Cofferdams Powerpoint Presentation

Cofferdams Powerpoint Presentation

 

Cofferdams are temporary enclosures to keep out water and soil so as to permit dewatering and construction of the permanent facility (structure) in the dry.

A cofferdam involves the interaction of the structure, soil, and water.  The loads imposed include the hydrostatic forces of the water, as well as the dynamic forces due to currents and waves.

Because cofferdams are typically constructed under adverse conditions in a marine environment, and because significant deformations of elements may occur at various stages of construction, it is difficult to maintain close tolerances.  Ample provisions must be made for deviations in dimensions so that the finished structure may be constructed according to plan.

 

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Mechanics of Civil Engineering Structures Free PDF

Mechanics of Civil Engineering Structures Free PDF

 

Practicing engineers designing civil engineering structures, and advanced students of civil engineering, require foundational knowledge and advanced analytical and empirical tools.

Mechanics in Civil Engineering Structures presents the material needed by practicing engineers engaged in the design of civil engineering structures, and students of civil engineering.

The book covers the fundamental principles of mechanics needed to understand the responses of structures to different types of load and provides the analytical and empirical tools for design.

The title presents the mechanics of relevant structural elements – including columns, beams, frames, plates and shells – and the use of mechanical models for assessing design code application.

 

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What are the main types Of Grout Used In Construction

What are the main types Of Grout Used In Construction

 

What Is Grout?

 

Grout is a thick paste that is used to fill gaps, voids, or joints. It is mainly a composite material used for grouting, repairing concrete cracks, filling gaps and sealing the joints between tiles, waterproofing, soil stabilization, etc.

In this article, I will discuss different types of grout materials used in construction, tile installation, and other works. Differing from mortar, grout has a low viscosity and lack of lime, which makes it thinner and easier to work with.

 

Types Of Grout:

1. Cementitious Grout:

Cementitious grouts are the traditional grouting material, used both in residential as well as some commercial applications. It is also known as slurry grouting or hydraulic cement grouting. Materials used in cementitious grout are :

  • Portland cement,
  • Filler particles of different sizes,
  • Water-retentive additive,
  • Colored pigments.

Cementitious grouts are available in a variety of colors that let you match or contrast with the tile. Water is mixed with the grout and then applied using a trowel. The water retentive ingredient in cementitious grouts slows down the drying time, allowing the cement to cure slowly achieving maximum hardness.

Cementitious grouts are further classified into three types:

  • Sanded grout
  • Unsanded /Non-sanded grout
  • Latex modified grout.

 

a. Sanded Grout:

Sanded grout is composed of portland cement, sand, and other additives. The sand used is relatively larger in size. It is typically recommended for tile floors where joints are 1/8 inch to 3/8 inch wide. Sand provides extra strength to the grout joints, as it is one of the best building materials.

Sanded grout is absorbent and easily attracts dirt, therefore it is always better to seal the joint when grouting is done. As sand easily makes scratches, this type of grout should not be used on easily scratched tile like marble.

Sanded tile grout is less costly than unsanded grout because sand is a cheaper filler than polymers. It also provides a tight lock and a neat & clean finish.

Sanded grouts are ideal for use in Kitchen floor Bathroom floor Entryways Shower pan etc.

 

b. Unsanded Grout:

 

Unsanded grout is made of portland cement and color powder pigments. No sand is used here hence also known as non-sanded grout.

This type of grout is suitable for joint thickness between 1/8 to 1/16 inches. Unlike sanded grout, it is useful in scratchable surfaces such as metal, glass, marble, and natural stone tile.

Unsanded grout provides a much smoother texture since the mineral particles present in it are very fine powders without having grit.  However, these grouts easily develop cracks due to lack of binding power.

Unsanded grout is costly than sanded and you may have limited color options. Unsanded grouts are suitable for use in Rectified tiles, Polished stones. Bathroom walls, Shower walls etc.

 

c. Latex Modified Grout:

 

Sanded grouts may be composed of a latex polymer additive which increases the strength and water-proofing properties of grout. The additives can be mixed in both dry and wet conditions.

 

2. Chemical Grouts:

 

Chemical grouts consist of polymers such as epoxy, acrylic, polyurethane, sodium silicate, or any other suitable polymer. It requires injection of chemical grouts into finer cracks that are not groutable by cementitious grouts. Some useful types of chemical grouts are discussed below.

