Sunday, June 13, 2010


 Stabilization in a broad sense incorporates the various methods employed for modifying the properties of a soil to improve its engineering performance. Stabilization is being used for a variety of engineering works, the most common application being in the construction of road and airfield pavements, where the main objective is to increase the strength or stability of soil and to reduce the construction cost by making best use of locally available materials.

Principles Of Stabilization:

Natural soil is both a complex and variable material. Yet because of its universal availability and its low cost winning it offers great opportunities for skilful use as an engineering material.

Not uncommonly, however the soil at any particular locality is unsuited, wholly or partially, to the requirements of the construction engineer. A basic decision must therefore be made whether to:
• Accept the site material as it is and design to standards sufficient to meet the restrictions imposed by its existing quality.
• Remove the site material and replace with a superior material.
• Alter the properties of existing soil so as to create a new site material capable of better meeting the requirements of the task in hand.

The latter choice, the alteration of soil properties to meet specific engineering requirements is known as “Soil stabilization.”

It must also be recognized that stabilization not necessarily a magic wand by which every soil property is changed for the better. Correct usage demands a clear recognition of which soil properties must be upgraded, and this specific engineering requirement is an important element in the decision whether or not to stabilize. Properties of soil may be altered in many ways, among which are included chemical, thermal, mechanical and other means.

The chief properties of a soil with which the construction engineer is concerned are: volume stability, strength, permeability, and durability.
Methods of stabilization may be grouped under two main types:
1. modification or improvement of a soil property of the existing soil without any admixture.
2. Modification of the properties with the help of admixtures.

Compaction and drainage are the examples of the first type, which improve the inherent shear strength of soil.
Examples of the second type are: mechanical stabilization, stabilization with cement, lime, bitumen and chemicals etc,.


Stabilization of soils with hydrated lime is applicable to far heavier clayey soils and is less suitable for granular materials and second it is used more widely as a construction expedient that is to prepare a soil for further treatment or to render a sufficient improvement to support construction traffic. As a temporary measure such modification or stabilization need not necessarily affected to the standards required for permanent construction. Quick lime or lime slurries may also be used for excessively wet or dry conditions respectively. It is therefore a very versatile stabilizer.

In roads lime stabilization is widely used for sub-base construction or sub grade improvement; nevertheless there is no sound reason why these roles should not be interchangeable.


The materials to be considered are lime, soil and water and it is important that the type of lime to be used is clearly defined. It is unfortunate that the term “lime” is used to describe calcium hydroxide (agricultural lime) calcium hydroxide (slaked lime or hydrated lime) and calcium oxide (quick lime). The term is used here and in general engineering practice to mean hydrated lime.


Calcium hydroxide is most widely used for stabilization. The stabilizing effects ultimately depend on chemical attack by the lime on clay minerals in the soil to form cementitius compounds (calcium silicate) and carbonate doesn’t do this. Lime is prepared by heating calcium carbonate (natural limestone) in kilns until carbon dioxide is driven off. The calcium oxide discharged from the kiln is known as “Quick lime” and because of lumpy condition and high heat of hydration, which makes it difficult to handle and store, particularly in humid climates it is usual slake the quick lime immediately forming hydrated lime (calcium hydroxide) as very fine powder. It is important to note that the hydration process involves a large reduction in density and this expansion is the basis of deep stabilization techniques using lime piles. Hydrated lime poses much less of a storage problem as it is no longer so susceptible to humidity: but both forms will revert to carbonate on prolonged exposure to air. The mean particle size is about 1/10th that of cement. On addition of lime to soil two main types of chemical reaction occur:

• Alteration in the nature of the absorbed layer through base exchange phenomenon and
• Cementing or puzzolanic action.

Lime reduces the plasticity index of highly plastic soils making them more friable and easy to be handled and pulvarised. The plasticity index of soils of low plasticity generally increase in the optimum water content and a decrease in the maximum compacted density, but the strength and durability increases.

The amount of lime required may be used on the unconfined compressive strength or the CBR test criteria. Normally 2 to 8% of lime may be required for coarse grained soils and 5 to 10% for plastic soils.


