Download PDF - CCANZ

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Download PDF - CCANZ

Volume 53 Issue No.3 September 2009

❯ Aesthetic Merits of Concrete

Architecture

❯ Brutal Concrete Holiday

Home in Swiss Alps

❯ Push-Over Concrete Art

❯ 2011 Rugby World Cup

– Stadia Update

❯ The Science and the Art of

Concrete Testing

❯ Revised New Zealand

Cement Standards


2

Rob Gaimster, CEO. Upfront…

concrete

Since taking office in November 2008

the National-led Government has based

its building and construction policy

platform around a desire to reduce

compliance costs, and to generally

remove what it considers obstacles to

sector productivity.

In line with this stance, Building

and Construction Minister Maurice

Williamson recently announced a new

package of measures. Two initiatives in

particular stand out:

The terms of reference for a review

of the Building Act 2004, which

is designed to cut red tape in the

building consent process, and

Changes to the Licensed Building

Practitioners (LBP) scheme, which

aims to raise skill levels among

tradespeople.

As a trade association committed

to representing the interests of New

Zealand’s cement and concrete industry,

and the wider building and construction

sector, CCANZ is generally supportive of

any evaluation and possible legislative or

regulatory reform.

However, it is with a sense of irony

that CCANZ currently finds itself in the

position of advocating for increased

regulation with regard to the Building

Code, in particular Clause E2 - External

Moisture.

Clause E2 is the Building Code provision

that seeks to safeguard people from

News…

CCANZ welcomed

Bassim Bahr

Aliloom as part of

the organisation’s

team of project

managers in June.

Bassim is a senior

structural engineer

with ten-years

New Zealand

experience at

Bassim Bahr Aliloom

illness or injury that could result from

external moisture entering the building.

In terms of functional requirements, this

provision stipulates that buildings must

be constructed to provide adequate

resistance to penetration by, and the

accumulation of, moisture from the

outside.

CCANZ holds the view that by not

containing an Acceptable Solution for

concrete or concrete masonry systems

within the E2 provision, the Building

Code (unintentionally) disadvantages

the concrete industry, as well as those

wishing to design, build or own a home

that uses these systems.

CCANZ understands the Department

of Building and Housing’s (DBH)

position to be that, as concrete and

concrete masonry systems do not have

a weathertightness issue they do not

require an Acceptable Solution.

While one can understand the DBH

logic, it does not address the situation

that has emerged amongst Building

Consent Authorities (BCA) across

the country, one that threatens to

undermine the overall objective of

reducing compliance costs and

streamlining consent processes.

The tendency of increasingly risk averse

BCAs to give detailed scrutiny to

concrete masonry designs, on the basis

that the Building Code does not contain

an Acceptable Solution for concrete

masonry, has led to inconsistencies

between those BCAs that have adopted

a pragmatic approach and those

that have chosen an overly cautious

and prescriptive interpretation of the

regulations.

The end result of this unfortunate

situation is that it is now more difficult for

the weathertight advantages of concrete

and concrete masonry systems, along

Sinclair Knight Mertz in Auckland. He

recently returned to New Zealand after

working on state-of-the-art structures

in Dubai.

CCANZ Chief Executive, Rob Gaimster,

welcomed Bassim’s appointment

highlighting the contribution he will

make to the organisation’s technical

capabilities and his ability to integrate

international advancements and best

practice into its knowledge base.

with their thermal, fire resistant, and

durability properties, to enhance New

Zealand’s building stock.

As residential applications of concrete

masonry clearly need careful

thought to ensure the Building Code

requirements of E2 are explicitly met,

the concrete industry, in particular

the New Zealand Concrete Masonry

Association (NZRMCA), has worked

closely with BRANZ to publish Concrete

Masonry: Guide to Weathertightness

Construction. This freely available Code

of Practice (www.nzcma.org.nz) enables

designers to access a comprehensive

set of instructions that provide

weathertightness for all applications of

masonry.

As a de facto Acceptable Solution,

Concrete Masonry: Guide to

Weathertightness Construction is

sufficient. However, without the “official”

seal of approval that comes with

inclusion in the Building Code, concrete

and concrete masonry systems

will remain disadvantaged, and this

country’s housing stock will continue to

be overly prone to moisture ingress and

eventual rot.

Maurice Williamson’s response to this

issue when I met with him recently was

sympathetic. He indicated to me that

DBH will endeavour to seek a shortterm

solution during the current review

process to redress the overly cautious

approach being taken by BCAs in

relation to consents for concrete and

concrete masonry houses.

Long-term, the Minister wants CCANZ

and DBH to continue to work together

on this issue to ensure that the

weathertight credentials of concrete and

concrete masonry are allowed to assist in

addressing the systemic failures identified

following the leaky building crisis.

“Securing the services of Bassim has

enabled CCANZ to achieve a complete

multi-disciplined technical team,”

says Mr Gaimster. “It also represents

somewhat of a coup in an extremely

competitive employment market for

engineers.”

Bassim will by based in Auckland, at

Holcim (New Zealand) Ltd’s Greenlane

office.


CCANZ-PR03958

International

concrete

Research Indicates Concrete Pavements

Economically Viable

By updating research into the economic merits of rigid and flexible pavements,

CCANZ has reconfirmed the advantages of constructing and maintaining concrete

roads in New Zealand.

In 2002 CCANZ commissioned URS New Zealand to

prepare an alternative pavement assessment for the SH 20

Mt Roskill project. Several concrete pavement options were

compared against an Open Graded Porous Asphalt (OGPA)

surfaced thin flexible pavement, favoured by Transit NZ at

that time for the project.

The economic evaluation outlined in the 2002 report

concluded that a plain concrete pavement option, with

a hessian tyned surface, was the preferred option from

an economic perspective as it had the least capital and

material cost, and the least comparative road user costs.

However, based on resource consent stipulations a rigid

pavement option was overlooked, and a flexible pavement

was chosen. Subsequently, Transit decided on a structural

flexible pavement.

Earlier this year CCANZ commissioned URS to prepare an

addendum to the 2002 report comparing various concrete

pavement options against the as-built structural asphalt

pavement.

The purpose of the addendum was not only to carry out an

updated comparison of concrete pavement options against

the flexible pavement adopted for the SH 20 Mt Roskill

project, but to also consider a range of other factors such as:

Changes in the New Zealand Transport Agency’s (NZTA)

Economic Evaluation Manual (EEM1) that have extended

the analysis period from 25 to 30 years, and reduced

the discount rate from 10 to 8%.

The widespread overseas adoption of grind and groove

surface technology for concrete pavements as a means

to improve surface characteristics.

The need to comment on Greenhouse Gas (GHG)

emissions from constructing, using and maintaining

different types of road surfaces, as well as possible

regulatory framework developments for noise

assessment.

The overall increase and ongoing volatility of bitumen prices

since 2002 was also a factor to be considered by the

addendum.

The final 2009 addendum report showed that all the concrete

pavement options considered would have had lower net

present value capital costs, and lower gross present value

cost investment and user costs, than the structural asphalt

option used for the SH 20 Mt Roskill project.

In terms of pavement noise, concrete pavement

construction technology has significantly developed since

the 2002 report, and is used extensively in Australia, North

America and Europe. Moreover, if the new draft standard

DZ 6806 Acoustics – Road traffic noise – new and existing

roads is approved to become NZS 6806, and is adopted by

NZTA, it could favour diamond ground, longitudinally tyned

plain concrete pavements.

