Concrete is the most used building material on the planet and worldwide demand for concrete is second only to water. In fact, concrete is responsible for 50-85% of the embodied carbon in any building project, and cement accounts for 7% of all global carbon emissions. It is therefore no surprise that the building and construction sector have been focusing on the cement and concrete industry for solutions to decarbonise. Demand for low carbon cement and concrete has been growing steadily over the past decade and is expected to grow further in coming years.
On 13 October MECLA hosted a Spotlight on Low Carbon Concrete, discussing low carbon concrete design and innovation and providing insights into past and present projects, as well as addressing research and innovation available to support the ongoing decarbonisation of the cement and concrete supply chain.
- Joe Karten, National Sustainability Manager at Built
- Benjamine Duncan, Head of Sustainability and Ethical Sourcing at Universal Store
- Richa Sud, Senior Sustainability Consultant at Taylor Thomson Whitting
- Clare Tubolets, Chief Executive Officer at SmartCrete
- Low carbon cement and concrete is already being used in many commercial projects around Australia
- Contractors have an important role to play as the lynchpin between clients and their aspirations, and have the ability to engage in deep consulation with suppliers and architects to achieve carbon reductions
- From the client side, building procuremenet specifications with sustainable ambitions integrated and updating design standards are important processes for realising carbon reductions
- There is hesitancy in the market to change, and move away from known products in construction. But there must be trust in the technical and test outcomes of low carbon concrete
- Engineers have an important role to play in driving carbon reductions. Taylor Thomson Whitting have a data reporting tool that informs their engineers on the balance of differnt materials being used in a project and produces visualisations of carbon to help inform materials specifications
- Finding clarity on benchmarks is important, as there is no real standardisation for this
- Framing emissions in mostly scope 1 and 2 creates a problem in complex supply chains. The majority of emissions in the sector comes from the suppliers, and neglecting scope 3 places a burden on the organisations upstream to innovate and abate. Accountability must be shared.
If you missed the session, read a summary of what was discussed below:
MECLA Chair Hudson Worsley welcomed everyone to the session and Evan Smith, National Sustainability Lead at Holcim Australia, introduced the speakers.
First speaker Joe Karten, National Sustainability Manager at Built discussed the restoration and refurbishment of two existing side-by-side buildings, the Norman Shelly Spirit Warehouse (1909) and the DC Electrical SubStation No. 164 (1930). The project predicated on the advantages of reuse and preservation, working to maintain the historic pieces of the buildings instead of knock them down. There were more than just benefits in carbon reduction came from reuse and re-lifing, there was also a cultural aspect captured of the cities history preserved through the practice.
Part of the design brief was to retain and re-life old parts of the building. This included the gantry lift, pictured below. Though not functional, many of these old pieces are integrated into the contemporary interior as art features. To make it stack up as a commercial development Built had to double the floor space, a challenging requirement given the preservatory ambitions of the project. The solution was to design an anti-extension, a floating bubble above the existing structure to showcase the heritage elements while providing more space above.
The SubStation Noo.164 achieved 5 Star Green Star and was subsequently uplifted to 6 Star, the first ever WELL Health-Safety rating for the company, a 5 star NABERS energy rating (pending), and 4 Star NABERS Water equivalent performance.
There were a number of challenges Built overcame throughout this project. For starters, there is no consistent convention to measure and model existing buildings’ carbon, so trying to show the benefit of retaining the building was hard to demonstrate. For example, because timber counts as sequestration material in construction, the preservation of the timber in the original structure counted a negative toward their sustainability metrics. At the end a 21% reduction in the upfront embodied carbon and 33% in total carbon reduction was achieved.
For the most part steel did the heavy lifting in structure, meaning Built could use supplementary cementitious materials without driving up the cost. Carbon reductions also came from the retention of existing brick facade walls and floors, integrated design, and using concrete mixes with an average 44% cement replacemen which achieved a 34.9% EC reduction on that specific element. In closing, Joe emphasised the important role contractors can play between clients and suppliers. Following Built’s white paper on Taking Action on Embodied Carbon, he described the lynchpin contractors can be between clients and their aspirations. By encouraging and engaging in discussions around carbon reduction with both architects and suppliers contractors can help facilitate reductions.
Benjamine Duncan, Head of Sustainability and Ethical Sourcing at Universal Store, added some colour to low carbon concrete use. She spoke about Universal Store’s new distribution warehouse in Australia. The clothing retailer used Holcim’s ECOPact concrete and provided insights from the perspective of the end customer.
Universal Store is experiencing rapid growth at the moment, meaning new facilities and stores are constant needs. The retailer’s customer base are young adult who, like the Universal Store team, care deeply about sustainability and worry about climate change. In her role Benjamine works to capture opportunities to integrate sustainability into developments, and you can learn more about the company’s sustainability strategy here.
The new 5,000 m2 distribution centre Universal Store built outside Brisbane near the airport, and the 2000 m2 office, involved 4490 m3 concrete poured in footings, tilt panels and slab. All of this used ECOPact Zero, carbon neutral ready-mix concrete from Holcim. At the end of it Universal Store achieved 88 Tonnes of CO2e save, in comparison to traditional concrete, before the remaining impact was offset.
Benjamine recommended a series of strategies for realising sustainability goals and carbon reductions in projects. She advocates updating design standards and consultation with stakeholders, taking responsibility and building into procurement specifications the sustainable ambitions. Benjamine recalled a hesitancy around change in the market place, often fed by a keenness to reduce risk by continuing on the known path; using known materials and material suppliers. This was particularly the case in using ECOPact as tilt panels. But that concern is not based on the technical specifications of the products, just lack of exposure to them.
Richa Sud, Senoir Sustainability Consultant at Taylor Thomson Whitting (TTW), presented on the demand for low carbon concrete. TTW is a structural civil façade engineering consultancy particularly focused on embodied carbon. She ran through the role of an engineer in demanding lower carbon concrete and highlighted significant design challenges rooted in data availability and reporting difficulties.
Late last year TTW developed a data reporting tool and a tracking tool. It informs engineers on the balance of different materials being used in project development and produces a visualisation of carbon in those projects, which can then help inform the material specifications for the projects. Operating off the information from this modelling engineers at TTW can then work with the suppliers to find those material efficiencies.
TTW completed a case study on commercial grid optimisation that helps reduce embodied carbon. TTW looked at structural systems and how they can reduce carbon through early design stages and material procurement. TTW is publicly committed to reducing the upfront carbon on their structural design work 50% by 2030. 2022 has been data collection to then set a benchmark to then set themselves against. Richa noted that finding clarity on benchmarks is an important process.
Clare Tubolets, CEO at SmartCrete was the final presenter on the day, and took listeners on a thought journey, asking how we support the journey to net zero as a nation. Clare explained how organisational focus on scope 1 and 2 emissions but not scope 3 leads to accountability issues across industry. The problem with that is in relation to complex supply chains, where the majority of emissions come from the supply side. Neglecting scope 3 leaves the supply side with the challenges of innovation and carbon abatement, while those downstream have less accountability because under their scope 1 and 2 lense they are not liable. Clare consequently emphasised the need for more attention to be paid to scope 3, and the need for innovation to realise our ambitions and get on track.
SmartCrete is a cooperative research centre looking at unlocking Australia’s innovation capacity to guarantee a long-term flourishing cement industry. They run three research programs: sustainability, engineered solutions, and asset management. Two projects they are working on are geopolymer modified concrete from recycled waste latex paint and the development of design guidelines for advanced fastenings into innovative concrete products.