Extra-cellular Substances for Concrete – SEPOLBE

The purpose of this project is to develop eco-friendly products (admixtures) which aim to replace products subjected to REACH authorisation in order to modify the concrete surface and to improve the corrosion resistance of rebars. Reinforced concrete are composite materials made of cement, aggregates and metallic reinforcements. This project deals especially with concrete that are more eco-friendly than the traditional Ordinary Portland Cement (CEM I): different cements containing components resulting from the recycling of by-products from the iron and steel industry, such as CEM II and CEM III, will be used. These new admixtures resulting from biotechnologies will allow decreasing the capability of concrete surfaces to be colonised by biofilms. The use of such product aims to control the surface bio-contamination of concrete and their durability. The active principles of the developed admixtures will consist of bacterial exo-products: two different ExtraCellular Substances (ECS) having anti-corrosive and anti-fouling properties will be used. These bio-products will have to fulfil two functions: (i) the inhibition of the corrosion of the rebars in reinforced and prestressed concrete, and (ii) the inhibition of the biocontamination of their surface. The implementation of such admixtures will consist in incorporating them as mass products in the concrete formulation. This industrial research project aims to offer new products allowing the elaboration of new materials i.e. concrete that are more eco-friendly and more resistant to natural environments. It implies 4 institutional research laboratories having expertise in concrete surface analysis and in physico-chemical analysis of layers developed on steel and concrete, in electrochemistry for the steel corrosion inhibition and in petrophysics for the physico-chemical characterisation of concrete. Knowledge in microbiology, chemistry and microscopy are also needed for the products development and the analysis of the surface biocontamination. One industrial partner is also highly implied for its expertise in concrete admixtures; it already offers a range of products for surface protection but no mass treatment product and no product against biological fouling. Finally, the products will have to satisfy the criteria allowing the establishment of the Sanitary and Environmental Data Cards (FDES). Eco-profiles of each developed product will be elaborated to constitute a base for the development of new materials having optimised performance. For that, the determination of the ultimate biodegradability according to the OCDE 301 standard as well as the determination of the aquatic eco-toxicity will be performed. These whole results will allow the determination of the acute toxicity class of the admixture. Due to the recent growth of the concrete protection agents market, the deliverables of this project, i.e. the couples (admixture, concentration), will then constitute eco-friendly and innovating answers with a high potential of valorisation. This project was submitted last year (SEXPOLBE) and was classified on complementary list. The improvements to this project concern the production way of extra-cellular substances (Task 2). The industrial participation remains important and is balanced by the scientific demand of the institutional partners.