Concrete Magazine - Volume 62. Issue 01

UPFRONT concrete MAGAZINE

RESIDENTIAL BUILDING SUPPLIES MARKET STUDY DRAFT REPORT

The Commerce Commission recently released its draft report for the residential building supplies market study.

Concrete NZ’s first impressions of the draft report are favourable:

• The recommendation for a national building products register as part of improving decision-making processes is sensible, as is making information about materials more accessible across the industry.

• The recommendation to improve the efficient functioning of the regulatory system is sound, and Concrete NZ supports competition being promoted as a key objective in the built environment.

• The recommendation to remove impediments for product substitution makes sense, but some caution is needed. It should not allow products that may not perform as part of a specific design for an approved building system - such as a wall with associated fire, moisture, bracing or acoustic characteristics.

• The system to get new products certified and appraised is too expensive.

In terms of cement and concrete, the Commission’s preliminary view is that there appears to be a reasonable level of competition occurring for both materials, although there are some elements of markets which could be better.

STUDY SCOPE

The Commission’s study considered factors that may influence competition around building supplies used to construct the major components of residential buildings, this covered:

• the industry structure for key building supplies,

• the nature of competition for these key building supplies; and

• barriers to the entry or expansion of new or innovative building supplies.

The study also took a detailed look into three key building supplies as case studies - concrete (including cement), plasterboard and structural timber.

CONCRETE (& CEMENT)

The cement and concrete case study, including the Commission’s preliminary view is that there appears to be a reasonable level of competition occurring for both materials, appears in the draft report as Attachment D.

Regarding cement, the Commission’s view is supported by the following findings:

• a new cement supplier entered the market in 2012, and now supplies between 5% and 10% of the market,

Editor/Advertising: Adam Leach +64 4 915 0383 adam@concretenz.org.nz

Subscriptions: Angelique Van Schaik +64 4 499 8820 admin@concretenz.org.nz

concrete is published quarterly by Concrete NZ

PO Box 448 Level 4, 70 The Terrace Wellington NEW ZEALAND

Tel: +64 4 499 8820 Email: admin@concretenz.org.nz Website: www.concretenz.org.nz

ISSN: 1174-8540

ISSN: 1174-9374 (online)

Disclaimer: The views expressed in concrete are not necessarily those of the Concrete NZ. 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, including advertisements.

© Copyright 2022 Concrete NZ

Advertorial

Cover image: Omāroro Reservoir, Mt Cook, Wellington

• price competition appears to be strong, driven by this new entrant, and a large player increasing its capacity,

• firms are responding to customer demand by innovating to introduce low-embodied carbon products to the New Zealand market; and

• customers of cement suppliers appear to be generally satisfied with the level of service and quality of product they receive.

Regarding ready-mix concrete, the Commission’s view is supported by the following findings:

• the threat of losing customers and/or market share constrains larger firms’ ability to impose price increases,

• customers appear to have the ability to switch between suppliers (and often do),

• many ready-mix concrete producers have entered the market in recent years,

• these producers appear to provide a competitive restraint at a local level; and

• firms are innovating to develop low-carbon products to win customers.

Other key takeaways from the draft report worth highlighting are that the price of ready-mix concrete has increased more slowly than other residential construction costs, and that cement prices have reduced in real terms over the past 10 years driven by competitive dynamics.

The draft report also looked at other factors that may be affecting competition for cement and concrete – such as the industry structure, nature of competition, pricing practices or acquisition requirements, as well as strategic, behavioural or regulatory barriers to entry or expansion.

The full draft report and related documents are available on the Commerce Commission’s website.

NEXT STEPS

The Commission will consider feedback on the draft, with the final report set for release in early December 2022. After which the Government will decide on how it will respond to the findings and recommendations.

Ngā mihi, Rob Gaimster Concrete NZ Chief Executive

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CONCRETE NZ CONFERENCE 2022

AS YOU WILL BE AWARE THE 2020 CONCRETE NZ CONFERENCE WAS CANCELLED, AND OUR ATTEMPTS TO HOST A CONFERENCE IN OCTOBER 2021 AND FEBRUARY 2022 WERE ALSO THWARTED DUE TO PANDEMIC RESTRICTIONS.

However, we are now ‘full steam ahead’ to host the conference from 13-15 October 2022 at the Energy Events Centre in Rotorua.

It therefore gives me great pleasure, on behalf of the Organising Committee, to either welcome you back or invite you anew to the 2022 Concrete NZ Conference.

This event is an excellent opportunity to keep abreast of recent advances in a broad range of topics relating to concrete construction, design, manufacturing and materials.

After seven years, we are returning to one of New Zealand’s favourite conference destinations - Rotorua. The Energy Events Centre is a modern venue with ample trade exhibitor space, and a vast area directly outside which is ideal for displaying heavy equipment and vehicles.

We are fortunate to have retained a high-profile keynote speaker to lead this year’s technical programme, one who will provide a unique insight on the sustainability of concrete structures.

Santiago Pujol, Professor of Civil Engineering at the University of Canterbury, has graciously recommitted to the 2022 conference. In his presentation, titled “The Future of Concrete”, he will share his concrete detailing expertise based on over twenty years’ experience testing concrete structures.

As always, the well-crafted conference social programme is designed to provide a platform for networking with friends and industry colleagues, old and new. Rotorua offers a range of entertainment options that will make the 2022 Conference memorable.

The combination of technical and social programmes holds the essence of Conference, made especially valuable by the attendance of enthusiastic people from across the concrete industry and building & construction sector.

This conference is also significant in that Concrete NZ welcomes a new conference organiser, Conferences & Events (C&E). The C&E team have picked up the reigns from Blue Pacific Events Management following Allan Bluett’s retirement and they look forward to getting to know you.

Please don’t hesitate to contact C&E using the various links below if you have any questions about the conference.

I look forward to seeing you in Rotorua.

Haere rā, Prof. Alessandro Palermo Organising Committee Chair

PROGRAMME OVERVIEW

SOMETHING FOR EVERYONE

The Conference Organising Committee has worked hard to bring together a stimulating and thoughtprovoking Technical Programme, however, they reserve the right to make changes to the programme as circumstances dictate.

For the full programme of plenary and concurrent sessions, visit the Technical Programme page on the Conference website - www.theconcreteconference.co.nz

CONFERENCE REGISTRATION - EARLY BIRD RATES

Date Day event Evening event

Thursday 13 October

Friday 14 October

• Conference day 1

• AGM

• Conference day 2

• Range of social activities

Saturday 15 October Conference day 3

President’s reception, casual conference dinner

Pre-dinner drinks, formal conference dinner and awards

Registration for the conference is open to all persons interested and involved in the building construction industry. Members or staff from the Organising Committee organisations are eligible for member rate registration options.

Registration type

Early bird rate until 16 September 2022 (excl. GST)

Standard rate from 16 September 2022 (excl. GST)

Full registration - Member $550 $650

Full registration - Non member $650 $750

Sponsor registration $495 $595

One day registration - Member $325 $425

One day registration - Non member $425 $525

Two day registration - Member $512 $612

Two day registration - Non member $612 $712

Student registration $390 $490

Dinners only (Thursday and Friday evenings) $295 $295

Thursday evening casual conference dinner $155 $155

Friday evening formal conference dinner and awards evening $155 $155

CONFERENCE ACCOMMODATIONATTRACTIVE OPTIONS

We are delighted to have been able to get fantastic rates with some of Rotorua's main providers! We recommend booking early as all rooms currently held for the conference must be released on Wednesday 14 September 2022, there will be no guarantee of accommodation after that date.

