Construction materials

civil techniques

Soil Nailing

abbu riyaz 1 May, 2023

Soil nailing is a construction technique to reinforce soil to make it stable and strong. Soil nailing technique uses for slopes and excavations alongside highways, railway lines. It uses for, excavations, retaining walls slopes, to make it more strong and stable.

The soil reinforces with slender elements like reinforcing bars name as nails. These reinforcing bars install into pre-drill holes and grouts. The nails install at an inclination of ten to twenty degrees with vertical reinforcement.

Soil Nailing employes when requiring slopes for excavation cannot provide due to space constraints. And employes in the construction of retaining wall. It is an alternative to retaining wall structures.

At excavation, the shotcrete, concrete and grouting materials apply to the excavation face to grout the reinforcing steel and nails. It provides stability to the steep soil slope.

Types of Soil Nailing:

There are various types of soil nailing techniques:

Grouted Soil Nailing
Driven Nails
Self-drilling Soil Nail
Jet Grouted Soil Nail
Launched Soil Nail

1. Grouted Soil Nailing

In this type, the holes drills in walls or slope face and nails inserts in the pre-drill holes. These holes fill with grouting materials like concrete and shotcrete.

2. Driven Nails:

Driven nailing use for temporary stabilization of soil slopes. In this method, the nails drive in the slope face at the time of excavation. This method is very fast. It does not provide corrosion protection to the reinforcement steel and nails.

3. Self-drilling Soil Nail:

In this method, the hollow bars use. Hollow bars drills into the slope surface and grout inject simultaneously during the drilling process. This method of soil nailing is faster than grout nailing. This method provides more corrosion resistance to nails than driven nails.

4. Jet Grouted Soil Nail:

In this method, jets use for eroding the soil for creating holes in the slope surface. Steel bars install in this hole and grouts with concrete. It provides good corrosion protection for the steel bars and nails.

5. Launched Soil Nail:

In this method, the steel bars force into the soil with high speed using compressed air mechanism. The installation of soil nails is fast. And control over the length of bar penetrating the ground is difficult.

civil techniques

Bitumen Requirements

abbu riyaz 1 May, 2023

There are many Bitumen Requirements in the construction of pavements. A bitumen mix use in the construction of flexible pavement. It serves the following needs.

Strength
Drainage and
Friction

Bitumen Requirments

The main Bitumen Requirements are,

1. Strength

It is one of the important Requirements for construction of flexible pavements. The bitumen layer composes of three main courses. They are,

Surface course
Binder and
Base course

Purpose of bitumen mix is to give Strength to pavements. And load dispersion throughout the layers of the pavement. The loads are dynamic or static loads. It transfers to the base subgrade through the aggregate course. A granular base with a bituminous surface course provides for roads of low traffic. It is sufficient and economical.

There is a higher amount of bitumen content in the wearing course. This makes the layer more flexible. This helps in increasing the durability.

2. Drainage

It is draining of water collects on the ground. The water is from excess rainfall, over irrigation, seepage from areas at higher levels. The water standing on roads causes damages to pavements. And increase maintenance cost.

Subsurface drainage facilitates using granular sub base in the construction of flexible pavement. Permeable asphalt treated base uses to provide positive surface drainage on major highways. This behaves as a separate course for facilitating subsurface drainage.

3. Friction

It is one of the important Requirements for construction of pavements. At vehicle passage in wet conditions, it needs the layer to provide slip resistance and friction. This makes the safety of the passengers.

The large and small size of asphalt mix gives the friction. On mixing the large and small mixture it forms a waterproof layer. The large surface mix uses to squeeze the water out from the bottom of a vehicle wheel.

civil techniques

Bituminous Materials

abbu riyaz 1 May, 2023

Bituminous Materials are of different types. Bituminous Materials is available in a variety of types and grades. The different types of Bituminous Materials are explaining in this post.

Bituminous Materials

The different types of Bituminous Materials are

Asphalt
Bitumen
Cutback Bitumen
Bitumen Emulsion
Tar

1. Asphalt

It is a mechanical mixture of inter mineral matter. There are two categories of asphalt, they are (a) Natural Asphalt and (b) Residual asphalt. The natural asphalt obtains naturally. The residual asphalt occurs by fractional distillation of crude petroleum oil with an asphalt base.