Although beyond the scope of the updated research, a

thorough Life Cycle Assessment (LCA) comparison of

the environmental effects of different pavement types

was recommended. This was based on the existence of

literature supporting concrete pavements as safer, longer

lasting and requiring less maintenance. The research also

acknowledged reports identifying concrete manufacture as

requiring less primary energy (and therefore generating less

GHG) than asphalt manufacturing.

It was stressed that as road use accounts for around

97% of the overall GHG profile of a pavement’s life-cycle,

in-depth analysis of vehicle fuel efficiency on different

pavement types should be part of any LCA.

With the recent release of the NZTA’s National Land

Transport Programme 2009-2012, along with the

Government’s ongoing development of a National

Infrastructure Plan, the opportunity exists for key decision

makers to seriously consider the range of advantages

offered through concrete pavements.

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3


4

concrete

Obituary... A True Pioneer

Emeritus Professor Tom Paulay 1923–2009

Well known for his distinguished career

and pioneering engineering theory, along

with his engrossing lectures, Professor Tom

Paulay passed away on 28 June 2009.

Born in Hungary, Professor Paulay served in the Royal

Hungarian Army and during World War 2 fought the Russian

Army in his homeland and in Eastern Poland. After his

discharge from the army in 1946 he studied one year of civil

engineering at the Technical University of Budapest.

In 1948 he fled to Austria and West Germany to escape

Stalin and Red Army control. In West Germany, Professor

Paulay enrolled at the Technical University of Munich but

the lack of financial resources ended his studies in civil

engineering. He spent three years in Germany as a stateless

refugee, working with a charitable organisation.

In 1951 he was granted a scholarship by a group of Catholic

students at Victoria University in Wellington and emigrated

to New Zealand with his wife and oldest daughter. After a

stint as a labourer in Oamaru, he resumed his studies in

civil engineering at the then Canterbury University College.

On completing his studies in 1954, he joined the consulting

engineering practice of Don Bruce-Smith where he worked

for the next eight years designing many reinforced concrete

buildings.

In 1961 he was invited by Professor Harry Hopkins to apply

for a lecturer position in the Department of Civil Engineering

at Canterbury University to teach structural design. He

completed his PhD. on the coupling of shear walls, under the

supervision of Professor Hopkins in 1969.

Professor Paulay was promoted to a personal chair in civil

engineering in 1975 in recognition of his contribution to

research and teaching. He retired from the University in 1988

and was made an emeritus professor the following year.

During his retirement, he continued his research interests and

supervision of postgraduate students.

Professor Paulay was one of the greats of 20th century

earthquake engineering - one of a handful of people round

the world who have shaped the art and science of seismic

design. His international status was recognised last year

by the International Association of Earthquake Engineering

with his election as a “Legend of Earthquake Engineering”.

With his death on 28 June 2009, an era of New Zealand

earthquake engineering has come to an end.

It is often said that Professor Paulay was the co-founder

or “father” of the theory and method of capacity design.

In the worldwide engineering community, and especially in

Europe, the name of Professor Paulay is inseparable from

the capacity design of ductile structures concept and design

method that changed earthquake engineering decidedly for

the better.

This innovative procedure deeply revolutionised the

conceptual design, the calculation and the detailing of

structures for earthquake loading and spread out to the

whole world. Moreover, until some years ago, Professor

Professor Tom Paulay

Paulay’s most creative and original contributions to the

nonlinear behaviour of buildings with torsion, and to the

stiffness of reinforced concrete structures, have strongly

influenced the science and professional community of

earthquake engineering, including Swiss and European

Building Codes. Professor Paulay introduced the philosophy

of capacity design into the first draft of the European Seismic

Design Code (later to become Eurocode 8) during the early

1980s.

Results of his research efforts included numerous technical

papers, and three co-authored textbooks, two in English,

one in German, which have become the standard texts

internationally for understanding and implementing the

seismic design of building structures, and which have

been translated into many languages. He put great effort

into contributions to design codes, both in New Zealand

and overseas, preferring to be a corresponding member.

His extensive efforts in this regard are reflected in New

Zealand seismic design codes that have influenced code

developments worldwide.

Professor Paulay served for many years on New Zealand

Standards Committees, notably the concrete structures

design standard. Not only did he bring his knowledge to the

finished documents, he motivated and inspired others with

his wisdom, insights, enthusiasm and hard work.

More than three decades of students at Canterbury

University and many others in earthquake-prone countries

have benefited from Professor Paulay’s teaching, wisdom

and inspiration. His clear insight into structural performance

and his emphasis on the different roles of analysis and

design enlightened his students. The outcome has been a

generation of New Zealand design engineers who understand

structures at a level that is envied in other countries.

Professor Paulay received numerous honours, both civic

and technical, including the OBE in New Zealand, The Order

of Merit of the Republic of Hungary, Fellowship of the Royal

Society of New Zealand, and honorary doctorates from

Universities in Switzerland, Hungary, Romania and Argentina.

Obituary courtesy of the Institute of Professional Engineers New Zealand (IPENZ)


concrete

Standards New Zealand UPDATE

The past few months has seen a collection of concrete related New Zealand Standards

revised. Below is a summary of the changes to four key documents.

NZS 3122:2009 Specification for Portland and

blended cements (General and special purpose)

Specifies requirements and methods for testing hydraulic

cements consisting of Portland cement or mixtures of

Portland cement and one or both of fly ash and ground

granulated iron blast-furnace slag. The outcome is to ensure

that the end user of the Standard benefits from being up to

date with current technology and in line with current industry

methods and practices. Supersedes NZS 3122:1995.

NZS 3123:2009 Specification for pozzolan for use

with Portland and blended cement

Specifies requirements for pozzolans that may be added

to concrete or used to manufacture type GB cement. The

NZS 3123:1974 requirements for type PP cement have

been replaced by NZS 3122:2009 provisions for blended

hydraulic cement containing natural pozzolan. Supersedes

NZS 3123:1974.

NZS 3106:2009 Design of Concrete Structures for

the Storage of Liquids

A revised Design of concrete structures for the storage

of liquids, NZS 3106:2009, which supersedes NZS

3106:1986, was published in July 2009.

The Standard provides design requirements and guidance

including design loads and seismic design criteria. NZS

3106 is a technical document used by engineers to design

concrete tank structures for facilities such as water storage

reservoirs and wastewater treatment plants.

The Standard was revised in line with current practice and

new technology, and to align with the loadings requirements

given in the AS/NZS 1170 series of Standards (especially

NZS 1170.5 Structural design actions – Earthquake

actions). The revised Standard:

Provides a basis for designing concrete structures for

the storage of liquids so that they will require only limited

periodic maintenance to remain serviceable for their

design life, and will not allow an uncontrolled, rapid loss

of the liquid contents in extreme events such as a major

earthquake.

Includes useful design and analysis guidelines and data

to assist the design process.

Contains commentary that provides examples and

applications, making the clauses clearer.

Supports public safety through designs that are safe

and serviceable.

NZS 4218:2009 Thermal Insulation - Housing and

Small Buildings

A revised Standard specifying Thermal insulation – Housing

and small buildings, NZS 4218:2009, which supersedes

NZS 4218:2004 was published in July 2009.