We’d like to encourage you to all stay at the conference hotels as this will mean that everyone’s in the same place giving more opportunities for you to network with new friends outside of the conference hours.

For any changes to accommodation bookings previously made at the Millennium Hotel and Jet Park Hotel, please contact us. We will arrange the changes for you. Please do not contact the hotels directly.

CONFERENCE SUPPORT - PATRONS, SPONSORS & EXHIBITORS

Over many years the Concrete NZ conference has been well supported by committed Patrons, Sponsors and Trade Exhibitors. The 2022 event will be no different, with a fantastic group of conference supporters already onboard.

While all the Patron spots are taken, there are still Sponsor and Trade Exhibitor opportunities available. Download the sponsorship prospectus for more details - www.theconcreteconference.co.nz

OUR PATRONS

OUR SPONSORS

CONFERENCES & EVENTS LTD - NEW CONFERENCE ORGANISER

Concrete NZ is excited to partner with Conference & Events (C&E) to bring the 2022 event to members and the wider building and construction industry.

C&E has over 29 years’ experience serving New Zealand and international organisations as a conference organiser. They provide a myriad of services, advice and support to ensure an exceptional event.

Meet Claudette van der Westhuizen, Conference Manager for Concrete NZ’s 2022 event in Rotorua.

GOLDEN BAY INVESTS $10 MILLION ON WELLINGTON TERMINAL UPGRADE

ONE OF WELLINGTON’S MOST VISIBLE INDUSTRIAL SITES IS GETTING A $10 MILLION UPGRADE WHICH WILL DELIVER SOME SIGNIFICANT ENVIRONMENTAL AND EFFICIENCY BENEFITS.

The major refurbishment will also increase the facility’s storage capacity and improve the resilience of Golden Bay’s North Island supply chain.

The silos of Golden Bay’s harbourside Wellington Terminal have towered over State Highway 1, adjacent to the InterIslander Ferry Terminal since the early 1950s. Every year, more than 100,000 tonnes of cement arrives by ship from Golden Bay’s Northland manufacturing facility and is then stored and distributed throughout the Wellington and Manawatu regions.

The site is now undergoing the biggest refurbishment in its history which will see aging equipment replaced, greater automation introduced and the facility itself upgraded inside and out, most visibly with a new exterior paintjob and rebrand.

Less visible for passing motorists will be an increased storage capacity, a site reconfiguration which will improve traffic management, new office facilities and upgraded ship discharge lines which will dramatically reduce load times.

Increasing capacity and reducing the load times enables more shipping voyages and reduces the number of truck movements on New Zealand’s roads. Golden Bay estimates that the upgrade

will result in a decrease of more than 1700 truck movements per annum and a corresponding reduction of CO2 emissions by 90% (around 344 tonnes).

Nick Traber, Fletcher Building’s Chief Executive, Concrete says: “Our Golden Bay Terminal has served Wellington well for many decades and has contributed to some of the region’s biggest infrastructure projects along with countless houses, driveways and other developments.

The upgrade is a key part of our strategy to remove bottlenecks in our operations to drive growth and reduce costs, as well as increase the resilience of our supply chain using all modes of transport (ship, rail, road). It’s a demonstration of our commitment to local manufacturing as New Zealand’s only and lowest carbon cement producer.

“Demand for cement continues to grow and we need a modern, efficient, and sustainable facility to deliver what our customers need. At the same time, we are continually looking for opportunities to further reduce our carbon footprint.

“The $10 million investment we are making will ensure the facility operates at the highest standards and is fit to support the needs of the region into the future.”

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UNIQUE COLLABORATION CREATES SOLUTIONS FOR DISTINCT KIWI CONSTRUCTION THREAT

A UNIQUE COLLABORATION OF NEW ZEALAND RESEARCHERS HAVE FOUND THE ANSWERS TO FIX THE DISTINCT NEW ZEALAND CONSTRUCTION THREAT OF EARTHQUAKE-PRONE PRECAST CONCRETE HOLLOW-CORE FLOORS.

“The seismic issues around hollow-core floors are not new but were brought into the spotlight by the damage caused in the Wellington CBD by the Kaikōura earthquake,” says Nicholas Brooke, coordinator of the ReCast Project, which has spent the last four years testing and verifying retrofit solutions to strengthen buildings with precast floors, which have been widely used in New Zealand construction since the mid-1980s.

This week, the project team, led by experts from the Universities of Canterbury and Auckland and supported by funding from the Earthquake Commission, BRANZ and Concrete NZ, will publish its findings in the Structural Engineering Society NZ (SESOC) journal to provide guidance for engineers and building owners considering retrofit options for existing buildings.

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“We focused on the least complex and most affordable retrofit solutions, tested them, verified them and developed design guidance for the different technologies,” says Brooke.

EQC Chief Resilience and Research Officer, Dr Jo Horrocks, says that the Recast Project strikes at the heart of EQC’s vision of investing in research that will strengthen buildings and protect people.

“Precast hollow-core floors have been recognised as a seismic risk for many years and EQC has been eager to support any research that will tackle this issue,” says Dr Horrocks.

“This research is incredibly valuable and detailed and we hope it will give engineers and building owners, especially in the Wellington area, the confidence to start repairing a building instead of demolishing them. Many owners may have been holding off investing in repairs, in fear of having to do more repairs later, but now they can be confident a retrofit will work.”

“New Zealand has suffered devastating impacts from earthquakes over the past 11 years, but from that trauma we have learned a huge amount and developed world-leading science and engineering solutions.

“We will continue to fund excellent research like this, because we know it saves lives and protects property – it’s all part of our role to help New Zealand to be better prepared for the next earthquake,” says Dr Horrocks.

Nicholas Brooke explains that precast concrete hollow-core floors have been a favourite option for New Zealand construction industry and developers since the mid-1980s and cover about 1.5 square kilometres of buildings floors around the country.

“The rest of the world was not so excited about hollow-core floors, so this is really a distinct New Zealand issue,” says Brooke, who explains that the weakness of the system was exposed in the 1994 Northridge earthquake in North America where buildings with hollow-core floors were severely damaged.

Professor Des Bull at the University of Canterbury was concerned about the New Zealand context and thanks to EQC funding spent nearly two decades investigating hollowcore floors before developing guidance on their assessment with Professor Richard Fenwick.

“Unfortunately, they published their findings shortly before the Darfield earthquake and their findings were a bit lost in the chaos of those earthquakes,” says Brooke, who adds the subject did not receive sufficient industry attention until the damage caused by the Kaikōura earthquake galvanised authorities and researchers into action.

The ReCast Project was launched with the universities in Canterbury and Auckland dedicating four PhD students and a Masters students for four years.

“It was truly a unique collaboration with PhD students from Canterbury working in the Auckland lab and vice versa, which we believe had not happened previously to anything like the same extent,” says Brooke.

