On Tuesday 7th June,聽Aarsleff Ground Engineering聽carried out the world鈥檚 first trial driving of cement free ultra low carbon precast piles manufactured using Cemfree concrete.
Cast and cured at Centrum Pile鈥檚 Newark headquarters, the piles were driven in non-working positions at a working Aarsleff site. The trial is part of a wider scope of work package plans Aarsleff鈥檚 sister company, Centrum Pile, are involved in as a partner in the LOCOWAG (Low Carbon Concrete within Aggressive Ground) project. Representatives from DB Group, the main partner on the project, and BRE attended site along with Aarsleff staff to witness the trial piling. The project is funded by Innovate UK and seeks to:聽
Develop, assess, and demonstrate AACM concrete formulations meeting user needs for foundations (buildings and infrastructure)
Demonstrate and assess use of AACMs in piling applications to de-risk adoption
Carry out laboratory tests to assess durability of AACM concrete formulations in sulphate-rich conditions (and other key performance characteristics), and compare with those of PC-based and other AACM-based concretes, as a driver for new industry-wide guidance/standards (such as BS8500, BRE IP 17/05 and BRE SD1)
Assess business models and barriers to market and address these
Convene an industry stakeholder group via A3CM UK to support the production of new industry guidance.
Aarsleff鈥檚 ongoing project on the site used to trial already established a tight drive for the standard precast piles, so it was clear prior to the trial driving that the Cemfree piles would be under onerous installation conditions pushed further by the selection of a Junttan with a 5T accelerated hammer for the trial works.聽
The trials were productive and progressive, allowing assessment of previous stages of the development project. The results demonstrated correlations between trial mix designation and performance, as well as confirming assumptions regarding the bespoke batching process utilised.
Speaking on the advancements in the project, Director of Centrum Pile, Darren Senior, said; 鈥淭he process of developing a Cemfree concrete mix designation to match the specific requirements of a precast pile in terms of early age strength gain, ultimate strength and the ability to be handled and driven under significant forces has not been an easy task. The LOCOWAG project and the DB Group team have worked tirelessly over the past 18 months to present various mix designs and trial results which have ultimately led to the mix selected for the trial. The information obtained during the casting process and trial driving will allow the fine tuning of the specific precast Cemfree mix design and ultimately subject to the development of the design codes and standards a market ready product. This will allow projects to benefit from enhanced environmental and sustainability metrics鈥�
The use of Cemfree concrete has a number of benefits that make this working group an extremely important step forward in the ground engineering industry. The most obvious benefit is the reduced embodied carbon of the product, as the current wide use of Portland cement as the binder in concrete accounts for around 5-8% of global CO2 emissions. Developing alternatives to this which lower the rate of greenhouse gas emissions are integral on the road to net zero.聽
Other benefits include the fact that Cemfree concrete is more resistant to chemical attack, which lowers the risk of utilising concrete as foundations in certain situations. The piles being cement free means their durability is increased and meets sulphate aggressive ground condition requirements easier.聽
The casting experience and trials undertaken have allowed further feedback to the working group who are continuously developing the chemical activator and bespoke mix designs for various implementations and markets including insitu piles and pre cast driven piles.聽
Speaking about the trials, Andy Waghorn, Director of Geotechnical Services at Aarsleff Ground Engineering, said; 鈥淪ustainability is at the core of Aarsleff Ground Engineering and as a Group we are aware of the need to leave a positive legacy for future generations. We recognise that key to improving environmental performance and sustainability is the determination to position ourselves at the forefront of the latest innovations in plant, products, and technology.聽
When DB Group presented the benefits of Cemfree concrete we quickly realised this was an exciting opportunity to be part of a revolutionary programme of research and development that has far reaching potential to significantly reduce carbon generation and water use in the construction industry in the very imminent future, aligning with our environmental and sustainability objectives and those of the Federation of Piling Specialists (FPS) to which we belong鈥�
This article was paid for by聽Aarsleff Ground Engineering
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