Precast • Issue 4 • 2021

CONCRETE MANUFACTURING & CONSTRUCTION ISSUE 4 2021

R49,00

PRECAST

IN THIS ISSUE: Twinstar Precast – solving the custom puzzle Precast bridges two communities Formwork – smooth innovations

CUTTING-EDGE APPROACH. CUTTING ZERO CORNERS. QUALITY CEMENT. WHAT GOES INTO IT MATTERS.

Our range of high quality cement is designed for specialised applications where early strength is required. The fine-particle mineral components mean our cement offers improved durability and a superior quality concrete. When you’re putting everything into delivering a quality product, you need quality cement that delivers every time.

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Creating Concrete Possibilities

| CONTENTS |

Editor’s NOTE

The precast concrete industry in South Africa has a very important story to tell right now. One of the few industries to thrive of late, precast concrete’s development, value, functionality and response to the opportunities and challenges in South Africa is an important reason for its exceptional experience.

Its diversity is remarkable, from lightweight concrete toilet tops to structures that enable municipalities to rapidly deliver reticulation and waste water infrastructure rapidly, while upholding extremely safe standards.

As the new editor of this publication, I could not be more excited to walk this road with you as 2022 reveals our industry’s leading role in the Fourth Industrial Revolution, sustainable development and the green economy.

I am grateful to know many of you already and am continuously inspired by your intrepid approach to the challenges of the day.

This year, I am thankful for the contributions you have made to our country as a whole and commit to doing my best to develop this publication on the principles that continue to serve precast concrete so incredibly well.

Wishing you all a safe, happy and healthy holiday season.

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| CONTENTS |

CONCRETE MANUFACTURING & CONSTRUCTION ISSUE 4 2021

PRECAST R49,00

COVER STORY 4

Twinstar Precast – solving the custom-precast puzzle

INDUSTRY NEWS 6

New CEO at ISG/School of Concrete Technology training programme

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ASPASA encourages collaborative approach

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“AccelerateHer” initiative

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The sixth International Conference on Concrete Repair, Rehabilitation and Retrofitting

11 Cement & Concrete SA’s Information Centre

PRODUCTS 12 Next-gen asset performance management 14 High-profile industrial sealants

GLOBAL INNOVATION 16 New cement makes concrete generate electricity 17 World-first forensic tool for fire-damaged concrete structure

PROJECTS 18 Affordable housing at Paarl Rock development 20 Precast slabs and beams – bridging two communities 23 Gauteng hotel and hospital among construction world's best 24 Limpopo project keeps superb time

TECHNICAL 28 Formwork release agents 30 Vlakfontein Reservoir gets water-wise 32 Innovative solution to concrete cracking

Find us online @precastmag

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IN THIS ISSUE: Twinstar Precast – solving the custom puzzle Precast bridges two communities Formwork – smooth innovations

ON THE COVER Twinstar Precast in Olifantsfontein boldly goes where others fear to tread by manufacturing all types of customdesigned and cast products for civil engineering contractors. While these once-off jobs are usually avoided by typical precasters due to their complexity, size and resource-intensive requirements, Twinstar Precast is specially geared to undertake this type of work and has been doing so for more than six years.

PRECAST is independently published

by Isikhova Media (Pty) Ltd Publishers: Isikhova Media Address: 10th Floor, Metalbox, 25 Owl Street, Milpark, South Africa Tel: +27 (11) 883 4627 www.isikhova.co.za Pubishing director/Editor-in-chief: Jason Aarons Tel: +27 (11) 883 4627 E-mail: jason@isikhova.co.za Editor: Nicholas McDiarmid Tel: 067 672 2503 E-mail: nicholas@isikhova.co.za Managing director: Imraan Mahomed Tel: +27 (11) 883 4627 E-mail: imraan@isikhova.co.za Director of brand strategy: Jenny Justus Tel: +27 (11) 883 4627 E-mail: jenny@isikhova.co.za Operations director: Thuli Majola Tel: +27 (11) 883 4627 E-mail: thuli@isikhova.co.za Creative director: Joanne Brook E-mail: joanne@isikhova.co.za Media sales: Tel: +27 (11) 883 4627 / 083 450 6052 / 072 383 3203

The views and statements expressed in this publication are not necessarily those of the editor or the publishers and neither the publishers nor the CMA accept responsibility for them. No person connected with the publication of this journal will be liable for any loss or damage sustained as a result of action following any statements or opinions expressed herein. The same applies to all advertising. Precast© 2021. All rights reserved. No part of this magazine may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage retrieval system, without prior written permission from the publishers.

Endorsed by:

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| COVER STORY |

TWINSTAR PRECAST – SOLVING THE CUSTOMPRECAST PUZZLE

Custom-built precast concrete products can often be the final pieces of a construction project puzzle: the perfectly-sized plinth, the architecturally perfect, but awkwardly shaped side-walls, the perimeter kerbs of a hospital helipad…

Twinstar Precast – one of the few custom precast concrete manufacturers – was founded w ith the objective of providing these critical pieces of the construction puzzle in the most reliable, cost-effective and client-centric manner possible. If you are wondering whether a particular puzzle piece could possibly find a concrete solution, Twinstar should be your first port of call.

The effort and time required to design and build once-off moulds for bespoke products can only be fully appreciated through hard-won experience. Simply surviving the first attempts requires methodical planning and an eye for optimisation (both budgetary and operational).

A well-founded operation Twinstar Precast was established in 2014 with the express aim of assisting specifying civil engineers and civil engineering contractors with complicated sites and situations where currently available precast concrete products would not work.

There will always be a demand for custom precast products and success in custom manufacturing is itself custom-made. A business based on disruptive production set-ups and highly fluid operating procedures, not to mention the specialised skills and additional supervision so often required, contradicts business sense.

Walking the custom precast concrete walk “We’re very committed to every client who walks through our doors. We’ve accumulated the knowledge and developed the techniques and solutions required for even the most unusual designs and structural challenges through our own determination to solve every puzzle in front of us,” explains director and founder Annemerie Coetzee.

“We know how to listen to a client and make the impossible possible.”

Sized for quality, not quantity The values lived by Coetzee percolate through Twinstar Precast’s entire operation

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| COVER STORY |

and, given the nature of its business, evidence of her integrity and personal commitment can be seen in the company’s continuous production of a staggeringly diverse range of products.

“We’ve deliberately kept our operations sized for the work we deliver,” she explains.

“I know exactly what we can commit to and precisely how to achieve the best outcomes for each client. We make our own moulds and have one truck with an excellent crane that enables us to deliver large concrete products in segments, to the great advantage of our clients. By keeping weight within the regulated range, we can save them hundreds of thousands of rands in transport costs.

We’ll guide the placement and fitting of the product and will be on site, if necessary.”

Coetzee notes that in most circumstances, Twinstar Precast has the capability to make adjustments to the design required. All practical considerations are done to ensure the product meets a client’s particular requirements.

The Twinstar “can-do” list Twinstar Precast’s expertise has been honed through both trial and error, as well as its willingness to try new solutions. The fundamentals that underpin its reputation include: • Mould-making, including wooden, fibreglass and polyurethane moulds.

• The ability to tool up and supervise the precise process for each unique job.

• Highly skilled specification and procurement of the right materials for each job, with the supplier network to guarantee satisfaction.

• The ability to ensure a functional mould and move from potential time-frames to precise delivery commitment only when a mould is completely strippable.

• Specialised experience in manufacturing the transformer and distribution boxes, plinths and cable markers for wind farms.

• Being geared for private-sector construction requirements • The manufacture of standardised products for the public transport, infrastructure and housing sectors.

• Laser-writing into the mould for masslabelling of concrete components.

Twinstar Precast (Pty) Ltd

well as the financial implications these have for councils and developers. The company manufactures manhole covers and frames, as well as stormwater gratings. These components can be bought as a loose items, or cast into the required precast concrete slabs The passion project of creating closures for decommissioned mine shafts in the Soweto region of Gauteng speaks to Twinstar’s commitment to improving lives across the board and preventing potentially crippling injuries for a generation of children.

Twinstar Precast has the experience and expertise to deliver the highly specified components needed for windfarms, with a highly accomplished track record: Noupoort; Loeriesfontein; Oyster Bay; Kangnas, Springbok in the Northern Cape; Paardekraal in Ceres; Karusa and Soetwater in Sutherland; Khobab in Loeriesfontein; Gibson Bay; Nxuba in Bedford, Eastern Cape; and Garob in Copperton.