The result is the largest SESOC journal with 11 articles and over 200 pages of design guidance for seismic engineers.

“It is the culmination of 25 years of research, building on the work of Des Bull and funding by EQC, that will be hugely valuable to seismic engineers in New Zealand and abroad.”

Examples of some of the retrofit options for precast concrete floors as they are earthquake-tested at the University of Canterbury.

The ReCast Project team, which includes some of the biggest names in seismic engineering in New Zealand, who worked on retrofit solutions for precast concrete floors get together in the earthquake laboratory at the University of Canterbury.

BCITO RELEASE NEW SUITE OF CONCRETE QUALIFICATIONS

AFTER A PERIOD OF SUSTAINED EFFORT AND COLLABORATION, BCITO, A BUSINESS UNIT OF TE PŪKENGA WORK BASED LEARNING LTD, HAS COMPLETED THE LAUNCH OF ITS NEW CONCRETEBASED QUALIFICATIONS.

New Zealand Certificate in Concrete Production (Level 4) with strands in Batching, Dispatching, and Concrete Testing (with optional strand in Tensile Testing)

This qualification has been successfully rolled out and includes the reworking of the assessment resources and learner resources. BCITO has also developed a transition process to ensure trainees in existing qualifications are transitioned through to the appropriate new qualification.

New Zealand Certificate in Concrete Construction Skills (Level 3) with strands in Formwork, Reinforcing, Placing and Finishing, Specified Concrete Finishes, Concrete Product Manufacture, Concrete Sawing and Drilling, and Precast Concrete Manufacture

Launched on 6 May, this qualification includes the reworking of the assessment resources and learner resources. A transition process has been developed to ensure trainees in existing qualifications are transitioned through to the appropriate new qualification.

New Zealand Certificate in Concrete Specialist (Level 4) with Strands in Concrete Sawing & Drilling, Prestressed Concrete and Precast Concrete, and the New Zealand Apprenticeship in Pre-Cast Concrete Manufacture

These qualifications and the apprenticeship* programme in precast concrete were released to industry on 31 May. This includes the reworking of the assessment resources and learner resources. BCITO has also developed a transition process to ensure trainees in existing qualifications are transitioned through to the appropriate new qualification.

* The apprenticeship is a combination of the NZ Cert in Concrete Construction L3 (Precast Concrete Manufacture strand) and the NZ Cert in Concrete Specialist L4 (with precast concrete strand).

New Zealand Certificate in Concrete Construction (Commercial and Civil Infrastructure) (Level 4) with optional strands in Premanufactured Elements and Post-tensioned Concrete

This qualification became available on 31 May, with a reworking of the assessment resources and learner resources. BCITO have also developed a transition process to ensure trainees in existing qualifications are transitioned through to the appropriate new qualification.

Visit the BCITO website for more detailswww.bcito.org.nz

BCITO SUPPORTS

APPRENTICESHIP BOOST EXTENSION

THE DECISION TO EXTEND THE APPRENTICESHIP BOOST INITIATIVE UNTIL DECEMBER 2023 HAS BEEN APPLAUDED BY BCITO.

Director of BCITO, Jason Hungerford, says that Apprenticeship Boost is essential for training the skilled pipeline of workers needed in the building and construction industry.

“With record demand for construction work, and despite current supply chain issues, New Zealand needs skilled workers more than ever. To have an innovative and responsive education system, targeted investment in vocational training is vital.”

BCITO has seen rapid growth in its apprentice numbers, which are now at record levels, since the Apprenticeship Boost was introduced in August 2020.

“At the end of August 2022, we had 22,400 apprentices undertaking training across our 15 trades. This is up 61 percent from the 13,900 apprentices in August 2020.

He says it gives employers support to continue training apprentices, particularly with some of the challenges currently being faced, such as the supply of building materials.

“Employing and training an apprentice is a large financial commitment for any employer, many of which are small and have limited resources. Apprenticeship Boost not only reduces the cost

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Director of BCITO, Jason Hungerford

of training but produces a skilled and long-term worker for the sector.”

BCITO is a division of Te Pūkenga Work Based Learning providing building and construction sector training in the workplace. Its speciality trades include carpentry, tiling, painting and

decorating, concreting, joinery, flooring, and stonemasonry, among others.

For information on eligibility criteria for Apprenticeship Boost and how employers can apply, go to the Work and Income websitewww.workandincome.govt.nz

STEADY GROWTH IN BCITO

BCITO

Sign-ups have been consistent through the middle of the year, with another increase likely during the final quarter of the year.

BCITO field staff are continuing to visit trainees and complete assessments, all whilst adhering to strict health and safety protocols as the threat of COVID-19 is still in the community.

Total

Concrete numbers have correspondingly grown at a steady rate over the course of the last six months.

It is also worth noting that there have been some employers and apprentices waiting for the new suite of qualifications to become available, so it is anticipated that enrolment numbers will experience a rise in the coming months.

QUALITY NEVER GOES OUT OF FASHION

ALTHOUGH THE BUILDING SECTOR IS BUSY MANAGING THE CONTINUED UNCERTAINTY CREATED BY COVID-19, WE MUST NEVER COMPROMISE BUILDING QUALITY.

Concrete NZ’s Precast Plant Certification Scheme provides purchasers and specifiers with peace-ofmind that their precast concrete products meet quality requirements.

Within a construction environment dominated by concerns around operating during the pandemic there have been recent reports of building material supply issues, and in turn, potential quality concerns.

The media recently picked-up on a recent industry survey which reported a number of concerns, including building consent delays, increased costs, customer complaints, and product substitutions due to a lack of building materials.

While the concrete industry is not immune to operating challenges such as a shortage of truck drivers, and is monitoring aggregate supply, there are no capacity issues that should force building contractors to replace the quality concrete products supplied by members of the Concrete NZ Precast Certification Scheme with inferior alternatives.

The Precast Plant Certification Scheme is gaining traction amongst Concrete NZ Precast members and their clients.

The manufacture of precast concrete products requires considerable experience and skill, as they often form a building’s primary structural system.

Poor precast manufacturing practices have the potential to compromise a structures durability and the life safety of its occupants.

In addition, safety considerations are paramount during the manufacturing, handling and installation of precast products, with any short cuts potentially resulting in unsafe outcomes with significant consequences.

The Precast Plant Certification Scheme provides specifiers, contractors and their clients with confidence that products purchased from a Precast Certified Plant are backed by an established operator with appropriate facilities, experienced staff and quality assurance programs.

Regardless of the application of the precast product - architectural, structural, cladding, civil or other - purchasing from a Concrete NZ Precast Certified Plant ensures that the product has been manufactured at a facility with systems audited by an independent, third-party body.

Certified Plants invest heavily in modern equipment, oversight procedures and staff training with the intention of delivering “quality”.

While cheaper alternatives may be available, cost must never be the only consideration.

Procurement decisions should always factor in quality as a prerequisite, and in terms of precast, the stamp to look for is the Concrete NZ “Precast Certified Plant” logo.

For more details on the Precast Certification Scheme and a link to the precast plants currently registered, visit the Concrete NZ websitewww.concretenz.org.nz

Images: Paul McCredie Photography.

