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On The LevelOn The LevelOn The LevelOn The Level
In This Issue
Page
Conference 2017 2
Rubber Ruler 3
Site Safe Online Learning 4
Mileage Rates 4
Concrete Supply 5
Code of Practice 6
CCANZ
Best Practice Guide 7 - 8
CCANZ
Ask Alistair 10 - 12
BCITO
Certification 13 - 16
New Members 17
NZMCPA PO Box 302-486 North Harbour Auckland 0751 Ph.: 027 5319940 E: [email protected] Web: mcpa.org.nz _________________________
Major Sponsor of NZMCPA
June 2017
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Conference, AGM & Awards
Registrations and applications are available through
our website link here, or contact Ed at
[email protected] for the forms.
Don’t forget, Conference Early Bird Registrations
close on Friday 14th July so don’t miss out.
Awards Entries are open until Friday 21st July 2017.
Debate
“Technology is Wasted in the Concrete Industry”
We need volunteers for the debate teams on the
Friday night. Contact Kristina on [email protected]
for details.
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Rubber Ruler
The season is now mud, cold, and rain. The concrete seems to want to take its time to go off, and we have forgotten the cycle. We went through the same thing twelve months ago at this time.
Perhaps it is just me as I am another year older this year. Is it time for me to start to think about standing aside, and let some new blood have a go? I never thought I would be having to decide about the time that I retire and “hang my trade guns up”.
Passing on our skills is more paramount as we get nearer that magical gold card age of 65 years young. It is quite ironic that we are NOT allowed to ‘discriminate’ by age, but the establishment says we can inherit the “National Super” and cash in and use our Kiwi Saver (if you were wise enough to take the advantage of paying in over the years). The law says one thing, but what do employers think looking after the aging workers?
You are probably reading this and thinking what the hell this opening has got to do with concrete placing. Quite a lot really as the young do not seem to be wanting to line up and take our places. The RR always keeps his views through “rose tinted glasses” and looks on the side of optimism. My statement about an aged trades’ workforce is supported by the Department of Statistics (NZ) report in 2015 that gives our average workers age of 58 years. That to me is too old! It does not matter which way we paint it; you may feel the same as when you were 30, but nature tells your body otherwise. I have discussed this question over the years with you - How do we get young people into our trade? We are still floundering around. You may have attended “talk fests” and we have tried to entice by trade qualifications and recognition. The
stumble of our trade is hard work, lower than expected wages, and working conditions. Youngsters compare these factors to other softer and easier work options.
Politically, I could say I hear the “blue N” party saying bring in the qualified labour, and the “red L” party saying we need better conditions and to get our own people into work.. Not being a drinker, I would say the beer slogan is about “yeah right”. Let’s do what we seem to do the best. Get a committee together and talk some more and wait ‘til after this year’s elections. I have contacts in various ITO’s and the trainee numbers are dropping off. Bluntly that means sign-up and young people flocking to get involved is not happening. The flow on is that ITO’s need numbers to get the cash to run their business. Media and others have said they have found a possible fix; “More females are required to balance up the numbers…” I look at statements like this the same way as when we decided that every loaf of bread sold in NZ will only be “thick and thin”. Whichever way you butter the bread not everyone will like it. If the wages/conditions of the concrete worker was the same as for the similar building trade (with same seniority/time) then we may have applicants lining up. Wage details from the ‘NZ Labour Survey’ show the average rates of pay per hour for concrete trades as $18.66, and builders as $25.43. That is roughly a difference of 36% in parity. I wonder why they are not lining up at our door?
You think you are confused! I know that I am at times, it is probably my age.
Kindest regards
RR
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Site Safe Launches Online Learning
IRD - Standard Mileage Rates For Motor Vehicles
The current mileage rate for motor vehicles is 73 cents per kilometre for both petrol and diesel fuel vehicles.
From the 2016-17 income year, different rates apply for hybrid and electric vehicles:
• Hybrid - 73 cents per kilometre.
• Electric - 81 cents per kilometre.
Site Safe has launched its first-ever blended online course.
The not-for-profit membership health and safety organisation has designed a
new course combining the advantages of online and in-class learning, so
trainees will now have even more flexibility when they renew Site Safety Cards
(Passports).
Chief Executive Alison Molloy says the new course will extend workers’ health
and safety knowledge, while also providing companies with another cost-
effective training option.
“ Our latest course, which gives trainees access to a range of online modules as well as in-class time with a health and
safety expert, is a direct result of feedback from the industry. Our new online modules are worker-focused, and allow
trainees to choose the topics that are directly relevant to the real-life risks they face on site.”