Hospitals, shopping malls and windfarms From specialised structures to weightbearing delivery areas, shopping malls, housing complexes, hospitals and cultural centres, windfarms, roads, bridges, airports and bike racks, Twinstar is uniquely positioned to cater for an extremely diverse range of industries. The company is solution-driven in all aspects of precast concrete and creates products ranging in weight from 2kg to 6 tons.

In 2018, it started with in-house manufacturing of polymer products. These polymer products have no metal components and reduce the safety risk of open manholes, as

Markets and range Twinstar Precast has a unique relationship with mainstream precast concrete companies who pass on referrals and use it to supply certain non-standard products for their clients. As far as possible, the company uses small local suppliers and SMMEs, rather than large corporate companies, to transport its products.

Tw instar Precast’s manufacturing facility is situated in Olifantsfontein, Gauteng and delivers anywhere in SA. Its crane-mounted trucks can offload products directly on site and can also help place slabs during installation. (These transport and installation services are available within Gauteng and the northern provinces.)

Tel: +27 (12) 670 9083 or 082 552 1915 E-mail: info@twinstar.co.za Website: www.twinstar.co.za

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| INDUSTRY NEWS |

SCT TRAINING PROGRAMME FOR 2022 COMPLETED

NEW CEO FOR THE INFRASTRUCTURE SPECIALIST GROUP Lwazi Goqwana has been appointed as the new chief executive officer for the Infrastructure Specialist Group (ISG), effective immediately. ISG is South Africa’s leading manufacturer of precast concrete solutions and products for the construction, infrastructure and mining sectors.

An engineer by profession with 25 years of working experience in manufacturing, construction, financial services, logistics, energy and government services. Goqwana has worked for multiple organisations including Unilever, Tiger Brands, Barclays Africa, Transnet and the Department of Public Enterprises.

“I'm very excited to be joining one of South Africa’s iconic companies. I look for ward to joining the ex ist ing management team as we lead ISG forward in a way that will enhance our competitive position in the market,” he says.

With an Honours degree in mechanical engineering from the University of Cape Town and an MBA in strategic general management from M ilpark Business School, Goqwana brings a wealth of technical and operational excellence as well as executive management experience to ISG.

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The construction industry’s new year’s resolution should be to budget for staff training to gain a competitive edge when, hopefully, work volumes increase again in line with government’s infrastructural development plans and the disruptive effects of the pandemic subside, says John Roxburgh, senior lecturer at the School of Concrete Technology (SCT), a division of Cement & Concrete SA (CCSA).

The school’s 2022 training programme has been completed and is now available.

Roxburgh says the SCT sees the coming year as one of opportunity, when the coronavirus hopefully begins receding and the South African economy starts growing again. The school will continue running its successful online e-learning courses in 2022, but also hopes to return to classroom-based lecture courses, providing lockdown restrictions permit and prevailing infection rates are low enough.

“The live classes will be kept small and high demand for any specific course will be dealt with by scheduling more courses.

However, the online platform and selfstudy courses are here to stay, as they align themselves with modern trends in terms of remote learning and increased access to both data and smart delivery devices.

E-learning and its associated benefits will form an integral part of SCT training in future,” he says.

The universally acclaimed Advanced Concrete Technology (SCT50) programme will be run by the SCT on a modularised self-study basis next year.

Roxburgh has urged the construction industry to invest in training in 2022.

“Concrete work on site is a major cost component in construction contracts. With trained staff – competent in all relevant aspects of concrete practice – contracts could be carried out more economically and quickly, with fewer costly site errors, repairs and damage to reputations. Trained staff give construction companies the edge and 2022, especially, promises to separate the men from the boys when it comes to winning tenders. Spending money now on training by the school is an investment in

the future of any company.

“SA urgently needs competent concrete practitioners and sales specialists in admixtures, construction chemicals, ready-mix concrete, precast concrete, concrete repairs, cement production, aggregate production, testing laboratories and the mining sector, among other potential careers.

“In fact, a good education in concrete technology can lead to a rewarding career in all concrete-related industries with the potential of starting one’s own business.

The long-established SCT has for decades provided trusted concrete technology education with a progression of courses that allow students to join at a level which matches personal competency. There can be no short cuts to becoming a good concrete technology practitioner and the SCT has all the educational requirements to help students meet their goals,” adds Roxburgh.

Successful students for all SCT courses receive certif icates of attendance/ competence and Continuing Professional Development points are awarded on selected courses.

For further information and access to the SCT 2022 training programme, tel: 011 315 0300 or e-mail: rennisha.sewnarain@cemcon-sa.org.za Website: www.cemcon-sa.org.za

SURFACE MINES DIG DEEP TO ENSURE SUPPLY Surface mines and quarries which are members of industry association ASPASA have committed to supporting the efforts of the construction sector to rebuild the industry and reverse the effects of ongoing Covid-19 lockdowns.

While the industry has been heavily affected by mine closures and restrictions as a result of the virus, it aims to work hard to ensure sufficient building material supplies for contracts and maintain pricing that is fair and sustainable for the industry.

“ASPASA members are focused on the longer-term goal of rebuilding the construction industry, rather than profiteering from material shortages. The pandemic will be with us for an extended time and it’s our opinion that we have to get back to business as usual as soon as possible,” says ASPASA director Nico Pienaar.

He adds that building materials are crucial to ensuring a reliable construction industry and supporting the efforts of the country to rebuild infrastructure damaged in the recent riots.

During the lockdowns, the industry faced challenges relating mainly to site closures, reductions in productivity and increased costs of compliance. However, this has changed with the evolving needs of the industry.

Pienaar believes that the biggest factors hampering the supply of materials at present are: • Rapidly rising costs of most goods and services.

• Container availability and transportation challenges.

• A shortage of global raw materials.

• Insufficient product testing capacity as a result of ramp-up.

• The use of illegal minerals on sites.

• Allowing Mafia-style businesses to take control.

• Corruption.

• Using unnecessary borrow-pits.

• Not buying from reliable suppliers.

“As a result, ASPASA strongly urges those responsible for drawing up and managing contracts to consider including provisos which ensure that we have an honest and reliable industry. In addition, the contractual challenges created by lack of product availability and inability to access approved products are likely to require design changes.

“We therefore encourage a collaborative approach to managing these risks and we invite all stakeholders in the construction industry to contact our members and find ways of ensuring sufficient supply for current and future contracts. During these tough times, we also encourage construction companies to use legal and reliable suppliers who’re ASPASA members,” says Pienaar.

• Contact ASPASA on tel: 011 791 3327, e-mail: nico@aspasa.co.za or visit: www.aspasa.co.za (Top): Nico Pienaar of ASPASA.

| INDUSTRY NEWS |

ACCELERATING WOMEN IN TRANSPORT Lafarge SA and Volvo Trucks SA have joined forces with other stakeholders to launch the “AccelerateHer” initiative, aimed at supporting and increasing women-owned truck operations in the country.

Ten women from KwaZulu-Nata l (KZN) will be selected for the pilot phase of the project, with the objective of growing it in other areas of operation throughout the country in phases. This ground-breaking initiative is intended to increase the number of female owner-drivers rendering a service to Lafarge operations in the area.

The successful applicants will receive intensive three-year training through the Commercial Transport Academy as part of Volvo Trucks’ Iron Women heavy commercial driver training programme. The programme, which has been running since 2019, will teach the participants to operate trucks safely, profitably and efficiently, enabling them to receive their commercial driver qualification.

The participants will also undergo intensive business training to empower them as owner-drivers, with a focus on aspects such as technology, finance, entrepreneurship, business and road transport management, as well as labour legislation and HR practices. In addition, they will be professionally mentored throughout the programme to ensure they have every chance of success once they complete it.

“The programme, which has been running since 2019, will teach the participants to operate trucks safely, profitably and efficiently, enabling them to receive their commercial driver qualification.”

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After they have qualified, the new female owner-drivers will be incorporated into the Lafarge KZN operations as active operators.

“We believe that, given the correct resources and support, these women-owned transport businesses have the potential to flourish and make a real change in the lives of the participants, their families and their communities,” says Noriko Solomon, aggregates and readymix director at Lafarge. “This project is another step towards economic inclusion; building accessible and sustainable communities for the future,” adds Kervin Ali, the company’s procurement director.

The Volvo trucks will be financed by Volvo Financial Services.

