Use of industrial byproducts - Demolition products

Every year, building and civil engineering activities generate over 100 million tonnes of demolition materials (see IDRRIM draft information note, June 8, 2010) and excavated material, most of which is considered inert waste.

The use of these materials, now envisaged after they have been cleaned and recycled, was very quickly considered a priority, as it offers at least three major advantages: savings in :

• landfills (inert waste storage volume) ;

• quarries (natural aggregate resources) ;

• transport.

In our Public Works context, materials are mainly derived from the demolition of residential or industrial buildings, concrete structures and roadways.

The aim of this article is to take a closer look at materials used in the deconstruction of buildings and engineering structures, whether reinforced concrete or not, without plaster or asbestos, or any other specific industrial waste.

Categories that contain, or could present the danger of containing, elements likely to cause disorders in our structures (plaster that could create swelling phenomena, for example), are not systematically recycled by Public Works companies.

The recycling of demolition materials, which requires expensive installations, is essentially carried out with the aim of substituting them for natural materials for the supply of aggregates, or gravels usable in techniques :

• earthworks ;

• roads ;

• railway ;

• airports ;

• industrial platforms, etc.

Recycling demolition materials is therefore used to make up for shortages of natural materials, particularly for work near or in large conurbations. As a result, manufacturing units are also mainly located around major cities, or close to industrial hubs.