NZS 4218 specifies thermal insulation requirements for

housing and small buildings for users of the Standard –

architects, designers, building consent authorities, and

window and glass companies. The revised version of NZS

4218:

Includes modified R-value tables and brings the

Standard into line with these increased performance

requirements. The construction R-values in this

Standard result in a low life cycle cost, based on current

insulation costs, energy costs, and heating behaviour.

Clarifies the three different ways of working out R-values

(Schedule method, Calculation method, and Modelling

method) and ensures consistency between the different

methods.

Touchstone - Standards New Zealand web-based

e-zine

For the very latest news on Standards relevant to you and

your industry, subscribe to Touchstone free. Published

monthly, Touchstone includes updates on New Zealand

Standards in development, superseded and withdrawn NZS

and AS/NZS Standards, ISO, IEC, Australian, and British

Standards.

Visit the Standards New Zealand website for further

information: www.standards.co.nz

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michael@cbecon.co.nz

www.cbecon.co.nz

5


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concrete

Testing Concrete: The Science and the Art

Sue Freitag, Principal Scientist (Concrete) at Opus International Consultants’ Central

Laboratories, outlines how getting the right result from concrete tests involves not only

performing the test correctly, but also selecting and specifying appropriate tests, sampling

regimes and methods of evaluating the results.

The “right” result is the result that tells you what you need to

know about your concrete. For example, will the concrete

you’re considering provide the physical properties and

service life your client needs? Was the concrete that was

delivered to site the quality that was ordered? Was it the

same as the batches delivered for the previous pour? Was it

placed and cured correctly? And, unfortunately, sometimes

you’ll want to know why it did not perform as expected.

Getting the right result is both a science and an art.

The Science – Test Methods

The science of testing concrete is relatively straightforward.

Standard tests exist for measuring most properties of

fresh and hardened concrete. They take into account the

scientific principles that determine the concrete property

and the factors that influence the result.

Standard concrete tests do not aim to reproduce site

conditions. Instead they specify laboratory conditions and

test procedures that ensure consistent results are obtained

from a given sample irrespective of when and where it is

tested. Results from different samples can then be directly

compared with each other or with a specified value without

needing to consider when or where the test was performed.

The ideal test measures a property that relates directly to

the performance of the concrete or concrete structure, uses

test specimens that are convenient to cast and handle,

and is practical to perform. Aspects of the laboratory

procedures that influence the results are understood and

readily controlled. To differentiate between acceptable

and unacceptable concrete performance the test must

be sensitive to significant changes in the property being

measured, and the range of results expected from different

batches of the same concrete tested in the same laboratory

and in different laboratories must be known and relatively

small.

The compressive strength test is close to the ideal

test. Cubes, cylinders and cores are easily produced

and handled. The result is directly related to structural

performance and is sensitive to relatively small changes in

concrete quality. The inherent variabilities associated with

compressive strength testing are well understood. These

advantages have led to compressive strength testing

becoming the principal means of quality control, with

statistically-based acceptance criteria that give the both the

purchaser and the concrete producer an acceptable risk

of low strength for an acceptable price. Similarly, slump,

density and air content are widely used to manage fresh

concrete properties.

Concrete testing is both a science…

… and an art.

The Art – Specification

Testing specifications for Normal concrete (as defined by

NZS 3104: 2003 Specification for Concrete Production)

are based on slump, air content and compressive strength.

They are relatively straightforward apart from the need to

decide when to take samples and where to take them from.

In the last ten years or so the concrete industry worldwide

has expressed interest in specifying concrete properties

other than compressive strength to achieve desired

performance characteristics. These include drying

shrinkage, resistance to abrasion or chemical attack and

the ability to prevent corrosion of steel reinforcement.

NZS 3104 defines the concrete as Special concrete when

such performance properties are specified.

Image courtesy Ricardo Cuerva Image courtesy Bryan D. O’Connor


Standard tests exist for many such “performance

properties”. Yet these properties are rarely measured

in New Zealand other than for research or product

development for specific projects. This is partly because of

a lack of understanding of the inherent variabilities of the

properties and the tests and hence the lack of associated

statistically-based acceptance criteria. The tests also

tend to take longer and cost more than strength, slump

and density/air content tests. These limitations place

more responsibility on the specifier to develop appropriate

test regimes and methods of evaluating the results.

Understandably, specifiers are often reluctant to accept the

risks associated with unfamiliar tests. But once the industry

as a whole accepts these risks it will begin to realise

the potential for innovation that is offered by specifying

properties other than strength.

For Special concrete the specifier or purchaser must specify

test methods, sampling regimes and methods of evaluating

the results. The tests must measure the critical properties

and be offered by laboratories with relevant experience, and

the sampling and testing programme must be appropriate

for the project size, timeframe and budget. Whether

the results are evaluated against a specified acceptance

criterion or by comparing different concretes the evaluation

procedure must be clearly prescribed and must take

into account the inherent variability of the test and of the

concrete supply.

Model specifications from materials suppliers or

specifications recycled from previous projects must be

reviewed to make sure they are suitable for the current

application. Flaws in the original version must be identified

and addressed. Clauses originally intended for proprietary

materials must be neither too restrictive nor inappropriately

modified to widen their scope. All relevant features must be

covered and irrelevant features deleted. Standard tests that

are quoted must be relevant, updated where necessary, and

readily procured.

Attention to these aspects will allow maximum value to

be gained from testing carried out and will reduce the risk

associated with performance specification.

Further information:

Cement and Concrete Association of New Zealand. 2003.

Specifying concrete for performance. CCANZ TR 10.

Freitag, S.A. and Bruce, S.M. 2007. Testing: how to get

useful results without spending more than you have to.

New Zealand Concrete Industry Conference, Taupo, New

Zealand 27-29 September 2007.

Gaimster, R. 2007. The cause for cores or a cause for

concern. New Zealand Concrete Industry Conference,

Taupo, New Zealand 27-29 September 2007.

Hover, K.C. 2005. Testing concrete – thinking beyond the

procedures. Concrete Construction, Dec 2005 pp 37-41.

Peek, A., Nguyen, N and Wong, T. 2008. Compliance

testing of concrete in construction projects. Corrosion &

Materials, vol 33 no. 6 pp 22-33.

concrete

7


8

concrete

Recycled Crushed Concrete for New

Christchurch Southern Motorway

A New Zealand Transport Agency (NZTA) decision to use recycled crushed concrete in the

construction of the new Southern Motorway is designed to have a wide range of positive

environmental benefits.

Work on the $180 million Christchurch Southern Motorway

project is scheduled to begin in March 2010. The project

will be one of the most significant roading projects to be

undertaken in the greater Christchurch area over the last

5-years. A key component of the project will be the use of

recycled crushed concrete as aggregate.

NZTA State Highways Manager for Canterbury-West Coast

Region, Colin Knaggs, says there are real pressures on

construction aggregate sources within greater Christchurch,

with reports suggesting that there is only around 10 years

supply remaining. In developing the Christchurch Southern

Motorway project the NZTA looked at more sustainable

supply alternatives, rather than being totally dependent

on importing aggregate from traditional sources such as

riverbeds and quarries.