 

a. Epoxy Grout:

 

Epoxy grout is consists of epoxy resin, silica fillers, pigments, and a hardener. It neither uses Portland cement nor uses water during the mixing process.

Epoxy grout is very strong and durable.  Additionally, it is highly resistant to stains, cracks, chemicals attack, harsh weather conditions, and climatic changes.

Epoxy grouts are considerably less porous than cementitious grouts and set up quickly. It is also much costlier than any other type of grout. With light maintenance, epoxy grout can last lifelong if applied correctly.

The strength and other properties make it perfect for any tile work, indoors or outdoors. It is suitable for use in High traffic areas like entryways, hallways, and foyers.

Any type of flooring exposed to harsh conditions like grease and acid. Kitchen counters and backsplash, bathrooms, etc. Keep in mind, porous and unglazed surfaces, such as limestone or quarry tiles need to be sealed before applying epoxy grout, otherwise, it can stain the tile surfaces badly.

Another major disadvantage that it is much more difficult to shape and slope. If not done correctly, it will look plastic.

 

b. Furan Grout:

 

Furan grout is similar to epoxy but composed of polymers of fortified alcohols. There is no water used in this type of grout installation. Furan is basically a combination of furan resin and a filler powder with an acid catalyst.

The acid catalyst helps the resin to cure making it a thermosetting resin that has unsurpassed chemical, physical, and thermal resistance.

The tile surfaces may be smooth, abrasive or non-skid hence it should be sealed with wax coating right after furan grout installation to protect from staining. Furan grout is the strongest and most expensive grout material available in the market.

Because of the difficulty of installation, it requires proper precautions and skilled labours. This type of grout is suitable for use in Brick pavers, Quarry tiles. Industrial projects, such as laboratories, factories, dairies, and meat-packing plants. Areas highly exposed to chemicals and/or grease.

 

c. Acrylic Grout:

 

Acrylic grout is an acrylic latex admixture composed for use as a substitute for water when grouting ceramic tile. It is specifically produced for use with AccuColor Portland cement grouts. Acrylic grout helps to make joints less susceptible to water penetration.

It is very much essential when grouting wet areas. The additive further helps the grout retaining its color and resisting stains. It gives good stability in freezes and thaws. It also enhances grout flexibility. It has greater adhesion properties. Additionally, you don’t need to cover the entire work surface.

You can just apply it in between tile joints. Another advantage of using acrylic latex grout is that it can be used in small spaces. It is mostly suitable for joint thickness less than 1/8 inch. This type of grout is especially suitable for use in Outdoors such as deck or garage projects. Fast-food restaurant floors. Marble work etc.

 

Standard Culvert and MEL Culvert Definition

Standard Culvert and MEL Culvert Definition

 

Introduction :

A culvert is a covered channel of relatively short length designed to pass water through an embankment (e.g. highway, railroad and dam).

It is a hydraulic structure and it may carry flood waters, drainage flows, natural streams below earthfill and rockfill structures. From a hydraulic aspect, a dominant feature of a culvert is whether it runs full or not.

The design can vary from a simple geometry (i.e. box culvert) to a hydraulically smooth shape (i.e. minimum energy loss (MEL) culvert)

Culvert Parts :

A culvert consists of three parts: the intake (also called inlet or fan), the barrel (or throat) and the diffuser (also called outlet or expansion fan) (Fig.1-a).

The cross-sectional shape of the barrel may be circular (i.e. pipe), rectangular (i.e box culvert) or multi-cell (e.g. multi-cell box culvert) (Fig.1-b).

The bottom of the barrel is called the invert while the barrel roof is called the soffit or obvert. The training walls of the inlet and outlet are called wing walls.

 

Fig 1. Sketch of a culvert: (a) box culvert

 

Fig 1. (b) MEL culvert

 

Standard Culverts :

A standard culvert is designed to pass waters at a minimum cost without much consideration of the head loss. The culvert construction must be simple: e.g. circular pipes and precast concrete boxes.

 

MEL Culverts :

An MEL culvert is a structure designed with the concept of minimum head loss. The flow in the approach channel is contracted through a streamlined inlet into the barrel where the channel width is minimum, and then it is expanded in a streamlined outlet before being finally released into the downstream natural channel. Both the inlet and outlet must be streamlined to avoid significant form losses

 

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