MASONRY MANUAL

RETAINING WALL SECTION REVISED

CONCRETE MASONRY IS A STAPLE MATERIAL OF THE CONSTRUCTION INDUSTRY, OFFERING STRUCTURAL AND ARCHITECTURAL ADVANTAGES IN A SINGLE MATERIAL AND IS RECOGNISED AS A MAJOR CONTRIBUTOR TO A SUSTAINABLE BUILT ENVIRONMENT.

The New Zealand Concrete Masonry Manual, which was created in the late 1970s as a guide to the design and construction of concrete masonry, has been undergoing review over the past several years.

An update of Section 6.1 Masonry Retaining Walls is now available for free download from the Concrete NZ website.

The retaining wall section, updated from the 2019 version, provides standard details for reinforced concrete masonry retaining walls. 2022 changes include:

• The foundation designs incorporate updates to the reinforced concrete design standard NZS 3101 that now require greater reinforcing content.

• Some wall designs that required larger wall reinforcing contents have been removed.

• The tables for walls carrying surcharge have been updated and 140 mm wall options have been removed from this category.

Section 6.1 has been prepared to provide designers and builders with some standard design details for reinforced concrete masonry retaining walls, however, it is emphasized that the contents of section 6.1 are intended to offer guidance only.

Professional engineering, and possibly geotechnical engineering, advice must be sought in relation to final design and submission for any building consent application.

Visit the Concrete NZ website to download the updated Section 6.1 Masonry Retaining Walls of the New Zealand Concrete Masonry Manualwww.concretenz.org.nz

Masonry

Omāroro Reservoir overlooks Wellington’s CBD from Mt Cook.

WATER RESERVOIR TO IMPROVE WELLINGTON’S EARTHQUAKE RESILIENCE

Bernie Napp – Concrete NZ, Sustainability & Policy Director

Shaped like a 70 metre diameter drum with a slightly domed roof, 14 metres above the floor at the highest point, the inside feels like being in a cathedral, lofty concrete columns holding up the half of the roof that has been poured, to number 45 on completion of the roof.

In early May HEB Construction repositioned the under-roof scaffolding to prepare a forest of formwork, and a criss-cross pattern of steel stress cables ahead of the second and final pour, completed in mid-July.

Getting the concrete delivery logistics right is crucial for success, says Russell Obee, HEB’s community engagement manager for the Omāroro reservoir project.

KEEPING THE CONCRETE FLOWING

Pours started at 3am and the bulk of the work completed by 7am or 8am to avoid city traffic, and to manage the remaining flow of 100 Firth concrete trucks through the day, ending at around 3pm. At six cubic metres of readymix per truck, that’s 580 cubic metres in a single pour.

To avoid a break in the pour, contingencies were in place by having all Firth sites and other concrete manufacturers in Wellington on standby in case of a break-down at a batching plant. On delivery, three concrete pumps conveyed the readymix to the roof, one of them a spare.

Concrete trucks ascended a steep narrow street lined with residential housing to access the site.

DUG INTO A HILL ABOVE THE WELLINGTON INNER CITY SUBURB OF MT COOK IS A CONCRETE WATER RESERVOIR WHICH WILL STORE 35 MILLION LITRES WHEN READY, TO SHORE UP THE CITY’S WATER SUPPLY AFTER AN EARTHQUAKE.

Obee lets people know well in advance of the next pour to move cars parked on the street elsewhere. “It is important to us that residents know what to expect ahead of time for the least possible disruption, so we communicate regularly throughout the project.”

Ambient temperature is key to a successful pour, neither too warm nor too cold. Wellington is rarely too hot for placing concrete; at the other end of the scale, the temperature has to be at least +2 degC, and rising rather than falling to avoid cracking and other problems on setting.

FILLING A NEED

The project was first envisaged in the 1970s but the Canterbury and Kaikōura earthquakes highlighted the vulnerability of Wellington’s water supply.

A major leak in a pipe saw the capital poised to run out of drinking water supply in January 2017.

In late 2020 Wellington Water contracted HEB to lead the Omāroro project, to be designed to withstand a 1:2000-year earthquake. Due for completion and handing to Wellington Water before Christmas 2022, the reservoir will more than double Wellington’s existing water storage for the CBD and low-lying suburbs.

The goal is to provide 80 percent of the water needs for 80 percent of Wellingtonians for days seven to 30 after a major earthquake striking the

capital and severing regular water supply. For an idea of scale, Omāraro’s capacity will be equivalent to that of 14 Olympic-sized swimming pools.

Concrete design is crucial to meeting the structure’s engineering requirements, having a strength of 40 or 50 MPa, depending on the structural component. A total of 4,000 cubic metres of concrete was deployed.

WALLS PRECAST ON SITE

Concrete lies at the core of the reservoir project and is close to the heart of HEB project manager Paul Reid. “Given that this is a large water-retaining structure, it’s fundamental that we get the concrete elements right first time,” he says.

The floor was placed in two pours and now supports 60 precast wall panels. Measuring 3.4 by 10.7 metres, and 325 millimetres thick, each panel weighs 30 tonnes. For that reason, Preco made the panels on site to avoid having to truck them as oversized loads through the city.

A 300 tonne Liebherr crawler crane on site has been a prominent Wellington landmark during the construction, to lift and place wall panels into position among tasks.

Steel cables run around the inside of the structure tying it all together, and to post-tension the wall panels. At intervals, special panels termed pilasters allow the stitching together of the whole with rebar steel. Once a feature of cathedrals, these structural

elements provide a termination point and access within the wall ducting from which to tension and lock-off the steel.

Ring beams of concrete will run around the base and the top of the panels as additional strengthening for the structure, which HEB expects to complete by mid-September.

ON A FIRST-NAMES BASIS

Community engagement has been a focus for HEB throughout the project. Since its early beginnings Obee has got to know many of the local residents by name. He and the HEB team have hosted many open days to showcase the project as it develops, with more than 300 people attending the most recent event.

Engagement allows the neighbours to see where 35,000 cubic metres of overburden are stacked prior to recontouring of land to bury the reservoir, how wastewater is managed, where heavy machinery is parked, and temporary roading access.

The company has been piling wood from pine trees removed for the project at places in the town

belt as lizard “hotels” to support the conservation of these native species, and Obee says they are in use. Flocks of kākā are a common sight in the area and do not seem perturbed by construction activity.

At any one time there have been up to 60 workers on site, and this figure will drop to around 20 for backfilling and completion of works, expected in mid-late 2023. At this time HEB will have planted native trees and shrubs and built a walking/cycling track connecting Brooklyn to the city that will wind around the site at an easy gradient.

The Omicron variant outbreak earlier this year caused some disruption. “We are on track, regardless,” Obee says. “The reservoir construction has been an essential service or a key utility under the Covid rules.”

Most of the construction was completed by the end of July, which is according to schedule and currently within the total project budget of $68 million. Then HEB will clean the entire structure and fill it and empty it twice before handing it over to Wellington Water.

BOOSTING YOUR CONCRETE’S PROFITABILITY

THE CONCRETE INDUSTRY IS A GREAT BUSINESS TO BE IN - BUT IT’S NOT WITHOUT ITS CHALLENGES.

