Concrete On-Site March 2021

MARCH 2021

CONCRETE MOMENTUM PAVERS CONTINUE THEIR ADVANCE

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IN THIS ISSUE: www.on-sitemag.com 26 Cleaner

concrete in sight as cement producers embrace innovation

CLEANER CONCRETE

CEMENTING CHANGE Lafarge, other cement producers innovating their way to low carbon concrete

BY DAVID KENNEDY

26 / MARCH 2021

cement is put to use on building projects throughout eastern Canada.

Contractors pouring the end product would never know the difference, but the new initiative could divert up to 80,000 tonnes of potlining from landfills and see it integrated into roughly a million tonnes of cement each year.

The research and development effort has been years in the making. Like other

additives – fly ash and silica fume being a couple of the best known byproducts added to cement in Canada – Alextra will cut down on the need to mine or source raw materials to produce cement.

The new initiative is just one small part of the wider recycling and reuse ecosystem at Geocycle.

“We’re open to almost any waste, even hazardous waste, that we can recycle,” says

© V. J. MATTHEW / ADOBE STOCK

A

t a handful of smelters throughout Quebec, mining and metals giant Rio Tinto extracts pure aluminum metal from the oxide alumina.

The process happens in electrolytic cells, known colloquially as pots, at roughly 1,000 C. Due to the prodigious amount of energy involved and repeated use, the lining that coats these pots eventually breaks down, resulting in a hazardous waste that’s typically been processed and then sent to landfills.

A new project launched last fall, however, means tens of thousands of tonnes of treated potlining will find a second life in construction. Lafarge Canada and Geocycle Canada – both subsidiaries of LafargeHolcim – and Rio Tinto, announced the new circular economy project last October.

After being processed into a product the companies call Alextra at Rio Tinto’s Potlining Treatment Plant in SaguenayLac-St Jean, Que., the revamped material makes its way to Lafarge’s cement production plant in Bath, Ontario. There, it’s used during clinker production as the required alumina material. The long chain comes to an end when concrete with Alextra-infused

Sophie Wu, head of Geocycle North America. There are just two requirements, she adds. “Waste that provides thermal energy, or can be ingredients of cement.”

On the ingredient side, byproducts from industries across Canada that offer iron, silica, alumina, or lime to Lafarge’s raw mix are considered. Foundry sands, fluid cracking catalysts, slags, iron fines and mill scale are a few of the most common.

When it comes to thermal energy-producing waste, which replaces some of the coal or natural gas firing Lafarge’s kilns, Geocycle’s inputs run the gamut. Using a method known as co-processing, waste material such as biomass, recycled wood, spent tires and agricultural products that have no other uses are added to cement kilns. The energy they contain is consumed during the combustion process and some of

their minerals integrated into the resulting cement. Even items like used shampoo bottles that cannot be sent to landfills are put to use generating thermal energy, while the process also locks in their contaminants that could otherwise escape into soil or groundwater if the products reached landfills.

One of the few restrictions is on waste that can be reused elsewhere. Wu notes the on-sitemag.com / 27

CLEANER CONCRETE

PHOTOS: LAFARGEHOLCIM

Left: The cement kiln at a Lafarge cement plant. The process emissions and thermal energy demands of cement produce the bulk of the CO2 emissions tied to concrete.

Below: The Bath, Ont. Lafarge plant, where Alextra is being integrated into cement.

company makes a point of not competing with high grade recycling, and is more often than not “getting rid of peoples’ headaches.”

From making use of approximately 3,000 tonnes of end-of-life tires at its Brookfield, N.S cement plant each year, to utilizing roughly 100,000 tonnes of waste typically bound for landfills each year at its facility in Richmond, B.C., co-processing has come to play an important role in trimming carbon dioxide emissions at Lafarge plants. Across its global operations since 1990, LafargeHolcim has reduced emissions by 25 per cent per tonne of cement produced.

Getting to zero CO2 emissions is the company’s ultimate goal, though both practical and technical obstacles will need to be overcome.

With the increased international focus on climate change, the wider cement industry is also working to slash emissions. Last fall, LafargeHolcim and the more than three dozen other large producers that make up

28 / MARCH 2021

the Global Cement and Concrete Association, signed a net zero “climate ambition” aiming for carbon neutral concrete by 2050.

Canada, along with other regions around the world, are now putting together technology road maps to get to zero, says Adam Auer, vice-president of Environment & Sustainability at the Cement Association of Canada (CAC).