“We’re excited about the new doors that will open for women in transport because of this joint initiative with Lafarge SA,” says Marcus Hörberg, vice-president of Volvo Group SA. “As a big supporter of the difference women can make in the industry, we’re very proud and humbled that the Volvo Trucks Iron Women project has been able to develop and make such a lasting impact on many people’s lives.”

Both companies are seeking to involve more stakeholders, including provincial and national government, in order to expand the reach and impact of the programme.

| INDUSTRY NEWS |

SIXTH INTERNATIONAL CONFERENCE ON CONCRETE REPAIR, REHABILITATION AND RETROFITTING The sixth International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2022) will be held at the UCT Graduate School of Business, Cape Town from 3-5 October 2022.

It will focus on service life extension of existing infrastructure and durability design of new concrete structures. The fields of concrete repair, rehabilitation and retrofitting, as well as concrete durability and structural performance, remain some of the most relevant for modern civil and structural engineering. To master the challenges arising from this, it is important to remain updated on recent developments in material technolog y, construction methods, performance assessment and

• Bonding Agents • Chemical Anchors • Concrete Bonding • Concrete Crack Repairs • Concrete Release Agents • Concrete Repair Mortars • Curing Compounds • Epoxy Adhesives • Epoxy Grout • Joint Sealants • Non Shrink Grouts • Pre Cast Repairs • Water Proofing Producing world-class products for YOU since 1958!

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| INDUSTRY NEWS |

non-destructive testing, as well as design, specifications and guidelines, and service life prediction models for both new and repaired/rehabilitated structures.

The ICCRRR is organised jointly by the Department of Civil Engineering at the University of Cape Town and the Karlsruhe Institute of Technology in Germany.

The international co-operation has always been the basis for the global success of the ICCRRR. The ICCRRR is intended to bring together researchers, practising engineers, infrastructure managers, concrete technologists, students and the supporting industry from around the world to share knowledge and experience on current developments in concrete technology, durability design and service life management, condition assessment of concrete structures, concrete repair, rehabilitation and retrofitting.

T he conference w i l l feat ure ora l presentations by authors of all accepted papers, keynote addresses by leading international experts, a series of conferenceintegrated technical workshops and a trade exhibition. The event will include a tourist programme for conference delegates and accompanying persons, as well as various social functions including a technical harbour cruise and a conference dinner on a wine farm.

The venue will be the Breakwater Campus of the University of Cape Town, situated in the heart of Cape Town’s most popular tourist attraction, the Victoria and Alfred Waterfront.

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• Automised condition assessment and the fourth Industrial Revolution • Analytical modelling • Applied technology and case studies Modern materials technology • Multi-functional materials and systems for durable construction and repair • New or novel materials for repair (ECC, SCC, SHCC, UHPC) • Smart materials and structures

CONFERENCE THEMES Concrete durability aspects • Causes and mechanisms of deterioration • Life-cycle assessments and service life design • Management and maintenance of concrete structures • Durability modeling and prediction • Optimising materials for improved durability

Concrete repair, rehabilitation and retrofitting • Repair philosophies, standards and guidelines • Repair methods, materials and systems • Electrochemical repair and cathodic protection • Concrete surface protection and coatings • Service life extension methods • Structural repairs and strengthening • Structural retrofitting for altered service conditions • Contractor experience and case studies

Condition assessment of concrete structures • Damage modelling and damage mechanisms • Condition assessment and damage diagnosis • Non-destructive testing technologies

Performance and health monitoring • Damage prognosis and service life predictions • Performance of repaired/retrofitted structures • Health monitoring of repaired/ retrofitted structures

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• Structural management systems • Smart structures and sensing technologies Education, research and specifications • Educational materials for concrete repair courses • Specifications and standards for concrete repair • Current and future research needs Contact information Conference Secretariat University of Cape Town, Upper Campus Rondebosch, 7701, South Africa E-mail: iccrrr@uct.ac.za/ Hans.Beushausen@uct.ac.za Tel: +27 (0)21 650 5181 Registration will open soon at https://iccrrr2022.org.

Important dates 1 January 2022 – Notification of abstract acceptance 31 January 2022 – Deadline for submission of full papers 28 February 2022 – Notification of paper acceptance 31 May 2022 – Early-bird registration

| INDUSTRY NEWS |

the Southern Hemisphere. The real value of the collection lies in the information that’s been gathered and the true potential of this is only realised by accessing and using that information,” says Battison. “Despite revolutionary changes in information technology in recent years, the Information Centre collection has kept pace with the latest trends in information dissemination and remains a valuable resource for cement and concrete information.”

64 YEARS AT THE CENTRE OF DEVELOPMENT The role Cement & Concrete SA’s (CCSA’s) Information Centre has played in providing knowledge for the sustainable infrastructural development of southern Africa and the training of top concrete technologists cannot be calculated, but must be immense, given the scope of service provided, says Susan Battison, its senior information specialist.

The Information Centre has steadily grown over the past 64 years and now has over 150 0 0 0 semina l reference items on cement and concrete, including information on the latest forms of, and new developments in, concrete.

Established in 1957 as part of the Portland Cement Institute (PCI), the centre has been a part of the PCI successors right through to CCSA, established in March this year. “The centre’s been a valuable and trusted source of information for hundreds of tertiary students who’ve become some of the world’s leading concrete technologists and now occupy top positions in universities, industry bodies and companies in many corners of the world,” says Battison.

She says placing monetary value on the Information Centre’s unique collection is impossible. “It’s the largest cement and concrete ‘library’ in Africa and probably

A published history Part of the CCSA Information Centre’s services is the sale of the newly-published and acclaimed 10th edition of Fulton’s Concrete Technology, as well as titles such as Architectural Concrete, Concrete Basics for Building, Concrete Road Construction, Guide to the Common Properties of Concrete, Concrete Industrial Floors on the Ground, Fundamentals of Concrete, Farm Reservoirs and many more. Other publications are listed on the website: https://www. cemcon-sa.org.za/information-hub/booksfor-sale/. Books may be purchased directly from the Information Centre in Midrand or online from BidorBuy at https://www. bidorbuy.co.za/.

Hanlie Turner, business development manager of CCSA, says the Information C ent re h a nd les t he sa le of a l l t he organisation’s publications. “Members of CCSA are entitled to take out printed reference works and enjoy a discount on any publication purchased. The business model of the Information Centre has changed within the CCSA stable to be a ‘membersonly’ library. Access to this invaluable collection of concrete technology reference works is highly valued by our members. In fact, the cost of membership of CCSA is insignificant, considering the value of the information able to be accessed,” she says.

(Above): The Information Centre of CCSA stocks the largest collection of cement- and concrete-related reference works in Africa. Bryan Perrie (seated on left), CEO of CCSA, is pictured with the staff of the centre.

Susan Battison is seated next to Perrie with Bongani Methula and Kizzy Shipalana standing.

“Established in 1957 as part of the Portland Cement Institute (PCI), the centre has been a part of the PCI successors right through to CCSA, established in March this year.”

| PRODUCTS |

For manufacturers, processes have undergone a number of revolutions in the past few decades, characterised by ever-greater automation and, more recently, machine learning and the Internet of Things (IoT).

Maintenance has seen comparative levels of change in recent years, with maintenance 4.0 digitalising previously manual processes and EAM delivering the ability to harness the power of data to predict asset failure and automatically direct a remediation process.

In recent years, many organisations have adopted varying iterations of EAM in their quest to reduce downtime and increase the lifespan of equipment. However, as we embark upon a new digital era, accelerated by Covid-19 and underpinned by initiatives such as Industry 4.0, many industry experts are questioning whether EAM goes far enough.

Beyond fabrication While the principles of EAM are absolutely valid, maintenance is typically a discipline confined to the factory floor, designed to monitor and optimise the management of equipment, reduce downtime and maximise productivity. However, with collaboration and connectivity across the enterprise representing some of the critical shifts in 2021, strong asset performance should – and, indeed, must – be an enterprise-wise goal.

In response to this shift, asset performance management has been heralded

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THE FUTURE OF MAINTENANCE? ENTER NEXT-GEN ASSET PERFORMANCE MANAGEMENT Infor’s Phil Lewis explains why enterprise asset management (EAM) is no longer enough for manufacturers to drive performance in an era dominated by digital as the next big thing in optimising assetorientated performance, marking an end to reactive maintenance management once and for all.

Managing labour and material costs Some businesses have been making do and getting by with asset management strategies that sell them short. These drive up the cost of maintenance labour and materials and increase the risk that critical assets will be offline when they are most urgently needed. The scene has been shifting over the past several years, with EAM offering greater visibility and sophistication for maintenance operations.