The Passport Plus - Flexi (Online + Classroom) is now open for online bookings and will be available at a special
introductory price for the first six months.
Trainees select any two modules from a regularly updated online library, which currently includes: asbestos, noise,
worker basics, manual handling, mobile plant and electrical safety. With the addition of the Passport Plus – Flexi, Site
Safe now offers a total of four new renewal options.
• Passport Plus - Flexi (Online + Classroom) 2hrs in-class & 2 online modules
• Passport Plus - Tools and Plant 4hrs in-class
• Passport Plus - Height 4hrs in-class
• Passport Plus - Worker Health 4hrs in-class
Successful completion of any Site Safe course, including
one and two-day courses, or entry-level Foundation
Passports, will renew Site Safety Cards/Passports. To learn
more, visit https://www.sitesafe.org.nz.
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Concrete Supply Issue In Auckland
The Auckland market is experiencing its strongest growth in over 40 years, and with this brings extreme
pressure points around the supply of concrete. There’s a lot of noise out there, and the issue has been a
topical discussion around the NZMCPA boardroom table for some time.
Rest assured, the NZMCPA is working behind the scenes to address this matter and we aim to provide
possible solutions to an issue that doesn’t appear to be going away anytime soon. What we can tell you at
this point in time, is that we are partnering with the NZRMCA to address some of the issues that our Members
are experiencing, such as lead times, driver shortages, delayed deliveries, and the quality of this perishable
product once it hits the site.
We’ve recently canvassed people across the industry both regionally and nationally, from concrete
contractors, builders, drivers, to dispatchers. The feedback indicates that the concrete shortage problem is
largely confined to the Auckland region. We hear your frustrations, and while there is no quick fix to the issue,
we can reinforce the recommendations proposed by the NZRMCA via CCANZ which aim to minimise
disruptions to your business.
The NZMCPA has formed a subcommittee to focus on this issue, led by Marty Black and supported by Brad
Robertson, Stu Packard and Bernie McIntosh. This committee will aim to channel communications/feedback
between Placers and Ready-Mix Companies in order to address the problems.
PLANNING is key, and will be for the
future. Placing orders well in advance
will certainly help to reduce some of
the issues.
Back in November 2016, the NZRMCA
published an article regarding ‘Ordering
Practices Key to Reducing Concrete
Delays’. Please take the time to read this
article and implement some of these
recommendations in the day to day running
of your business [click for the link]
We were recently given the opportunity to
address the NZRMCA meeting in Auckland
and we presented our case to about 20 of
their members. This has resulted in some
positive steps being considered in an effort to
improve the situation. A report on that
meeting will be sent to members shortly.
The NZMCPA will keep you updated on how
we are progressing with this issue and in the
meantime, please don’t hesitate to contact
us if you have feedback/input on this topical
problem.
Martin Black
NZMCPA Board Member
NZ Interna�onal Conven�on
Centre, Auckland 2017
NZ International Convention Centre, Auckland 2017
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NZMCPA Develops Code of Practice
A ‘Code of Practice’ has been created and developed by the NZMCPA Board, with support from the Cement &
Concrete Association of NZ (CCANZ), the NZ Ready Mix Concrete Association (NZRMCA), Members, and other
key industry Associates.
The development of this document was prompted in part by the Pinto coverage which was aired on TV3 – Story
last year. Current circumstances have identified that Concrete Contractors have little/no specifications for the
placement of domestic driveways. Therefore, the need to develop this document was escalated.
As Concrete Contractors are accountable
for the placement of concrete, it was
imperative we took the lead with
developing this document for our
industry.
The Code of Practice is an important
document that involves our Members and
the document will be sent to print shortly.
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The construction of defect-free concrete ground
floor slabs, also called ‘Slab-on-Grade’ or ‘Slab-
on-Ground’, requires experience and skill. The
concrete placer has to contend with a number of
variables, including changeable weather,
concrete properties and ground conditions.
Defects in concrete slabs or pavements
represent the majority of all concrete defects,
resulting in significant costs for repair and
associated disruption in the use of the floor or
pavement.
To assist in this area, the Cement & Concrete
Association of NZ (CCANZ) and the NZ Ready
Mixed Concrete Association (NZRMCA) have
updated Technical Report (TR) 09 Surface
Delamination in Slab-On-Ground Construction
with Technical Report (TR) 16 Best Practice in
Casting Concrete Ground Floor Slabs and
Pavements.
TR16 outlines the most common defects in
concrete ground floor slabs and best practice to
help avoid them. It is particularly relevant to
specialist concrete placers but also to
supervisors of concrete slab construction.