2. Bitumen

It is a complex organic material occurs naturally and artificially at the distillation of petroleum. These bitumen posses some desirable properties. They are,

Durability
Good adhesion with aggregate
Better compaction and
Easy mixability

3. Cutback Bitumen

Bitumen mix with a volatile solvent is cutback bitumen. This enables its application considerable at low temperature. Base on quantity, character, and volatility, the cutback bitumen divides into three types. They are,

Rapid Curing (RC) cutback bitumen
Medium Curing (MC) cutback bitumen
Slow Curing (SC) cutback bitumen

4. Bitumen Emulsion

A liquid product form by mixing molten bitumen with hot water in the presence of an emulsifying agent. It consists of soap or resinous bodies. On application, the water evaporates the emulsion breaks up and bitumen left in place. The change of color from chocolate brown to black indicates the breaking of the emulsion. Its classifications are,

Rapid setting (RS)
Medium setting (MS) and
Slow setting (SS)

The main advantage of the emulsion is it employes at the wet weather and it rains. These materials use for maintenance and repair works.

5. Tar

A dark, thick flammable liquid consisting of a mixture of hydrocarbons, resins, alcohols, and other compounds. This obtains by destructive distillation of coal, oil, petroleum wood and other organic materials. It is brown or black bituminous material with high viscosity. It uses in road-making and for coating. And has great variation in viscosity.

civil techniques

Bitumen Road Construction

abbu riyaz 1 May, 2023

Bitumen Road Construction has significant properties and various advantages.The Bitumen Road Construction mostly employs in the construction of roads worldwide. It is an organic material occurs naturally and artificially by distillation of petroleum. Bitumen uses in construction mainly for its unique properties. For the construction of a flexible road and for a smooth ride and comfort bitumen employes.

Use of Bitumen Road Construction

The main uses of Bitumen road constructions are for its

Economic conditions
Physical properties
Melting point
Recycling properties
Adhesive Nature
Varieties of Colour

1. Economic conditions

Bitumen forms by distillation process of petroleum and oil product like crude oil, etc. Crude oil itself is a composition of hydrocarbons. On refining process bitumen gains as a waste. The treatment of the waste makes an impurities-free bitumen.

The primary oil products consumption rate is high worldwide. This increase the demand for oil products like petrol, etc. Increase in oil productions forms more waste which is processing as bitumen in treatments. And bitumen obtains easily without any extra or a new manufacturing process. And widely employs as a construction material without the requirement of other new sources.

2. Physical Properties

Bitumen acts as a thermoplastic and it is a viscoelastic material. It is easy to handle the bitumen at normal condition. The physical and the chemical properties of Bitumen cause a flexible pavement and roads. The bitumen is rigid in cool climates and flexible in high temperatures make a smooth movement. The bitumen mix properties vary base on the stress levels.

3. Melting Point

The melting point of bitumen is low. It makes the melting progress faster and reduces work timings. And operations like surface dressing, wearing resistance are completing quickly within time. At high temperatures, the aggregate composition covers the effect of deformation of bitumen. As its melting point is low.

4. Recycle

Other construction materials are rarely recyclable and mostly employes for landfills. In bitumen, it is easily recyclable. It transports to a recycling plant. It recycles and if necessary old bitumen mix with new bitumen and new aggregates forms. This process is asphalt recycling process.

5. Adhesive Nature

It is Adhesive in nature. It is free from hydrocarbon and other chemicals. And it is not toxic. The by-product refines mostly to get rid of organic materials and impurities. The materials in the road mix bind together under strong bonds. This makes mix stronger and after setting time and ready for vehicle movement.

6. Varieties of Color

Bitumen is naturally black in color as the organic material in bitumen is black in color. In modern constructions with the help of technology, coloring pigments add in bitumen to obtain desire varieties of color. This makes coloring bitumen costly as it needs high chemicals.

civil techniques

Scaffolding types

abbu riyaz 1 May, 2023

There are many scaffolding types. Scaffolding is a temporary structure to support the original structure and workmen. And use as a platform to carry on the construction works. Types of scaffolding vary with the type of construction work. Scaffolding is of timber or steel. It is stable and strong to support workmen and other construction material place on it.