Rising costs are cutting into profit margins; increased competition from other building materials is impacting market share; and social and political pressures are pushing concrete producers to review their production practices.

Despite these significant challenges, concrete producers remain resilient by taking action to ensure their businesses stay profitable and productive.

Businesses of all sizes can demonstrate this resilience. Here are four places to start.

TECHNOLOGY INNOVATION

Many producers are using advanced dispatch and quality software and fleet management technology to unite data from the quotation phase to job scheduling, order entry, resource planning, material planning, mixing software, dispatch and delivery.

CarbonCure system and CO2 Tank at Lauren Concrete in Austin TX

These technologies can control costs by automating manual tasks, centralizing dispatch processes and performing batching from the plant closest to the delivery site.

This can also help reduce waste. For example, on a large project, there could be up to 50 trucks per day delivering concrete.

With the right technology in place, producers can give their contractors access to each truck’s GPS location and estimated arrival time so that there is no wastage created from trucks arriving when the site is not ready.

One of the key benefits of digital technologies is data.

When data is connected across different systems and analyzed, it unlocks incredible insights that help inform business strategy.

Data analysis connects the dots between seemingly disparate scenarios and can help

business leaders make changes that will drive efficiencies, meet new market demands and increase profits.

ADDRESSING LABOUR SHORTAGES

Finding qualified drivers is one of the biggest challenges for producers.

The ability to drive a concrete truck is a unique skill, as drivers must understand the technical considerations regarding where to safely place the truck, how to properly engage the pumping mechanism and so on.

It’s an important role in ensuring the safety of road users and site workers.

Plus, the driver is the last connection between the plant and the site to ensure quality is maintained.

Tapping into local post high school education providers is a great way to expose your business to qualified talent.

CarbonCure Control Box at Concrete Plant Control Room

CarbonCure at Conewago Manufacturing in Hanover, Pennsylvania

Offer internships, training or apprenticeship programs to encourage young graduates to join your business.

You can also establish partnerships with groups such as veterans’ associations, institutes of technologies and universities, or women reentering the workplace after raising their families to bring more diversity to the workplace and re-train talent.

No matter the industry, younger workers are typically more technologically savvy and environmentally conscious than the generations that came before them.

Adopting some of the initiatives described in this article is a good way to align with the values of Millennial and Gen Z job candidates and attract them to your company.

More and more, helping the environment will also help with employee recruitment and retention.

Investing in new technologies and business processes can help concrete producers prepare their organizations to meet the demands of an ever-changing market and maintain and increase profits along the way.

REDUCE CONCRETE PRODUCTION COSTS BY REDUCING CEMENT QUANTITIES

Reducing production costs is one of the fastest ways to boost profitability. For concrete producers, this means reducing the use of their most expensive ingredient - cement.

Replacing or reducing the quantity of cement in a mix can significantly lower costs while still producing high quality concrete.

Globally, the price of cement is increasing at an annualized 2.0% to USD $129 per metric ton in 2022i (in some regions, it’s increasing by 50%-100%ii).

The recent increase in costs can be attributed to booms in home and building construction, as construction activity increased following the initial onset of COVID-19 in 2020.

One way to reduce cement usage is to optimize mix designs with Supplementary Cementitious Materials (SCMs) like fly ash, a by-product of the coal industry that is cost competitive with cement but without compromising concrete’s performance.

Studies have proven that SCMs increase the strength of concrete over time to levels greater than that of traditional concrete mixes.

Another way to reduce production costs is to adopt innovative technologies, like CarbonCure, which injects captured carbon dioxide (CO2) into fresh concrete during mixing.

Upon injection, the CO2 immediately transforms into a mineral, improving the compressive strength of the concrete.

This increased strength allows producers to safely decrease cement levels in their mix designs.

ADOPT SUSTAINABLE PRODUCTION METHODS TO COMPETE FOR MARKET SHARE

Facing the challenges of rising costs, the public pressure for sustainable building materials, and changes to regulation favouring green building practices, the concrete industry is undergoing a transformation.

Forward-thinking concrete producers are strategically planning for the future and looking to new innovations so they can effectively reclaim market share and leverage their sustainability leadership as a competitive advantage.

And it’s not a moment too soon. The mass timber construction (MTC) industry is looking to gain traction in many key building markets over the past few years.

There’s a perception in the market that wood’s inherent ability to store carbon makes it a more sustainable building choice.

However, recent research proves only a small amount (around 15 percent) of the carbon originally stored in a living, standing tree is sequestered in the final wood product.

Producers can also gain new market share by partnering with innovators like CarbonCure Technologies and offering sustainable concrete products to a market that’s hungry for solutions.

When concrete producers inject CO2 into concrete using CarbonCure, those emissions are locked away forever and kept out of the atmosphere. Meanwhile, businesses who are first to adopt these carbon saving technologies and practices also stand to lock in their market dominance and elevation as the sustainability experts in their regions.

Through smart marketing and competitive bidding, these producers can celebrate the benefits of adopting sustainability: environmental and financial.

i Price of cement. (22 February 2022). IBISWorld. https://www.ibisworld.com/us/bed/price-of-cement/190/

ii Rajesh, K. (4 June 2021). Soaring prices worsen construction sec woes. The Pioneer. https://www.dailypioneer.com/2021/ pioneer-exclusive/soaring-prices-worsen-construction-secwoes.html

12.8-HECTARES – NEARLY ALL OF IT WILL BE CONCRETE!

WITH BUILDING PRODUCT SHORTAGES AND SUPPLY ISSUES HOT TOPICS IN THE NEWS FOR THE NEW ZEALAND BUILDING AND CONSTRUCTION INDUSTRIES AS THEY NAVIGATE NEW ZEALAND’S CURRENT BUILDING REQUIREMENTS, THE CONSTRUCTION OF THE NEW WINSTONE WALLBOARD’S PLANT IN TAURANGA, WHICH KICKED OFF AT PACE IN JANUARY 2021, WILL BE WELCOME NEWS TO MANY.

Located in the Tauriko business estate - on a site over two and a half times the size of the current Penrose site - the new facility is scheduled to open in 2023 and will ensure Winstone Wallboards is ideally placed to meet New Zealand’s future demand for plasterboard.

The 12.8-hectare site, which when completed will have a finished pavement area of a whopping 90,000 m2, will eventually consume an expected 30,000 m3 of concrete and has every type of slab and foundation being used - all supplied by Firth from its state-of-the-art concrete plant based at Mount Maunganui.

The enormity of the project has seen Fletcher Construction, the main contractor tasked with the build, instil experts to work on the various

stages of construction. Conset Construction are specialists in very large foundation slabs, Brian Perry Civil (BPC) are undertaking the concrete foundations, detailed excavation, piling and ground improvement, and Higgins Construction will carry out the external works and drainage.

With Conset Construction undertaking the large floor slabs, Firth is also supplying, often simultaneously, concrete to BPC for the foundations. “The large pours normally start at 1am and finish at about 6am which is when our normal work demands begin for the day at Firth Mount Maunganui,” says Willie Waters, Area Ops and Sales Manager for BOP. “There have been some quite large post tension floors, requiring around 400 m3 of concrete at a time. We have

At Fosroc, we know great construction demands solid foundations. We deliver tailored, functional construction solutions - both above and below ground. Talk to us to future-proof your buildings and infrastructure.