Using Recycled Crushed Concrete (RCC) will cost

approximately the same as obtaining the same quantity

of virgin aggregate from usual sources. Furthermore, as

much of the concrete will be sourced from several significant

demolition projects planned for Christchurch in the next few

years, the reuse of concrete that would have otherwise been

disposed of in local landfills makes real environmental sense.

In 2007 the NZTA was granted consents to stockpile

CO2 Footprint of RCC for New

Christchurch Southern Motorway

As part of the preliminary planning stages for the new

Christchurch Southern Motorway project, the New

Zealand Transport Agency (NZTA), then Land Transport

New Zealand, commissioned Opus International

Consultants to determine the carbon footprint of

different methods of obtaining 60,000m³ of AP65 subbase

for use in construction.

The cases modeled by John Patrick,

Opus International Consultants’

Research Manager (Pavements),

were aggregate from the Waimakariri

riverbed to placement, and the use of

Recycled Crushed Concrete (RCC) to

stockpile, and then placement.

The research demonstrated that

when the energy consumed in

transporting riverbed aggregate

from source (50 km round trip)

and processing it using electricity,

is measured against the energy

consumed in transporting in RCC

from source (15 km round trip) and

processing it using diesel, the CO2

emissions per tonne of material were

essentailly comparable.

However, when the CO2 uptake of

crushed concrete (4% of the mass

of concrete) was considered along

with the emissions associated with

transporting the demolition concrete

to waste, then the use of RCC offered

significant advantages over riverbed

aggregate.

Recycled Crushed Concrete at Christchurch stockpile

60,000 m3 of RCC at locations near the site of the new

Southern Motorway. Site preparation works for the storage

site have been completed, and RCC material is being

stockpiled as it becomes available from demolition sites

around Christchurch.

Mr Knaggs says that locating these stockpiles near the new

Southern Motorway construction area will mean less heavy

vehicle noise, exhaust emissions and traffic congestion that

would inevitably result from the transportation of aggregate

from traditional sources further afield.

Recycling Concrete

Pavements - American

Concrete Pavement

Association (ACPA)

This comprehensive

guide addresses

facts about

recycling concrete

for use in new

concrete pavement

structures. It

describes concrete

pavement recycling

as a proven

technology that offers an alternative

aggregate resource that is both economic

and sustainable. Concrete recycling is

a relatively simple process that involves

breaking, removing and crushing hardened

concrete from an acceptable source to

produce recycled concrete aggregate, a

granular material that can be produced for

any application for which virgin aggregate

might be used.

To borrow this item email

library@cca.org.nz


FRC – Not All Fibres Are the Same

As a result of developments in fibres and Fibre Reinforced Concrete (FRC) CCANZ

Information Bulletin IB 39 Fibre Concrete is currently being revised.

By outlining the different fibre types

and different fibre reinforced concretes

commonly available in New Zealand,

this summary article seeks to address

various points of confusion about FRC

technology and design.

What is the purpose of using fibres

in concrete?

Unreinforced concrete has excellent

compressive strength but is a brittle

material that deforms elastically under

tension until it cracks. At this point it

rapidly loses its load carrying capacity,

i.e. it does not have any post-crack

ductility. Steel reinforcement bars or

mesh usually provides this ductility, but

it can also be provided by fibres.

The basic concept of FRC is that fibres

arrest the growth of micro cracking

and/ or provide post-crack ductility in

concrete. Steel and macro synthetic

fibre reinforcement, like conventional

reinforcement, only become effective

after the concrete has cracked. It is

how and at what stage this cracking is

controlled that differentiates fibre types.

Micro and cellulous fibres help in

preventing plastic shrinkage cracking.

Fibres range in type based on their

base material (e.g. steel, synthetic, or

cellulose), their size, and their shape.

Steel and macro synthetic fibres

enhance the toughness, ductility,

and energy absorption capacity of

hardened concrete. However, in the

case of macro synthetic fibres, these

properties may only be realised at crack

widths approaching or exceeding those

recommended at the serviceability

limit state, and long-term performance

should be considered1 , 2 . Both fibre

types can be used to contribute to the

load bearing capacity of a concrete

member3 , 4 . They do not contribute

significantly to reducing or eliminating

plastic shrinkage cracking. At normal

dosages they do not affect the flexural

strength of concrete, but they do control

drying shrinkage cracking.

Micro synthetic fibres and cellulose

fibres at appropriate dosages are

particularly useful at limiting the

widths of micro cracking in concrete

in its plastic state. These fibres also

lower the permeability of concrete

and improve its impact and abrasion

resistance. Micro synthetic fibres

in concrete are used to improve fire

performance because they melt at

about 150-160°C leaving voids for the

passage of moisture vapour that would

otherwise lead to explosive spalling.

Generally, these products provide no

level of capacity / crack control if the

concrete cracks in its hardened state.

NRMCA publication CIP 24 cautions

against the use of micro synthetic

fibres for the control of cracking as a

result of external forces, replacing any

moment-resisting or structural steel

reinforcement, decreasing the thickness

of slabs on grade, or increasing ACI or

PCA control joint guidelines5 .

Blends of steel or macro synthetic fibres

and micro or cellulose fibres can be used

to provide a combination of benefits to

plastic and hardened concrete.

When considering FRC it is important

to note:

No two fibres are the same, and

a fibre should be selected for a

particular application and designs

based on the properties of the FRC

pertaining to the selected fibre.

The effects of fibres on the

concretes that they reinforce

depend on a number of factors –

the fibre type, its dimensions, its

properties, the dosage of fibres

used in the concrete, and the

properties of the matrix the fibres

are contained in.

Empirical design guides e.g.

CSTR 636 , ACI 544.4R7 and NZS

31018 have been developed and

published for steel reinforced

concrete. However, these guides

may not necessarily be suitable

for macro synthetic fibres in

consideration of their different longterm

performance.

concrete

The unloading tunnel and rail track support slab at Fonterra’s Te Rapa storehouse made extensive

use of steel fibre technology.

Test reports or certification, from

reputable independent testing

authorities, should either be

provided or the FRC should be

tested to verify that it satisfies the

properties required of it, e.g. the

ultimate and serviceability states

of NZS 3101 Concrete Structures

Standard.

It is imperative to recognise that a FRC

designed and tested with a particular

type and brand of fibre cannot be

assumed to have the same properties

as a FRC made from different fibres.

This includes fibres that may look

the same but come from different

manufacturers or suppliers.

The revised IB 39 Fibre Concrete will

be available via the CCANZ website

shortly.

1 Concrete Society, Technical Report 34 Concrete industrial

ground fl oors – a guide to their design and construction,

3rd edition, The Concrete Society, Camberley. 2003.

2 Concrete Society, Technical Report 65 Guidance on the

use of macro-synthetic fi bre reinforced concrete, Concrete

Society, Camberley. 2007.

3 British Standards Institution, BS EN 14889-1:2006, Fibres

for concrete. Steel fi bres. Defi nitions, specifi cations and

conformity, British Standards Institution, London, UK.

4 British Standards Institution, BS EN 14889-2: 2006, Fibres

for concrete. Polymer fi bres. Defi nitions, specifi cations and

conformity, British Standards Institution, London, UK.

5 NRMCA, Concrete in Practice: What, why &how, CIP

24 Synthetic fi bers for concrete, National Ready Mixed

Concrete Association, silver spring, MD, USA.

