inspec
JULY 2014
BUNBURY PORT AUTHORITY
WHARF PILE
REMEDIATION
inside
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MESSAGE FROM PHIL
BODDINGTON GOLD MINE
RIO TINTO PUMP STATION
996 HAY STREET
4 KCGM NEW AWARDS
5 BUNBURY PORT AUTHORITY
5 LEINSTER AND MT KEITH
6 TECHNICAL - CONCRETE CRACKING
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BURRUP SEAWATER LINE
WHEATSTONE PIPE SPOOLS
CALTEX AWARD
CONTACT US
A MESSAGE
PHIL HARCOURT
MANAGING DIRECTOR
FROM PHIL
It gives us great pleasure to announce
we have expanded our operations to the
east coast of Australia to accommodate
the growing need for our services and
capabilities in that region.
We have been fortunate to engage a very
experienced management team to kick off
Duratec Australia (ES) Pty Ltd in Melbourne
and Sydney.
Front cover: Repairing the
steel reinforcement of a pile at
Bunbury Port Authority’s Berth
1 and 2 project.
Even more fortunate that we have been
successful in immediately securing a large
maintenance contract at Caltex Kurnell in
NSW. This is a great start for our eastern
states division.
WELCOME TO OUR WINTER
EDITION OF INSPEC
HIGHLIGHTING RECENT
PROJECTS AND PROVIDING
SOME RECENT COMPANY
ACHIEVEMENTS.
The Old Treasury Building balcony
remediation project continues to receive
accolades - this time we have been
rewarded by winning the City of Perth
Heritage Award in conjunction with
Maitland Heritage Engineering.
As our company grows, we are always
seeking quality feedback from clients
to provide an insight into how well we
deliver our projects. This is very much
appreciated as it assists our quest for
continual improvement. Your feedback on
our projects and this newsletter is most
welcome.
PROJECT AWARD
BODDINGTON CIL TANK
REFURBISHMENT
DURATEC HAS RECENTLY
BEEN AWARDED A
MAINTENANCE CONTRACT
TO REFURBISH GOLD
PROCESSING LEACH TANKS
AT BODDINGTON GOLD
MINE.
2 INSPEC JULY 2014
The contract involves the project management and implementation of the complete
refurbishment of two tanks from isolating and emptying, to the repair and/or
reinstatement of the internal protective coating system.
The works will include a full inspection of the protective coating and steelwork using
NDT equipment and coating thickness gauges. All gearboxes, motors, the agitator shaft
and downcomers will be removed, repaired and/or replaced.
Hydroblasting will be used to remove damaged or out-of-spec coating areas, before the
re-installation of a high performance elastomeric urethane with plural component spray
equipment. The final stage will be re-commissioning the tank to continue to produce
gold for the client.
PROJECT REVIEW
RIO TINTO DAMPIER SALT UTILISED
DURATEC’S CONCRETE REPAIR
EXPERIENCE TO COMPLETE A
REFURBISHMENT OF PUMP
STATION 1B IN DAMPIER.
RIO TINTO DSL
PUMP STATION 1B
The discharge side of the pump station was showing signs
of deterioration and required demolition and re-construction.
After thorough cleaning and excavation of the soil around
the area, a technical survey of the degraded concrete was
undertaken to determine the extent of the repairs. A rock
breaker was used to remove most of the concrete with the
remainder removed manually by jackhammers.
Damaged steel reinforcement was removed and replaced before
formwork was installed to enable the concrete to be reinstated.
In total, 16½ cubic metres of concrete was used to repair the
pump station using a concrete boom pump. All pipework was
sealed using a polyurethane sealer.
The works were completed safely while adhering to
environmental requirements. Pump Station 1B has now been
returned to its original condition and full operation.
Above: Original condition of the pump station.
Inset top: Rock breaker removing the degraded concrete.
Inset bottom: Formwork installed ready for concrete reinstatement.
Below: Completed pump station.