Yet business rarely sits still for very long.

With the rapid rise of Industry 4.0, it is essential for asset management to keep up.

Maintenance 4.0 is the set of tools and strategies which is helping companies optimise operations by deploying the mountains of data now available to keep equipment and production lines in peak operating condition.

(Left): Phil Lewis of Infor.

| PRODUCTS |

What is new and what matters Organisations which have already embraced EAM are fast witnessing the extent to which gains can be made by upping the ante when it comes to maintenance.

Once there is a system that can capture asset condition correctly and maintain an electronic system of records, it is hard to imagine life before it.

For many companies, this is just the start. With an avalanche of operating data from multiple sources, there are many opportunities to take another step up into predictive and preventive maintenance.

APM is the tool that allows manufacturers to make sense of the data, develop a more profound understanding of assets, predict and prevent failures, improve failure management and improve budgeting and cost control – all without having to install, then try to manage and maintain multiple software operations.

APM pulls in data that has traditionally been stored in an EAM system, as well as data from a wide range of asset measurement solutions, then applies algorithms, artif icial intelligence (AI) or machine learning models to enable decision support, predictive analytics and what-if analyses.

The result is improved analyses and greater automation to increase asset efficiency, manage asset reliability and sustainability, improve customer-centricity and optimise total cost of ownership.

The five components of APM First the asset registry, which gives managers visibility into asset inventories

and risks, tracks metadata on each device and monitors the device’s position in the larger system, as well as its current condition.

Second is the work history, which consolidates work orders, closing codes, solution codes and more into a comprehensive portrait of an asset’s life-cycle and provides a foundation for predicting future failures.

Third is real-time condition data, readily available through a complex web of IoT and industrial IoT sensors and instrumentation. An APM system makes sense of the continuing cascade of incoming data on individual devices, parts and components, triggering alerts and work orders when pre-set tolerance limits are exceeded.

Fourth: Algorithms and modelling analytics turn data into action, allowing organisations to predict how assets will behave in real time and use AI or machine models to perform what-if analysis.

Lastly, connectivity between an APM solution and other elements of a corporate ERP adds depth and texture to APM plans, while driving actions beyond the realm of maintenance and asset management.

A company-wide APM strategy built on transparency and real-time visibility stands to translate the potential benefits of digital, Industry 4.0 and IoT into very tangible improvements for the bottom line and underpin future planning. For those already on their asset management journey, this next evolution is crucial in marking out visionaries and future leaders.

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Email: sales@panmixers.co.za Tel: +27 (0) 11 578 8700

| PRODUCTS |

HIGH-PROFILE INDUSTRIAL SEALANTS Joint sealants and auxiliary products supplied by abe Construction Chemicals, part of the Chryso Southern Africa Group, have recently been specified for several high-prof ile projects in Gauteng and KwaZulu-Natal (KZN).

Firstly, Dowsil 890-SL silicone joint sealants, for which abe is the sole South African distributor, was specified as sealant of the external concrete hardstand area at DSV Park, a massive new warehouse complex near OR Tambo International Airport in Kempton Park for the major logistics company, DSV South Africa.

Dowsil (formerly Dow Corning), which produces its wide range of acclaimed sealants in Belgium and the USA, is widely recognised as a global leader in its field.

For the construction of DSV Park, Dowsil 890-SL sealant was applied by abe-approved applicator, Safrispec, to the joints at an external concrete hardstand area of about 150 000m 2 . A total of 65 000 linear metres of the highly-regarded sealant had to be applied between 200mmthick concrete surface panels that cover 2 300m 2 , says Jeandré Myburgh, abe technical sales consultant, based at the company’s Boksburg head office.

A mong the sealant’s features that

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inf luenced its selection by specifying engineers, MV W Consulting and the f loor i ng cont r actor, RCR F loor i ng Applications, are: • Self-levelling.

• Movement capability of 100% for extension and 50% compression.

• UV stability and weather-resistance.

• Flows into irregular joint widths and does not require special application tooling.

• No heating or special preparation required.

• Short skin-over time of an hour or even less at standard conditions.

• Dowsil’s 15-year warranty on the 890SL’s performance.

Jeandré says abe also supplied various sizes of ultra-f lex ible abe dura.cord preformed joint filler, (manufactured from low-density, closed cell polyethylene), which form part of the material to seal the concrete joints.

T he ma in cont ractor for t he construction of DSV Park, completed in March this year, was WBHO. Dowsil 890-SL was also among the products supplied by abe for repairs to existing joints and sealants at the Gautrain Midrand bus depot. Grant Furrows, abe

technical sales consultant, who collaborated with Myburgh for this project, says the sealing of about 40 000 linear metres was required for this project, being handled

by Con-Solve Civils and scheduled for completion in November 2021.

“Abe is also supplying dura.rep FMC cement-based concrete grouting for the joint repairs at the bus depot. This popular product is non-shrinking, with aggregate a nd add it ive content t hat prevent s segregation during application, as well as improved strength and low permeability,” (Top): DSV Park.

(Above): Gauteng Bus Depot joints repaired and sealed.

| PRODUCTS |

explains Grant. “Abe’s epidermix 344 epoxy adhesive, with its exceptional strength and bonding capacity, is also being used for the refurbishment of the depot’s concrete surfaces.”

Finally, 22 000 linear metres of Dowsil 890 -SL joint sealant, which can also effectively be applied to seal joints on high-traffic roads, has been specified for the N2 concrete highway’s realignment at the northern ends of the Umhlali and Umvoti bridges in KZN. The aim of the long-awaited SANRAL project is to flatten sharp corners to increase safety on the busy highway and reduce the high number of accidents that have occurred in the past in the areas under realignment.

Da r r yl L ayc o c k , tec h n ic a l s a les consultant at the abe KZN branch, is assisting the specialist sub-contractor, Duncan Civils, in a supervisory capacity with the application of abe concrete repair products (dura.rep ZR Primer, epidermix 345 wet-to-dry epoxy and dura.rep FR), used specifically on the bridge structures, as well as Dowsil 890-

SL highway sealant and the dura.cote WB coating system, for this project.

The overall contract was awarded to Raubex KZN, which appointed abeapproved applicator Duncan Civils.

(Right): Sealant application at DSV Park.

(Below): The Gauteng Bus Depot depot hardstand area.

| GLOBAL INNOVATION |

ELECTRIFYING: NEW CEMENT MAKES CONCRETE GENERATE ELECTRICITY Engineers from South Korea have invented a cement-based composite that can be used in concrete to make structures that generate and store electricity through exposure to external mechanical energy sources like footsteps, wind, rain and waves.

By turning str uctures into power sources, the cement will crack the problem of the built environment consuming 40% of the world’s energy, they believe.

Building users need not worry about getting electrocuted. Tests showed that a 1% volume of conductive carbon fibres in a cement mixture was enough to give the cement the desired electrical properties without compromising structural performance, and the current generated was far lower than the maximum allowable level for the human body.

Researchers in mechanical and civil

engineering from Incheon National University, Kyung Hee University and Korea University developed a cement-based conductive composite (CBC) with carbon fibres that can also act as a triboelectric nanogenerator (TENG), a type of mechanical energy harvester.

They designed a lab-scale structure and a CBC-based capacitor using the developed material to test its energy harvesting and storage capabilities.

“We wanted to develop a structural energy material that could be used to build net-zero energy structures that use and produce their own electricity,” says Seung-Jung Lee, a professor in Incheon National University’s Department of Civil and Environmental Engineering.

“Since cement is an indispensable construction material, we decided to

“Tests showed that a 1% volume of conductive carbon fibres in a cement mixture was enough to give the cement the desired electrical properties.”

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use it with conductive fillers as the core conductive element for our CBC-TENG system,” he added.

The results of their research were published this month in the journal Nano Energy.

Apart from energy storage and harvesting, the material could also be used to design self-sensing systems that monitor the structural health and predict the remaining service life of concrete structures without any external power.

“Our ultimate goal was to develop materials that made the lives of people better and did not need any extra energy to save the planet. And we expect that the findings from this study can be used to expand the applicability of CBC as an allin-one energy material for net-zero energy structures,” says Lee. Publicising the research, Incheon National University quipped: “Seems like a jolting start to a brighter and greener tomorrow!”