6 Concrete Society, Technical Report 63 Guidance for the

design of steel-fi bre reinforced concrete, Concrete Society,

Camberley. 2007.

7 American Concrete Institute, ACI 544.4R-88 Design

considerations for steel fi bre reinforced concrete

(Reapproved 1999), American Concrete Institute,

Farmington Hills, MI, USA.

8 NZS 3101: 2006 Concrete structures standard. Standards

New Zealand, Wellington.

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10

concrete

Perceptions of Beauty:

How Do We See Concrete Buildings?

Morten Gjerde, Senior Lecturer at Victoria University of Wellington’s School of Architecture,

looks at the debate surrounding the aesthetic merits of concrete architecture, and

discovers that a range of features that include façade depth and attractive aging mean

concrete buildings are appreciated by architects and the public alike.

Recent controversy surrounding the

proposal to demolish a British concrete

housing project reminds us of the love

/ hate relationship the public seems

to have with concrete buildings, at

least as it is projected in the media.

Robin Hood Gardens was built in

East London in the 1960s and is now

earmarked for demolition by the British

Government. Media reports have

tended to focus negatively on the raw

concrete finishes used throughout the

development. Controversy emerged

when designers argued against the

demolition, citing the project as an

important example of Neo-Brutalist

architecture. Moreover, the project

was one of the few realised by the

architectural team of Alison and Peter

Smithson, who espoused the use of

concrete in its raw format – béton brut,

using the French term – during the

heyday of Neo-Brutalism.

This debate over the relative aesthetic

merits of concrete architecture

was in part addressed during the

writer’s recent sabbatical leave to

Oxford Brookes University in the UK.

Underpinned by literature in the field

of environmental psychology, the

research set out to determine design

characteristics that people find more

visually pleasing in an urban setting

and also to identify those that are not

favoured. The project also addressed

the question of whether professionally

trained designers evaluate their

environments differently than those

with no formal training. If there are

real differences in perception between

architects and those who have to live

with their work then the arguments

about the relative merits of Robin

Hood Gardens can more easily be

understood.

More than 400 people were consulted

by way of surveys conducted in the

UK and in New Zealand. Although the

research did not consider concrete

buildings exclusively, the collected

data helps illuminate discussions of

how they are perceived generally.

Robin Hood Gardens was built following New Brutalist aesthetic principles. The movement took its

name from the French - Béton Brut, or raw concrete - but the English meaning was used to express

public perceptions of the architecture.

The effective manipulation of concrete elements in street scenes such as this from Birmingham were

judged favourably by the research respondents

An overarching observation is that

concrete buildings are generally judged

positively by most people. It appears

that one of the principal factors is the

textural quality of concrete. External

finishes such as exposed aggregate

and board-formed have been found to

stimulate the observer’s visual sense

and in the context of underlying order

(such as that provided by a regular set

out of window openings) the observer

has a pleasing aesthetic experience.

Even when featuring a smooth finish,

exposed concrete would be preferred

over many other smooth engineered

materials because of visual interest

created by textural variegations in the

surface.

A façade that is modelled threedimensionally

is also judged very

positively by people. Modelled

surfaces provide visual interest at a

Image courtesy Keith Paulin


The visual appeal of the General Accident Building in Christchurch is enhanced through the use of

regular and ordered exposed aggregate precast concrete claddings panels. The depth of the façade

enables strong patterns of light and shade to play across the façade during the day as well to shade

the interior offices.

higher, more immediate, perceptual

level. This causes the eye to roam

over the whole of the building in

much the same way as a person

tends to scan a piece of art. In the

clear light conditions of New Zealand

the sun plays an important role in

animating the surfaces with light and

shadow. In today’s construction world,

surface modelling can be achieved

more effectively with concrete than

any other material. This is because,

as a monolithic material, concrete

avoids the expense and risks to

weathertightness that are inherent in

solutions that make use of sheet based

products to create façade depth.

This observation applies equally to

proprietary curtainwall systems and

is one reason so many contemporary

buildings feature flush, visually bland

cladding solutions. The research

clearly confirms people’s preferences

for articulated surfaces similar to that

of the General Accident Building in

Christchurch.

It would be hard to imagine a negative

reaction to buildings such as the

General Accident Building because

it features another characteristic that

is perceived positively by observers,

that of obvious and subtle patterns of

regularity. Researchers in the field of

psychology note that humans have an

innate desire to group similar elements

to create patterns or rhythms. This

phenomenon is a central feature of the

Gestalt theories of visual perception.

Relating this back to façade design,

patterns can effectively be created with

repeated use of similar components

such as precast concrete elements.

The field studies confirmed this

phenomenon, not only apparent in

concrete buildings but also in others.

The most positive reactions are made

concrete

in relation to intermingled patterns that

generate rhythms similar to those upon

which music is based. In the case of

the General Accident building the ‘bass

line’ might be evident in the regular

beat of the punched window openings

with the harmonies expressed in the

subtle lines of the panel joints that

trace over the entire surface.

Another factor affecting aesthetic

judgement is that of weathering.

This was particularly apparent in the

reactions to a collection of office

buildings in Birmingham. All of these

buildings were showing their age, yet

reactions to factors related to care and

maintenance were generally positive.

This finding was discussed in more

detail with a focus group and the close

resemblance of the concrete to natural

stone meant that such patterns of

aging were seen to be graceful. In

comparison, painted and prefinished

contemporary materials that are not

maintained in near perfect condition

are viewed negatively. The inherent

qualities of the exposed concrete

appear to be more forgiving to the

natural weathering processes.

Addressing the question of differences

in aesthetic judgement between

building designers and the public, the

research found that there was no basis

for such claims. Instead both groups

were found to favour similar aesthetic

outcomes; however architects’ views

tended to be more pronounced at

the extremes of agreed good and

bad design. With this knowledge we

can return to consider the underlying

reasons for the failure of the Robin

Hood Gardens project. Indeed it has

little to do with the aesthetics of the

exposed concrete. The media reports

have got it wrong, as the research

findings confirm that designers and

the public favour similar aesthetic

outcomes. Instead, it is likely that

the planning layout of the project

and poor sense of personal security

arising from the planning conspire

to make living there undesirable. In

this circumstance, like so many

others, concrete has been maligned

by association with a poorly planned

project, typical of so many that were

built in the brave world of European

Modernism. Bolstered by the research

findings it may be time to look for new

and appropriate ways of incorporating

concrete cladding into building design

to generate visual pleasure.

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12

concrete

Eden Park and Stadium Christchurch

Upgrade Gather Pace for 2011

New Zealand recently celebrated ‘Two Years to Go’ until the opening match of the

upcoming Rugby World Cup between the All Blacks and Tonga on Sept 9 2011. The

countdown is also underway for stadia redevelopments around the country, an undertaking

Firth Industries is assisting to complete by supplying concrete for Eden Park and Stadium

Christchurch.

Auckland’s Eden Park

The Eden Park redevelopment involves

construction of a new permanent

three-tier 21,500 seat South stand; 50

new corporate boxes; a new, unroofed,

two-tier east stand (replacing the

eastern terraces) with 8,600 capacity;

and the extension of the ASB stand

with a 2,000 seat lower bowl (replacing

the Panasonic stand) - increasing

capacity from 45,000 to 60,000

people.

