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What are the type of Soil Stabilization of Highway Embankment?
Amol M.
Soil stabilization of highway embankment Soil Stabilization • Mechanical stabilization: Improvement of soil properties can be achieved by changing particle gradation. The engineering performance depends mainly on grain size distribution and plasticity. Significant changes in the properties can be maRead more
Soil stabilization of highway embankment
Soil Stabilization
bentonite reduces permeability coefficient k. Asphalt
• Mechanical stabilization: Improvement of soil properties can be achieved by changing particle gradation. The engineering performance depends
mainly on grain size distribution and plasticity.
Significant changes in the properties can be made by the addition or removal of suitable soil fractions.
Granular fraction imparts strength and hardness. Fine fraction imparts cohesion, water, retention capacity and it acts as filler.
• Extreme caution is required for adding fine to roadbases and subgrades.
• The common technique of soil alteration is the addition of sodium montmorillonite (bentonite) to reduce the permeability of the soil. Addition of 10% of
have been also tried.
Lime Stabilization :
Hydrated (or slacked) lime is very effective in
treating heavy plastic clayey soils. Lime may be used alone or in combination with cement, bitumen, or flash. Lime has been mainly used for stabilizing the
road bases and subgrades.
• On addition of lime to the soil, two main types of
chemical reactions occur i) alteration in the nature of the adsorbed layer through base exchange phenomenon and ii) cementing or pozzolanic action.
Lime reduces P.I. of highly plastic soils making them more friable and easy to be handled and pulverized.
The P.I. of low plasticity generally increases. There is generally an increase in the O.M.C. and decrease in the compacted density, by strength and durability
increases.
• Normally 2 10 8 % of lime may be required for coarse-grained soils and 5 to IO % for plastic soil.
Cement Stabilization :
The soil stabilized with cement (Portland) is known as soil cement. The cementing action is believed to be the result of chemical reactions of cement with silicious soil during hydration. The binding action of individual
particles through cement may be possible only in coarse-grained soils. In cohesive soils, only some of the particles can be excepted to have cement bonds and the rest will be bonded through natural cohesion.
Bitumen Stabilization :
• Earth roads can be improved by spraying the dry soil surface with a stabilizer such as aspheric and cut back bitumen oil, tars, or emulsions in small quantities. The bituminous materials when added to soil impact cohesion or binding action and reduce water absorption. About 4 to 7 % by weight of
bitumen is required. Any inorganic soil can be
stabilized well-graded soils give goods results from 10^3 mm/s to 10^8 mm/s in case of silty sands. Local clays may be used.
These are the methods of stabilization
See lessWhat is Stucco Plaster?
AdityaBhandakkar
Stucco in English refers to coating on outside and plaster refered to internal coating. Stucco plaster are categorised into two types: Traditional Stucco plaster: It is a mixture of lime, sand, and water. Modern stucco plaster: It is a mixture of Portland cement, sand, and water. In modern stucco plRead more
Stucco in English refers to coating on outside and plaster refered to internal coating.
Stucco plaster are categorised into two types:
Traditional Stucco plaster:
It is a mixture of lime, sand, and water.
Modern stucco plaster:
It is a mixture of Portland cement, sand, and water.
In modern stucco plasters, lime is replaced by Portland cement for increasing durability. For many special purposes, Instead of lime plaster, gypsum player use.
To improve structural properties, acrylic and glass fibers are used in modern stucco.
See lessWhat is the moisture content limits in plastered walls before we take up the painting work?
CB Sowmya
The maximum moisture content is limited to 12% in plastered walls before painting or application of any coating.
The maximum moisture content is limited to 12% in plastered walls before painting or application of any coating.
See lessWhat Reinforcements are used in the Process of Prestressing?
Tips_and_tricks
In prestressing, we use strands of steel usually called as tendons. They are made of high strength steel. However, there are other terms in pre stressing based on the size of the tendon. The following are the terms in an increasing order of size. Wire - small wire (single) Strand - 2 or more wires TRead more
In prestressing, we use strands of steel usually called as tendons. They are made of high strength steel. However, there are other terms in pre stressing based on the size of the tendon. The following are the terms in an increasing order of size.
- Wire – small wire (single)
- Strand – 2 or more wires
- Tendon – group of strands
- Cable – Group of tendons
- Bar – single bar – dia of 10 mm or more
See lessWhy should curing not be done by ponding and polythene sheets?
Tips_and_tricks
The disadvantages of ponding: Evaporation is high Constant monitoring Excess water is needed The initial work for ponding must be done However, it is a very simple process and doesn't need skilled labours, thus the disadvantages maybe overruled by that advantage. The disadvantages of polythene sheeRead more
The disadvantages of ponding:
However, it is a very simple process and doesn’t need skilled labours, thus the disadvantages maybe overruled by that advantage.
The disadvantages of polythene sheets:
However, this method if installed properly retains moisture inside the concrete for a longer period of time.
See lessWhat is the meaning of Soil Reinforcement?
Vivek Patel
Soil reinforcement is a process of improving soil stability against slope failure. Basically geogrid is used as reinforcement in soil stabilization Various type of geogrid is classified as: Extruded Geogrid type Woven Geogrid type Bonded Geogrid type Best on stretching Uniaxial geogrid type BiaxialRead more
Soil reinforcement is a process of improving soil stability against slope failure.
Basically geogrid is used as reinforcement in soil stabilization
Various type of geogrid is classified as:
Best on stretching
Geogrid is widely used in canal embankment, highway embankment and soil slope stabilization.
See lessWhat is Bursting Reinforcement?
CB Sowmya
Bursting reinforcements are provided in Post-tensioned prestressed members or where bursting forces are prevailing. In post-tensioned members, the transfer of stress is through the anchorage blocks. The concrete in the vicinity of the anchorage block up to the length of the larger transverse dimensiRead more
Bursting reinforcements are provided in Post-tensioned prestressed members or where bursting forces are prevailing. In post-tensioned members, the transfer of stress is through the anchorage blocks.
The concrete in the vicinity of the anchorage block up to the length of the larger transverse dimension of the structure is defined as the anchorage zone. This anchorage zone is very high in bursting forces. These bursting forces can be computed using the stress trajectory studies.
From the stress trajectories, bursting forces can be found and corresponding bursting reinforcements can be provided. These reinforcements are also called the end zone reinforcement or bursting links. This zone can be cast separately using a high grade of concrete to ensure safety.
See lessWhy is propping required for long structures once the formwork is removed?
CB Sowmya
The formworks are removed after the concrete has reached a strength at least twice its removal stress. But the members should be supported with the help of props. The reason is because of creep due to the Interfacial transition zone (ITZ). The interfacial transition zone is formed in the concrete beRead more
The formworks are removed after the concrete has reached a strength at least twice its removal stress. But the members should be supported with the help of props. The reason is because of creep due to the Interfacial transition zone (ITZ).
The interfacial transition zone is formed in the concrete between the aggregates and the mortar. This zone comprises of high Water cement ratio and hence is the weakest part of the concrete. Due to the high WC ratio, the hydration reaction in the ITZ produces a porous framework in the early stages. This porous network will be filled in subsequently by stronger gels such as CSH gel as the hydration reaction proceeds. But for this to take place, sufficient time is needed. As time increases, the ITZ becomes stronger.
This is why the creep coefficient reduces as we delay the age of loading. When the props are moved, the self-weight of the structure acts on it, which is equivalent to loading the structure.
We know that the creep coefficient when loaded at
Seven days – 2.2
28 days – 1.6
One year – 1.1
Due to the high creep coefficient, the structure may become susceptible to sagging when the props are removed soon.
See less