Commercial slab construction is often carried out
by specialist subcontractors. Clients and main
contractors should satisfy themselves that the
subcontractor has the necessary skills and
experience to undertake the slab in question.
Most defects in concrete ground floor slabs and
pavements are cracks in the slab. Cracks may
merely be aesthetically annoying. However, they
have the potential to be more serious -
threatening the durability of a slab or the surface
wear performance.
Best Practice Guide to Casting Concrete Ground Floor Slabs and Pavements
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Cracking in concrete can be reduced through good design, planning, and skilled execution. TR16
details five common defects in concrete slabs, explaining why they occur and how to avoid them.
They are:
• Plastic Shrinkage Cracking
• Delamination
• Thermal Cracking
• Drying Shrinkage Cracking
• Plastic Settlement Cracking
Login into the NZMCPA website to download a copy – www.mcpa.org.nz
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Ask Alistair CCANZ STRUCTURAL ENGINEER ALISTAIR RUSSELL LOOKS AT HOW TO GET THE BEST OUT OF YOUR GROUND FLOOR SLAB BY GETTING IT TO CRACK WHERE YOU WANT IT TO.
SAW CUTS
Most conventional ground floor slabs are saw cut at between 3 and 5m centres. The cuts are provided in an attempt to
force the concrete to crack where the designer intends. Although often specified, the reason for cutting the slab is often
not fully understood. In this article we explore this ubiquitous construction method by providing answers to some
frequently asked questions.
WHY DO WE SAW CUT GROUND FLOOR SLABS?
As concrete dries, it shrinks. If the slab is restrained at the edges, or by friction along the base, tension stresses will
develop in the concrete over time. If these exceed the tensile capacity of the concrete, it will crack. Tensile stresses also
develop in the concrete due to induced bending moments created by curling of the slab. Joints, and a saw cut is a type of
joint, are provided in an attempt by the designer to direct where the concrete will crack.
WHY ARE THEY NORMALLY PROVIDED AT 3 TO 5 M CENTRES?
If a slab is unreinforced,
NZS 3604:2011 Timber-Framed
Buildings requires saw cuts be
provided at 3m centres. For
conventionally reinforced slabs,
the spacing between saw cuts is
typically limited to between 4 and
5m. Why do we need so many
saw cuts? Calculations are
sometimes performed evaluating
the expected tensile stresses in a
slab as it shrinks, created by
friction along the base. These
calculations usually assume only
axial stresses are developed, and
generally show that the joints can
be placed considerably further
apart than 5m.
However, these calculations fail to
consider that a slab can often only lose moisture from the top surface. This creates a shrinkage gradient that causes the
slab to curl. Although the amount of curling might be small, the tensile stresses it develops in the slab are large. Unless
precautions are taken to avoid slab curl, saw cuts in conventionally reinforced slabs should be provided at 4-5m centres.
SHOULD I CUT EVERY SECOND REINFORCING BAR CROSSING THE SAW CUT?
Saw cut joints are normally designed as tied joints located between free isolation joints. Shrinkage movement is expected
to be concentrated at the free joints, and the saw cuts are provided to prevent unsightly random cracking between the
free joints. The saw cuts are not expected to open up. For this common design situation, reinforcement crossing the saw
cut should not be cut. The reinforcement is placed in the ground floor slab to control shrinkage cracking. It is normally
proportioned to ensure that if the concrete were to crack, the reinforcement across the crack would not yield – therefore
ensuring that the crack width remains small. If some of the reinforcement is cut at the location of a saw cut, the
reinforcement might yield at this location if the concrete cracks, meaning that the cuts will open up more than is strictly
necessary. Continued next page
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WHEN SHOULD THE CONCRETE BE CUT?
The preference would be to use an early entry saw and cut the slab within 6-8 hours of placement. Cutting early means the
risk of random cracking from restrained early thermal contraction is reduced.
If a conventional diamond edged circular saw is used, the slab should be cut as soon as it is sufficiently hard to get a clean
cut (typically within 24 hours).
HOW DEEP AND WIDE SHOULD THE SAW CUT BE?
A saw cut should be one-quarter the thickness of the slab, though this depth can be reduced if an early entry saw is used.
The width is dependent on whether the cut will be sealed with a flexible sealant. If the joint is not going to be sealed, a single
pass of the saw blade is sufficient. This typically creates a cut approximately 5mm wide. If the joint is to be sealed, the
practicalities of installing the sealant and the movement that is expected across the joint need to be considered. The more the
expected movement, the wider the joint will need to be. To be effective, a de-bonding tape, or backing rod, is required in the
joint to prevent the sealant from sticking to the bottom of the cut. This means that a practical minimum width for a sealed joint
is 10mm.