If the industry hits its targets, the effect will be considerable. According to a commonly cited 2018 study from think tank Chatham House, roughly eight per cent of global CO2 emissions are tied to cement manufacturing. The combustion of fuels to make clinker, which requires heating kilns to approximately 1,500 C, is particularly energy intensive, accounting for about 30 per cent of emissions, Auer says. Process emissions, the result of chemical processes that take place in the kiln, account for the majority of the rest. To cut back across the board, companies are working on ways to reduce both the amount of clinker in

cement and the amount of cement in concrete.

For its part, Lafarge Canada launched a new product range called ECOPact last November. The range offers a quantified reduction in CO2 of between 30 and 70 per cent, achieved by a process of mix design, optimization and material selection. The company is also working on and committed to launching a carbon neutral mix in the future.

The wider industry is taking a similar route to lower carbon concrete and emerging carbon capture technologies, Auer says.

Lehigh Cement, a unit of HeidelbergCement, for instance, launched a new line of cement called EcoCemPLUS last month.

Produced at the company’s Edmonton plant through inter-grinding clinker, fly ash, limestone and gypsum, the mix is now available across the Canadian Prairies. It reduces emissions 22 per cent, compared to the company’s general use product.

The producer also teamed up with the International CCS Knowledge Centre in 2019 and began mapping out a business case for carbon capture technology at its Edmonton plant. It is now working on engineering design, targeting late 2021 to complete the feasibility work. Across the Atlantic, it is already developing a full-scale capture and storage project at a cement plant in Norway.

As the term implies, carbon capture does not prevent the initial release of CO2 but contains the emissions at the plant before they can escape. The CO2 can then be stored, or put to use for other purposes, though currently, options are limited.

“At the moment, the only real economic use for it at scale is to store it either through enhanced oil recovery or through just straight up geologic storage,” Auer says, noting Canada hosts favourable conditions for both.

To hit its mid-century climate pledge, as well as its intermediary CO2 reduction target of 20 per cent by 2030, LafargeHolcim sees carbon capture as a “must.” It is

CLEANER CONCRETE

PHOTO: LAFARGEHOLCIM

The low carbon fuel system at one of Lafarge’s cement plants.

experimenting with capture technologies in 20 separate pilot projects around the world, including one at the Richmond cement plant designed to capture flue gas typically released into the atmosphere.

Auer sees carbon capture as the future of cement production. He expects costs for the technology to fall as advances are made and more uses for the captured carbon emerge. He points to synthetic fuel, carbon-based nanomaterials and even manufactured aggregates as a few examples of possible uses.

“Using captured CO2 to create synthetic aggregates would replace the virgin aggregates that would normally go into concrete, avoiding both the quarrying of virgin aggregates but also sequestering all of that carbon,” he says.

Bringing concrete’s carbon footprint to zero will not happen all at once, but momentum is building, driven by both producers and end users.

“The majority of contractors are not there yet,” Wu says, but adds that leading builders, private owners and governments

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are pushing initiatives forward.

Last summer, the Canadian government said it was considering setting mandatory minimum requirements for the procurement of low-carbon concrete. In a request for information, calling on the construction industry to weigh in on the feasibility of establishing a baseline for cleaner concrete, Ottawa said the eventual requirements would begin by mandating the use of concrete that relies on Portland Limestone Cement. Now readily available, PLC reduces emissions by up to 10 per cent. If the federal government moves ahead with the initiative, the targets would get more aggressive from there.

Auer says the federal government is still working through its implementation process, but that he hopes to see PLC become the baseline for cement across the country.

“PLC is kind of a no-brainer solution,” he says. “You can reduce your emissions by up to 10 per cent and it doesn’t cost you any more money and most importantly, it doesn’t preclude any of the other

decarbonization strategies that are coming online. So you can still use supplementary cementitious materials, you can still use these emerging mineralization technologies like CarbonCure and Solidia, and others that can basically be stacked on top of PLC.” The CAC estimates all three levels of governments buy up to half of all construction materials in Canada, either directly or indirectly, so momentum on the public side would go a long way.

In the private sector, Auer says the association has been expecting demand for cleaner concrete to pick up for the past decade, but it is only recently that owners and buildings tenants are slowly becoming a force for change.

Today, lower carbon mixes come at a premium, but the benefits of minimizing embodied carbon and developing CO2-neutral buildings have businesses showing more willingness to foot the added bill. In the not too distant future, low, or even net zero concrete, may be table stakes in Canadian construction.

