The laboratory

The Design and Construction Joint Venture has a control laboratory to ensure the quality of concrete products and in the future the quality of infrastructures built in concrete (Xblocs, infrastructure, anti-wind wall, slab of shipping berths).

Calais Port 2015 will use a few hundreds of thousands of cubic metres of concrete. The Design and Construction Joint Venture decided to avoid risks related to outside deliveries and ensure complete freedom in times of supply, and so implemented on site a concrete plant and a control laboratory from the launch of the works.
In France, a concrete is mainly controlled by the resistance to compression at 28 days. This value depends on the relationship between the different ingredients that make it up (water, sand, pebbles, cement) and the quality of implementation (concrete vibration, climatic conditions, quality of the mold release).

The laboratory allows to develop concrete formulations taking into account the quality of its components and optimizing their cost to get the quality at the right price matching exactly the use dedicated to. 

It is often necessary to make the concrete pumpable (most liquid as possible) but without altering its quality ; this is why adjuvants are used in this view.
After completing the formulation study, the laboratory checks continuously the product quality, including checking through tubes. Standards generally impose a series of three tests pieces (two for controls and a third as a precaution). To save time on validation of the characterization of the concrete at 28 days, some specimens are placed in the ovens to speed up setting and an arithmetic law allows then by crushing the test specimen at 7 days to anticipate the result in 28 days.
Working teams need these conclusions to anticipe demoulding operations and optimize the formwork material rotations.The time spent by the laboratory technicians has an indirect impact on performances and the construction site progress.

The Xblocs factory is the most perfect illustration ; it allows to produce up to 40 Xblocs of 4 m3 per day with a reduced number of formworks.