Property Lime
Quick lime
(Cao) Hydrated lime
Calcium and magnesium oxides
Carbon dioxides-at kiln


Not less than 92 percent

Not more than 3 percent
Not more than 10 percent
Not less than 95 percent

Not more than 5 percent
Not more than 7 percent

Not more than 12 percent on 180*180
Cement standard sieve.

Construction Sequence for Lime Stabilized Bases:

1. Shaping the Sub-grade and scarifying the soil.
2. pulvarising the soil.
3. Adding and mixing lime.
4. Compacting.
5. Finishing
6. Curing.
7. Adding wearing surfacing

There are three methods for carrying out these operations:

• Mix in place method
• Traveling plant
• Stationary plant method.

Mix in place method:
In this method, the subgrade is first shaped to the required grade and is cleared of undesirable materials. It is then scarified to the required depth of treatment and the soil is pulvarised until atleast 80% of the material (excluding stones) passes a 4.75mm sieve. If another soil is to be blended, it is mixed with the loose, pulvarised soil. The pulvarised soil is spread and shaped to proper grade. Calculated amount of lime is then evenly distributed over the surface and intimately mixed. Water is added as required for compaction and the soil lime water is turned into an intimate mixture. No strict time limitation for completion of job is however necessary since soil lime cementation reactions and are slow. It is fairly easy to process coarse grained soil. Adding lime in proportions of1 to 4% can facilitate Pulvarisation and mixing of plastic clays.

Mix in place method is considered cheaper and more adaptable to different field conditions, but the processing of soil is not so thorough and accurate as with other methods.

Traveling Plant method:

In this method, the pulvarised soil is heaped into a window and the lime is spread on the top. An elevator to a mixer carried on a traveling platform where water is added and mixing is done lifts the soil and lime. The mixture is then discharged on to the subgrade. It is spread with a grader and compacted. A uniform subgrade surface with controlled depth of treatment is possible. The plant is however costly.

Stationary plant method:
In this method, the excavated soil is brought to a stationary mixing plant. At the plant lime and water are added and mixed with the soil. The mixture is then transported back to the desired location, dumped, spread and compacted. Similar to traveling method, the method affords an accurate proportioning of materials and thorough mixing. The method is slower and may prove expensive due to additional haulage of soil.


The mix design procedures start from an estimate of the likely lime requirement followed by detailed tests as necessary for the particular circumstances. These should be based on a knowledge of the appropriate properties, mechanisms criteria etc. as described below.


The properties of lime-stabilized soils vary in a similar manner to that found with cement-stabilized soils. The differences lie mainly in the effect of additive content, the effect of time and the effect of temperature.

The unconfined compressive strength of soil lime mixtures increase with increasing lime content to a certain level usually about 8% for clay soils. The rate of increase then diminishes until no further strength gain occurs with increasing lime content: in contrast to cement stabilization where the increase in strength continues to quite high cement contents (20%) (Fig 5.1). Because with lime soil mixtures there is no rapid cementation akin to the setting of concrete the effect of delay in compaction is far less important with lime stabilization (fig 5.2) and indeed, an enhanced stabilizing effect may be obtained by leaving the material loose or by breaking up lightly compacted material and recompacting after 24-hours delay. Because there is, in general no urgency for compaction, the process of lime stabilization is more flexible in the field. However it was pointed out that where a rapid increase in optimum moisture content occurs as a result of lime stabilization “it may be more economical to compact quickly than to add extra water”.

The gain in strength with time of a compacted soil-lime mixture broadly follows the pattern for soil-cement mixtures (fig 5.3) but the effect of temperature is more marked. The more rapid gain in strength with increasing temperature may be one reason for the widespread use of lime in warmer climates.

Lime has an almost instantaneous effect in most cases on the plasticity of a clay(fig 5.4) and therefore upon the strength. Figure 5.5 shows a four-fold increase in strength after six minutes for clay mixed with lime: by contrast the change in strength with cement is delayed until the initial hydration set takes place. Lime improves texture, rendering a clay more workable, so much so that lime stabilization is often used for this purpose alone in clayey soils as a preliminary to shaping and compaction or to cement stabilization without regard to any possible strength increase in the compacted state.