NZ

*Fosroc

Come and talk to us at the Concrete NZ Conference 2022!

worked very closely with Conset to get everything there on time.”

“The whole project is a combination of all different types of slabs,” say Mark Whiteford, Commercial Operations Manager for Conset Construction. “The 90,000 m2 floor is the largest we have undertaken and includes different types of foundations - fibre only slabs, combi slabs (which include mesh) plus post-tension slabs. Our relationship with Firth is a long standing and reliable one.”

Adam Plimmer, Central Regional Manager for BPC talks about working with Firth. “We have been on site now for over 18 months and things are progressing well. We have a, long- standing relationship with Firth and our businesses know each other and work well together. Firth is capable of supplying huge volumes of concrete at the highest quality, at varying capacity for any project.”

“We know and trust Firth. On projects of this size things can crop up. Our team knows that

PROJECT PRINCIPALS

Customer: Winstone Wallboards

Main Contractor: Fletcher Construction

Concrete slab contractor: Conset Construction

Foundations contractor: Brian Perry Civil

Product: Firth Certified Concrete

it can pick up the phone and speak to Willie Waters, Gavin Allden or Cam Lee and issues can be addressed. I would say that transparency, communication and coordination are the reasons why things work so well for us when working with Firth.”

With approximately 8,000 m3 of concrete yet to deliver Willie says, “We have supplied the bulk of what is required with all the major pours expected to be completed by the end of November. Then there will be odds and sods required until the project completion date which will be about June 2023.”

Designed with sustainability in mind, the new plasterboard manufacturing and distribution plant will reduce carbon emissions by up to 10 percent, providing a strong base for Fletcher Building to achieve their target of 30 percent reduction by 2030. Site plans include extensive recycling capabilities for both water and plasterboard waste, with new GIB® plasterboard being able to contain some recycled content.

We produce and supply consistent quality cement that you can rely on. We call it NZ grade - you know where it’s made, what it’s made of, who made it and that it’s made for the NZ market. It’s Genuine so you can trust it.

Being Genuine is part of our fundamental approach to do business.

NZ BUILDING CODE

H1 ENERGY EFFICIENCY 2021 REVISION

AT THE END OF 2021 THE MINISTRY OF BUSINESS, INNOVATION AND EMPLOYMENT (MBIE) PUBLISHED THE 5TH EDITION OF THE NEW ZEALAND BUILDING CODE CLAUSE H1 ENERGY EFFICIENCY.

The new edition contains the most significant changes to H1 Acceptable Solution (AS) and Verification Method (VM) in more than a decade. The changes came into effect on 29 November 2021 and apply to new buildings.

Following recent consultation however, MBIE has made the decision to extend the transition period to increase wall, floor and roof insulation in new homes to 1 May 2023, but will still be proceeding with increases to window thermal performance on 2 November 2022.

This extension only applies to housing. For commercial and other buildings, the transition period ends 2 November 2022, after which only the 5th edition is current.

Visit MBIE’s Building Performance website for more information - www.building.govt.nz/buildingcode-compliance

H1 ENERGY EFFICIENCY 5TH EDITION

As with the previous version, the revision provides three ways of showing compliance:

1. Table (or Schedule) Method. This is the most popular method where tables provide the required R values for walls, roofs, windows, skylights and slab-on-ground.

2. Calculation Method. Comparing the energy performance to a reference building which allows for a reduction in the Table Method’s R values in some parts of the envelope at the cost of a higher R value of another part.

3. Verification Method. Using thermal modelling software to determine the thermal resistance of the design.

SUMMARY OF CHANGES

1. AS1 and VM1 will cover buildings up to 300 m2 and all residential buildings (housing).

2. Newly introduced AS2 and VM2 cover all buildings > 300 m2 other than housing.

3. Newly introduced AS3 and VM3 cover the energy efficiency of HVAC systems in commercial buildings.

4. The number of climate zones has been increased from three to six.

5. R values for thermal wall, floor and roof insulation have been increased two to three fold with the aim of reducing the energy required for space conditioning by around 40 percent when compared to previous requirements. However, for concrete floors the R value has only been increased by around 15 percent.

6. The new R value for concrete walls is now 2.0, which is about double the previous value for concrete walls.

7. The R value for residential concrete slabon-grade has been increased by around 15 percent, compared to a 100 percent increase in the R value for timber ground floors. Larger concrete slabs still comply without any insulation, however small to medium size houses require at least an edge insulation with an R value of 1.0.

8. R values have been doubled for windows, skylights and roofs.

CLIMATE ZONES

Climate zones have increased in number from three to six. Figure 1 illustrates the old and the new climate zones.

IMPLICATIONS OF H1 CHANGES FOR CONCRETE ENVELOPE PARTS

The implications for H1 compliance of concrete envelope parts (walls, floors and roofs) are shown in table format on the following pages. In short, this means increasing the thickness of the thermal insulation.

Note: For explanatory purposes, Tables 1, 3, 5-8 below are based on the common insulation material EPS (VH grade). Tables 2 and 4 indicate how other insulation materials perform.

Figure 1: Old and new climate zones

Image: Cranko Architects.

THERMAL INSULATION: CONCRETE WALLS

and housing, the changes mean that walls now require two to three times the

For concrete walls of buildings up to 300 m

to the previous requirements depending on the climate zone.

from 1/05/2023*

The implications of the H1 changes to wall insulation for buildings ≤ 300 m2 and housing are shown in Table 1.

*R from 1/5/2022 for housing. However, for other buildings ≤ 300 m2 the transition period ends 2/11/2022.

Table

Phenolic

2.00

XPS 54 2.00

PU Foam 60 2.00

Mineral Wool 66 2.00

EPS, VH grade 70 2.00

Glassfibre, fine grade 80 2.00

EPS, SL grade 82 2.00

Polyfibre 90 2.00

Glassfibre, rough grade 104 2.00

* R values are indicative only. It is recommended that the insulation supplier is consulted for accurate information.

For concrete and timber walls of buildings > 300 m2 other than housing, the changes mean that walls require about three times the insulation compared to the previous requirements.

Insulation

2/11/2022

Insulation

The implications of the H1 changes to wall insulation for buildings > 300 m2 other than housing are shown in Table 3.

Table 4: Insulation Materials

Phenolic board 58 2.75

XPS 74 2.75

PU Foam 83 2.75

Mineral Wool 91 2.75

EPS, VH grade 96 2.75

EPS, SL grade 113 2.75

Glassfibre, fine grade 110 2.75

Polyfibre 124 2.75

Glassfibre, rough grade 143 2.75

* R values are indicative only. It is recommended that the insulation supplier is consulted for accurate information. An R value of 2.75 has been used to represent an average across the climate zones in Table 3, row “R from 2/11/2022.”

THERMAL INSULATION: CONCRETE FLOORS

The R-values for

floors of

that

conditioned

using

tables of H1/AS1

AS2 Appendix

(based on areato-perimeter ratios);

in Verification Method H1/VM1 Appendix F.

footprint

The implications of H1 changes for concrete slabs on grade for buildings ≤ 300 m2 and housing are shown in Table 5.

