Name: concrete pavement joint types and functions
Uploaded: 2025-06-13T10:43:57.000Z
Duration: 1 min 28 s
Channel: JoVE

Propõe-se a extensão de um pavimento de concreto liso existente para construção com lajes de concreto, garantindo o mínimo de rachaduras no pavimento.
Um engenheiro de pavimento decide fornecer juntas de construção, expansão, isolamento e contração para controlar rachaduras no pavimento.
As juntas de construção são lacunas fornecidas entre a nova laje e uma laje existente para permitir quaisquer movimentos possíveis na nova laje. Barras de cavilha embutidas no concreto unem as lajes adjacentes.
As juntas de dilatação são vãos fornecidos entre as lajes adjacentes para permitir a expansão térmica do concreto.
Sua construção envolve a disposição das barras de cavilha em fileiras na direção transversal do pavimento e o despejo de concreto sobre as barras.
A lacuna deixada é então preenchida com cargas compressíveis e selantes.
As juntas de isolamento são fornecidas onde o pavimento encontra um bueiro. Uma junta de meia polegada de largura ao redor do bueiro, preenchida com um material compressível, forma a junta de isolamento.
Finalmente, a junta de contração é fornecida serrando uma ranhura no pavimento de concreto recentemente endurecido orientada perpendicularmente à direção do fluxo de tráfego.
Isso ajuda a localizar e controlar a formação de rachaduras durante a contração do concreto.

exemplo de projeto: juntas em pavimentos de concreto

As juntas de pavimento de concreto são essenciais para manter a integridade estrutural e a longevidade do pavimento, controlando onde e como o pavimento racha. Essas juntas podem ser categorizadas com base em suas funções, como juntas de contração ou controle, juntas de construção, juntas de isolamento e juntas de expansão.

As juntas de contração são normalmente formadas ao serrar uma ranhura no concreto logo após ele ter endurecido. Isso cria um plano vertical enfraquecido, incentivando deliberadamente a fissuração neste local predeterminado em vez de aleatoriamente na laje de concreto.

As juntas de isolamento são usadas onde um pavimento de concreto encontra outra superfície ou um objeto fixo, como uma interseção de rodovia ou um dispositivo de utilidade como um bueiro. Essas juntas incluem um material compressível que preenche toda a profundidade da junta, permitindo que estruturas ou superfícies adjacentes se movam independentemente do pavimento.

As juntas de construção ocorrem onde o concreto fresco encontra o concreto endurecido, geralmente visto no final de um dia de pavimentação. Essas juntas gerenciam transições entre diferentes seções do pavimento e embutem barras de pino ou tirantes entre as seções.

As juntas de expansão são empregadas para acomodar a expansão potencial de lajes de concreto. Essas juntas são cruciais para evitar o desenvolvimento de altas forças de compressão, o que pode levar à lascamento da junta ou explosões estruturais. Elas normalmente contêm dispositivos de transferência de carga, como pinos ou barras de tirante, que facilitam o movimento principalmente na direção da junta. Geralmente, as juntas são preenchidas usando materiais de enchimento e selantes.

Exemplo de projeto: juntas em pavimentos de concreto

Propõe-se a extensão de um pavimento de concreto liso existente para construção com lajes de concreto, garantindo o mínimo de rachaduras no pavimento.
Um pavimento ...

design-example-joints-in-concrete-pavements

Education

JoVE Core

Civil Engineering

Engenharia Civil

Unit 1

Unidade 1

Design Examples

Exemplos de Projeto

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

Design Example: Joints in Concrete Pavements

concrete pavement joint types and functions

Concrete pavement joints guide where slabs crack and help protect the pavement over time. They support the structural integrity and long life of the concrete by controlling movement and cracking.

Contraction joints, also called control joints, are made by sawing a groove into the concrete soon after it hardens. This groove creates a weakened vertical plane. It encourages cracking at a planned location instead of letting cracks form randomly across the slab.

