Competency Demonstration Report (CDR) - Career Episode 1

This CDR report describes a project on the compressible strength of bio-concrete with different SRB concentrations. It includes project background, objectives, distinctive activities, identified issues and their solutions, and project review.

Competency Demonstration Report (CDR)
Career Episode 1

CE 1.1: Project Introduction
Name of the Project : Determination of Compressible Strength of Bio-Concrete
with Different SRB Concentrations
Geographical Location : Please Fill
Project Duration : [Please Fill]
Organization : Please Fill
Position in the Project : Team Member of the project
CE 1.2: Project Background
CE 1.2.1:Characteristics of the Project
This project is generally based on the analysis of the compressible strength of concrete
when various concentrations of sulphate reduction bacteria are applied on it. It has been found
that in spite of being a very popular construction material, concrete has a number of problems
that include low tensile strength, little resistance to cracking and limited ductility. However, the
main focus of this particular project is the chemical attack on concrete i.e. effects of acidic
chemicals like sulphate on the concrete. Due to acidic effects of sulphate, the concrete often
erodes and causes bad impact on the overall structure. Furthermore, the chemical changes result
in weakening of the cement binder. Sulphate reduction bacteria can absorb the sulphate from the
concert and convert it into Hydrogen disulphide gas so that the concrete is not affected by the
acidic chemical reaction of the sulphate.

CE 1.2.2: Objectives developed for project
The main objectives that were developed for the purpose of the project were as follows.
 To determine the compressive strength of bio concrete when it is incorporated
with various concentrations of sulphate reducing bacteria (3%, 5%, 7%) in 3%
sodium chloride solution
 To collect regular concrete and compare results with the same
CE 1.2.3: My area of work
My field of work in this project was Civil Engineering whereas I was assigned in the
project specifically as a Structural Engineer. In this project, I needed to use my technical
expertise that I developed during my course in Structural Engineering and I used various
concepts, theories and technologies learned during the course for fulfilling my duties in the
project.
CE 1.2.4: Project Group

Figure 1: Members of the Project Group
CE 1.2.5: My responsibilities throughout the project
Being selected as the leader of the project team, I was assigned with a number of
responsibilities that are listed as follows.
 I needed to divide the project into several phases and work packages and allocate
the work packages to myself and other team members.
 I needed to undertake some verbal meeting sessions to discuss the project
including the concept, possible technical problems and solutions.
 I needed to conduct Sieve Analysis in order to determine the standard size that is
used in concrete mix.
 I needed to assist my team mates during the slump test to determine workability
of concrete matrix.
 I needed to assist my team mates during data analysis and documentation of the
results obtained from the project.
CE 1.3: Distinctive Activity
CE 1.3.1: Comprehending the Theory of the project
This project is mainly based on the study of concrete and the application of sulphur
reduction bacteria in order to prevent corrosion of the concrete from sulphate action. Concrete is
a strong material that is widely used around the world to build large structures like buildings,
monuments and others. Although concrete has high compressive strength, it has very low tensile
strength and hence can easily break with the application of strong tensile force. Again, concrete
can be easily corroded by sulphate compounds resulting in deformation of the structures. Hence,

our focus was to minimize the issues for more efficient use of concrete in construction. I
determined that on application of sulphate reduction bacteria (SRB), the sulphate chemicals can
be neutralized and corrosion of concrete can be prevented.
CE 1.3.2: Engineering Knowledge and Skills applied in the project
In this project, I needed to use my engineering skills and knowledge that were helpful for
me throughout the course of the project. Since our target was to develop a proper solution of
sulphur corrosion of concrete, I first determined a number of possible feasible solutions. I
determined the positives and negatives of each of them and then finally selected the sulphur
reduction bacteria as the most feasible solution. However, there were significant challenges in
implementing the same and I needed to conduct various analyses and tests with various
concentrations of RSB in order to find the best possible solution.
CE 1.3.3: Accomplishment and Task Performed
I accomplished a number of activities in the project including sieve analysis, slump test
and pH control. For the purpose of the slump test, I wanted to determine the workability of
concrete mix and also to ensure the mixture of the concrete was not too liquid. The slump test
results are shown in the following table.
Mixture Slump (mm) Types of slump
Control 35 True
3% SRB 32 True
5% SRB 33 True
7% SRB 33 True
The solution that I prepared for the concrete was alkaline in nature but also, I needed to
maintain the pH level of the solution in order to avoid chemical changes in the solution. Hence, I
conducted the pH control test throughout the project and found out the following results.

Weeks PH value
Week 1 12.25
Week 2 12.23
Week 3 12.20
Week 4 12.21
Week 5 12.2
Week 6 12.22
Week 7 12.18
Week 8 11.5
Week 9 12.18
CE 1.3.4: Identified Issues and Their Solutions
One main technical issue that I faced in the project was that I needed to maintain the
alkalinity of the RSB solution during the entire course of the test period. Unless the pH level of
the solution was maintained, the chemical tests could not have been conducted.
I solved this problem by using NaCl (sodium chloride) in the solution that helped to
maintain the pH level of the sample. I maintained the pH level at around 12 and conducted the
chemical tests over the entire test period of 9 weeks.
CE 1.3.5: Plan for producing creative and innovative work
During the project, I planned to produce some creative or innovative work that improved
the quality of the project. I used graphical representation to determine the differences between
control and microbial samples. When I compared control sample with 3% RSB microbial
sample, I generated the following graph.

Figure 2: Strength Differences between Control and Microbial Samples
CE 1.3.6: Collaborative work
The project was significantly complex and individual effort was not sufficient to
complete all the duties within time or scope of the project. Hence, I chose to collaborate with
other members of my team and together, we set out to execute the project and solve challenges
and issues faced during the same. We helped each other during the entire project and ensured all
the problems are solved together before we proceeded to complete our own duties and
responsibilities in the project.
CE 1.4: Project Review
CE 1.4.1: Project Overview
The entire project was conducted to determine the effect of various RSB concentrations
on the strength of concrete. From the results of the project, I determined that this particular
bacterium used in the project can grow and replicate even in critical environmental conditions.

Moreover, during the entire sulphur absorption process by the bacteria, CaCO3 was deposited
that increased the strength of the concrete solution.
CE 1.4.2: My contribution to work
I was an active contributor in the project as I took responsibilities of many roles in the
project. While I took part in duty allocation and managing my team members, I conducted team
meetings as well as assisted my team members in various activities in the project. I fulfilled my
duties in the project as well and also ensured all requirements of the project have been met.