Our Executive Director, Craig Heidrich, has recently presented virtually at the 11th EUROSLAG Conference in Cologne, Germany.

The main agenda for the presentation addressed the standard specification for low-carbon concrete using iron and steel slags. In particular, the journey the association has embarked on, and the things discovered along the way.

Every journey comes with its challenges and this was no exception. The use of steel furnace slag (SFS) found its way into traditional aggregate markets such as asphalts and road bases. However, Craig spoke about the opportunity to look beyond this by utilising granulated blast furnace slag (GBSF) in cementitious applications; a challenge the association set for themselves.

This journey started in 2012, with the hope of eliminating a Portland cement system using ambient temperature curing. This addressed the opportunity to use those materials and capture their intrinsic nature such as increased density.

Craig elaborated on the inherent need to transition into a field environment whereby case studies and learnings across the supply chain from resources to the end user are utilised, foregoing the laboratory and university-level testing which is consistently undertaken.

Craig also discussed the innovation journey towards new standards related to low-carbon concrete, with the prevalence of observing the key enablers regarding the adoption of new materials like iron and steel slags. This was achieved by looking across the supply chain of resources, processors, value adders, users/consumers, and influencers, all of which were ranked with issues regarding manufacturing, placing and finishing, durability, variability, economics, and standards and codes. Subsequently, the primary enabler being standards and codes.

We have all witnessed the ongoing charade of ESG reports, net zero goals, events, and sustainability jargon in various reports documenting the environmental impact of concrete and cement, although genuine action on the ground is few and far between. However, the emergence of product category rules (PCRs) to develop environmental product declarations (EPD) is coming to the forefront. Craig makes a powerful observation, specifying the need to address the international consistency regarding PCRs and to establish the boundaries around how we quantify energy inputs or carbon footprint on the contributing materials. 

To inform people of the new types of concretes and provide a how-to for the engineering community, critical information for the separate standard specification was found through a series of demonstration projects. This included Toowoomba Wellcamp airport, the deep-sea water port at Port Kembla, and the City of Sydney. All projects received ongoing monitoring and evaluations of the materials and performed exceptionally well with further intrinsic benefits found. The Toowoomba Wellcamp airport consisted of a 70,000 square metre runway all built out of low-carbon concrete and using conventional paving equipment. Although challenging, it proves to be a huge milestone project. Craig explains, “This demonstrates we can build these large pieces of infrastructure and monitor them to demonstrate they are still performing well,’ he said. Additionally, a study at Port Kembla which utilised steel furnace slags witnessed a 20% increase in density – a very positive characteristic. If you would like to learn more about this study, click here.

- Toowoomba Wellcamp Airport 

Projects like these helped form the new Standard Specification for Geopolymer Low Carbon Concrete.

Craig emphasises the importance of the specification explaining, “I truly believe it’s the first of its type across the globe in terms of holistic standard specifications interacting with a major code and addressing all of the adjustments you need to do in terms of the testing methods and how you would design for the durability requirements," he said. 

Standards and specifications remain a key enabler for change, Craig explains, "If you can't get those elements right it can't provide the right tools to the design community to essentially have a crack at these types of concretes and increase uptake," he said.

He continues, “EPDs are going to be playing an important role but they must be internationally aligned with PCRs to accelerate the uptake of EPDs and to demonstrate the nature of these materials in a product status… EPDs are just one part of the whole equation and require a balanced approach," he said.

If you would like to watch Craig's EUROSLAG speech, click here.