Stabilization small amount of activator, it can react chemically

Stabilization of soft soils by deep mixing with binders is the most
frequently used method of ground improvement. The binders react with water to
form cementitious composite materials. The most common binders employed are cement
and lime, but a variety of other binders may also be used for stabilization of
soils. This section contains a summary of the performance of lime, cement, fly
ash and blast furnace slag.

 

1.1     
Cement:

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It’s one of the major
stabilizing agent because it’s can produce the required effect on their own. Hydration processes start when cement is mixed with
water and other components for a demand application resulting into hardening
phenomena. Hardening of cement will intercept soil as glue without changing the
structure of soil.

This
process can be affected by:

 

presence of foreign matters or
impurities
water-cement ratio
curing temperature
presence of additives
specific surface of the mixture.

 

Depending on factors participatory, the
ultimate effect on Hardening and gain in strength of cement stabilized soil may
vary.

However, Cement stabilized soils have the following improved properties:

decreased cohesiveness (Plasticity)
decreased volume expansion or
compressibility
increased strength

 

1.2     
Lime:

There are two major types of limestone using these
days in construction one of them is calcium oxide (quicklime) and the other is calcium
hydroxide. When we expose limestone to a high temperature it will produce quicklime
and when we add water to it will produce hydrate lime. For soil
stabilization with lime, soil conditions and mineralogical properties have an important effect on the long-term strength ear. Calcium hydroxide works to
increase the PH ,causing the silica and alumina in the clay particles to become
soluble and interact with the calcium in a pozzolanic reaction. And this
reaction can form a cemented structure that increases the strength of the
stabilized soil.    

 

1.3     
Fly Ash:

Fly ash is a processing
by product generated at coal-fired electricity generating power plants that
contain silica, alumina, and calcium-based minerals. Compared to lime and
cement it has a low cementitious properties and its cannot produce the required
effect on their own because its belongs to secondary binders. However, in the presence of a small
amount of activator, it can react chemically to form cementitious compound that
works to improved strength of soft soil. Fly ashes are easily available, cheaper
and environmental friendly.

1.4     
Blast
Furnace Slags:

These are the by-product
in pig iron production. The chemical composition are similar to that of cement the only different is that blast furnace
slag has latent hydraulic properties which can
develop when we add lime or alkaline material.

 

Itemize slag in three forms, namely:

 

1.   Air-cooled slag :

Hot slag when we leave it
to cool
slowly in the open airs that will result in to crystallized
slag then we can crush it and used as aggregate.

2.    
Granulated
or Pelletised slag:
using water during quenching process will form granulated blast furnace slag , while, the use of air in the process of quenching may result into
formation of pelletised slag.

Expanded slag :
Under certain conditions, steam produced during cool of hot slag may
give rise to expanded slag

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