With acknowledgement to Rod Sweet, Global Construction Review

| GLOBAL INNOVATION |

WORLD-FIRST FORENSIC TOOL FOR FIRE-DAMAGED CONCRETE STRUCTURE When concrete is exposed to intense fire, materials in the concrete can decompose, leading to a deterioration of strength. Yet there is no widely accepted method of evaluating this damage, making the choice between repair and demolition difficult.

Now a team of researchers, led by Dr Youngsun Heo of the Korean Institute of Civil Engineering and Building Technology (KICT), have developed the Fire Forensic Investigation of Structure (F2IS) tool that can answer the question.

“After fire exposure, service life of concrete structure can drop within two weeks, depending on the damage level,” says Heo. “The higher the volume of pores in concrete arising from fire, the faster the dramatic reduction of life expectancy. If the structure isn't going to be rebuilt, immediate diagnosis and subsequent repairing work should be proceeded even when there's minor damage.”

By taking tiny 1-2g samples for every 10mm of depth of fire-damaged concrete, F2IS can predict the impacts of the fire – such as temperature, length of time spent in the heat and how heat diffused through the structure – with 80% accuracy.

Using this data and deep learning, the tool assesses which key features to address that embrace a series of protocols involving practical sampling design (PSD), experimental design (ED) for selecting appropriate chemical devices for analysing specific samples, chemical profiling algorithm (CPA) for singling out key features from chemical results; and a deep learning interface algorithm (DIA) for comparing CPA results and standard data pre-stored in a large data platform. It takes less than two weeks to complete.

The patent for F2IS was approved earlier this year (August). The team plans to develop a rehabilitation system that can chemically cure the decomposed hydration products to fill in the cracks and help the structure recover.

Citations: Concrete Institute of Australia and Cosmos (Above, from left): With a portable hand-drilling device, samples of only 1-2g are being taken at every 10mm depth, up to 40mm so that the least damage to the concrete specimen is achieved.

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PRECAST | ISSUE FOUR | 2021

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| PROJECTS |

Construction is underway at Paarl Rock, the fifth building in Concor’s 22ha Conradie Park development in Cape Town.

Piling for the eight-storey block began in May 2021, marking the start of a one-year building programme, according to Mark Schonrock, property development manager at Concor. Paarl Rock will comprise 266 architecturally designed apartments in an affordable model for first-time home-owners.

An artist's impression of the majestic block that anchors the development.

Piling The block is underpinned by 158 continuous flight auger (CFA) piles, which present a quicker solution than bored or driven piles. With depths of 8 -11m, the piles could be completed in just three weeks, Schonrock says, improving the pace of the project.

“We've also installed two tower cranes – a 55m jib and a 45m jib – to facilitate our programme of work,” he says. These will lift and move concrete for vertical columns, as well as reinforcing bars for slabs and columns, and all formwork around the site.

The beauty of slabs below the surface Horizontal concrete slabs will all be posttensioned, a current eff iciency trend which reduces the amount of costly rebar required.

The planned slab thickness has also been reduced from 285mm to 255mm. While a relatively small reduction, this will allow a saving of some 450m 3 of concrete over the planned area of 15 000m2 of slab work.

“Pouring of slabs will be conducted by a truck-mounted boom placer which enhances construction efficiency, especially where large continuous pours of 200-220m3 are required on this project,” he says.

Mixed-use on the rise The Paarl Rock block will include ground floor retail space, two lifts and a rooftop deck on the sixth floor facing westwards at Devil’s Peak and overlooking the Cape Town central business district towards Signal Hill. To minimise the cost of long-term maintenance on the outside walls, the design makes use of facebrick – but with a difference.

“Different colours and shapes of facebrick have been specified to create texture and variety in the façade,” he explains. “Patterns are also created with rustication, using bricks of different shapes or with varied orientation.”

A perforated design is also used for the brick walls in front of drying yards, letting through

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The right mix of concrete

CASTS NEW LIGHT ON AFFORDABLE HOUSING

| PROJECTS |

“Paarl Rock’s innovations include an energy-efficient hot water system for residents, lowering their cost of living and taking load off the national grid.” light and air, while also lending an attractive texture to the building façade. The laying of facebricks requires a somewhat elevated level of skill and attention, and also takes longer, so the best artisans are tasked with the rustication work.

Building skills beyond simply labour Schonrock notes that Cape Town still offers a good pool of bricklaying skills, but the long period of depressed conditions in the sector will be felt in skills supply as building activity improves. As part of its corporate contribution to skills development, Concor conducts a range of training on its Conradie Park site.

“Through the National Youth Service Programme, for instance, we're training six local bricklayer learners,” he says.

“Beg inning in November 2020, they completed a six-month training course and were then placed with selected subcontractors to work on the current project.”

Paarl Rock’s innovations include an energ y-ef f icient hot water system for residents, lowering their cost of living and taking load off the national grid.

A centralised hot water generation system on the ground f loor raises the upfront cost, but provides many long-term benefits to users. An on-roof solar generator will assist in ‟over-heating” water during the day in a specially-designed storage vessel to around 85-90ºC. “Tapping into off-grid power in this way means that residents can save on what they pay in water-heating bills,” says Schonrock.

The development is also conserving water and reducing water costs by supplying

its own irrigation needs from a master incoming line of treated effluent – at just 5-10% of the cost of potable water. The water quality from this line, which is clean enough to be discharged into river systems, is further treated on site and also used for all irrigation and cleaning purposes.

Concor has been on site at Conradie Park – where the old Conradie government hospital closed about a decade ago – for about two-and-a-half years, preparing the infrastructure for the developments.

Public utilities Roads have been installed, along with stormwater drains and a dedicated sewage reticulation system. A pump station was installed to move sewage over the Elsie’s River canal to the main Athlone sewer system and three new electrical substations were constructed.

The Conradie Better Living model is one of seven ‟game-changer” projects which has been prioritised by the Western Cape government. This aims to improve the lives of citizens through the Finance Linked Individual Subsidy Programme, providing affordable housing situated near the city’s main arterial routes and job opportunities.

(Above, from left): An artist's impression inside one of the units with plenty of light and views and an overhead shot of the site, showing the public precinct starting to take shape, the main entrance circle, the town square and Heritage Precinct.

(Left, from top): Current rental stock units being constructed, gearing up for first tenanting in the near fuure and a view of the overall site with roads and bulk services installed.

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| PROJECTS |

The Senqu bridge sub-structure consists of 90m-high piers.

“The LHDA has been visionary in the way it’s approached the contract and its relationship with all stakeholders.”

The Senqu, Mabunyaneng and Khubelu bridges are situated on the A1 national route, which is the main access road between Oxbow and Mokhokong. The Mabunyaneng bridge (120m) and Khubelu rridge (270m) superstructures consist of variable-depth prefabricated posttensioned concrete beams, with in-situ cast reinforced concrete top slabs. The substructures consist of reinforced concrete wall-type piers and closed-wall abutments with wing walls. The design of these two bridges was carried out by Leporogo

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Precast slabs and beams

BRIDGE TWO COMMUNITIES

| PROJECTS |

The Senqu bridge features an extradosed staycable portion with a 100m centre-span.

Specialist Engineers.

The impoundment of the Polihali Dam will result in the flooding of the existing bridges and road in these locations and access to Mokhotlong will be lost unless the bridges are reconstructed at higher levels. The project is therefore located in the mountainous Lesotho Highlands, where minimum temperatures of up to -20˚C have been recorded. Hence the remote nature of the site, coupled with extreme weather conditions, pose a significant logistical challenge.

Complex suspension An elaborate preliminary design process was fol lowed to deter mine the most feasible alternatives that would meet all the required constraints influencing these bridges. One of the most important of these was the influence of the structures on local communities who would be affected by the dam development.

Senqu bridge consists of an 825m-long, incrementally launched box girder deck and an extradosed stay cable portion to allow for a 100m centre span. One of the main

construction constraints for this bridge is that construction must be completed in time for the impoundment of the dam.

The construction time could be reduced by constructing the bridge from both sides.

In addition, flooding of the Senqu River might delay construction when a pier is constructed in the centre of the river.

In order to accommodate these two constraints in the design, the normal practice of a temporary steel launching nose was removed and replaced by supporting the front portion of the deck with cable stays.

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| PROJECTS |

This pier in the centre of the river was removed, resulting in a 100m centre span above the water. The span was formed by stitching together the two decks launched from either side of the river, meeting in the centre of the span. The sub-structure consists of 90m-high piers based on spread footings.

