Demolition sites, a mine for producers of construction materialsAFP May 29, 2019
The quarry and building materials sector wants to strengthen the recycling of its products used in construction and public works, and aims for a 90% recycling rate for demolition site waste, by favoring short circuits.This result would cover 30% of French needs for construction, with aggregates (gravel, sand) recycled, said the president of the Unicem federation, Nicolas Vuillier, Tuesday during a meeting with the press on a recycling platform in Gennevilliers (Hauts-de-Seine).
"We must promote the products of deconstruction", he summarizes.
To illustrate the “short loop” strategy, Unicem presented a route in the Paris suburbs leading from a major demolition site, in Colombes, to the Gennevilliers recycling platform, from which recycled concrete aggregates leave, crushed, cleaned, graded for new use.
In Colombes, on a large site of 44.000 m2 previously occupied by the Thales group, backhoes and shredders are working to reduce old office buildings to rubble, to make room for a new district.
Large concrete slabs are first dismantled by a giant clamp, then these blocks are broken up by a crusher which extracts the scrap metal contained in the reinforced concrete. In the middle of the back and forth of the excavators, an operator permanently sprinkles the site to reduce the amount of dust.
Ultimately, the site will produce by the end of 2019 some 63.000 tonnes of concrete, in addition to 300 tonnes of scrap metal and 3.000 tonnes of industrial waste which will be treated in a specialized sector.
"The recycling rate will be over 95%", according to Eric Corbière, site manager for Cardem, a subsidiary of Eurovia (Vinci group) specializing in the deconstruction of buildings.
Within a few months, the site will receive a crushing unit to complete the recycling work. The crushed concrete can be directly reused in road applications.
“On each site, the choice must be made between crushing on site or on an outdoor platform”, explains Mr. Corbière. “Below 10 to 15.000 tonnes of concrete, we don't bring a crusher.”
A few kilometers away, the recycling platform of the company SPL in Gennevilliers receives rubble for demolition of buildings, earth from excavation or road mix waste.
This raw material is crushed, sorted, crushed, sieved, washed, to be reused in the form of sand, gravel or fine earth. Road mix waste is reincorporated at 10% to 30% in the manufacture of new mix.
As for non-exploitable waste, such as very clayey soil, it is used to redevelop and rehabilitate quarries.
More and more extraction sites are accompanied by a recycling platform, to offer recycled aggregates.
'' This completes their activity by saving the natural ”resource, says Christophe Jauzon, president of the Unicem circular economy commission. “We are not in opposition between careers and recycling activities, but in complementarity.”
Unicem had concluded with the State in 2016 a “commitment for green growth” which aimed at a 50% increase in the production of recycled aggregates. The commitment was reached, according to Unicem.
For its part, the European Union has set a target of 70% collection, recycling and recovery of construction waste by 2020. "Today, we have reached this 70%", assures Mr. Jauzon.
Construction waste in France is estimated at 227 million tonnes, 93% of which is “inert waste” (non-hazardous). According to Unicem, 148 million tonnes are recycled, in accordance with the European target. For recyclable waste, the rate even reaches 80%.
"We can progress, but we are already at a fairly high level", observes Christophe Jauzon.
Unicem is preparing to sign a new “commitment to green growth” for the 2019-2022 period. "The first engagement worked well", welcomed the president of Unicem Nicolas Vuillier.
Among the new objectives, a recycling rate of inert waste brought to 90% by 2025 and a coverage of more than 30% of the needs of aggregates for construction in France.
