Comparative analysis of carbon footprint between pile foundation type: A perspective on the construction procedure.-Paper

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The study compares the carbon footprints of three deep-foundation methods—continuous flight auger (CFA), bored piles (BRD), and micropiles (ROOT)—using 70 high-rise building projects designed in Balneário Camboriú, southern Brazil, between 2019 and 2024. The projects include 16,615 piles, with an average length of 32 m for CFA, 51 m for BRD, and 22 m for ROOT.<br /><br />Emissions were estimated with the EFFC-DFI Carbon Calculator, covering primary sources (materials and construction energy) and secondary sources (transport, waste handling, and equipment). Because the projects were not under construction, some inputs, including transport distances and productivity, were estimated.<br /><br />Across the database, concrete produced substantially more emissions than steel: approximately 55.1 million kg CO₂ compared with 9.3 million kg CO₂. Diesel emissions were about 3.0 million kg CO₂, or roughly 5% of emissions from concrete and steel. Secondary sources contributed approximately 5.5 million kg CO₂—about 8% of total emissions—so material use was the dominant source.<br /><br />The average carbon emission efficiency index (iCEE) was 61,466 kg CO₂/MPa for CFA, 122,736 for BRD, and 71,604 for ROOT. CFA therefore generally had the lowest footprint among the solutions assessed. However, the database contains mostly CFA projects, and the results reflect local soil conditions and project assumptions; the BRD and ROOT benchmarks should consequently be used with caution. Overall, the findings emphasize that optimizing foundation design and reducing concrete consumption offer greater opportunities for emissions reduction than focusing solely on construction-related secondary emissions.

Keywords

carbon footprint

deep foundation

continuous flight auger

bored piles

micropiles

concrete emissions

steel emissions

CO2 emissions

high-rise buildings

foundation design