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www.gomaco.com ❘ info@gomaco.com GOMACO offers the full range of concrete slipform pavers, curb and gutter machines, placer/spreaders, texture/cure machines and bridge/canal finishing equipment. GOMACO equipment features our exclusive and proprietary G+® control system, created in-house by our software engineers from the wants and needs of contractors paving in the field. We’ll show you the new Navigator controller with a 10-inch touchscreen that allows ground personnel to simply control and view all attachments from one location. We are also introducing our new high-production system for the C-450 cylinder finisher for bridge decks and flat slabs. At the heart of GOMACO equipment is our passion for concrete and our commitment to our customers. We look forward to visiting with you about your upcoming paving projects and your concrete paving equipment needs.

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CONCRETE PAVING

Concrete Momentum Precision, productivity and data collection capabilities coming together for concrete paver makers

With canadian contractors prepping for the spring construction season, the top concrete paving equipment manufacturers break down the latest tools crews could have at their disposal. More automation, telematics and emissions controls are all available as OEMS build in new enhancements

GOMACO Working to keep its pavers and control systems cutting-edge, Gomaco has stayed focused on adapting its G+ digital control system in recent years, building on the platform first introduced in 2011 while keeping it easy to understand and operate.

The control system initially included features such as a display with a machine “run screen and control loop deviation meters, giving operators fine-tune grade and steer performance using a high-definition, multi-coloured bar graph meter which indicated machine deviations,” says Kevin Klein, vice-president of Engineering and Research & Development.

“G+ has grown from there and continues to change and improve with each new version released,” he says. “We’ve expanded on all of those initial features of

the G+ and continued to improve them.”

On the automation front, for instance, leg positioning with rotary-sensored slew drives on Gomaco four-track pavers send G+ information on the pivot arm position and work together with the track rotation sensors to maintain tracks in the straightahead steering line.

“It also allows the tracks to steer farther than ever before and easily turn radii,” Klein says.

Using software known as Navigator, G+ also keeps track of a range of available paving accessories – from tie bar inserters (TBI), side bar inserters (SBI) and power transition adjusters (PTA), as well as 3D and stringline systems and the Gomaco smoothness indicator (GSI).

“The Navigator touchscreen can be mounted anywhere on the paver and allows

ground personnel the ability to fine-tune the paver’s performance and configure settings for the GSI, SBI, TBI, and PTA onboard the paver,” Klein says, adding that the onboard GSI, reads the smoothness profile of the new pavement using either a real-time localized roughness graph or a simulated California profilograph.

Gomaco Remote Diagnostics, or GRD, covers the telematics on the company’s pavers. The platform gives contractors realtime analysis of their ride quality, letting them monitor the paver’s smoothness on their phone or laptop.

“With [GRD], we can take a contractor request who is paving in Belgium, write the software in-house here in Ida Grove, Iowa, and send that program or update to the machine on-site in Belgium. Or Canada. Or Texas. Anywhere in the world,” Klein says. on-sitemag.com / 33

CONCRETE PAVING

GUNTERT & ZIMMERMAN 2020 may have been a long way from normal for the global construction equipment industry, Salima Ismaylova, the inside sales and marketing coordinator at Guntert & Zimmerman (G&Z) says, but it didn’t stop the progress at the heavy-duty highway and airport construction equipment manufacturer.

“For the last two years our focus has been on upgrading all G&Z product line power units to Tier 4 Final engines due to the EPA emission standards regulations,” she says. “Multiple factors such as fuel efficiency, quality, and a reliable dealer network made us switch to the Cat engines of different capacity across all models.”

In addition, the electrical and hydraulic filtration systems on G&Z pavers’ power units have been re-designed for ease of access, monitoring, troubleshooting and service, as well as to keep vibration isolated from the centre tractor module to improve component life and reduce noise.

To help contractors keep as productive as possible and stay competitive by offering an aggressive paving schedule when bidding jobs, G&Z has set out to streamline the width change process, which is traditionally a time-consuming endeavour.

Telescopic Paving Kit End Sections, or simply TeleEnds, let crews perform width

changes in less than two hours without needing to remove the paving kit, Ismaylova says. Unlike past solutions, which typically forced contractors to sacrifice smoothness for a speedier width change, the new innovation has no adverse effects on pavement smoothness.

On the software side, G&Z has developed NoLine Software for its pavers capable of directly interfacing with third-party stringless offerings from Leica, Topcon and Trimble, saving contractors time on time on surveying, stake driving, string set-up, among other advantages.

From a data tracking standpoint,

G&Z’s Equipment Guidance and Operation Network (EGON) Telematics system lets crews keep closer tabs on diagnostics, machine utilization, fuel consumption, performance and maintenance requirements.

“Very often, our service team will know about an issue, failure or an impending problem in the equipment system before it comes to the attention of the operator on-site,” Ismaylova says. “If a problem does arise, our technicians look at the transmitted information and advise the crew on site what the trouble is, where it is located and how they can fix it.”