“Fletcher Construction is the main

contractor for the project and are

utilising Dominion Constructors to do

the concrete structure works,” says

Marc Hainen, Chief Operating Officer

Firth Northern.

“Firth is supplying approximately

10,000m³ of in-situ concrete to

Dominion Constructors which is

keeping Firth’s Auckland branches at

Stadium Christchurch upgrade scheduled for completion in January 2010

Leonard Road and Hamer Street very

busy,” he says.

“Firth has also supplied considerable

volume of concrete indirectly on this

project to Concretec,” says Hainen.

“Concretec New Zealand Ltd is the

pre-cast manufacturer supplying

selected pre-cast sections for the Eden

Park redevelopment and these are also

made from Firth concrete.”

Most of the structure on the main

stand has been completed and work is

now beginning on the new East stand,

which will replace the old terraces. The

project is on track to be completed well

before the World Cup begins in 2011.

Stadium Christchurch

The three old eastern stands being

replaced at Stadium Christchurch had

reached the end of their structural life

and construction of a new stand began

in July 2008.

The new stand will be named “The

Deans Stand” in honour of the Deans

family, which has had connections

with Canterbury rugby for more than

100 years. It will seat 13,420 people,

increasing the capacity from 36,000 to

39,830.

The roof of the new stand will be

larger than the other main stand

in the stadium providing cover to

approximately 80% of the seating area.

“Firth has supplied a total of 6000m3 of concrete to Fletcher Construction

and their various subcontractors,”

says Dominic Sutton, Area Manager

for Firth Canterbury/West Coast. “The

final structure pours for the stadium are

now underway, and site works outside

the stadium have begun.”

Firth has provided technical expertise

to the project including adding special

shrinkage reducing admixtures to the

concrete. Sutton playfully adds, “While

we haven’t done any red and black

(Canterbury rugby colours) concrete

we’ve been quite tempted.”

Gordon Murdoch, Project Manager on

the project for Fletcher Construction,

comments, “Progress is going well

on the project and about 70% of the

stadium structure and 50% of the roof

has been completed.”

Still to complete is a lounge at level

three behind the stadium, a ramp

providing access into the stadium

and a concourse at level one. The

concourse will run from the new Deans

stand right around to the existing

Hadlee, Tui and Paul Kelly Stands

enabling event goers to walk a full 360

degrees around the stadium.

The targeted date for completion of the

upgrade of Stadium Christchurch is set

for January 2010.


concrete

NZ Permeable Pavement Study A Success

A new type of road surface gaining popularity overseas as a result of its environmental

benefits has been successfully trialled by researchers from the University of Auckland’s

Faculty of Engineering on a 200m 2 section of Birkdale Road on the North Shore.

Concrete block permeable

pavements are a type of pavement

surface suitable for trafficking that

also acts as a stormwater drainage

system. In conventional pavements,

stormwater is allowed to run across

the surface to gullies, where it is

collected and then directed into

pipes for quick removal, as it is

undesirable to allow water into

conventional sub-base material.

In contrast, concrete block

permeable pavements have a dual

role that enables them to act as

the drainage system as well as

supporting traffic loads. They allow

stormwater to pass through the

surface (between each block) and

into the underlying permeable subbase

(either coarse graded aggregate

and/or hydraulically bound coarse

graded aggregate) where it is stored

and released slowly, either into the

ground or to a drainage system.

Significant reductions in stormwater

contaminants that may eventually

flow in to streams, rivers and

harbours can also be achieved.

Dr Elizabeth Fassman and ME

student Samuel Blackbourn from the

University of Auckland’s Department

of Civil and Environmental

Engineering monitored the

effectiveness of the surface over two

years. Results show it decreased

stormwater run-off at peak flow by an

average of 75 percent during most

storms, and reduced the volume of

total run-off by about 40 percent,

when compared to run-off from

asphalt on the same road. Storms

with less than 7mm rainfall produced

only a slow trickle of run-off that was

too low to measure accurately. Runoff

from the permeable pavement

also had on average 70 to 80 percent

less sediment, copper, and zinc.

“The water quality was as good as

water treated by detention basins

or constructed wetlands, which are

commonly used to control stormwater

but can take up a lot of space,” says

Dr Fassman. “Permeable pavement

is emerging internationally as an

important stormwater management

technology. We set out to prove

this technology works under local

conditions, and in comparison to

international studies it performed well,

despite the challenging conditions.

Essentially we tried to doom it to failure

by installing it on a busy roadway. Most

permeable pavements overseas are in

car parks or quiet roads.”

Seattle in the United States has been

an avid adopter of the technology,

installing the surface widely on

footpaths and some roadways to

control stormwater run-off. UK

uptake is also growing fast, with

some 500,000m 2 of concrete block

permeable pavements being installed

in Ireland just on retail developments

alone over the last seven years.

“There are miles of roads and car parks

in Auckland, and if they were converted

to this surface it would make a huge

impact on protecting our waterways

and streams, and preventing stream

erosion,” Dr Fassman says.

The trial also confirmed the best

installation techniques for the system,

how susceptible it is to clogging, and

how it responds under the weight of

heavy traffic.

The Auckland Regional Council and

North Shore City Council supported

the trial. The researchers have

delivered a report on the performance

of permeable pavement, and

observations about maintenance and

installation procedures. Guidelines on

how to design and install the system

are being updated by the North Shore

City Council.

Trial section under construction

Completed trial section

Dimensions of permeable pavement system

13


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concrete

A Concrete Stranger in an Alpine Village

The spirit of the times has finally arrived in Vná, a tiny village in Unterengadin, Switzerland.

Architects Andreas Fuhrimann and Gabrielle Hächler have built a holiday home in the

village that would appear avant-garde even in an urban environment.

The architects chose to meet the

challenge of balancing the village’s

traditional Engadin architecture with

the “spirit of the times” by clearly

referencing the surrounding houses,

while radically reinterpreting their

elements. The result is a sculptural

structure that has the simplicity and

‘rustic directness’ of the local buildings,

but combines them with contemporary

comfort and architectural refinement.

Fuhrimann Hächler have acknowledged

the village’s stony appearance by using

lightweight concrete, which enabled

a homogeneous wall structure to

be achieved without cladding. The

exaggerated wall thickness echoes

the traditional method of construction,

while allowing for the distinctive inclined

window reveals.

The house has three storeys, which are

connected via a single flight of stairs.

The ground floor is a utility area, while

the first floor houses three bedrooms

and two bathrooms. On the top floor

is the living room with an open-plan

kitchen under a gable roof.

As is often the case in Fuhrimann

Hächler designs, the interior walls take

the form of sculptural furniture. For

instance, the bathroom washbasin

and the bathtub merge into the wall.

The same technique is used for the

bedroom wardrobes. In the living

room, the interior wall becomes part of

the room furniture. Rather than divide

the storey, the wall organises it, flowing

its way through the room, opening to

the fireplace, revealing perspectives,

and becoming a balustrade, before

passing over into the kitchen.

The exterior of the building is also

sculptural in form. Despite appearing

unapologetically sharp, the building’s

floor plan contains no right angles.

The walls have slight bends and each

upper floor overhangs the floor below it

at an acute angle. The architects were

inspired by the typical deformations of

the old surrounding houses and their

curious bays and corner extensions.