Reaction Mechanism

Lime reacts with the clay minerals of the soil, or with any other fine, pozzolanic component such as hydrous silica, to form a tough water-insoluble gel of calcium silicate, which cements the soil particles. The cementing agent is thus exactly the same as for ordinary Portland cement, the difference being that with the latter the calcium silicate gel is formed from hydration of anhydrous calcium silicate (cement) whereas with the lime the gel is formed only after attack on and removal of silica from the clay minerals of the soil. The with contrast cement stabilization is that the latter is essentially independent of soil type: as illustrated by fig 5.6 which shows the rate of gain of strength for cement stabilized soils is different for each soil type.

The silicate gel proceeds immediately to coat and to bind clay lumps in the soil and to block off the soil pores in the manner shown by fig 5.7. In time, this gel gradually crystallizes into well defined calcium silicate hydrates such as tobermorite and hillebrandite, the microcrystals of which can also interlock mechanically. Note that reaction proceeds only whilst water is present and able to carry calcium and hydroxyl ions to the clay surface (i.e. whilst pH is still high). The reaction thus ceases on drying, and very dry soils will not react with lime. (Or cement).
The mechanism of the reaction can be represented thus:

NAS4H + CH --- NH + CAS4 H -- NS + degradation product

Where S = Sio2 H = H2O A = Al2O3 C = CaO N = Na2O


The criteria developed for soils treate with lime fall into two broad groups as does the usage of the material. Where the lime treatment aimed at “modifying” the soil properties by reducing plasticity improving workability increasing grain size etc.. The lime treatment is aimed at permanent and substantial “stabilization” of a soil then the criteria are based on strength bearing capacity etc..
Lime modification of soil has been used for three main purposes: to reduce the plasticity of an otherwise acceptable mechanically stable material to improve the workability of a soil and its resistance to deflocculation and erosion and to produce a rapid increase in strength in wet clay soil as a construction expedient. Criteria are not always available to measure the adequacy of the treatment. For the first named purpose the liquid and plastic limit and plasticity index are determined with varying amounts of lime added to the soil until the normal plasticity requirements for an untreated material are met. In most cases there would be in addition an increase in UCS and bearing capacity but this is not usually taken into account.

The procedure for evaluating the effectiveness by plasticity changes may be misleading, however, in kaolinitic or illitic soils where only small and slow changes in plasticity index occur. For these soils a better procedure is to adopt a strength test.


Process Purpose Requirement
Lime “modification” Improvement of access on wet site.
Improvement of workability and pulvarization. Large increase in plastic limit. Rapid increase in bearing strength.
Large and rapid decrease in plasticity increase in proportion passing 3/16 in. sieve.
Lime “stabilization” Improvement of subgrade material.
Improvement of base material. Increase in bearing capacity
Decrease in swell
Decrease in plasticity
Increase in strength or bearing capacity (min CBR 880).


Soil Type Content for modification Content for Stabilization
Fine crushed rock
Well graded clay gravels
Sandy clay
Silty clay
Heavy clay
Very heavy clay
Organic soils 2-4 percent
1-3 percent

Not recommended
Not recommended
1-3 percent
1-3 percent
1-3 percent
not recommended Not recommended
~3 percent

Not recommended
~ 5 percent
2-4 percent
3-8 percent
3-8 percent
not recommended

Design Procedure:

Mix design therefore, consists of adding varying amounts of lime to the soil and observing the effect, after a suitable curing period. on the plasticity, aggregations, strength or bearing capacity, when a suitable additive level may be determined. A useful guide is to allow 1 percent of lime (by weight of dry soil) for each 10 percent of clay in the soil. For closer determination, two samples prepared at _+- 2 percent of this lime content will usually reveal the optimum economic percentage. While the changes in plasticity are accepted fairly readily, there is, unfortunately, a conservative attitude to the improvements in strength, bearing capacity and stress-strain behavior.

Addition of lime to a soil with inadequate mechanical stability will improve strength, bearing capacity and resistance to water softening. In clay soils, lime will often cause rapid changes in plasticity and this in effect will “dry out” the soil. This is the basis of the use of lime stabilization as a construction expedient or for pre-treatment prior to cement stabilization. Lime stabilization is in general more tolerant of construction delay than cement stabilization and more suitable for clay soils.


  1. I'm searching the net regarding soil stabilisation and I'm lucky I found your blog. It is very informative. Thanks for sharing!

