Doubling Sustainability of Concrete Foundation Piles through Enlarged Bases and Screw-in Displacement Methods-Paper

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The paper compares the embodied carbon and design performance of three foundation systems for a typical two-storey residence with a basement on the Gold Coast, Australia: steel helical piles, continuous-flight-auger (CFA) piles, and concrete PAILE piles installed by a screw-in displacement method.<br /><br />PAILE piles use a slender reinforced-concrete shaft and an enlarged, preloaded base to achieve bearing capacity with less material. The study’s designs used 40 MPa concrete and assumed concrete overbreak of 50% for PAILE and 30% for CFA. Its carbon comparison focused on material-related embodied emissions, rather than providing a full lifecycle assessment of installation equipment.<br /><br />Estimated total embodied emissions were 60,027 kg CO₂ for helical piles, 35,623 kg for CFA piles, and 14,851 kg for PAILE. Per kilonewton of allowable pile capacity, the respective figures were 1.69, 0.97, and 0.29 kg CO₂. Thus, the PAILE option produced roughly one-quarter of the helical-pile emissions and less than half those of CFA in this example.<br /><br />The reported savings stem mainly from the optimized pile geometry and reduced use of high-carbon steel. The authors also identify potential construction benefits: continuous installation, in-process measurement of pile resistance for quality assurance, reduced ground heave and vibration, and use of smaller equipment. They argue that preloading the enlarged base improves load–settlement performance and that the concrete construction offers durability advantages in corrosive conditions.<br /><br />The authors conclude that enlarged-base, screw-in displacement piles can substantially reduce material use, carbon emissions, installation time, and risk. These results are based on a specific comparative design example and its stated assumptions.

Keywords

embodied carbon

foundation systems

helical piles

CFA piles

PAILE piles

reinforced concrete

screw-in displacement piles

carbon emissions

pile design

Australia