INSPEC JULY 2014 3
PROJECT REVIEW
996 HAY STREET
DURATEC HAS BEEN CARRYING OUT A
LARGE FACADE REFURBISHMENT PROJECT
FOR THE OWNERS OF 996 HAY STREET.
The owners of 996 Hay Street engaged Duratec to provide
facade refurbishment services to their main tower and townhouse apartment complex in Perth’s CBD.
Utilising mast climbers, swing stages and rope access personnel,
the entire facade is undergoing a program to rectify concrete
degradation issues and improve aesthetics with external
painting.
Duratec will also provide waterproofing to the pool deck area
and underground car park, crack injection and repairs, window
sealing, and perform an integrity survey on structural columns.
PROJECT AWARD
NEW WORKS AT
KCGM FIMISTON
Duratec has been successful in securing two major contracts at KCGM. The first involves the blasting and coating of an entire
conveyor belt structure which feeds the main stockpile at the Fimiston plant. This project was awarded as a sub-contract
arrangement for Downer EDI Engineering who will perform steel fabrication repair works on the conveyor.
The second project involves concrete repairs to ball mill one and the SAG gantry crane area. Utilising both shotcreting and form
and pour methods to repair degraded concrete, existing concrete elements will also benefit from crack injection and protective
coatings and precision grouting of structural support column bases.
Duratec has had a long association with KCGM and look forward to delivering these projects to a high quality and safety standard.
4 INSPEC JULY 2014
PROJECT REVIEW
BUNBURY PORT
AUTHORITY
DURATEC HAS COMPLETED THE FIRST STAGE
OF THE BUNBURY PORT AUTHORITY’S 5
YEAR DESIGN AND CONSTRUCT CONTRACT.
The first stage involved the remediation of 14 wharf piles
at the Outer Harbours Berth’s 1 and 2.
A complex scaffolding system was installed to enable
access to the piles with a technical survey being performed
to determine the extent of repairs and a fit-for-purpose
remediation option.
The piles underwent hydro-demolition to remove the
concrete cover before all reinforcing and ligatures were
repaired. The steel was then sandblasted and primed.
A mortar was pumped into custom-made formwork to
reinstate the pile’s cover concrete. Sacrificial anodes
were also installed to extend the life of the repairs.
A video of the project can be viewed at
www.duratecaustralia.com.au/Projects/Marine
PROJECT REVIEW
MINE SITE KITCHEN
MAKEOVERS
DURATEC HAS BEEN ENGAGED AT BOTH BHP
BILLITON’S MT KEITH AND LEINSTER SITES TO
REFURBISH THEIR KITCHEN AREAS.
Maintaining a safe and healthy environment in food processing
areas is vital - particularly when feeding hungry mine workers.
The kitchen floors that cater for both Mt Keith and Leinster Nickel
Operations had shown signs of wear and tear from many years
of service.
What is vital in projects of this nature is the speed of turnaround
to minimise downtime and using fit-for-purpose materials that
provide excellent wear resistance without any odour.
INSPEC JULY 2014 5
TECHNICAL ARTICLE
CRACKING IN
CONCRETE - PART ONE
Crack formation in concrete is a complex phenomenon
with many potential causes and remedies. They may
affect appearance only, or they may present significant
loss of long-term durability and structural distress.
Their significance depends upon the type of structure
as well as the nature of the cracking.
concrete pours a temperature differential can be created
between the exterior ambient conditions and the core of
the mass concrete resulting in volumetric changes which if
restrained result in cracking.
3. Chemical reactions: if concrete is made using non inert
reactive aggregates then expansive chemical reactions,
(delayed ettringite, alkali silica reactions), can take place
which result in surface map cracking.
Successful long-term repair of cracks in concrete is completely
dependent upon development and implementation of repair
procedures that address the causes and not just the symptoms.
This article describes the causes of cracking and a subsequent
article will address the methods and techniques of repair.
4. Thermal shock: concrete subject to extreme external
temperature will crack due to volumetric change and base
restraint.
