Experimental Investigation: Expansive Soil Stabilization with Pond Ash

This civil engineering project details an experimental investigation into the stabilization of expansive soil using pond ash. The project involved laboratory tests to assess the effectiveness of pond ash in improving soil properties. The student, as a team member, focused on understanding soil stabili...Read More

CE 1.1 Information of Project
Name of this Project: An Experimental Investigation of Stabilization of Expansive
Soil by using Pond Ash
Project’s Location: [Please fill]
Duration of the Project: [Please fill]
Organization Involved: [Please fill]
Position within Project: Team Member
CE 1.2 Background
CE 1.2.1 Characteristics of the Project
Soil stabilization is referred to as the physical, chemical, mechanical or a combined
methodology to change a natural soil for meeting any type of engineering purpose. The most
basic improvements involve incrementing the total weight bearing ability, tensile strength as
well as overall performances of the in situ sub soils for making road pavements stronger. An
ash pond is an engineered structure that is being utilized at the fossil fuel power stations for
the disposal of 2 types of coal combustion products like fly ash and bottom ash. I have been a
part of a popular experiment of soil stabilization with pond ash. We have conducted several
laboratory tests for improving the respective engineering properties of expansive soil as the
soil comprises of high swell and shrink properties. We had mixed the pond ash with soil in
several properties.
CE 1.2.2 Objectives of the project
I have used pond ash for conducting this particular experiment of soil stabilization.
Pond ash is responsible for reducing the complexities of the process and experiment and

hence we decided to select this particular object for the work. It is also referred to as an
industrial waste that works as a residue after combustion of coal. The objectives of the work
include:
 To complete an experimental investigation for stabilization of expansive soil.
 To use a residual industrial waste, called pond ash for the experiment to ensure that
the process becomes easier.
 To ensure that the project is being done after gaining proper knowledge about soil
stabilization.
 To understand the bearing capacity of the soil for identification of the correct process
and make the experiment a successful one.
 To identify the scope of the soil stabilization for enhancement of physical properties
and also increase in the shear strength of the soil.
 To control the shrink swell properties of the soil for making it more effective.
 To improve load bearing capacity of a sub grade for supporting foundation and
pavement.
CE 1.2.3 My work area
While starting my professional career as an engineer, I and two of my team members
decided to execute a project of soil stabilization under an expert’s guidance. Being an
experienced civil engineer, I suggested soil stabilization as it is the most effective technique
that can be used for improvement of soil durability through compaction, direct shear and
CBR. It could be done by adding as well as finding the variances within different percentage
of pond ash within soil. Moreover, I also checked that technique would be making
improvement in the natural soil and also increment the weight bearing capabilities to a high
level. Hence, we took permission from our head of the department and started the
experiment.

Head of the Department (HOD)
Project Supervisor
Team member (Me)Team member Team member
CE 1.2.4 Project chart
Figure 1: Structure of the team
CE 1.2.5 My responsibilities
I was assigned with the work to understand the entire concept of soil stabilization
from several resources. I checked that the innovations of soil stabilization were being used
from last 25 years and hence it was needed to select a proper and appropriate material that
can be effective in using the specific technique to stabilize the soil. I selected pond ash for
this purpose, so that it can easily penetrate the surface and then bind soil particles strongly. I
was even able to identify the benefits of soil stabilization easily and promptly and hence use
them in our project. I even noted the soil properties for the work, which include swelling,
specific gravity, sieve analysis, IS Light compaction, laboratory California bearing ratio test
and direct shear test. Moreover, I did CBR and sieve analysis tests entirely.

CE 1.3 Personal Engineering Activity
CE 1.3.1 Theory of Project
The theory of this project was the main vital part to complete the work successfully. I
noted down the soil properties for this work. For swelling, the black cotton comprises of a
major tendency to swell a small or more proportions when it is submerged in water. The
degree of expansiveness and differential free swell index is provided below:
Table 1: Swelling soil properties
I also checked that the specific gravity values range between 2.6 to 2.8 and these
would be coarse grained soils. However, the silt soil values would range between 2.65 to 2.68
and the values lesser than 2.0 would contain organic matter. The details of sieve analysis is
provided below:

I even understood CBR and direct shear test for the work and hence gain major
knowledge without any issue.
CE 1.3.2 Engineering knowledge and application of skills in the Project
I have used my knowledge and intellect of soil stabilization for ensuring that the
project work becomes successful. I have even applied my technical knowledge for
conducting tests like sieve analysis and CBR testing.
CE 1.3.3 Tasks performed by me
The methodology that I have used in this project work was extremely systematic.

Figure 2: Methodology used in the project
Since, I was working from India, I focused on the main soil types in India, which
included alluvial soil, black soil, red soil, forest and hill soil, desert soil, saline and alkaline
soil, peaty and marshy soil and many more. We collected our sample from Kankipadu near
Vijayawada, Krishna district in Andhra Pradesh. We took the sample below 1 m from ground
level as the soil present there was lack of organic matter. I conducted different tests like
swelling, sieve analysis, compaction test, liquid limit, plastic limit, CBR, direct shear and
then added pond ash with different percentages.

Table 2: Free Swelling Index, where result is 80 (high)
Table 3: Specific Gravity

Table 4: Liquid Limit
Figure 3: Graph plotting of liquid limit (Result = 52.51%)
The plastic limit for the soil was also calculated by us and it is provided below:

Table 5: Plastic Limit for the project
The results of IS Light Compaction are provided below:

Table 6: IS Light Compaction

I also conducted a proper sieve analysis and got the following graph and results from
it.
Figure 4: Graph plotting for sieve analysis
From graph

CBR2.5 = 0.09%
CBR5.0 = 0.06%
Figure 5: Graph of direct shear

The results of the experiment conducted by us are provided below:
Table 7: Results of the experiment

CE 1.3.4 Issue identified and mitigated
1.3.4.1 Issue
I was unable to get proper results from the laboratory California bearing ratio or CBR
test as the load on plunger was not appropriately given by us. As a result, the ratio test results
were inaccurate and were not matching with our expected outcomes.
1.3.4.2 Mitigation
I decided to do the test once again under our expert’s guidance and this time we
became successful in getting the correct data, which are as follows:
Penetration (mm) Load On Plunger (kg) Corrected Load (kg)
0 0 0
0.5 0 0
1.0 0.8 0.4
1.5 2 1
2.0 3 1.5
2.5 4.2 2.1
3.0 5.2 2.6
3.5 5.6 2.8
4.0 7.1 3.55
5.0 8.8 4.4
7.0 11.8 5.9
10.0 15.15 7.57
12.0 16.8 8.4
Table 7: Results of CBR test

CE 1.3.5 Plan for innovation
We focused on the minute details of the work, such soil specifications and different
techniques, which would turn out to be effective for our work. This led to such an innovative
work in our project.
CE 1.3.6 Collaborated work
It was a group project work and I completed it with 2 team members under the
guidance of an expert in such civil engineering works. Our supervisor focused on quality and
made sure that no team member is working under pressure and hence works were equally
divided.
CE 1.4 Overall Project Summary
CE 1.4.1 Overview of the Project
The team members compared to soil and 8% pond ash with soil for the work, so that
the values are being increased for dry density, CBR and direct shear. On the other hand,
OMC and swelling gets reduced. We checked that soil stabilization with 10% pond ash is
weak as compared to the 8% and 6% pond ash stabilization. Moreover, plasticity index value
was also increased with the experiment.
CE 1.4.2 My Contributions
I researched about soil stabilization process and gave preference to it, since it
provided better results. Moreover, CBR test and sieve analysis was conducted by me and I
was successful in completing them.