10 October 2007

Welcome to the University of the Witwatersrand

Investigational Project

Presentation

Presentation by:

MR. A. James

MR. C. Strehlau

Acknowledgements:

Prof. P. Marjanovic and the Faculty of Environmental Engineering

PowerCem Africa

“…a presentation into the findings of

a report documenting the

strength-enhancement and

anti-leaching capabilities of a

cement enhancer: PowerCem!”

8.6 million km2 and

growing

sahara desert

4300m and deepening

Pacific Ocean

3.5◦

C

The expected rise in global mean temperatures in the next 100 years

Carbon dioxide

and the largest

single contributor

of all green house effects?

Every ton of manufactured cement represents 5.1Giga-Joules of energy consumed, equating to 1200kg of CO2 pumped

into the atmosphere.

The use of PowerCem enables the reduction of CO2 equivalent emissions in global cement production by up to 50%.

0

400

800

1200

Equi

vale

nt k

g's

of C

O2

Emitte

d du

ring

m

anuf

actu

reGreenhouseemmision duringCementmanufacture

Greenhouseemmision duringequivalentPowerCemmanufacture

Carbon Dioxide emission comparison:

So, what exactly is PowerCem? PowerCem is:

A fine grained powder

Based on Alkali-earth metals

Comprised of natural & synthetic Zeolites

Environmentally friendly!

Capable of entrapping heavy metals such as Chromium 6+

Added to mortar or concrete in relatively small amounts (no more than 2 kg/m3 under normal applications)

Proven to increase the strength and flexibility of concrete and cement products

Able to provide for decreased permeability against water ingress and increased resistance to salts and acids

Technically PowerCem is:

Very bold claims!

This is how we went about testing some of these claims…

The following 4 slides outline:

The practical work undertaken

Our order of approach

The mixing device

The steel moulds

Freshly mixed and cast!

SandWater

PowerCem

Metals SolutionO.P.C

.

Step 1: We cast 192 identically sized cement bars

Sand

3500g

OPC 700g

H20 175g

280g

350g

0ml

0ml

0ml

0g

0g

PowerCem

175g

280g

350g

4ml

40ml

CR 6+ 200ml

0g

0g

0g

Step 2: We Mixed 192 specimens toC.E.N. standards

1 Day

2 Days

7 Days

14 Days28 Days

Step 3: We tested the bars for compressive and flexural strength after:

We made sure that we tested all specimens as closely as possible to the C.E.N. EN 196-1:2005 standards.

Step 4: We pulverised the duplicate bars we had cast and sent the remains for chemical analyses and leaching potential.

Step 5: The crushed samples were sent to the Wits Environmental chemical laboratory where they were each chemically leached with acidic and alkaline solutions

Step 6: This resulting solution was then sent to the (Chemistry Building) Environmental Chemical Laboratory where the liquid samples were analyzed using a Automatic Optical

Emission Spectrometer

Next we reveal a summary of key findings - after having analysed all structural and chemical test data.

0.0

4.0

8.0

Stre

ngth

, M

Pa

0.25 0.4 0.5

Water Cement Ratio

Pure O.P.C.

PowerCem: 1 %mass of O.P.C.

PowerCem: 3 %mass of O.P.C.

PowerCem: 4 %mass of O.P.C.

Finding 1: Flexural strength comparison after 28 days:

Finding 2: Compressive strength comparison after 28 days:

0.0

4.0

8.0

12.0

16.0

Stre

ngth

, M

Pa

0.25 0.4 0.5

Water Cement Ratio

Pure O.P.C.

PowerCem: 1 %mass of O.P.C.

PowerCem: 3 %mass of O.P.C.

PowerCem: 4 %mass of O.P.C.

Finding 3: Total average gains achieved when including PowerCem in concrete:

174%169%

100%

0%

50%

100%

150%

200%

Tota

l Str

engt

h in

crea

se

Normal Cement PowerCem(Compression)

PowerCem(Tension)

Finding 4: Total average costs comparison

Typically, about 50 R/m3 on materials can be saved, but if carbon credits are taken into account than the effect is close to 200 R/m3

Final Finding: The Chromium 6+ immobilisation…

Acidic: 90.51% Cr 6+ Encapsulation

Alkaline: 99.15% Cr 6+ Encapsulation

“If we always going to do what we’ve always done, we’re always going to get what we’ve always got…”

Solutions to yesterdays problems exist!

Lets ensure that fresh water supplies don’t turn to salt water…

Keep Greenland frozen!

minimise the occurrence of major

hurricanes

and we’re hoping polar bears will be saved from extinction…

“If not us, then who?”

PowerCem is

More durable Better quality Cheaper

But most importantly, has a significantly

smaller ecological footprint.

The End.

We thank-you for your attention.

Questions?

10 October 2007