The windows, which are arranged

according to criteria associated with

the interior rooms, create an additional

INTERNATIONAL STORY

An avant-garde presence in a traditional village

Subtle curves merge elements with an organising sense of flow

unforced façade that is typical of the

village.

The concrete walls are unplastered

and visible indoors and out, as are the

ceilings and floors, which have simply

been ground and given a hydrophobic

coating. Plywood panelling has been

used in the living room and bedrooms

to replicate the traditional unpretentious

atmosphere of a mountain house.

The 46 cm thick exterior walls were

constructed from Liapor lightweight

concrete and the outer surfaces given

a hydrophobic coating. The interior

walls and ceilings were constructed

using normal concrete. In order to

minimise cold bridges, the ceilings

rest only partially on the exterior walls.

Concrete placement occurred storey-bystorey,

and the layering remains visible.

Despite borrowing from the traditional

Engadin houses, the new building is

a strange newcomer in the traditional

village setting. Yet such a striking

presence has brought a sense of

modernity that has been cautiously

embraced by local residents as a sign

of an encouraging future.

opus C –

Concrete Architecture & Design

www.opusc.com


INTERNATIONAL STORY

concrete

15


16

concrete

Handcrafted Concrete Furniture

When designer Carine Stelte set out to create stylish, contemporary and practical furniture

using concrete she was motivated by a clear vision – “The design reflects my longing for

perfection and aesthetics. It was my desire to own an armchair made of concrete, for

indoor and outdoor use.”

The use of glass fibre reinforced concrete has lent the cs1

design a slender elegance, or “filigree plasticity”, that belies

its strength and durability. Such symbiosis of form and

material, along with the single casting mould, underpins the

unique seamlessness of the design.

Stelte considered this contradiction between the delicate

construction (the material thickness is only 25 mm) and

traditional perceptions of rough concrete a challenge to be

embraced.

Carine Stelte Each individual cs1 chair is signed

The cs1 chair – stylish and robust

“First reactions to the idea were always skeptical. However,

I am happy not to have compromised my idea, creating with

cs1 something completely new and unique, an armchair that

combines purity of concept with a durable material language.“

Each cs1 chair is a hand-made original, and carries the

designer’s signature and a unique identification number.

www.carinestelte.com

www.object-design-solutions.com


concrete

Push Over – When Art Meets Engineering

Civil engineering and artistic vision came together in concrete recently when University

of Auckland civil engineering undergraduate students Jedediah Martin and Sumit Anand

collaborated on a piece of avant-garde art with artist Simon Glaister.

Push Over at the St Paul Street Art Gallery

The project, called Push Over, involved replicating a

concrete beam-column unit that supports the ceiling at

Auckland’s St Paul Street Art Gallery, earthquake testing it

in a research lab, and then exhibiting it next to the original

structure.

Associate Professor Jason Ingham, of the Department of

Civil and Environmental Engineering, says replicating the

unit was a significant undertaking. The crucifix-shaped

beam-column unit is reinforced with steel, stands 4.3

metres high and 3.8 metres across, and weighs 5.8 tonnes.

The artist and a team of engineering undergraduate

students built the unit at the Stresscrete precast yard in

Papakura as part of their final year course work. It was

then transported by crane and truck to the University of

Auckland Civil Engineering Test Hall, where it was subjected

to maximum earthquake simulations and load testing. The

damaged replica was then carefully transported to the

gallery for display.

“The construction process helped to foster interaction

between the university and local concrete industry, and

demonstrated concrete’s versatile properties,” Professor

Ingham says. “Additionally, the exhibition enhanced the

public’s knowledge of concrete construction and its seismic

performance.”

Simon Glaister, who is an artist from the AUT Art Gallery

and a qualified civil engineer, says the work drew an

analogy between the notions of structural, cultural and

environmental collapse. “Amongst other things, the project

playfully critiqued the authority of the museum within the

avant-garde, the nature of authorship, our obsession

with the innovative and new, and our society’s perverse

fascination with catastrophe,” he says.

The main sponsors of the Push Over project were Chartwell

Trust, Stresscrete, Fletchers (Golden Bay Cement and

Pacific Steel), Cassidy Construction, and Bridgemans

Concrete.

17


18

concrete

CCANZ Library

Listed below is a small selection of recently acquired material by the CCANZ library. To

borrow one of these titles, simply email library@cca.org.nz

The library catalogue can be accessed electronically via www.ccanzlibrary.org.nz

Liquid Stone: New Architecture in

Concrete

Jean-Louis Cohen and

G. Martin Moeller, Jr.

In a series of essays by

top architects, engineers,

and scholars, Liquid Stone

explores the nature of

concrete, its past and future,

from technical, artistic, and

historical perspectives. Over

thirty buildings by leading

international architects

including Nouvel, Hadid, Holl,

Foster, and Calatrava are

presented through detailed

descriptions, photographs,

and technical drawings.

The book concludes by

detailing newly emerging concrete based materials. Here selfconsolidating,

ultra-high-performance, and translucent concrete

are illustrated, suggesting new directions for both architecture and

engineering.

Sprayed Concrete Lined Tunnels

Alun Thomas

Practising engineers on site,

in the design office or in client

organisations will find this book

an excellent introduction to

the design and construction of

sprayed concrete lined (SCL)

tunnels. The complex behaviour

of the early age behaviour of the

sprayed concrete requires careful

management.

This book covers all aspects

of SCL tunnelling – from

the constituents of sprayed

concrete to detailed design

and management during

construction. Although there is a

close interdependence between all the facets of sprayed concrete,

few engineers have the right breadth of experience and expertise,

and this urgently needs to be transferred to the wider engineering

community.

Design of Hybrid Concrete Buildings

UK Concrete Centre

This design guide is intended to

provide the structural engineer

with essential guidance for

the design of structures that

combine precast and in-situ

concrete in a hybrid concrete

structure.

It introduces the options

available for hybrid concrete

structures, and goes on to

explain the key considerations

in the design of this type of

structure.

Bearings, interface details,

consideration of movement,

composite action, robustness

and the effects of prestressing are all explained in this guide.

Design examples are included where appropriate. The importance

of overall responsibility and construction aspects are also

described.

High-Strength Concrete: A Practical

Guide

Michael A. Caldarone

This practical book presents the

means and methods for designing,

producing and using high-strength

concrete. Higher compressive

strengths allow for a reduction in

the cross-sectional dimensions of

columns and walls in buildings.

Its greater stiffness allows for

increasing building heights while

controlling sway and occupant

comfort. Civil structures such

as bridges have benefited from

greater span lengths, shallower

beam sections, wider girder

spacing, and extended service life.

Illustrated with real life examples,

through documented case histories, High-Strength Concrete is a

valuable resource for contractors, producers, inspection agencies,

as well as engineers and researchers.

Library Quiz

To be in the draw to win a copy of Liquid Stone: New Architecture in Concrete answer the following simple question:

Which Indian city is synonymous with the concrete architecture of Le Corbusier?

Email your answer to library@cca.org.nz. Entries close Friday 6 November 2009.

Congratulations to Stuart Caulfield of Calder Stewart Construction, who correctly answered the July 2009 Library Quiz to receive a free

copy of the British Research Establishment’s (BRE) Sustainability in the Built Environment: An Introduction to its Definition and

Measurement.