*R from 1/5/2022 for housing. However, for other buildings ≤ 300 m2 the transition period ends 2/11/2022.

Table

Values

R until 1/11/2022

req. not req. not req. not req. not req. not req. R from 2/11/2022 2.2 2.2 2.2 2.2 2.2 2.2

Insulation

Buildings with large slabs that have an area-to-perimeter ratio of 6.5 or more do not require insulation. An example of this would be a 676 m2 slab with a square footprint of 26 m x 26 m.

Buildings with smaller slabs (e.g., 300 - 400 m2) can apply an R 1.0 vertical edge or underfloor insulation.

The implications of H1 changes for concrete slabs on grade of buildings and >300 m2 other than housing are shown in Table 6.

THERMAL INSULATION: ROOFS

The implications of H1 changes for concrete roofs of buildings ≤300 m2 and housing are shown in Table 7.

*R from 1/5/2022 for housing. However, for other buildings ≤ 300 m2 the transition period ends 2/11/2022.

(e.g.,

The implications of H1 changes for concrete roofs of buildings >300 m2 other than housing are shown in Table 8.

Dr Giuseppe Loporacaro is an architectural engineer at the University of Canterbury.

ADVANCES IN 3D CONCRETE PRINTING TECHNOLOGIES ARE CREATING EXCITING OPPORTUNITIES TO BUILD HOMES FASTER, MORE SUSTAINABLY AND AT REDUCED COST. UNIVERSITY OF CANTERBURY (UC), ARCHITECTURAL ENGINEER DR GIUSEPPE LOPORCARO IS LEADING A RESEARCH PROJECT TO REFINE LOW-CARBON, SEISMICALLY RESILIENT SOLUTIONS FOR 3D PRINTED HOMES SUITED TO NEW ZEALAND CONDITIONS.

Research in this field has been gaining momentum at UC over recent years. In the Department of Civil and Natural Resources Engineering, a machine has been built to 3D print concrete walls by extrusion and students at both undergraduate and postgraduate level have been exploring materials for the process.

Over the next three years, Dr Loporcaro and his team plan to further extend their knowledge and expertise as they seek to unlock the potential of this alternative construction technology. The first phase will involve further refinement of materials used for 3D concrete printing.

“Low carbon is an important aspect of our research,” says Dr Loporcaro. “We plan to build on our research to date, developing sustainable material for 3D concrete printing, for example, re-using mussel shell waste and other resources. We also plan to optimise the shape of elements so as to reduce the total amount of material needed along with carbon dioxide emissions.

The project’s second phase will focus on design and structural engineering. “We will really be focusing on what a 3D printed house would look like in Aotearoa New Zealand and considering how to make something suitable for our communities, rather than repeating what has been done overseas.”

Creating seismic resilience by integrating high strength steel into 3D concrete printed walls - possibly alongside natural fibres or other reinforcements - is a key research goal.

Callaghan Innovation will be sharing their expertise on concrete in this project, providing advice and feedback as the research proceeds.

“We are also actively partnering with a 3D concrete printing company in New Zealand called QOROX. They will be part of our technical advisory team and the partnership will also allow us to print larger scale 3D printed elements.”

With demand for housing in New Zealand outstripping supply – made worse by a global pandemic and associated supply chain disruption –there is clearly a place for alternative construction technology that brings greater automation to the sector. New low carbon approaches are also needed if Aotearoa New Zealand is to achieve zero carbon by 2050.

“Affordability is another big issue in our housing market; 3D concrete printed homes would offer a cheaper alternative and would help bring down the costs of construction.”

This UC-led research, which also aims to finetune specifications for materials and structural design, is on track to bring commercial 3D concrete printed housing one step closer to full commercial reality.

Roadex provides business to business Road Transport services primarily for manufacturers supplying products to the Infrastructure and Construction sectors.

TAKE TWO BUILDINGS

AN INDEPENDENTLY ASSESSED LIFE CYCLE ANALYSIS COMPARED TWO APARTMENT BLOCKS –ONE WITH A CONCRETE STRUCTURE, ONE MADE OF CROSS-LAMINATED TIMBER, BUT OTHERWISE VIRTUALLY IDENTICAL. BELOW, THE UK CONCRETE CENTRE PICK OUT FIVE KEY FINDINGS.

A concrete-framed building may not be significantly more carbon-intensive than a cross-laminated timber (CLT) one, according to a life cycle analysis (LCA) conducted on two notional apartment blocks. The concrete structure could also help to make useful carbon savings in a National Grid increasingly supplied by intermittent renewable sources. These are two of the key findings of the LCA, which was commissioned by The Concrete Centre, with the aim of gaining a better understanding of carbon emissions over the lifespan of a relatively conventional concreteframed residential building – and by extension showing how future designs can be optimised.

The analysis focused on two study buildings, one made of concrete, the other CLT. Both were 2,500 m², six-storey blocks in London, containing 22 flats. They were of the same size, shape and layout, with the same functional requirements, and the same heating, hot water and ventilation systems, all designed to meet the Future Homes Standard. The concrete building comprised a reinforced concrete (RC) frame, with exposed 225 mm-thick slabs supported on a foundation of RC ground beams, pile caps and piles. The frame was made using a C32/40 concrete with 50 percent GGBS. The substructure works used an FND3 and FND4 concrete with 70 percent GGBS. The internal walls were made with concrete blocks finished with a wet plaster to maximise their thermal mass, which was also the purpose of exposing the soffits. The CLT building comprised 160 mm-thick, five-layer panels for the floors, spanning unidirectionally onto 100 mm-thick, three-layer loadbearing wall panels. These were finished with mineral wool insulation and plasterboard to provide the

necessary fire resistance and noise transfer performance. This building was also supported on a foundation of RC ground beams, pile caps and piles.

Analysis of the two buildings over a 60-year study period was carried out in early 2020, using IES ApacheSim for the dynamic thermal modelling and the OneClick tool for the LCA. Wherever possible, embodied carbon rates were determined using environmental product declarations (EPDs) for specific products. Where these weren’t available, generic data sources were used such as the OneClick tool and the ICE database.

The results offer a practical insight into the relationship between embodied and operational carbon, and the interplay between different building materials, systems and design needs. The study also provided useful lessons on undertaking an LCA. We pick out some of the key findings.

Life cycle carbon analysis of a six-storey residential building

1THE CONCRETE BUILDING’S WHOLE-LIFE CARBON EMISSIONS WERE ONLY ABOUT 6 PERCENT HIGHER

The whole-life carbon emissions after 60 years were estimated to be around 710 kgCO2e/m² and 670 kgCO2e/m² for the concrete and CLT buildings respectively. Predicting whole-life emissions does, of course, come with a degree of uncertainty as it is looking many years into the future and depends on LCA factors such as the future carbon intensity of grid-supplied electricity. But with this caveat, the difference between the average whole-life emissions was quite small, with the concrete building being only around 6 percent higher.

