Abstract

The aim of this study is to evaluate an admixture whose active component is an eco-respectful biopolymer having steel corrosion inhibiting properties. Many means of concrete steel reinforcements protection against corrosion are on the market, but few of them are eco-friendly. This study has an environmental stake for the sustainable development of concrete structures improving their aging resistance and using eco-friendly products. Bacteria (Lactobacillus reuteri) allow the production of a biopolymer called EPS 180 whose presence as admixture in concrete will improve their eco-friendly quality regarding: (i) their production using eco-respectful products like biopolymers and Ground Granulated Blast Furnace Slag (GGBS for CEM V). Actually, corrosion of rebars is a frequent pathology of civil engineering works against which the means are generally not satisfying the environmental criteria. The biopolymers, produced by bacteria of milk, are harmful for human beings and a little quantity of biopolymers is used for the tested admixture. The samples were manufactured using 2 cement bases including a CEM V that is more eco-friendly than traditional CEM I because containing industrial byproducts. Capillary imbibition tests and water total porosity showed the low influence of the admixture on the pore structure of mortars. After immersion in natural seawater of cement pastes reinforced with steel C15 rebars, electrochemical measurements showed that the biopolymer does not affect the free corrosion potential of reinforcement nor the composition of passive layer but inhibits the reaction cathodic reduction of oxygen.