POWER CURBERS A new control system from Power Curbers & Power Pavers, is taking the company’s machines to the next level. Fred Bryan, vice-president of Sales for Power Curbers Companies, says the SlipSmart Control Solution has improved all aspects of slope controls, including draft and cross-slope.

“We’ve also enhanced our machinery’s positioning valves with more refined movements to complement slope control advances,” he says. “These changes give the operator more precise, smooth control of the machine, which results in a higher-quality slipformed product.”

Along with integrating seamlessly with 3D or stringless guidance systems from Leica, Topcon and Trimble, Power Curbers

34 / MARCH 2021

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CONCRETE PAVING

has added a range of automated features to its slipformers aimed at simplifying the operator’s job. As a few examples, Bryan points to the electric rather than hydraulic vibrator control system, an automatic steering compensation system and smart vibration controls that let the operator monitor and set the target frequency of individual vibrators that the system will automatically increase or decrease hydraulic flow to maintain. On its four-track

WIRTGEN Productivity and precision have driven the design philosophy at Wirtgen from day-one, Tim Nash, director of Concrete Products for Wirtgen America says, adding that an ethos of continual improvement extends from the hardware to the rideability to the control system of its slipform pavers.

Unsurprisingly, applying automation technology is one area of focus for the equipment maker in 2021 and beyond.

Mobility features, on-site and job-tojob, are improving uptime and simplifying maneuverability, Nash says. Hydraulic leg

36 / MARCH 2021

pavers, the company also offers a steering mode selector that operates independently of stringless, stringline, or manual guidance, letting crews easily switch between front-steer or all-crawler paving, transport mode, 360-degree spin and crab crawl, among others.

On the telematics front, Power Curbers has a number of units currently in the field helping contractors with asset management and remote diagnostics.

“We recognize the value in telematics solutions and will apply them wherever we can to aid operators, increase uptime, and provide utility to our customers,” Bryan says. “We believe developing our telematics solution will further these goals by simplifying troubleshooting with remote diagnostics, increasing uptime with predictive maintenance, and adding utility through machine locating and asset management.”

swing, 90-degree track turn and push-button counter rotation are a few examples of the technology available on Wirtgen pavers. They are far from the only ones.

“When looking to the paving operation itself, the diverter plow in place of traditional augers has been a step in the right direction,” Nash says. “[It] not only gives operators quick and efficient control of material spreading with joystick control but this system can also be programmed for automated concrete spreading.”

Among other popular features, Nash pointed to the exclusive automatic rear lift

feature, which mitigates stop/start roughness when concrete supply is insufficient resulting in smoother pavements and less hand work behind the paver, as being a favourite for finishing crews.

On the sustainability side, Wirtgen offers Eco Drive on all its pavers. A computerized engine control, the system automatically controls engine RPM based on the functions that are engaged at any given time, saving on fuel consumption.

“This saves the operator from manually having to raise/lower which in actual practice doesn’t get done often – operators typically leave the engine at 2100 RPM all day long despite periods of inactivity,” Nash says.

WITOS, the firm’s proprietary telematics system has been standard on all Wirtgen pavers since 2016. It collects a huge range of data, from location and fuel consumption to production hours versus total engine hours. WITOS also lets operators create geo-fences and will bring more metrics tied to project scope as telematics technology and interfaces continue developing, Nash said.

ALLEN ENGINEERING With the overall aim of putting more precise and productive equipment in the hands of customers, Allen Engineering has introduced a new enhancement to its bridge deck finishers (BDFs). The patent pending feature fine-tunes how the machine advances and enables an easier movement transition for the paving carriage.

In essence, a BDF advances when the carriage moves to the end of its cycle and

momentarily stops, Mark Conte, the sales director for Paving Equipment Products at Allen, says. While in the past, an operator had to increase the carriage speed to advance the machine travel, the latest upgrade has separated these functions.

“What we did at Allen Engineering was separate those functions out so now the carriage speed and the machine advancement are on their own separate circuits,” Conte says. “Let’s say the carriage is

moving too fast and you’re getting a rough finish – you can dial that down now, without affecting the machine advancement travel rate.”

“Similar to slipform paving, you never want that carriage to stop moving,” Conte says, adding that this is complicated by ready-mix deliveries, which as concrete crews all know, rarely play out as planned.

With the functions separated, operators are able to get the desired finish, as well as match progress on-site to ready-mix delivery. Allen integrated the enhancement while making no changes to the operator’s console.

As the name implies, the majority of these applications are bridge decks, but the company’s BDFs are also put to use on road and airport paving projects. Allen continues to work on a range of other innovations to add to its product lines.

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