5. Corrosion of reinforcing steel: carbonation or chloride
induced growth of corrosion products on embedded
reinforcing steel in concrete results in expansive cracking of
the cover concrete.
Cracking in concrete can be grouped into two categories:
• Cracks that occur in freshly placed plastic concrete before
and during hardening; and
6. Errors in design and poor detailing: cracking can occur as
a result of inadequate provision of and poorly positioned
joints, insufficient reinforcing steel content in concrete,
improper foundation design and underestimation of service
loads.
• Cracks occurring after hardening of the concrete.
Cracking of freshly placed concrete:
1. Plastic shrinkage cracking: these occur most commonly on
the exposed surfaces of freshly placed floors and slabs as
a consequence of rapid loss of moisture from the concrete
due to low humidity, wind or high temperatures. Shrinkage
of the upper surface of the concrete occurs whilst restrained
by the concrete below, resulting in development of tensile
stresses in the weak concrete and formation of shallow
craze cracks.
7. Poor construction practices: cracking may occur due to
addition of excess water to the concrete, poor vibration,
over finishing, poor curing and protection, lack of insulation
or too high placing temperatures of mass concrete and
incorrect positioning of expansion joints.
8. Construction overloads: cracking of pre-stressed concrete
can occur if incorrect de-tensioning procedures are applied
at an early age of the concrete. Similarly, mishandling of
pre-cast concrete panels during transportation and erection
and construction equipment or material storage overloads
can cause cracking of concrete.
2. Settlement cracking: after initial placement, vibration and
finishing, concrete has a tendency to continue to consolidate
around reinforcing steel, and unless re-vibrated, will crack
along the line of the reinforcing bars. Cracking of this type
may also occur through formwork movement.
9. In-service overloads: application of in-service loads well in
excess of ultimate design loads may lead to cracking of the
concrete.
Cracking of hardened concrete:
1. Drying shrinkage: loss of water from the concrete in
excess of the volume required for hydration of the cement
results in volumetric shrinkage which with underlying base
restraint results in crack development generally full depth
of the element.
Duratec Australia possesses extensive experience in the
evaluation and determination of the root cause of cracking of
concrete, enabling correct selection of the appropriate repair
procedure which extends the life of the asset.
2. Thermal stress: hydration of cement in concrete is an
exothermic reaction and in the case of very large mass
Type of cracking
Classification
of Cracks
Plastic
settlement
Plastic Shrinkage
Early Thermal
Contraction
Long-term Drying
Shrinkage
Crazing
Corrosion
Reinforcement
6 INSPEC JULY 2014
Alkali-aggregate
reaction
Position on
Diagram
A
Subdivision
Most Common Location
Primary Cause
Deep Sections
Excess bleeding
G
Over
reinforcement
Arching
Change of depth
Diagonal
Random
Over
reinforcement
External restraint
H
Internal restraint
B
C
D
E
F
I
Top of columns
Trough and waffle slabs
Roads and slabs
Reinforced concrete slabs
Reinforced concrete slabs
Thick walls
Thick slabs
Thin slabs and walls
J
Against formwork
K
Floated concrete
Slabs
Impermeable
formwork
Over-trowelling
L
Nature
Columns and beams
Lack of cover
M
Calcium Chloride
Precast concrete
N
“Fair-faced” Concrete
Rapid early drying
Rapid early drying,
steel near surface
Excess heat
generation
Excess temperature
gradients
Inefficient joints
Damp locations
Secondary Causes/
Factors
Rapid early drying
conditions
Remedy
Reduce bleeding
(air entrapment) or
revibrate
Time of
Appearance
10 minutes to 3
hours
Low rate of
bleeding
Improve early curing
30 minutes to 6
hours
Rapid cooling
Reduce heat and/or
insulate
1 day to 2-3 weeks
Excess shrinkage,
inefficient curing
Rich mixes
Reduce water content,
improve curing
Improve curing and
finishing
Several weeks or
months
1 day to 2 weeks
Poor curing
Poor quality
concrete
Excess calcium
chloride
Reactive aggregate plus high-alkali
cement
Eliminate causes listed
Eliminate causes listed
Several weeks or
months
1-7 days,
sometimes much
later
More than 2 years
More than 5years
PROJECT REVIEW
BURRUP SEAWATER
LINE
DURATEC WAS ENGAGED BY THE
WA WATER CORPORATION TO
REPAIR A SEAWATER PIPELINE ON
THE BURRUP PENINSULA.