  2. Dear Colleagues,

    We’re representatives of Kalmatron® Corporation manufacturer of Concrete Class Upgrading Admixtures, Remedial Coats, and Concrete Regenerative Sprays.

    Restoration of damped and soggy areas up to the finished objects such as stadiums, airports runways, auto & rail roads, water canals and ponds, Cement Plants, Thermal power plants, Fertilizers plants, Steel plants Sulfur producer and Ports Jetty such as Hydro Carbon Surfactant, Hydro Carbon Surface Treatment Material, etc.

    · Initial Solubility of KF-D with water 100%
    · The final product of hardening is insoluble even by acid or water containing salts.
    · Complete Reducing of Blaining of standard mix
    · The time of hardening is adjustable by different consumption of KF-D.
    · KF-D has no influence on environment.
    · The applications of KF-D by injection or sorption treatment created a chemically changed structure with increased density and reduction of hydraulic conductivity or Coefficient of Permeability.

    Are any other Airports, Federal Highway, Stadiums etc.. using a newer product

    The application of KF-D and EMS treatment creates a chemically changed structure of soil and building materials liner with a reduction in hydraulic conductivity. The degree of improvement depends on initial density of the structure. For crumbling soil it is almost 100 times more effective than for untreated soil in stopping of leaks and moisture flow or seeping.

    KALMATRON® KF-D designed as an admixture to the Cement’s Soils Containing Sealers of the CMS (Crumbled Material’s Sealant) for enhancement of soils consolidation with strength accelerating and any required level of liquid impermeability.

    KF-D performs as a compactor of crumbled concrete and densifier of disintegrated and/or soggy soils.

    KF-D provides stable consolidation of injected structures with increasing of compressive strength up to 40%.

    KF-D improves liquid impermeability of Earth-Material’s Structures (EMS) and concrete/masonry building’s elements.

    KF-D stabilizes the flowing of soggy soils of the fields, offshore, sinkholes, foundations, and etc.

    KF-D is a cost‐effective solution that utilizes unusable structures to be restored up to impermeable to the liquids without the need of isolating membranes or water mitigating solutions and devices.

     No Drying Shrinkage and post hardening deformations;
     Exothermic heat is lower by 50%;
     100% water impermeability of EMS and EBS at 3½” to 5” thick layer;
     Strong adhesion to any porous material;
     Increased pumpability;
     Increased workability;
     Eliminates palpability;
     No shrinkage cracks;
     No cracks, flakes, efflorescence and slid areas;
     No bleeding or oozing;
     Highest resistance to climate corrosions;
     Highest freeze-thaw resistance;
     No curing is required.

    It is correct about high probability of rock fill particles rearrangement, but unfortunately there is no universal recipe because every time situation is different. Very often ground stabilization solves the problem by soil premix with additive and placement rock fill after

    For areas with active filtration or high water table, KF-D must be injected.

    We have favorable prices with free ocean freight and discounts. Sampling is available also.


    With Best Regards,
    Mr. Dilip Shah
    NRD Industries
    E-mail : nrdindustries@gmail.com,
    Skype ID: dilipshah26
    Dr. Alex Rusinoff
    Visit us at:
    www.greenbuiltconcrete.com NEW!
    www.drivewayoverlay.com NEW!

  3. This is a really interesting post! I learned so much about soil stabilization! I didn't even know it existed before reading this post. h http://www.tluckey.com/structural_chemical_grouting_harrison_OH.html

  4. I've heard of soil stabilization before. I've never heard of lime stabilization though. I can see why it would be important to stabilize soil with lime in it. Soil that's saturated with lime would make it heavier. It seems like it would be important to stabilize roads that are saturated with lime, or else it could make road conditions dangerous.

  5. Very detailed post on civil engineering and ground works. Soil stabilization actually increase and improved workability and load bearing ability of any construction that's help to enhance engineering properties..

  6. very good explanation and very detailed post. may i know if you have a blog about soil stabilization using cement? because right now we are conducting a thesis about it. thanks

  7. Veterinary Or Bvsc Admissions-2015

    Veterinary science is the application of medical, diagnostic, and therapeutic principles to companion, domestic, exotic, wildlife,
    and production animals.Veterinary schools are distinct to departments of animal science, which usually offer a pre-veterinary school
    and provides graduate veterinary education in disciplines such as microbiology, virology, and molecular biology.