Precast core slabs and beams The Mabunyaneng bridge (120m) and Khubelu bridge (270m) superstructures consist of variable-depth prefabricated post-tensioned concrete beams, with insitu cast reinforced concrete top slabs.

The sub-structures consist of reinforced concrete wall-type piers and closed-wall abutments with wing walls. The design of these two bridges was carried out by Leporogo Specialist Engineers.

Three-d imensional models of the bridges were created in Revit and the normal standard tender drawings, as required by the construction industry, were generated from these models. The 3D models were used to better visualise the structure and construction process for the client and prospective tenderers. For this purpose, an interactive model of the bridge was created to allow the client to visualise the structure in its surroundings before and after dam impoundment.

A construction sequencing video was also prepared to demon st r ate t he i ntended construction process to the client and potential tenderers.

In addition, drones were used to create videos and surveys of the construction site, which have a number of purposes. These are to provide the client with a record of the sites before construction, give the design team a better view of the construction area and show the sites to prospective tenderers.

All of these innovations were particularly relevant during the Covid-19 pandemic so as not to delay the tender process, but still provide prospective tenderers unable to visit the bridges with the required site and construction information.

Virtual tender An innovative virtual tender briefing was carried out in March 2021 for the Senqu bridge, with the tender closing in July

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2021. It is anticipated that ground will be broken in the second quarter of 2022. The duration of construction is estimated at three years for the Senqu bridge and two years for the Mabunyaneng bridge and Khubelu bridge respectively.

Local skills and contract teams During construction supervision, Zutari will provide a range of staff, many of whom will relocate to site for the duration of the project. All prevailing Covid-19 regulations will be adhered to and a site-specific health and safety management plan will be compiled by the successful tenderer and reviewed by Zutari prior to commencement of construction.

Local labour requirements are part and parcel of the tender philosophy and will be co-ordinated via the Lesotho H i g h l a nd s Wat er P r oje c t implementing authority, the Lesotho H i gh l a nd s D evelopment Aut hor it y (LHDA). During the tender design stage, skills development was overseen by the Zutari team, with senior staff members working closely with and imparting their k nowledge and exper ience to junior staff members. In addition, two young professionals were seconded by the LHDA to Zutari. These individuals were fully integrated into the Zutari design team and hence gained invaluable experience.

Key members of the Zutari team are chief design engineer and senior bridge design eng ineer Johan Kotzé, senior engineering geologist Salona Naidoo, senior road design engineer François van

Reenen, environmental specialist Tau Mahlelebe from White Life Consultants and occupat iona l hea lt h and safet y specialist Evert de Vries.

Zutari’s bridge team has a long history of successful bridge designs, including the Siphofaneni River bridge, a 375m incrementally launched box girder bridge in 2013 in Eswatini, the Olifants River bridge, a 166m-long bridge with a 93m arch, also in 2013 and the Malibamatso bridge, a 465m-long incrementally launched, posttensioned girder bridge in 1988 in Lesotho.

“The L H DA , t hrough its Project Management Unit, has been instrumental in making a success of the project thus far. Although it operates within a highly regulated environment due to the multinational and multi-disciplinary nature of the project and overall programme, it’s been visionary in the way it’s approached the execution of the contract, particularly its relationship with all stakeholders,” says Natie Wilson, Zutari technical director: Transportation Services.

(Above): The Senqu Bridge.

(Left): Natie Wilson, Zutari technical director: Transportation Services.

QUICK FACT An innovative virtual tender briefing was carried out in March 2021 for the Senqu bridge, with the tender closing in July 2021. It is anticipated that ground will be broken in the second quarter of 2022.

| PROJECTS |

Gauteng hotel and hospital among

CONSTRUCTION WORLD'S BEST Concor Construction has been recognised for excellence at the Construction World Best Projects 2021 Awards, with two of its projects each receiving an award.

While the two projects entered were quite different, the hallmark of quality construction underpinned both of them.

The Radisson RED Hotel was Highly Commended in the AfriSam Innovation Awards for Sustainable Construction category, while the 300-bed Covid-19 facility at the Jubilee Hospital site in H a m m a n s k r a a l , nor t h of P retor i a , received a Special Mention in the Building Contractors category.

Space in a compact design Situated in the vibrant Oxford Parks mixed-use precinct in Rosebank, Johannesburg, the contemporary 222-roomed Radisson RED Hotel was designed to meet a minimum five-Green Star Custom Hotel rating. The base build specification was provided by dhk Architects, while the interior design spec was by Source IBA. Concor took the project through to furniture, fitting and equipment stage, including beds, chairs, TV sets and the physical backbone for wifi connectivity.

With its architecturally compact design which incorporates functionality on an optimised footprint, the hotel comprises seven levels above a ground floor, as well as a roof level for plant and services. It is a concrete structure based on conventional and post-tensioned slabs with grids to suit the room sizes.

(Above): The roof plant being installed and insulated with a view west towards the sunset and the screen wall around the plant under construction.

Radisson RED is committed to sustainable design and the hotel contains numerous elements underpinning its five-Green Star Custom Hotel rating. This rating recognises that the building demonstrates “South African excellence” and is a step above the Best Practice level.

(Above, from top): A complete aerial view of the south-east corner showcasing a unitised glazed curtain wall with aluminium features, facebrick façades and plant on the roof, with the screen wall completed; the entrance to the 300-bed Covid-19 facility at Jubilee Hospital in Hammanskraal and the Concor team responsible for the Radisson RED Hotel in Rosebank, Johannesburg, which was Highly Commended in the AfriSam Innovation Awards for Sustainable Construction at Construction World Best Projects 2021.

Jubilee Hospital The fast-track construction on the Jubilee Hospital project saw it being handed over to the Gauteng Department of Health just five months after work began in November 2020. Selecting alternative building technology enabled Concor to speed up construction without compromising the standards demanded by a world-class medical facility.

Concor used a modular approach in its construction plan, with units completed and put into operation while others were still being constructed. To suit this rapid roll-out, wet services and ventilation systems were carefully selected, as all mechanical services had to be commissioned on a stand-alone basis.

Concor demonstrated its commitment to socio-economic development on both projects with a focus on upskilling small local business at the Radisson RED project and employing more than 230 local skilled and unskilled individuals from Hammanskraal at the Jubilee Hospital Project.

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| PROJECTS |

“Coreslabs” keep fast-track project

AHEAD OF SCHEDULE

A new development that will provide accommodation for a large international contracting team who have been appointed to work on an industrial project in Limpopo is progressing ahead of schedule. This is only two months after the building contractor, Projects 2000, broke ground on this R32 million building project.

The impressive progress made in such a short time bears testament to the vast skills and experience of the entire professional team, who include iCosmoplan Architects & I ndust r ia l Des ig ner s , con su lt i ng engineer Fanoy Consulting, MVM Africa Electrical Engineers and quantity surveyor Quanto 2000. This is in addition to specialist sub-contractor Coreslab, which manufactured and installed the many hollow-core slabs that make up the floor space of this development, including two sleeper blocks and a lodge.

T he c o m p a n y ’s s u s p e n d e d s l a b solution played a critical part in helping the contractor to accelerate the works programme.

A total 1 170m 2 of hollow-core slabs was installed by Coreslab in only four days. This enabled the contractor to commence fitting out the rooms below and the brickwork above almost immediately after they were installed.

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The hollow-core slabs are manufactured to the highest quality and cut to size at Coreslab’s factor y. They are then transported to site, where they are positioned onto the load-bearing walls and grouted into place according to the building plan.

This is before they are covered with either a 30mm topping or 50mm structural screed, depending on the engineer’s requirements.

Core-drilling is then undertaken to create voids for the electrical services to complete the installation.

The contractor on this project would never have achieved this impressive production rate if it had used conventional cast-in-place methods to construct the floor slabs, considering that it takes up to 28 days for concrete to cure before the shutters can be stripped so that work can commence above and below the slab.

The use of hollow-core slabs also eliminated the need to install tons of support and scaffolding in preparation for the concrete pours for traditional in-situ (Top): Hollowcore slabs eliminated the need to install tons of support and scaffolding.

(Left): The company’s suspended slab solution played a critical part in helping the contractor to significantly accelerate the works programme.

| PROJECTS |

slab construction. Extensive propping underneath the slab also restricts work below on a conventional building project.

Moreover, the solution eliminated the need to co-ordinate a large team of rebar and shutter hands, as well as the delivery of construction materials to a very remote worksite. Rather, Coreslab’s hollow-core slabs are manufactured in a controlled factory setting which is far removed from the many variables on a construction site.