CAN THE NUMBER OF SAW CUTS BE REDUCED OR ELIMINATED?
Yes, but you will need to explore using expansive cements or post tensioning.
Continued next page
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JOINTS IN SLABS
WHAT IS AN ISOLATION JOINT?
An isolation joint is a joint where no tensile or compressive force can be transferred across the joint. In other words, the joint is
free to open and close. The joint may or may not be doweled to assist shear transfer across the joint (more on this later).
DO I NEED EXPANSION JOINTS?
Yes. It is important to recognise that concrete expands on heating, and this expansion needs to be accommodated. It is not,
however, typical for on-ground slabs to have joints that can accommodate expansion from day one. All joints open as
shrinkage occurs, allowing some expansion to be accommodated. The norm would be to provide saw cuts and construction
joints, which after some shrinkage can accommodate expansion of the concrete.
Concrete roads are essentially on-ground slabs that are exposed to the elements. The design philosophy for jointed
pavements is as described above, and excellent performance is achieved. Expansion joints that allow expansion from an early
age will be required when using expansive cements, or for elevated structures exposed to the elements such as bridges and
upper floors of car parking buildings.
HOW SHOULD I LAY OUT MY JOINTS?
Sensible layout of the joints will greatly reduce the chance of unwanted random cracking. Given its importance, the layout of
joints should be shown on the drawings.
When planning the joint layout, first look for re-entrant corners. These represent stress raisers, and are the most common
position for cracks to propagate from. It is almost possible to guarantee that a crack will form at this location so ignore them at
your peril. Figure 1 shows a sensible layout for a re-entrant corner.
Think carefully about penetrations and box-outs. If square, these can create sharp re-entrant corners that trigger cracks.
SHOULD I DOWEL AN ISOLATION JOINT?
The benefits of an isolation joint are:
♦ You may be able to reduce the floor thickness as load is transferred across the joint.
♦ The risk of creating a step between adjacent slabs due to differential warping is eliminated.
For trafficked joints, particularly when forklifts are involved, it is highly desirable to dowel the isolation joints.
SHOULD I ARMOUR THE EDGE OF THE JOINT?
Tied joints, such as saw cuts, are not normally armoured along their edge. The reinforcement that ties the joint typically
prevents it from opening up. Sufficient durability can normally be achieved by the use of concrete with an appropriate
compressive strength.
At isolation joints, the joint will open up as the concrete shrinks. Where the joint is trafficked, particularly with solid-tyred
forklifts, it is sensible to provide some armouring to the edge of the joint. This is typically achieved by using angles cast into the
concrete or by using proprietary systems that incorporate steel plates.
Ar�cle first appeared in CCANZ Concrete magazine Vol 59. Issue 2.
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BCITO Concrete Qualifications
Did you know that BCITO offers many different qualifications specifically designed for different industry roles? Depending on what area of the industry you’re working in there’s sure to be one that suits your role in particular.
Here’s the full rundown of what’s on offer and what topics are covered in each apprenticeship. You should seriously consider the option that’s tailored just for you if you’d like to become a qualified professional or to upskill your team.
Compulsory Elec�ves
For those new to the concrete industry
looking to gain solid all-round industry
knowledge and skills
Na�onal Cer�ficate in Concrete Core Skills
(Level 2)
Tool use
Concrete produc�on
Concrete tes�ng
Health and safety
Environmental prac�ces
Problem solving
Safe working prac�ces
Time management
First aid
Communica�on
Construc�on equipment
For Concrete Construc�on workers
Na�onal Cer�ficate in Concrete
Construc�on (Level 4)
Health and safety
Construc�on equipment
Construc�on processes
Installing precast components
Codes of prac�ce and legisla�on
Placing and curing concrete
Repairing exis�ng concrete structures
Measuring techniques
Scaffolding and working at heights
Li0ing equipment
Use of concrete moulds
Confined spaces
Tes�ng concrete
For those who are involved in Concrete
Produc�on:
Na�onal Cer�ficate in Concrete Produc�on
(Level 3)
Health and safety
Concrete industry prac�ce
Concrete materials
Use and maintenance of equipment
associated with concrete produc�on
Handling orders and produc�on and
ready-mixed concrete
Tes�ng concrete
Confined spaces
Forkli0 driving
For Masonry Product Producers
Na�onal Cer�ficate in Concrete Product
Manufacture (Level 3)
Knowledge of the masonry product
manufacturing process
Safety
Plant and equipment
Make masonry products
Curing concrete
Tes�ng products
Secondary processing
Ordering and dispatching