    Contact for more information : 9492066112, 8977368354,040-66443636
    website: www.way2universities.com

  8. Dear Colleagues,

    In the lime & dolime handling route, their dust cause irritation to the skin. Continuous exposure makes horrible for working at those place for me. Though full boiler-suit, hand gloves, dust-masks, googles are worn, the itching effect could not be 100% ruled out. Compressed air is used for dusting-off before coming back to office from those site.

    We are afraid it wouldn't economically reasonable. Looks like it is an enormous area that must be covered by soil from another area and mixed with KF-D. Of, course you can try to propose as a a mix of cement, sand, and KF-D with dusty surface.

    It is correct about high probability of rock fill particles rearrangement, but unfortunately there is no universal recipe because every time situation is different. Very often ground stabilization solves the problem by soil premix with additive and placement rock fill after

    For areas with active filtration or high water table, KF-D must be injected.
    The application of KF-D and EMS treatment creates a chemically changed structure of soil and building materials liner with a reduction in hydraulic conductivity. The degree of improvement depends on initial density of the structure. For crumbling soil it is almost 100 times more effective than for untreated soil in stopping of leaks and moisture flow or seeping.

    Improves density and impermeability of soil or severely deteriorated structures. KF-D added to standard EMS mixes can be used for injections under or into sinkholes, foundations, tunnels, dams, wet and polluted soils, etc.
    Strengthens the standard EMS formula and increases waterproofing.
    Improves binding with standard concrete fillers and particles of soil.
    Applicable as a dust controlling premix.

    Do not hesitate to ask about sample for your trials even on a job site.

    This technology brings a new economical concept, where KALMATRON® reduces the cost per square foot of concrete up to 2 times. Our clients say:
    ”We can not afford to work without KALMATRON®.”
    The most economical on The World Market.
    With Best Regards,
    Dilip Shah/Ms. Helen Alex Rusinoff
    NRD Industries. USA
    WhatsApp & Viber: 0018483911248
    E-mail : nrdindustries@gmail.com
    Skype ID: dilipshah26
    Visit us at:
    www.greenbuiltconcrete.com NEW!
    www.drivewayoverlay.com NEW!

  9. thanks guys.. but i need a help on the other types of soil stabilization, i only see lime,cement and mechanical stabilization anytime i search for the types but i have assignment requiring 40 types please i need you guys help....my email is...oribehenryemeke@gmail.com....thanks guys.

  10. Thanks for explaining the benefits of soil stabilization. It seems like Lime is a great option for many different projects since it is so versatile. It makes sense that it is used to prepare soil for further construction, since it can ensure that the soil will support the construction traffic. It seems like a good thing that there are options to make soil and construction safer. http://www.hiways.com.au/stabilization/technologies/subgrade-stabilisation

  11. Really this usfull Nice Microtek Direct Blog .and good information.please Thanks for sharing this post.

    stabilizer for AC

  12. can you please explain the reaction mechanism when the soil is stabilized with bio enzyme

  13. Good one you explain. all building and civil related work to must use for the pre engineering process is very well done to introduce. its call us for PEP. Majorly access material is aluminium scaffolding for access and tools used for core work. Thanks for the opportunity. and Thanks Admin.

  14. Very Good Point about the your blog when I search in google your blog get ranking good all blog post are very informative. Kindly post about Interior Designs In Chennai & Modular Kitchen in Chennai related.

  15. This is great one to see your blog last time I see same design to my friend constraction building in chennai. Majorly used Aluminium scaffolding equipment used for glass room design. Really very gud looking.

  16. Very nice blog.EXPANDO is an expansive mortar chemical that cracks rocks and concrete. It is a concrete cutting, granite breaking and general demolition solution. This non-explosive demolition agent is easy to use, cost effective and a safer option for silently breaking up hard materials like rock or concrete. Simply drill, mix and pour.
    Non Explosive Cracking Agent

  17. I need purchase of Diesel Boom Lift used for many purposes such as maintenance and construction work and emergency access.

  18. Good one you explain. all building and civil related work to must use for the pre engineering process is very well done to introduce. its call us for PEP. Majorly access material is aluminium scaffolding for access and tools used for core work. Thanks for the opportunity. and Thanks Admin.