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STABILISATION OF TOPSOIL
Transcript of STABILISATION OF TOPSOIL
Project management and Scheduling
Assistant Prof. Khaled Altarawneh
Final year project for the degree of B.Sc in Civil Engineering
Civil Engineering Department
Previous studies shows
that eggs consumption in Jordan
reached 80 million in 2015. Unlike other stabilization materials such as cement, lime and fly ash, eggshell waste is obtainable
and cheap. And not widely used
in most parts of the world.
This project aimed to study the improvement on soil stabilization with the use of
eggshells waste as replacement
for other stabilization
Soil Stabilization is the process
of improving or treating the
engineering properties of soil
layers by adding other soil types,
mineral materials or by blending
and mixing appropriate chemical
This study aimed to use eggshells powder which consist of
98.2% CaCO3 as a stabilization material.
In this project, the possibility of
using ESW as a stabilizing material
for topsoil on the North of Jordan
The study utilizes sieve analysis, Atterberg limits and consolidation test by adding different percentages of eggshells (5%, 10%, 20%) and acid, in order to check the efficiency and the improvement that occurs on soil properties.
Problems associated with topsoil
Most of the structures include some type of structural element with direct contact with ground.
Any problem occur on soil will immediately cause failure to the structural element and maybe the whole structure.
Constructing over a strong soil or stabilizing the existing soil is a major factor to avoid or minimize the
Soil stabilization using lime
When lime is added to a clayey soil
it has an immediate effect on the
properties of it.
Studies showed that almost no
displacement occurs when adding
lime to expansive soils. Also the
Unconfined Compressive Strength
increases with the increase
of lime percentage.
Soil stabilization using solid waste
The cutting stone slurry waste is
cheap, obtainable and contain a limestone fines so it can be used to stabilize soil.
Using it increases the maximum dry density, the unconfined compressive strength,
reduces the optimum water content,
also both liquid limit and plastic limit decreases which cause a decreasing
in swelling pressure and
Soil stabilization using other materials
Burned olive waste & Karak Ash can be
used as a soil stabilizer.
Adding Karak ash changes soil classification
from A-7-6 to A-4 as per AASHTO and
Burned olive waste increases the maximum
And both of them reduces the plasticity
of soil and increases unconfined
Soil stabilization using ESW
In 2009 an estimated 62.1 million
metric tons of eggs produced worldwide, adding ESW is useful to stabilize soil and can minimize the waste disposal problem.
Adding ESW to soil increases the unconfined compressive strength and plastic limit and reduces the plasticity index.
ESW can be mixed with other
materials like lime, cement,
The materials used in the project experiments are:
Topsoil samples were collected from Irbid/North of Jordan. The samples were oven dried at 105 C. Topsoil classified as A-2-7(0) based on AASHTO classification system and as Clayey sand based on USCS.
Wasted chicken eggs used
in tests. Eggshells collected from local homes, bakeries
and restaurants. The eggshells washed and dried before grinding.
Eggshell contain 99.83% CaO
Acid (H2SO4) used in this
thesis to decrease the PH so
the solubility increase in
order to improve the effect
of eggshells to change the
origin properties of soil.
The test performed on soil specimens with 5% and 10% of eggshells in addition to the one without eggshells, with applying 2 kg as an initial load and doubling it every 24 hours until it reached 8 kg. When loading phase finished it is followed by unloading and reloading phases with the same technique.
Sieve analysis performed according to AASHTO T 27. Using mechanical shaker for 15 minutes using U.S. standard sieves.
The Atterberg limits are a basic measure
of the critical water contents of a fine-grained soil. They are plastic limit and
Liquid limit is defined as the moisture content at which soil begins to behave as a liquid material and begins to flow. It performed according to AASHTO T 89. This test conducted on a soil passing sieve No.40 without eggshells, with 5% ,10%,20% eggshells and with addition of acid.
Plastic limit defined as the lowest moisture content at which a soil will just begin to crumble when rolled into a thread approximately 3 mm in diameter.
It performed according to AASHTO T 90 and conducted on a soil passing sieve No.40 without eggshells, with 5% ,10%, 20% eggshells and with addition of acid.
The test is conducted
to determine the settlement due to primary consolidation, the rate of consolidation under normal load, the degree of consolidation at any time, to plot the pressure -void ratio relationship, coefficient of consolidation at various pressures, compression index, swelling index and recompression index.
One of the important requirements for a successful project is the good management. The first step was dividing the project into tasks and activities, and then putting all of them in a certain timeframe. Coordinating the efforts of people was an essential part in order to accomplish goals and objectives of the project.
Work breakdown structure
WBS, it defines the key objectives first and then identifies the tasks required to reach those goals. The primary requirement or objective is shown at the top, with increasingly specific details shown below.
A Gantt chart used in project management, to show activities displayed against time. This help
to show at a glance:
The various activities.
When each activity begins and ends.
How long each activity is scheduled to last.
The overlap with other activities and how much it was.
Dependency, and the start and end date of the whole project.
The work performance
Gantt chart created using Microsoft office Excel.
Atterberg Limits Results
Atterberg Limits Results
The addition of 20% ESW lower the LL by nearly 33% from its value without ESW. The PL has also shown a decreasing trend with the increase in ESW%, but less than that observed in LL.
Addition of Acid
10% ESW added to the samples with and without acid. Hence to study the effect of lowering pH in ESW efficiency in soil stabilization. According to the results, adding acid lower the PI of topsoil by ~21.3%, while increasing both LL and PL by ~15% and ~39%, respectively.
Effect of adding Acid
The increase in LL is attributed to the decrease in ion exchange activity between calcium from ESW and Aluminum and Silicon in the topsoil.
The unexpected decrease of PI is mostly because of the high increase in PL rather than the slight increase in LL.
According to the Cassagrand’s plasticity chart, adding acid will convert the topsoil from the clayey behaviour to the silty behaviour but with higher plasticity .
Consolidation test Results
Decreasing tendency for soil compressibility and swelling with the addition of 10% ESW as compared to the topsoil without ESW.
The tests with 5% ESW have not showed this trend. The reason is attributed to the poor ESW grinding which may increase the porosity of these samples unexpectedly.
The increase of consolidation coefficient is also attributed to the increase of the soil voids as a result of the coarseness of the ESW added.
Decrease in specific gravity value as ESW% increase
Conclusion and future work
Common soil stabilizers are cement, lime, bitumen, fly ash and others. Even though their wide availability, however they are not freely available.
As a source of lime for soil stabilization, ESW has not been well studied in the literature in spite of its wide availability and cost affordability.
Adding ESW to the topsoil has not shown a considerable enhancement in its mechanical
properties as evidenced by the Atterberg limits
and consolidation tests.
The reason is attributed to the low solubility of
calcium in the coarse ESW under neutral pH.
Lowering pH has enhanced the calcium solubility
but lower the ion-exchange between aluminium
and silicon in the topsoil and the released calcium
Controlling pH is not an effective tool to enhance the stabilization efficiency of
ESW to topsoil.
In future, it was suggested that the stabilization of topsoil with ESW can be effectively enhanced under neutral pH
with simple grinding of ESW to a grain
size finer than 75 µm.
THANKS FOR LISTENING
Stabilization of soil