In-depth safety knowledge
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For those working in Placing and
Finishing Concrete
Na�onal Cer�ficate in Concrete (Placing
& Finishing) Level 3
Health and safety
Measurement
Placing and finishing specific types
of decora�ve concrete
Concrete industry opera�ons, plant
and equipment
Site prepara�on
Curing
Reinforcing
Cu5ng and drilling
Placing and finishing specific types of
decora�ve concrete
Tes�ng
Defects and remedial work
Specified flat concrete
For those involved in Sawing and Drilling
concrete
Na�onal Cer�ficate in Concrete
Construc�on (Sawing & Drilling) (Level 3)
Health and safety
Concrete industry opera�ons, plant
and equipment
Knowledge of slurry control
Performing sawing and drilling
opera�ons on site
First Aid
Confined spaces
Performing deep floor, wire or track
mounted sawing opera�ons
Performing large core and deep
drilling opera�ons
For those who manufacture concrete
pipes:
Na�onal Cer�ficate in Concrete Product
Manufacture (Pipe) (Level 3)
Reinforcing and cast-ins
Producing concrete
Cas�ng cylinders
Curing concrete
Checking and fixing
Making pipes including: Jacking;
Rubber ring jointed; Inspec�on
chambers; Flush joint; Skid rings
Machinery includes: Plant and
equipment Opera�ng overhead
cranes
Moving and storing includes:
Storing and dispatching; Receiving,
storing and maintaining material
Confined space entry
For those working with Precast Concrete
Na�onal Cer�ficate in Precast Concrete
(Level 3) with strands in Structural,
Prestressing, Precast & Tradi�onal Tank
Health and safety
Specifica�ons
Moulds and de-moulding
Environmental management
Plant and equipment
Fabrica�on and reinforcing
Curing and remedial work
Handling, li0ing and transport
Confined space entry
Tes�ng
Orders for materials and products
Manufacture and fabrica�on of
moulds
Cu5ng and drilling concrete
Crane opera�on
Structural precast - Manufacturing
precast concrete panels, beams,
columns and stairs
Prestressing - Manufacturing
prestressed beams, columns,
flooring units and panels
Precast tank - Manufacturing precast
concrete tanks
Tradi�onal tank - Manufacturing
tradi�onal concrete tanks
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With unprecedented levels of construction activity generating an abundance of new opportunities for concrete businesses around New Zealand, it’s important to ensure you keep up with demand.
Getting enrolled or involved in training allows you to:
• Add value to your business and your people
• Give back to your industry
• Improve skills
• Build a positive workplace culture
Experience Recognition
As well as apprenticeships for those new to the concrete industry, BCITO can also deliver these qualifications in a way that suits those who already have skills in concrete. That’s called Experience Recognition - where BCITO may be able to recognise existing experience. You or your staff may be able to get formally qualified through this delivery method in a much shorter timeframe if you’ve been working in the concrete industry for a while now.
If you’re an employer interested in taking on a new apprentice, you’d like more detailed information about how apprenticeships work or want to know more about Experience Recognition, contact BCITO today on 0800 4BCITO (422 486) or visit www.bcito.org.nz/concrete
Image: BCITO
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Paveco Ashburton Ltd.
Tony and Lynn Worsfold have experience in the concrete industry spanning over 32 years. They founded Concrete
Plus in Christchurch and then went on to form Paveco Ashburton Ltd in 2003 which began leading the way with
concrete contracting in the Ashburton/Mid Canterbury District.
Fifteen staff work for the company and they specialise in installing concrete driveways, patios, paths, entrance ways,
tennis courts, concrete pool surrounds, house floor slabs, shed floor slabs, commercial floor slabs, wintering barns,
silage bunkers, dairy platforms, feed pads and dairy yards.
Aardvark Concrete Services (2000) Ltd.
Aardvark Concrete Services is a
specialist concrete pumping
company covering the Greater
Wellington and Taranaki regions.
They do all types of concrete
pumping for civil engineering
projects, commercial and residential
buildings. They also do a wide
variety of domestic work including
driveways, patio areas and house
slabs. Aardvark’s work
encompasses a wide and varied
range of concrete services from
exposed aggregate driveways to
spraying concrete walls.
Established in 1999, Aardvark
Concrete now employs 26 full time
staff in the Wellington and New
Plymouth areas. Aardvark has 28
Pumps available for use which help
provide the expertise and resources
to successfully undertake any size
project.
Aardvark Concrete Services has a
large range of Boom and Line
Pumps, Speciality Spray Concrete
Pumps and also Electric Grout
Pumps. Collectively Aardvark has
229 years of industry knowledge in
the company so they see
themselves as a market leader in
this industry and well prepared for
any project.
New Members