next stage is the final set. By then, the paste has solidified completely, and further handling can no longer change its shape. Cement strength is still very low at this stage because hydration of...

soundness of cement

Cement Expansion Tests for Soundness

Cement soundness is the ability of cement paste to keep its volume after it sets. If cement is unsound, it can expand later and damage a structure. This problem can come from free lime, magnesia, and calcium sulfate in the cement. Free lime hydrates very slowly. As it reacts, it can expand and cause unsoundness. It is also hard to detect because it intercrystallizes with other compounds in the cement structure. Magnesia can also react with water. It forms crystals that may disrupt the cement...

strength of cement

Cement Strength Tests and Standards

Cement strength is measured with standard tests that use mortar, not neat cement paste. Cement paste alone is hard to shape into specimens that give consistent and reliable results. For that reason, the test samples are usually made with cement and sand. For compressive strength, ASTM C 109-05 uses a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485. The mixture is cast into 2-inch cubes and cured in saturated lime water at 23°C until testing. This method measures how well the...

types of cement i

Portland Cement Grades and Uses

Portland cement comes in several grades with different properties and uses. Its chemical composition and hydration behavior help determine how it performs in concrete. These differences matter in general construction, fast repairs, large structures, and places where sulfate exposure is a concern. Type I, or Ordinary Portland Cement, is the common choice for general construction. It is used when special properties are not required. This type has moderate sulfate resistance and moderate heat of...

types of cement ii

Special Portland cements are made for specific building needs, such as added durability, color, or lower cracking risk. One major example is Portland blast-furnace cement. It is made by blending Portland cement clinker with granulated blast-furnace slag, which makes up about 25 to 65 percent of the cement by weight. Portland blast-furnace cement sets at about the same rate and has about the same fineness as ordinary Portland cement, which is Type I cement. Its early strength is lower, but it...

pozzolans

Pozzolans in Stronger Concrete Mixes

Pozzolans are siliceous or aluminous materials used with Portland cement to improve concrete performance. They react with the calcium hydroxide formed during cement hydration. This reaction helps increase strength and durability. The usefulness of a pozzolan is measured by its pozzolanic activity. One common test is the strength activity index from ASTM C 618-93. It compares the compressive strength of cement mixtures made with and without pozzolan. Fly ash is a common artificial pozzolan. It...

key terms and concepts

Explore Portland blast-furnace, white and colored, expansive, and waterproof cements, and see how each type supports strength, appearance, and moisture resistance.

Special Portland Cements for Durability | 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

Special Portland Cements for Durability

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