News from the Associations

PRESSS Design Handbook Seminars

A series of design seminars about Precast Seismic Structural Systems (PRESSS) is

scheduled to be held throughout the country during October.

The seminars will be led by Dr Stefano Pampanin, Associate Professor at the

University of Canterbury, who has conducted extensive research and played a key

role in the development and practical implementation of PRESSS-type structures –

also known as Hybrid Ductile Jointed Systems.

A PRESSS Design Handbook comprising a full design example of a multi-storey

building with frames and walls, and computer software for the connection analysis

of such systems, will be provided to seminar attendees.

PRESSS Technology is a method of joining precast walls, beams and columns in

a ductile manner. It uses un-bonded post-tensioning cable that allows structures

to resume their original position after earthquakes have stopped, with negligible

structural damage. The method utilises the same principle as vehicle suspension.

In the 1990s, Professor Nigel Priestley of the University of California, San Diego, led

the pioneered research into this method of building low-cost precast concrete that

would meet building codes and enable structures to withstand major earthquakes.

Today the construction system is becoming more widely used.

Buildings that employ PRESSS design are simple to construct and combine widely

used building methods in a particular way. Research on projects in the USA, New

Zealand and Italy has shown that PRESSS Technology enables buildings to be

constructed more cheaply and quickly.

The seminars will be held in:

Christchurch – Tuesday, 27 October

Wellington - Thursday, 29 October

North Harbour - Tuesday, 3 November

Auckland - Wednesday, 4 November

Taupo - Friday, 6 November

Further details will be posted on the New Zealand Concrete Society website as

they become available: www.concretesociety.org.nz

9th Symposium on High Performance Concrete:

Design, Verification & Utilization

8-12 August 2011. Christchurch, New Zealand

The New Zealand Concrete Society is pleased to announce the 9th International

Symposium on High Performance Concrete – Design, Verification & Utilization to be

held in Christchurch, August 2011.

The symposium will be a continuation of the successful previous symposia held

every three years since 1987. The symposium will bring together engineers,

designers, researchers and scientists from around the world to promote better

understandings on common interests ranging from the most recent researches

to the latest applications of high-strength and high performance concrete for

construction.

Visit the conference website for further details: www.hpc-2011.com

concrete is published quarterly by the Cement & Concrete Association of New Zealand,

Level 6, 142 Featherston St, WELLINGTON. Tel: (04) 499 8820, Fax: (04) 499 7760.

Email: admin@cca.org.nz Website: www.cca.org.nz ISSN: 1174-8540

Disclaimer: The views expressed in concrete are not necessarily those of the Cement & Concrete Association of New Zealand. While the information contained

in the magazine is printed in good faith, its contents are not intended to replace the services of professional consultants on particular projects. The Association

accepts no legal responsibility of any kind for the correctness of the contents of this magazine.

CONTACTS:

concrete

New Zealand Ready Mixed

Concrete Association

Ph (04) 499 0041

Fax (04) 499 7760

Executive Offi cer: Rob Gaimster

President: Graham Payne

www.nzrmca.org.nz

New Zealand Concrete Masonry

Association

Ph (04) 499 8820

Fax (04) 499 7760

Executive Offi cer: David Barnard

President: David Aitken

www.nzcma.org.nz

Precast NZ Inc.

Ph (09) 638 9416

Fax (09) 638 9407

Email: ross.cato_precastnz@xtra.co.nz

Executive Offi cer: Ross Cato

President: John Marshall

www.precastnz.org.nz

New Zealand Concrete Society

Ph (09) 536 5410

Fax (09) 536 5442

Email:

concrete@bluepacifi cevents.com

Secretary/Manager: Allan Bluett

President: Chris Munn

www.concretesociety.org.nz

New Zealand Master Concrete

Placers Association

Ph (06) 873 4428

Fax (06) 873 4429

Email: offi ce@mcpa.org.nz

Business Manager:

Carol McMillan

www.mcpa.org.nz

DIARY DATES 2009:

October

8-10 Combined Concrete

Industry Conference

Rotorua

www.theconcreteconference.co.nz

Advertising in concrete magazine

To discuss advertising opportunities in concrete magazine call Adam Leach (04) 915 0383.

A rate card is available from www.cca.org.nz/pdf/ratecard

19


AT LAST A TRANSPARENT

PERFORMANCE

COMPARISON FOR

STEEL FIBRES

www.bosfa.com

What does the CE Mark mean to you and your business??

Guaranteeing the quality and the strength of a steel fibre reinforced concrete

element requires the use of a reliable and reputable fibre. For years it has been

difficult for engineers, concrete companies and builders alike to legitimately

compare the expected performance of the different fibres available.

For this reason EN 14889-1, currently the only international performance based

quality control manufacturing standard for steel fibres, requires manufacturers to

declare a minimum fibre dosage to achieve a required post crack flexural strength

in a reference concrete. This enables complete transparency when comparing the

performance of different fibre types and ensures a minimum level of quality of the

steel fibre itself.

0749-CPD

NV BEKAERT SA – Bekaertstraat 2

B-8550 Zwevegem – Belgium

EN 14889-1

09

Certificate: BC1-251-0024-0003-006

DRAMIX ® : RC-55/35-BN

Steel Fibres for structural use in concrete mortar and grout.

Group 1: cold-drawn wire

- Information and regulated characteristics:

Shape deformed

Bundling glued

Coating -

FIbre length (mm) 35

Diameter (mm) 0.62

Tensile strength (N/mm2 ) 1270

Aspect ratio 56

- Consistence with 30kg/m3 fibres - Vebe time = 8 sec

- Effect on strength in reference concrete: 30kg/m3 To obtain >1.5N/mm2 at CMOD = 0.5mm and

>1.0N/mm2 at CMOD = 3.5mm

CE LABEL EXAMPLE

WHAT DOES ALL THIS MEAN TO YOU?

In Europe only products with the CE Marking, like

Dramix ® steel fibres, can be sold in the European

member states. In countries where it’s not yet

compulsory it is becoming common practice for

engineers to specify compliance with EN 14889-1

in project documentation.

Every bag of product supplied to the market has a CE

label that details the fibre tensile strength, geometry

and fibre dosage required to meet performance limits

described in the manufacturing standard.

There are two types of classification, Class 1 for

structural use and Class 3 for non structural use

(structural use is where the addition of fibres is

designed to contribute to the load bearing capacity of

the concrete element). A CE marked fibre for structural

use in sprayed concrete, flooring and precast should

not be used at a lower dosage than the declared

minimum value mentioned on the fibre CE label.

1. A product that complies with the 14889-1 quality level Class 1 for

structural use.

2. A product that is submitted to continuous quality control.

3. A label that mentions the minimum dosage required to meet

a specified performance in a reference concrete.

REALISE GREATER ENGINEERING EFFICIENCY WITHOUT

COMPROMISING QUALITY ON YOUR NEXT PROJECT. TALK TO

THE LEADER IN FIBRE REINFORCED CONCRETE ENGINEERING

CALL 1300 665 755 (AUS), 0800 665 755 (NZ) or visit bosfa.com

SHOTCRETE

PRECAST

SEGMENTAL LININGS

SLAB TRACK

SLABS ON

GRADE

Dramix ® : ISO 9001 ACCREDITED

LL_BOS2461_0909

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