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civil techniques

Jet Grout Soil Nailing

abbu riyaz 1 May, 2023

The Jet Grout Soil Nailing method use for eroding the soil for creating holes in the slope surface. Steel bars install in this hole and grout with concrete. It provides good corrosion protection for the steel bars. Soil nailing is a technique in which soil slopes, excavations or retaining walls are reinforced by the insertion of steel reinforcing bars.

Soil nailing uses to stabilize existing slopes and excavations. The top-to-bottom construction is advantageous compares to the other retaining wall systems.

As construction proceeds from the top to bottom, shotcrete or concrete applies to the excavation face to provide continuity. In short Soil, Nailing increases the shearing resistance of soil by acting in tension.

In the present construction times, soil nailing employes large in railway construction work. It uses for the stabilization of side lopes in existing track-road. And laying of new tracks adjoining to an existing one.

Types of Jet Grout Soil Nailing

There are three types of Jet Grouting Soil Nailing, they are,

Single fluid jet grouting
Double fluid jet grouting and
Triple fluid jet grouting.

1. SIngle fluid jet grouting

In this Single fluid jet grouting, the grouting takes place by using grout. In this method of the single jet grouting, the grout force into the soil with the very high-speed mechanism. And grouting carries out.

2. Double fluid jet grouting

In Double fluid jet grouting, the grouting takes place by using Air and grout. In this method of the double jet grouting, the grout and air force into the soil with the very high-speed mechanism.

3. Triple fluid jet grouting

In Triple fluid jet grouting, the grouting takes place by using Air, Water, and grout. In this method of the triple jet grouting, the grout, air, and water forces into the soil with the very high-speed mechanism.

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

Footings

abbu riyaz 1 May, 2023

Footings designs to resist the shear force causes by imposing loads. Footings constructs in open space and known as open foundations. It provides with natural slopes on all sides. It employs for a depth up to 5 m. The base of the structure enlarges or spreads to provide individual supports. These type of foundations provides for the structure of moderate heights built on the dry ground.

Types of footings

Wall Footing
Isolated footing
Combined footing
Inverted footing
Continous footing
Cantilever footing
Grillage footing

1. Wall Footing

Footings are of simple or stepped on wall footing. The base course of the footings is of concrete or other material. These footings employ only for simple structures. It has one projection beyond the width of the wall on sides. The width of the concrete base is equal to twice the width of the wall. In single footings, the brick footing is widely employing.

2. Isolated or column footing

It uses to support individual columns. It is in step or has a projection in the concrete base. In heavy loads, steel reinforcement provides in both directions in concrete bed. An offset of 15 cm provides on all sides of the concrete bed. In brick masonry, offset is of 5 cm on all sides in regular layers.

3. Combined footing

A combined footing supports more columns in a row. The combined footing is of rectangular shape if both the column carry equal loads. In unequal loads it of trapezoidal shape. It is rigid and resisting on the homogeneous soil.

4. Inverted arch footing

Inverted arch footing use on the soft soil to reduce the depth of foundation. Loads above an opening transmit from supporting walls through inverter arches of soil. In this type of footing, the end columns are stable enough to resist the outward pressure causing by arch section.

5. Continuous footings

In this type of footing, a single continuous R.C. slab provides a foundation of more columns in a row. It is suitable for locations liable to earthquake activities. This prevents differential settlements in structure. To have a better stability deeper beam constructs in between columns.

6. strap or cantilever footing

It consists of more individual footings connects by a beam known as a strap and known as cantilever footing. This type of footing uses where the distance between the column is greater. It serves to transfer column loads on the soil with equal and uniform soil pressure.

7. Grillage footing

This type of footings uses to transmit heavy loads from steel columns to the soils having low bearing power. This type of arrangements avoids deep excavation. And provides a necessary area at the base to reduce the intensity of pressure. Grillage footings are of roll steel joists and name as grillage beams to providing in single or double tires.