Isolation joints are used where the pavement meets another surface or a fixed object. Common examples include a roadway intersection or a utility fixture such as a manhole. These joints use compressible material that fills the full depth of the joint, so the pavement and nearby structure can move independently.

Construction joints appear where fresh concrete meets hardened concrete, often at the end of a paving day. They handle the transition between sections of pavement. Dowel bars or tie bars are embedded between the sections to help connect them.

Expansion joints allow concrete slabs to expand without building up too much compressive force. That helps prevent joint spalling and structural blowups. These joints usually include load transfer devices such as dowels or tie bars, which support movement mainly along the joint direction. In general, joints are finished with filler materials and sealants.

Concrete Pavement Joint Types and Functions

design example: dimensioning of concrete masonry construction

design-example-dimensioning-of-concrete-masonry-construction

Sizing a Storeroom with Masonry Blocks

Sizing a storeroom with concrete masonry blocks starts with matching the wall plan to the actual block size and mortar joints. The site has concrete masonry units with a nominal size of 8 by 8 by 16 inches. The storeroom is planned with external dimensions of 12 feet long and 8 feet wide. The wall layout uses nine blocks along the length and six blocks along the width. Each block is actually 7 and 5/8 inches high and wide, and 15 and 5/8 inches long. A 3/8 inch mortar joint is included, so the...

design example: joints in concrete pavements

Concrete pavement joints guide where slabs crack and help protect the pavement over time. They support the structural integrity and long life of the concrete by controlling movement and cracking. Contraction joints, also called control joints, are made by sawing a groove into the concrete soon after it hardens. This groove creates a weakened vertical plane. It encourages cracking at a planned location instead of letting cracks form randomly across the slab. Isolation joints are used where the...

design example: aggregate gradation

Choosing Well-Graded Sand for Concrete

Well-graded sand is important in concrete because aggregate choice affects strength, mix proportions, and cost. In concrete, sand is the common fine aggregate. When more than one sand source is available, its gradation often guides the selection. Gradation means the particle-size distribution of the sand. Engineers measure it with sieve analysis, which uses standard sieve sizes from 150 μm to 10 mm, from ASTM No. 100 to the 3/8 in. sieve. This test shows how much sand stays on each sieve and...

design example: managing concrete workability

design-example-managing-concrete-workability

Concrete Slump Test in Hot Weather

Concrete slump testing helps track workability during a raft foundation pour in hot weather. Workability means fresh concrete is easy to place, compact, and finish. In this example, the concrete had to be prepared for a large foundation, so keeping it workable was important for quality and durability. The first slump test showed low workability. The mix was losing water quickly, and the high temperature made the coarse aggregates hotter as well. To reduce that effect, the site engineer cooled...

design example: distributing reinforcements in concrete sections

design-example-distributing-reinforcements-in-concrete-sections

Sizing Steel Bars for a Concrete Beam

Sizing steel bars for a concrete beam helps meet a required reinforcement area. In reinforced concrete design, the steel must be arranged so the beam stays strong and uses material efficiently. This example uses a beam that needs a total steel cross-section of 4 square inches. The available bars in the example have a nominal diameter of 1.693 inches. Each bar provides a cross-sectional area of 2.25 square inches. When the engineer divides the required area by the area of one bar, the result is...

design example: sustainability in concrete building

design-example-sustainability-in-concrete-building

Green Features in a Concrete Building

A sustainable concrete building can use several green design features to save energy, water, and materials. Concrete is a flexible material for these choices, so it supports eco-friendly construction in commercial buildings. One strategy is to place a concrete parking area under the building. Open areas can use pervious concrete paver blocks, which let rainwater pass through and collect in an underground cistern. That stored water can then be reused for gardening, which improves water...

key terms and concepts

Learn how contraction, isolation, construction, and expansion joints control cracking, movement, and support in concrete pavements.

Concrete Pavement Joint Types and Functions | 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.

Concrete Pavement Joint Types and Functions

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