The bay of Saint-Jean-de-Luz is protected by three seawalls, built under Napoleon III. They require regular maintenance works, and in 2016 three sets of major repair works were schedules by the Pyrenees-Atlantiques office, following damage caused by recent storms.
To repair the berm on the Artha seawall, which lies in the middle of the bay, work was carried out against the clock, when conditions allowed, using CXB Hyperfluide C35/45 XS3 Dmax 10 S4 underwater adapted concrete. Scheduled into a four to five hour window each day at mid-tide, during which formwork and pouring took place, the response team reached the site by boat, with materials dropped by helicopter from the Socoa Fort heloport. The concrete had to be poured within two hours, togive it time to set before the tide came in, meaning it was a race against time. Twenty two to three minute rotations were anticipated and Cemex delivered 80 m3 of liquid concrete, using three rotating raking wheels, for this first portion of the works.
For the repair of the seawalls at Sainte-Barbe and Socoa, Cemex recommended innovative concretes, adapted to suit the new requirements on the Fisheries and Port division. The CXB Hydro solution was chosen for Sainte-Barbe as it was non-leaching and seawater resistant. Being laitance-free, it also handled the environmental challenges raised by the departmental waterways authorities, including the risk of some concretes leaching into the seawater, particles harmful to the flora and fauna, and the pollution of beaches. On 19 and 20 September 2016, 12m3 of this concrete was poured onto the seawall, with excellent returns on plasticity and handling.
The final portion of the work began at the end of 2016. The Socoa seawall was strengthened using Promptis, a new type of leach-resistant, ultra-quick-drying concrete.
Within these three sets of works, Cemex affirmed its ability to offer targeted, innovative solutions, tailored to challenging environments. The swell resistant nature of the concretes will be carefully monitored over the coming months to optimise the strengthening of the seawalls.
Read the article online at: https://www.worldcement.com/europe-cis/03032017/cemex-helps-to-strengthen-seawalls/