They are dispatched to site on a just-intime basis and lifted directly from the truck trailers using one of Coreslab’s mobile cranes. This also frees up available space on building sites.

Alternatively, the contractor could have batched and pumped its own concrete on site. However, this might have delayed the project, considering the need to introduce extra quality control measures. For this reason, Projects 2000 decided to rule out the use of rib-and-block systems to construct the suspended concrete slabs, as it would have had to install such systems itself. By delegating the construction of the suspended slabs to a specialist in the field, potential errors were mitigated to ensure a finish of the highest quality the first time around.

The use of hollow-core slabs also provided a safer solution by doing away w ith the need to work at heights on scaffolding. The precast concrete elements are manufactured at ground level in the factory and installed on site by a small team of skilled and experienced workers.

This includes a foreman, surveyor, rigger and crane operator. Notably, there has not been a single lost-time injury on this project, in line with the mine’s own strict occupational health and safety protocol.

Coreslab undertook its first site visit on 2 June 2021, when Projects 2000 was still at foundation level for the three structures.

By 27 June, Coreslab had surveyed the three blocks, completed all its inspections and manufactured the precast concrete elements. The first slab was placed on 2 July at 13h16 and the entire installation was completed on 3 July at 09h01.

“This project was certainly not without its challenges, considering its fast-track nature and that the worksite’s located about 300km from our factory. It just goes to show that nothing’s impossible

for Coreslab, especially when great team dynamics are involved. Projects 2000 worked at an impressive rate, so we had to constantly think on our feet to devise solutions quickly in order not to delay the principal contractor and satisfy the end client. There was also no available cellular signal on site, so we had to communicate via WhatsApp. Countless trouble-shooting calls were made between Thomas White of Projects 2000 and me to keep the project on schedule,” says Johan Muller of Coreslab.

Johnny O’Reilly, owner of Projects 2 0 0 0 , s ay s t he c ompa ny h a s b e en constructing concrete floor slabs in this manner for many years and, in most instances, has relied upon Coreslab to provide its service.

“Coreslab’s known for the very high quality of its precast concrete elements and installation work – so much so that we even refer to hollow-core slabs as ‘Coreslabs’ within the company. It was therefore a given that we’d approach this long-standing partner to assist us with fasttracking another project,” says O’Reilly.

Projects 2000 was appointed as the principal contractor for this development based on t he compa ny’s more t ha n 20-year-long legacy of delivering quality real estate development assets in the larger Limpopo province, including malls, commercial and industrial space.

The two two-storey “sleeper” blocks toget her house 80 rooms, whi le t he lodge includes administrative space, a kitchen, a lounge and a bar, as well as a swimming pool. The four structures have an industrial look and feel, in line with the client’s brief to provide cost-effective, yet quality accommodation for members of the contracting team, who include highly qualified and senior personnel.

T he project a lso prov ided a mple opportunity for Projects 2000 to innovate.

Among the challenges was completing a R32 million development in the fourmonth contractual period, while also working in an extremely outlying area of the province. The construction site is located on a game farm within vicinity of the industrial project.

To mitigate delays, site sur veying started many weeks prior to the contractor breaking ground. Essential construction

“The use of hollow-core slabs also eliminated the need to install tons of support and scaffolding in preparation for the concrete pours for traditional in-situ slab construction.” materials were also procured and stored in a lay-down area on site well ahead of the construction commencement date. This included the bricks, flooring, wall tiles and roof trusses required for the project.

A large builders’ camp also had to be established on site to provide convenient accommodation for the many people who would eventually work on this project, as the closest urban node is located about 300km away from the worksite.

With employees located on site, work could also commence very early each morning, avoiding the expense and time needed to transport workers to and from the construction site every day.

The workers numbered 150-170 during the project’s peak earlier this year, with up to 60% of them members of the many sub-contracting teams.

L ouw W h it ehe a d of C o s mopl a n Architects & Industrial Designers is also very impressed with the way the project has progressed and looks forward to its completion well ahead of the contractual completion date.

“Coreslab’s demonstrated once again that hollow-core slabs are an ideal solution for any fast-track project, again completing the installation with minimal effort,” he says. “I’ve also visited Corelab’s factory in Polokwane on a number of occasions and am very impressed with the quality control measures in place there to ensure outstand ing work mansh ip on a l l its projects.”

Moreover, Whitehead credits Projects 2000 for its sound upfront planning. Only 5 000 bricks will remain of the 700 000 ordered for this project once it is completed – just one example of the high levels of accuracy achieved by the professional

PRECAST | ISSUE FOUR | 2021

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team during the early planning phases.

Whitehead considers this development to be one of his many flagship projects. This is considering the extent of innovation that had to be deployed by the entire professional team to deliver the infrastructure in such a short time. Extensive modif ications also had to be undertaken to the original design while construction was underway to contain costs. This required careful planning by the design and contracting teams to avoid costly delays.

A case in point was the innovative planning of the services in and around the shaft to maximise the use of minimal floor space in the rooms, which are about 16m2 and feature a work area and amenities.

Moreover, the design incorporates many cost-effective green elements to reduce its energy use. Whitehead specified heat pumps that only use one-quarter of the electricity required by a geyser, while also being a more affordable alternative to solar water heaters. The bedrooms and entertainment areas have been positioned to receive direct sunlight and take advantage of cooling breezes throughout the day. Aerolite in the ceilings also lowers the natural exchange of heat that occurs in the building. Roof tiles were chosen because they stabilise the building’s interior temperature and, in so doing, reduce the need for heating and cooling. They were also a more cost-effective solution than IBR sheeting to cover the roof. He included lightemitting diodes in the design wherever possible to reduce the draw on energy.

The structure has been designed to accommodate a large solar photovoltaic installation at a later stage.

Importantly, Whitehead also designed the “sleeper blocks” and lodge area to cater to the needs of disabled people.

(Below): A total of 1 170m2 of hollowcore slabs were installed by Coreslab in only four days.

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| TECHNICAL |

Understanding the crucial role formwork plays in the production of quality concrete and moulds in the manufacture of precast elements, the Chryso ® DEM range has introduced much-needed f lexibility to the industry. Previously, it had been a case of one-size-fits-all when it came to release agents.

Aesthetics of the finish Discerning clients, developers, manufacturers and specifiers are increasingly particular about the aesthetics of concrete finishes. To achieve the desired texture and colour finish on the concrete’s surface, it is imperative that formwork surfaces are adequately prepared in terms of cleanliness and that an optimal release agent is selected for the application.

As different form-face materials have varying longevity, absorbency and texture characteristics, specialised release agents are required to realise the full aesthetic potential of the formwork, eliminating wastage of time and materials.

Not only will the optimal release agent reduce the likelihood of imperfections and (Right): Chryso offers a range of application-driven release agents.

(Below, from left): The Chryso® DEM range is easy to use, adds consistent quality and when – applied correctly – release agents eliminate staining and colour deviation.

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FORMWORK RELEASE AGENTS

| TECHNICAL |

“The top-quality release agents in the Chryso® DEM range provide greater coverage, are easy to use and add consistent quality, which is important on construction sites, as well as in precast plants.”

surface defects (particularly blow holes) in the concrete, but – if applied correctly – it will ensure that there is no staining or deviation from the specified colour finish.

Precast plants The top-quality release agents in the Chryso ® DEM range provide greater coverage, are easy to use and add consistent quality, which is important on construction sites, as well as in precast plants.

Chryso® DEM Bio 10 is a vegetablebased, biodeg radable and non-tox ic release agent which will not pollute the environment. It has a low odour and is therefore safe to use in confined spaces such as mining, tunnelling and any poorly ventilated areas. It is suitable for use with all types of formwork: metal, wood, plastic, polystyrene and fibreglass.

Another product in the range is Elio

(Top, left and above): Specialised release agents are required to realise the full aesthetic potential of the formwork.

VP, a hydrocarbon oil-based agent, which is suitable when producing concrete pipes with roller-compacted pipe technology.

The Elio VP significantly reduces surface defects. The low viscosity oil creates less surface tension against the sides of the pipe steel moulds, resulting in less outer concrete surface damage when demoulding.

Chryso ® DEM Oleo WB is a waxbased delayed-release agent for wooden formwork used on conventional jobsites and for wooden pallets for cement-based brick manufacturing. This release agent

temporarily protects and extends the life of veneer-laminated shutter boards, decreasing the frequency of re-lamination.