The pipe had shown signs of corrosion in certain
areas and after Duratec had excavated the ground
around the pipe to enable access to the repair area,
full encapsulation was erected to contain any dust and
paint overspray.
A three-coat protective coating system was applied
including zinc-rich primer, high build epoxy and
polyurethane topcoat.
PVC backed bitumen tape was installed in nominated
areas as per the scope of works to provide extra
protection.
All works were thoroughly inspected by Duratec’s
NACE 3 qualified inspector who tested for chloride
contamination, profile depth and coating thicknesses.
PROJECT REVIEW
PIPE SPOOLS FOR
WHEATSTONE
DURATEC WAS SELECTED TO APPLY
SPECIALISED COATINGS TO PIPE SPOOLS FOR
THE CHEVRON WHEATSTONE GAS PROJECT.
The spools were coated in Perth using special heated
variable-ratio plural component spray equipment. The
imported specialised pipe coating system is a 3:1 ratio
100% solids Novalac epoxy resin system. It has good
flexibility, excellent impact resistance and can resist cathodic
disbonding up to 150ºC.
The pipework passed stringent quality testing by Bechtel
before being shipped to the new gas plant near Onslow.
INSPEC JULY 2014 7
PROJECT AWARD
CALTEX NSW
AWARD
DURATEC HAS
SECURED A LARGE
MAINTENANCE
CONTRACT AT
CALTEX, KURNELL
IN NSW.
Duratec Australia (ES), having just started new operations on the
East Coast, has been immediately successful in securing a large
maintenance contract in NSW. The project is for Caltex Refineries
(NSW) Pty Ltd, which includes the Kurnell Wharf remediation works.
The works include concrete repairs to piles and soffits under the wharf
deck. Access will be provided by fixed scaffolding. The degraded
concrete will be removed by a combination of hydro-blasting and
manual demolition and steel reinforcement is prepared and coated by
a zinc-rich primer. The concrete will be reinstated by ‘form and pour’
and wet spray methods.
The works will be carried out while the wharf remains fully
operational and to Caltex’s stringent safety, quality and environmental
requirements.
Duratec’s NSW staff have had a long association with Caltex Refineries
and are looking forward to continuing to extend the life of their
assets.
“EXTENDING THE LIFE OF YOUR ASSETS”
WWW.DURATECAUSTRALIA.COM.AU
SPECIALIST MAINTENANCE
AND PROTECTION
HEAD OFFICE
108 Motivation Dr, Wangara WA 6065
P: (08) 6267 2370
E: [email protected]
KALGOORLIE
Lot 33 Yarri Rd, Parkeston WA 6433
P: (08) 9021 5277
KARRATHA
U1/3890 Coolawanyah Rd, Karratha WA 6714
P: (08) 9185 6077
PORT HEDLAND
11 Pinga St, Wedgefield WA 6721
P: (08) 9185 6077
MELBOURNE
U1/5 Redland Dr, Mitcham VIC 3132
P: (03) 9873 2300
SYDNEY
Suite 608, 91 Phillip St, Parramatta NSW 2150
P: (02) 9893 1824
• ASSET CONDITION SURVEYS
• HIGH PERFORMANCE COATINGS
• CONCRETE REPAIR
• INDUSTRIAL FLOORING
• CATHODIC PROTECTION
• MINE SITE MAINTENANCE
• BLASTING AND COATING
• TANK MAINTENANCE
• PRECISION GROUTING
•WATERPROOFING
• BUILDING FACADES
• STRUCTURAL STRENGTHENING