Abstract
The incorporation to the concrete matrix of additives that may delay or even completely avoid the initiation of corrosion during the service life of the structure is a long pursued topic. New promising technology achieving increasing interest is to incorporate the corrosion inhibitor encapsulated in a layered double hydroxide (LDH). The LDH follows a controlled release of the inhibition part that at the same time is efficient with chloride trapped. Another type of nanostructure additive offering self-protection ability in concrete is polyhedral oligomeric silsesquioxanes (POSS) developed to exhibit either water-repellent or corrosion inhibitive functionalities. In the present paper, a concrete made with CEM I+30%FA developed within H2020-EU project LORCENIS was considered to enhance the performance of concrete infrastructures in a marine environment. The LDH (0.5, 1 and 2 %) and POSS (2 and 4 %) was explored. Accelerated and natural Cl transport laboratory tests have been performed in connection with rebar corrosion initiation. The obtained results showed that the accelerated transport indicates a Cl transport decrease with the concrete maturity, more effective for concretes with LDH and POSS. The effect is more effective with natural Cl transport, probably as consequence also of the fly ash contribution in the refinement of the pore and bound capacity. The study confirmed a significant retardation on rebar corrosion initiation.