It can also be used to coat pallets for protection, when stacking cement-based bricks on them.

Chryso ® DEM Oleo F W is hydrocarbon-based, making it suitable for use with all types of formwork. However, it is not suitable for precast applications. It ensures ease of formwork release and also temporarily protects and extends the life of metallic formwork from corrosion.

Chryso® DEM Oleo SM is a mineralbased delayed-release agent, ideal for use with metallic or wooden formwork for wet precast. It does not stain or affect the colour of the concrete when applied correctly. It is the perfect solution when white cement is used for specia l ised architectura l finishes. In addition, it can handle the high temperatures of steam-curing and prevents rusting in steel formwork.

Chryso® DEM Oleo RT is a hydrocarbon oil-based, delayed-release agent for the roof tile industry, developed specifically for use with aluminium roof tile pallets.

This ready-to-use range of release agents reduces the likelihood of errors, which may occur in other release agents where mixing of various components is required.

When applied correctly and for the specific purpose, the Chryso® DEM range does not modify cement hydration and since it is water-repellent, it is not affected by rain.

These products are manufactured locally by Chryso Southern Africa at its production plant in Jet Park, Johannesburg and comply with regulations for the transport and disposal of hazardous materials.

While generally regarded as a minor item on a bill of quantities, the specification and selection of an appropriate release agent and application method may be critical to the success of the project, affecting both the quality and colour of the surface finish. A release agent is a low-cost item, yet vital in relation to the cost of formwork and moulds.

It thus makes sense to use the appropriate release agent for the correct application and formwork substrate, in order to protect and extend the life of the formwork or mould, ultimately resulting in financial benefits.

As each release agent contributes differently to the off-form finish, care in the selection of the release agent is critical.

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Responsible contractors have realised the growing strain on SA’s scarce water resources and a new admixture is geared to conservation efforts with its water-reducing admixtures for concrete.

A recent example of this was in the construction of the Vlakfontein Reservoir near Standerton, Mpumalanga. This is probably one of the largest cylindrical post-tensioned concrete reservoirs in the world, with an inner diameter of 154m and a heavily reinforced 11,8m-high wall.

A dynamic mix According to Patrick Flannigan, technical manager: concrete business unit at Chryso Southern Africa, the project made use of several admixtures to reduce water and improve workability. “One of these is our Plast Omega 178 plasticiser, which – when used in a concrete mix – permits a reduction in water content without affecting the consistency, also referred to as the workability,” he says. “It can also increase the slump – or flow – without affecting the water content of the mix.”

The V la k fontein Reser voir has a groundwater drainage system constructed with three layers of 5MPa no-fines concrete.

The 8 000m3 of no-fines concrete comprises a 50mm-thick layer of 9,5mm stone mix, followed by a 245mm and 125mm layer of 19mm aggregate.

To facilitate consistency and ensure that the aggregate would bind mechanically and hydraulically, Chryso® Easydrain was introduced to these mixes for the cement paste. This specialised admixture fluidises the concrete, assists with a homogenous mix and improves curing to reduce the chance of cracking. The bonded aggregates, once (Above): The Khutsong Reservoir project marked the first time a pre-tensioned floor had been used for a reservoir in Africa.

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A WATER-WISE STEP ON YOUR WAY TO SUSTAINABILITY

| TECHNICAL |

dried, will not loosen. An additional drainage layer of around 2 200m3 of no-fines concrete will be poured around the reservoir.

O nce t he no -f i nes concrete wa s completed, a layer of 200mm 35MPa concrete was pumped in 13 pours of approximately 250m 3 each. The mix included Chryso ® Serenis, a shrinkagereducing admixture. This, together with Chryso® Omega 178 superplasticiser, reduces water and assists with workability.

C h r y s o ® C WA 10 c r y s t a l l i n e waterproofing agent will provide integral waterproofing and reduce permeability in the concrete. The crystals prevent water penetration and protect the concrete against corrosive groundwater and chemicals.

Chryso’s water-reducing admixtures were also used in the Khutsong Reservoir near Carletonville, Gauteng. Due to the danger of sinkholes in this region and the possibility of ground movement, the reservoir was the first to be constructed with a pre-tensioned concrete floor.

The scale of the work required 212 truck loads of concrete for the f loor, successfully poured within a day. The 1 267m 3 concrete f loor used pumped mixes at 35MPa at a thickness of 450mm.

In this demanding contract, the concrete mix included Chryso® ZA 1559, a newgeneration, multi-dose, water-reducing plasticiser.

(Left): Evaporation was controlled using Chryso Profilm 19 evaporation reducer at the Khutsong Reservoir project.

(Below): Situated near the Putfontein offramp, the

210ml Vlakfontein Reservoir has a project value of over R100 million.

Advantages of broad applications “This admixture allows a wide range of dosages to be applied without any excessive retardation at the higher dosages,” says Flannigan. “The multi-dose characteristic of Chryso® ZA 1559 also gives concrete extended workability.”

He notes that, in addition, it improves the cohesion and lowers the viscosity of a concrete mix. This results in improved homogeneity and compaction, allowing for superior off-shutter finishes. With less need to add extra water, Chryso ® ZA 1559 reduces the permeability of concrete, thereby improving its durability.

“The product may be used in mixes extended with limestone or commonly-used supplementary cementing materials like ground granulated blast furnace slag, fly ash and silica fume,” says Flannigan. “At the same time, it doesn’t undermine the early-age strength of concrete. In fact, in certain cases, it can improve it.”

Chryso® ZA 1559 has applications in readymix concrete and mechanically mixed site concrete, as well as conventionally placed, pumped and highly reinforced concrete. It conforms to the requirements of SANS 50934-2 (EN 934-2) standards, which are approximate equivalents of ASTM C494 Type A. Water evaporation was successfully control led w ith Chr yso ® Prof ilm 19 evaporation reducer, while shrinkage of the reservoir floor was reduced using Chryso® Serenis shrinkage-reducing agent.

A minimum of 180 litres of water per cubic metre had to be used and fly ash was added, as the heat of hydration had to be controlled due to the mass pour. The end strength did not exceed 45MPa.

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INNOVATIVE SOLUTION TO CONCRETE CRACKING For concrete applications with an elevated risk of cracking – such as floors, screed and precast panels with large surface-tovolume ratios – Chryso Serenis brings peace of mind.

Contractors and manufacturers alike need to be confident that they can prevent their concrete structure from cracking or curling, to ensure the success of their applications. Cracks can weaken concrete, compromise its durabilit y and allow ingress of corrosive elements like water, chlorides and ice. They can also ruin the appearance of concrete.

These outcomes are the result of shrinkage, which happens at all ages in the life of concrete; a length of concrete cast can shrink by as much as 0,08%. While concrete has excellent plasticity when it is fresh and high mechanical strength has set, it can only withstand minor deformation. When shrinkage comes up against a mechanical constraint, the concrete may crack.

As a ready-to-use, shrinkage-reducing admixture for concrete and mortars, Chryso Serenis can reduce shrinkage by up to 80%, depending on the conditions and concrete mix design. This makes it ideal for all applications requiring minimal shrinkage, including injection grouting, high- and ultra-high performance concrete and special structures.

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The phenomenon of curling or bending in f ine concrete parts or elements can also be addressed by Chryso Serenis. As evaporation takes place mainly from the surface of concrete, there is always more shrinkage there. As the concrete shrinks, the edges rise.

The severity of this action depends on the surface-to-volume ratio, but even the slightest curling can endanger an element’s integrity, leading to breakage during transport, unloading or even under its own weight. By reducing the amount of shrinkage, Chryso Serenis is able to minimise the risk of curling.

It can also allow users to increase the distance between shrinkage joints. Industrial f loors made from concrete, for instance, are normally divided into areas of 5m x 5m, bordered by shrinkage joints sawn into the surface of the concrete. More distance between shrinkage joints means time saved on laying floors, reduced maintenance costs and improved overall appearance.

Chryso Serenis works by reducing the capillary tensions, thus impacting the most important mechanism at the origin of shrinkage. It does not have a spreading effect and does not modify the water demand of concrete, nor impact the water-to-cement ratio. It is compatible with new-generation and traditional superplasticisers.

(Top): Beat concrete cracking with Chryso Serenis.

(Above ): Chryso Serenis is a ready-to-use shrinkagereducing admixture for concrete and mortars.

(Below ): Chryso Serenis brings peace of mind for precast panels.

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