The Impact of Construction Schedules on Embodied Carbon
In multi-storey construction, cycle time per floor is a critical factor during the feasibility stage. To maximize efficiency, builders often opt for higher concrete strengths (40-50 MPa) to meet load requirements sooner. This allows for earlier formwork stripping and faster progression to subsequent tasks like services fit-off and façade installation.
While the traditional view has been that the extra cost of high-strength concrete is justified by quicker construction, this perspective shifts when considering embodied carbon in your feasibility analysis.
For example, consider a 100m² suspended slab with a 200mm thickness. Using High-Early Strength Cement achieves 35-45 MPa compressive strength in just 3 days[1], allowing for early formwork stripping. This concrete, with a final compressive strength of 56-67 MPa, costs $311/m3[2] and carries an embodied carbon of 599.96 kg CO2e/m3[3]. This is equivalent to the Embodied Carbon in a return flight from Sydney to the Sunshine Coast[4].
In contrast, regular concrete reaches 35 MPa compressive strength in 7 days[1], costing $262/m3[2] and resulting in a significantly lower embodied carbon of 342.22 kg CO2e/m3[3]—almost half of that of the high-strength mix and equivalent to the Embodied Carbon in a return flight from Sydney to Wagga Wagga[4].
Here’s a quick comparison:
As Infrastructure NSW's Embodied Carbon Policy comes into effect in April 2025, it's more important than ever to consider how construction schedules might influence not just cost, but also the embodied carbon of your materials.
At Quantum Insights Advisory, we specialise in Carbon Planning and Engineering, offering expert guidance during the feasibility and planning phases to help you meet these new requirements while optimizing cost, carbon and time impacts.
[1] Cement Australia – High Early Strength Cement[2] Rawlinsons 2024[3] Australian Life Cycle Assessment Society Construction Sector Database ver1.42[4] https://secure.noco2.com.au/