Bond strength development of blended concretes using hot-dip galvanized steel reinforcements

摘要

The building of more sustainable structures is becoming a mandatory requirement. Differentrnalternative are followed, as the use of blended cements to diminish the CO2 emissions and energyrnsaving, as of new reinforcement, as hot-dip galvanized, to increase the service life of reinforcedrnconcrete structures. But the effects of these changes on the technical performance of concreternstructures are not determined yet. Mineral additions in high content decrease concrete mechanicalrnstrength at early ages, while the interaction between concrete and galvanized steel is different to thatrnof carbon steel, what questions its bond strength. The present paper studies the bond developingrnstress of conventional and hot-dip galvanized steel reinforcement embedded in concrete made withrnordinary Portland cement (OPC) and with a type of ternary blended cement containing 36% fillerrnplus blast furnace slag. A detailed analysis of the rebars superficial geometry and pull-out tests havernbeen carried out. Results indicate that the ribs of a hot-dip galvanized rebar are lightly wider andrnrounder than the ones of a conventional rebar and they present a smaller height because of therngalvanized coating heterogeneity. Maximum bond stress measured for galvanized steel is similar tornthat of conventional reinforcement. Furthermore, greater stresses are developed when OPC concreternis used.