engleski

Designing high performance grout for corrosion protection of prestressing steel in concrete

Portland cement grout is used in post-tensioned and retaining structures to provide bond between prestressing steel and surrounding material and to transmit the stresses from the steel to the concrete. Other important role of the grout is to fill the voids between protective duct and prestressing steel, suppressing the flow of water and chloride ions. The grout is the last but most important corrosion protection layer in prestressed structures. Therefore, besides satisfying requirements for the mechanical and physical properties, high performance grout should have capability of protecting prestressing steel from corrosion. The aim of the research presented in this paper was to evaluate the influence of different grout mixtures on corrosion behaviour of prestressing steel. First, thorough investigation of mechanical and physical properties of different grout mixtures was performed, such as: dimensional stability, fluidity, bleeding and strength development. After that seven high performance grout mixtures were chosen for testing of chloride penetration corrosion testing. From the presented research it can be concluded that high performance grout with low chloride diffusion coefficient, good homogeneity and volume persistency can assure longer durability of prestressed structures.

grout; prestressed concrete; prestressing steel; chloride diffusion; corrosion

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