Westhaven’s coastal urban defence project utilises Firth EcoMix – EC40
Auckland’s waterfront has long been considered one of the city’s most treasured assets, a vibrant joining of land and sea - a jewel in the crown of the city. The area has undergone a series of upgrades over the years, transforming it into desirable public spaces that attract both locals and tourists, with the development of the Westhaven Seawall and coastal promenade by Eke Panuku Development Auckland being a recent project of significance.
Low carbon concrete a must …
“I was attending a conference where Bernice Cumming, Architectural Consultant for Firth was presenting the benefits of Low Carbon Concrete (Firth’s EcoMIx) for projects,” says Ethan. “We discussed the Westhaven project which was nearing design completion. Once we were ready to proceed, I approached Bernice for help with the concrete mixes required for this marine environment.”
“Why do we use Firth? We were looking for consistency as they have supplied a large proportion of concrete for the whole area. We also know that Firth is willing to push for innovative design elements with their mixes - we were wanting an urban, coastline concrete mix that included special aggregates and offered the lowest embodied carbon we could achieve.”
“Initial discussions with Ethan indicated that their client wanted to aim as high as possible to get the most sustainable concrete mix for the project,” says Bernice. “We worked to achieve the best Global Warming Potential (GWP) number with the hope we could produce an EC50 mix. However, as this is a marine environment, the mix required a high fly ash component, with the inclusion of pebble and shell, meaning to achieve the performance and durability required of this public space we were able to reach a very high EC40.”
Nestor Lising, Project Engineer for JFC says, “I have worked for JFC for nine years and we have mostly used Firth for our concrete supply during that time. Their proximity to downtown is great for our central projects, and I'm enjoying seeing their product innovations coming through on our projects."
“Once the mixes were settled on we did a few trials with the EC40 mix design. This was signed off by the guys at LandLAB. We broke ground in early March last year and completed the structural completion at the end of February with the opening in April.”
“The new trees and planting are yet to go in but it’s very close to completion,” adds Ethan. “All feedback we have received has been extremely positive.”
This scenic walking and cycling route now connects the various parts of the waterfront offering amazing views of the Waitematā Harbour, enhanced public access, and a safer, more enjoyable space for recreation. The seawall upgrade plays a crucial role in protecting the coastline from erosion and rising sea levels, while incorporating modern design elements that reflect the city’s coastal context.