Scaffolding Types in Construction:

Following are types of Scaffolding in construction:

Single scaffolding or brick layer’s scaffolding.
Double scaffolding.
Cantilever scaffolding.
Suspended scaffolding.
Trestle scaffolding.
Steel scaffolding.
Patented scaffolding.

1. Single Scaffolding or bricklayer’s scaffolding.

Single scaffolding use for brick masonry and called as brick layer’s scaffolding. This is most commonly employs in the construction of brickwork. Single scaffolding consists of standards, ledgers, putlogs. Standards drive into the ground at a distance of about 1.5 m to 2 m apart. And about 1.2 m away from from the wall to construct. The standards connect to each other by ledgers placing at right angles. It secures in position with rope lashing.

2. Double Scaffolding:

Double Scaffolding is stronger so its use for stone masonry. The formwork is similar to single scaffolding. This type of wall is completely independent of walls and no holes are drill in the wall to support putlogs. To make it more strong rakers and cross braces use.

3. Cantilever Scaffolding:

cantilever scaffolding employes where it is not possible to fix the standards into the ground. In this, scaffolding the standards supports by series of needles. And these needles pull out through holes in the wall. It provides on side of a busy street without obstructing the traffic on the road. It is important in the construction of multistorey and industrial buildings.

4. Suspended Scaffolding:

These Scaffolding types are suitable for light steel frame construction, maintenance work like painting, pointing, distempering, etc. In this type, standards don’t rest on the ground.

The working platforms suspend from rooftops by means of wire ropes and chains. And there is a mechanical arrangement to raise or lower the platform.

5. Trestle Scaffolding:

In this scaffolding types, the working platforms support on tops of mobile devices like movable tripods and ladders. These employes for work inside the room, like paintings, repairs etc., up to a height of 5m.

6. Steel Scaffolding:

The steel scaffolding is similar to timber scaffolding in which wooden members replace by steel tubes. And rope lashings replace with couplings and screw-nuts. Steel tubes fix with steel couplers and fittings. It is very easy to construct or dismantle and has greater strength, durability, and fire resistance. It gives more safety to workers.

7. Patented Scaffolding:

Patented scaffoldings are of steel. And equip with special couplings and frames. It is readymade scaffolding and available on the market. In this type of scaffolding, a working platform arranges in brackets and adjustable to a level.

civil techniques

Scaffolding

abbu riyaz 1 May, 2023

Scaffolding is a temporary structure uses in building operations to support platforms for workmen. And helps with structural materials, and materials required during construction of high rise buildings. It uses for above height of 1.5 meters. This temporary scaffold is useful in building construction, repairs, demolition, maintenance and repair works.

It sets one or both sides of the wall according to needs. It sets one side of wall or buildings for ordinary works. For major quality works scaffold to sets on both sides of walls. The height of the scaffolding is adjusting according to the work.

Components of scaffolding

Standards
Ledgers
Braces
Planks
Put-logs
Guard boards
Toe-boards

Standards: These are vertical members of the scaffolding.

Ledgers: Ledgers are horizontal members at right angles to the standards and parallel to the wall.

Braces: Braces are members fix diagonally to the standards.

Planks: They forms the horizontal platforms for supporting men, materials, and appliances.

Put-logs: These members place on horizontal members at right angles to the wall.

Guard boards It uses at working level to guard against materials.

Toe-boards Toe-boards place parallel to the ledgers and using for protection at high levels of the working platform.

These components/members of the scaffold are secure by means of rope lashings, rails, and bolts.

Advantages of scaffolding

The first advantage of using scaffold is to complete the work task safely.

Easily installs and complete various work tasks without hassle.

With scaffold, the worker can reach many meters high as possible.

It provides large space to keep your construction tools and more usable workspace.

LIghtweight and cost-effective.

It is easier for workers to maintain their balance on a flat platform than on a ladder step.

Provide access to difficult places when buildings are constructs and reduce time to complete work.