2

BOTH BUILDINGS MEET THE RIBA 2025 AND 2030 CLIMATE

Challenge embodied carbon targets The results also provide some insight into the relative contributions of operational and embodied emissions. In both the concrete and CLT buildings, embodied carbon was predicted to account for about 75 percent of the total – made up of approximately one-third structure, one-third services and the final third made up of architectural elements such as finishes and cladding.

When the carbon emissions from the operational energy are excluded, the embodied impact of both

buildings was around 500 kgCO2e/m², with the concrete building marginally higher. This meets two key industry benchmarks: the RIBA 2025 and 2030 Climate Challenge targets. The study built on this result by developing a “low2” scenario for the concrete building. This improved the carbon performance of the base design through seven material and system enhancements that worked within the fixed design constraints adopted for the study. These included increasing the GGBS in the superstructure from 50 percent to 70 percent, switching from PIR to EPS insulation and using a heat pump refrigerant with a lower GWP. Collectively, the changes reduced the embodied carbon to around 430 kgCO2e/m² using this data set.

Floorplans were the same for both buildings. They also had the same heating, hot water and ventilation systems

3THE CONCRETE BUILDING HAD SIGNIFICANTLY BETTER PASSIVE COOLING

Both buildings adopted a high standard of solar shading and ventilation to reduce the risk of overheating as far as practicable, but the concrete design also made use of the structure’s thermal mass.

Overheating analysis using the CIBSE TM59 methodology found that, for the period 2020-40, the concrete building could remain cool by using this thermal mass, coupled with night cooling and some very low-energy ceiling fans. The CLT building, on the other hand, needed active cooling in summer, so includes an air-source heat pump, serving chilled water fan-coil units. By 2041-80, summertime external temperatures are anticipated to rise by around 1°C, and under these conditions, the concrete building also requires a small amount of active cooling.

4OPERATIONAL ENERGY CONSUMPTION WAS ABOUT THE SAME

The concrete building was predicted to use less energy for cooling than the CLT option and slightly more for heating, but overall the two balanced each other out and there was no significant difference in the total energy consumption for any of the time periods or occupancy scenarios. Overall energy consumption was close to 43 kWh/ m2/yr throughout the 2020-80 period. This is reduced to 34 kWh/m2/y when energy produced by the roof mounted PV array is included. It’s worth noting that the study assumed a reasonable active cooling set point of 24°C for the modelling. In practice, occupants may of course opt for a lower setting closer to 20°C, resulting in more energy being used for cooling. The extent of any increase is however likely to be more modest in the concrete building, with its better passive cooling performance.

5THE CONCRETE BUILDING’S PEAK SPACE HEATING LOAD WAS ON AVERAGE 25 PERCENT LOWER

For the period 2020-40, the peak electrical load for space heating was on average 25 percent less in the concrete building, as a consequence of its higher thermal mass. When hot water heating was included, the total peak heat electrical demand was estimated to be around 15 percent lower than for the CLT building.

This matters because, by reducing peak electrical demand, the National Grid is better able to balance out supply and demand. This will become an important attribute of high thermal mass buildings, as they can be actively controlled to store and release heat in response to the peaks and troughs of renewable energy supply. In this way, the building’s energy demand can be shifted away from periods of high grid carbonintensity – that is, when fossil fuels are needed to meet a shortfall in renewable power. The net result is carbon savings at a national level.

This article, authored by The Concrete Centre, draws on technical analysis completed by Max Fordham, on behalf of The Concrete Centre. The initial designs that formed the basis of the analysis were developed by Adam Khan (architect), Price and Myers (structural engineer) and Max Fordham (environmental and services engineer).

CONCRETE NZ LIBRARY

LISTED BELOW IS A SELECTION OF RECENTLY ACQUIRED MATERIAL BY THE CONCRETE NZ LIBRARY. MEMBERS CAN EMAIL LIBRARY@CONCRETENZ.ORG.NZ TO BORROW.

CONCRETE HOUSES: FORM, LINE, AND PLANE BY STEVE HUYTON AND CHERYL WEBER

Robust and raw, concrete has been a rudimentary building material for centuries, but it is only relatively recently that architects have begun exploring its softer, tactile side in the design of houses. Concrete is durable, recyclable, and thermally efficient, and it goes up quickly compared to wood or metal framing. The appeal for architects, though, is its plasticity and potential for magic, making poetry out of the mundane.

Witness concrete’s endless form-making possibilities in this collection of contemporary homes by A-list architects in diverse locations across Japan, Australia, Spain, Brazil, South Africa, the US, and more. Along with exquisite colour photography and plans, the architects share their design approach to projects ranging from 10,000 square feet on spectacular sites, to compact urban gems. This close-up of 20 striking houses celebrates the texture and physics of a material that has long been taken for granted.

CONCRETE PLAYGROUND HARDCOVER BY TRISTAN MANCO AND GIULIA RIVA

At the end of 2020, the concrete factory in Ghent, popularly called ‘the Betoncentrale’, was demolished. Cultuur Gent, the cultural department of the City of Ghent, aims to keep the memory of this graffiti paradise alive. A team of experts selected the 10 most important street artists who were active onsite: ROA, Klaas van der Linden, and Bue the Warrior, among others. This book showcases the most beautiful work that adorned the walls of the factory. Street art expert Tristan Manco frames the local scene in its international context and Giulia Riva, a street art blogger, spoke to the artists about their memories of that unique place.

PROCEEDINGS OF THE SUSTAINABLE CONCRETE MATERIALS AND STRUCTURES IN CONSTRUCTION

2020: TOWARDS SUSTAINABLE GREEN CONCRETE

This book gathers a selection of peer-reviewed papers presented at the Sustainable Concrete Materials and Structures in Construction 2020, held at Universiti Tun Hussein Onn Malaysia, Malaysia, in August 2020. The contributions, prepared by international scientists and engineers, cover the latest advances in and innovative applications with the theme “Towards Sustainable Green Concrete”. The articles in this book cater to academics, graduate students, researchers, as well as industrial practitioners working in the areas of concrete materials and building construction.

LIBRARY QUIZ

To go in the draw to win a copy of Concrete Playground Hardcover by Tristan Manco and Giulia Riva answer the following question:

At its highest point, how high is Wellington’s new Omāraro reservoir?

Email your answer to library@concretenz.org.nz Entries close Friday 21 October 2022.

Congratulations to Nam Nguyen of Conset Construction, who correctly answered the Vol. 61 Iss. 04 Library Quiz to receive a copy of Illustrated History of Cement and Concrete: The Exciting Development of Two Outstanding Building Materials by Rainer Nobis.

CONTACTS

Concrete NZ Readymix Sector Group

Ph (04) 499 0041

Chair: Kerry Newton Convenor: Rob Gaimster Concrete NZ Masonry Sector Group

Ph (04) 499 8820

Chair: Dene Cook Convenor: Ralf Kessel

Concrete NZ Precast Sector Group

Ph (04) 499 8820

Chair: Rakesh Nauhria Convenor: Dave McGuigan

Concrete NZ Learned Society Ph (04) 499 8820

President: Alessandro Palermo Convenor: Adam Leach Concrete NZ Reinforcing Stakeholder Group

Ph (04) 499 8820

Chair: Kelvin Busbridge Convenor: Dave McGuigan